Update upstream source from tag 'upstream/1.0.28'

Update to upstream version '1.0.28'
with Debian dir ec5bb298266630fc3801ff6dc0c258f6df7ba979

1 files changed, 3592 insertions, 0 deletions

diff --git a/backend/genesys_gl124.cc b/backend/genesys_gl124.cc
new file mode 100644
index 0000000..a535d58
--- /dev/null
+++ b/backend/genesys_gl124.cc
@@ -0,0 +1,3592 @@
+/* sane - Scanner Access Now Easy.
+
+   Copyright (C) 2010-2016 Stéphane Voltz <stef.dev@free.fr>
+
+
+   This file is part of the SANE package.
+
+   This program is free software; you can redistribute it and/or
+   modify it under the terms of the GNU General Public License as
+   published by the Free Software Foundation; either version 2 of the
+   License, or (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful, but
+   WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software
+   Foundation, Inc., 59 Temple Place - Suite 330, Boston,
+   MA 02111-1307, USA.
+
+   As a special exception, the authors of SANE give permission for
+   additional uses of the libraries contained in this release of SANE.
+
+   The exception is that, if you link a SANE library with other files
+   to produce an executable, this does not by itself cause the
+   resulting executable to be covered by the GNU General Public
+   License.  Your use of that executable is in no way restricted on
+   account of linking the SANE library code into it.
+
+   This exception does not, however, invalidate any other reasons why
+   the executable file might be covered by the GNU General Public
+   License.
+
+   If you submit changes to SANE to the maintainers to be included in
+   a subsequent release, you agree by submitting the changes that
+   those changes may be distributed with this exception intact.
+
+   If you write modifications of your own for SANE, it is your choice
+   whether to permit this exception to apply to your modifications.
+   If you do not wish that, delete this exception notice.
+*/
+
+#define DEBUG_DECLARE_ONLY
+
+#include "genesys_gl124.h"
+
+#include <vector>
+
+/****************************************************************************
+ Mid level functions
+ ****************************************************************************/
+
+static SANE_Bool gl124_get_fast_feed_bit(Genesys_Register_Set* regs)
+{
+    return (bool)(regs->get8(REG02) & REG02_FASTFED);
+}
+
+static SANE_Bool gl124_get_filter_bit(Genesys_Register_Set* regs)
+{
+    return (bool)(regs->get8(REG04) & REG04_FILTER);
+}
+
+static SANE_Bool gl124_get_lineart_bit(Genesys_Register_Set* regs)
+{
+    return (bool)(regs->get8(REG04) & REG04_LINEART);
+}
+
+static SANE_Bool gl124_get_bitset_bit(Genesys_Register_Set* regs)
+{
+    return (bool)(regs->get8(REG04) & REG04_BITSET);
+}
+
+static SANE_Bool gl124_get_gain4_bit (Genesys_Register_Set * regs)
+{
+    return (bool)(regs->get8(REG06) & REG06_GAIN4);
+}
+
+static SANE_Bool
+gl124_test_buffer_empty_bit (SANE_Byte val)
+{
+  if (val & BUFEMPTY)
+    return SANE_TRUE;
+  return SANE_FALSE;
+}
+
+static SANE_Bool
+gl124_test_motor_flag_bit (SANE_Byte val)
+{
+  if (val & MOTORENB)
+    return SANE_TRUE;
+  return SANE_FALSE;
+}
+
+/** @brief sensor profile
+ * search for the database of motor profiles and get the best one. Each
+ * profile is at a specific dpihw. Use LiDE 110 table by default.
+ * @param sensor_type sensor id
+ * @param dpi hardware dpi for the scan
+ * @param half_ccd flag to signal half ccd mode
+ * @return a pointer to a Sensor_Profile struct
+ */
+static Sensor_Profile *get_sensor_profile(int sensor_type, int dpi, int half_ccd)
+{
+  unsigned int i;
+  int idx;
+
+  i=0;
+  idx=-1;
+  while(i<sizeof(sensors)/sizeof(Sensor_Profile))
+    {
+      /* exact match */
+      if(sensors[i].sensor_type==sensor_type
+         && sensors[i].dpi==dpi
+         && sensors[i].half_ccd==half_ccd)
+        {
+          return &(sensors[i]);
+        }
+
+      /* closest match */
+      if(sensors[i].sensor_type==sensor_type
+        && sensors[i].half_ccd==half_ccd)
+        {
+          if(idx<0)
+            {
+              idx=i;
+            }
+          else
+            {
+              if(sensors[i].dpi>=dpi
+              && sensors[i].dpi<sensors[idx].dpi)
+                {
+                  idx=i;
+                }
+            }
+        }
+      i++;
+    }
+
+  /* default fallback */
+  if(idx<0)
+    {
+      DBG (DBG_warn,"%s: using default sensor profile\n",__func__);
+      idx=0;
+    }
+
+  return &(sensors[idx]);
+}
+
+
+static SANE_Status
+gl124_homsnr_gpio(Genesys_Device *dev)
+{
+uint8_t val;
+SANE_Status status=SANE_STATUS_GOOD;
+
+  RIE (sanei_genesys_read_register (dev, REG32, &val));
+  val &= ~REG32_GPIO10;
+  RIE (sanei_genesys_write_register (dev, REG32, val));
+  return status;
+}
+
+/**@brief compute half ccd mode
+ * Compute half CCD mode flag. Half CCD is on when dpiset it twice
+ * the actual scanning resolution. Used for fast scans.
+ * @param model pointer to device model
+ * @param xres required horizontal resolution
+ * @return SANE_TRUE if half CCD mode enabled
+ */
+static SANE_Bool compute_half_ccd(const Genesys_Sensor& sensor, int xres)
+{
+  /* we have 2 domains for ccd: xres below or above half ccd max dpi */
+  if (xres<=300 && sensor.ccd_size_divisor > 1)
+    {
+      return SANE_TRUE;
+    }
+  return SANE_FALSE;
+}
+
+/** @brief set all registers to default values .
+ * This function is called only once at the beginning and
+ * fills register startup values for registers reused across scans.
+ * Those that are rarely modified or not modified are written
+ * individually.
+ * @param dev device structure holding register set to initialize
+ */
+static void
+gl124_init_registers (Genesys_Device * dev)
+{
+  DBGSTART;
+
+  dev->reg.clear();
+
+  /* default to LiDE 110 */
+  SETREG (0x01,0xa2); /* + REG01_SHDAREA */
+  SETREG (0x02,0x90);
+  SETREG (0x03,0x50);
+  SETREG (0x04,0x03);
+  SETREG (0x05,0x00);
+  if(dev->model->ccd_type==CIS_CANONLIDE120)
+    {
+      SETREG (0x06,0x50);
+      SETREG (0x07,0x00);
+    }
+  else
+    {
+      SETREG (0x03,0x50 & ~REG03_AVEENB);
+      SETREG (0x06,0x50 | REG06_GAIN4);
+    }
+  SETREG (0x09,0x00);
+  SETREG (0x0a,0xc0);
+  SETREG (0x0b,0x2a);
+  SETREG (0x0c,0x12);
+  SETREG (0x11,0x00);
+  SETREG (0x12,0x00);
+  SETREG (0x13,0x0f);
+  SETREG (0x14,0x00);
+  SETREG (0x15,0x80);
+  SETREG (0x16,0x10);
+  SETREG (0x17,0x04);
+  SETREG (0x18,0x00);
+  SETREG (0x19,0x01);
+  SETREG (0x1a,0x30);
+  SETREG (0x1b,0x00);
+  SETREG (0x1c,0x00);
+  SETREG (0x1d,0x01);
+  SETREG (0x1e,0x10);
+  SETREG (0x1f,0x00);
+  SETREG (0x20,0x15);
+  SETREG (0x21,0x00);
+  if(dev->model->ccd_type!=CIS_CANONLIDE120)
+    {
+      SETREG (0x22,0x02);
+    }
+  else
+    {
+      SETREG (0x22,0x14);
+    }
+  SETREG (0x23,0x00);
+  SETREG (0x24,0x00);
+  SETREG (0x25,0x00);
+  SETREG (0x26,0x0d);
+  SETREG (0x27,0x48);
+  SETREG (0x28,0x00);
+  SETREG (0x29,0x56);
+  SETREG (0x2a,0x5e);
+  SETREG (0x2b,0x02);
+  SETREG (0x2c,0x02);
+  SETREG (0x2d,0x58);
+  SETREG (0x3b,0x00);
+  SETREG (0x3c,0x00);
+  SETREG (0x3d,0x00);
+  SETREG (0x3e,0x00);
+  SETREG (0x3f,0x02);
+  SETREG (0x40,0x00);
+  SETREG (0x41,0x00);
+  SETREG (0x42,0x00);
+  SETREG (0x43,0x00);
+  SETREG (0x44,0x00);
+  SETREG (0x45,0x00);
+  SETREG (0x46,0x00);
+  SETREG (0x47,0x00);
+  SETREG (0x48,0x00);
+  SETREG (0x49,0x00);
+  SETREG (0x4f,0x00);
+  SETREG (0x52,0x00);
+  SETREG (0x53,0x02);
+  SETREG (0x54,0x04);
+  SETREG (0x55,0x06);
+  SETREG (0x56,0x04);
+  SETREG (0x57,0x04);
+  SETREG (0x58,0x04);
+  SETREG (0x59,0x04);
+  SETREG (0x5a,0x1a);
+  SETREG (0x5b,0x00);
+  SETREG (0x5c,0xc0);
+  SETREG (0x5f,0x00);
+  SETREG (0x60,0x02);
+  SETREG (0x61,0x00);
+  SETREG (0x62,0x00);
+  SETREG (0x63,0x00);
+  SETREG (0x64,0x00);
+  SETREG (0x65,0x00);
+  SETREG (0x66,0x00);
+  SETREG (0x67,0x00);
+  SETREG (0x68,0x00);
+  SETREG (0x69,0x00);
+  SETREG (0x6a,0x00);
+  SETREG (0x6b,0x00);
+  SETREG (0x6c,0x00);
+  SETREG (0x6e,0x00);
+  SETREG (0x6f,0x00);
+  if(dev->model->ccd_type!=CIS_CANONLIDE120)
+    {
+      SETREG (0x6d,0xd0);
+      SETREG (0x71,0x08);
+    }
+  else
+    {
+      SETREG (0x6d,0x00);
+      SETREG (0x71,0x1f);
+    }
+  SETREG (0x70,0x00);
+  SETREG (0x72,0x08);
+  SETREG (0x73,0x0a);
+
+  /* CKxMAP */
+  SETREG (0x74,0x00);
+  SETREG (0x75,0x00);
+  SETREG (0x76,0x3c);
+  SETREG (0x77,0x00);
+  SETREG (0x78,0x00);
+  SETREG (0x79,0x9f);
+  SETREG (0x7a,0x00);
+  SETREG (0x7b,0x00);
+  SETREG (0x7c,0x55);
+
+  SETREG (0x7d,0x00);
+  SETREG (0x7e,0x08);
+  SETREG (0x7f,0x58);
+  if(dev->model->ccd_type!=CIS_CANONLIDE120)
+    {
+      SETREG (0x80,0x00);
+      SETREG (0x81,0x14);
+    }
+  else
+    {
+      SETREG (0x80,0x00);
+      SETREG (0x81,0x10);
+    }
+
+  /* STRPIXEL */
+  SETREG (0x82,0x00);
+  SETREG (0x83,0x00);
+  SETREG (0x84,0x00);
+  /* ENDPIXEL */
+  SETREG (0x85,0x00);
+  SETREG (0x86,0x00);
+  SETREG (0x87,0x00);
+
+  SETREG (0x88,0x00);
+  SETREG (0x89,0x65);
+  SETREG (0x8a,0x00);
+  SETREG (0x8b,0x00);
+  SETREG (0x8c,0x00);
+  SETREG (0x8d,0x00);
+  SETREG (0x8e,0x00);
+  SETREG (0x8f,0x00);
+  SETREG (0x90,0x00);
+  SETREG (0x91,0x00);
+  SETREG (0x92,0x00);
+  SETREG (0x93,0x00);
+  SETREG (0x94,0x14);
+  SETREG (0x95,0x30);
+  SETREG (0x96,0x00);
+  SETREG (0x97,0x90);
+  SETREG (0x98,0x01);
+  SETREG (0x99,0x1f);
+  SETREG (0x9a,0x00);
+  SETREG (0x9b,0x80);
+  SETREG (0x9c,0x80);
+  SETREG (0x9d,0x3f);
+  SETREG (0x9e,0x00);
+  SETREG (0x9f,0x00);
+  SETREG (0xa0,0x20);
+  SETREG (0xa1,0x30);
+  SETREG (0xa2,0x00);
+  SETREG (0xa3,0x20);
+  SETREG (0xa4,0x01);
+  SETREG (0xa5,0x00);
+  SETREG (0xa6,0x00);
+  SETREG (0xa7,0x08);
+  SETREG (0xa8,0x00);
+  SETREG (0xa9,0x08);
+  SETREG (0xaa,0x01);
+  SETREG (0xab,0x00);
+  SETREG (0xac,0x00);
+  SETREG (0xad,0x40);
+  SETREG (0xae,0x01);
+  SETREG (0xaf,0x00);
+  SETREG (0xb0,0x00);
+  SETREG (0xb1,0x40);
+  SETREG (0xb2,0x00);
+  SETREG (0xb3,0x09);
+  SETREG (0xb4,0x5b);
+  SETREG (0xb5,0x00);
+  SETREG (0xb6,0x10);
+  SETREG (0xb7,0x3f);
+  SETREG (0xb8,0x00);
+  SETREG (0xbb,0x00);
+  SETREG (0xbc,0xff);
+  SETREG (0xbd,0x00);
+  SETREG (0xbe,0x07);
+  SETREG (0xc3,0x00);
+  SETREG (0xc4,0x00);
+
+  /* gamma
+  SETREG (0xc5,0x00);
+  SETREG (0xc6,0x00);
+  SETREG (0xc7,0x00);
+  SETREG (0xc8,0x00);
+  SETREG (0xc9,0x00);
+  SETREG (0xca,0x00);
+  SETREG (0xcb,0x00);
+  SETREG (0xcc,0x00);
+  SETREG (0xcd,0x00);
+  SETREG (0xce,0x00);
+  */
+  if(dev->model->ccd_type==CIS_CANONLIDE120)
+    {
+      SETREG (0xc5,0x20);
+      SETREG (0xc6,0xeb);
+      SETREG (0xc7,0x20);
+      SETREG (0xc8,0xeb);
+      SETREG (0xc9,0x20);
+      SETREG (0xca,0xeb);
+    }
+
+  /* memory layout
+  SETREG (0xd0,0x0a);
+  SETREG (0xd1,0x1f);
+  SETREG (0xd2,0x34); */
+  SETREG (0xd3,0x00);
+  SETREG (0xd4,0x00);
+  SETREG (0xd5,0x00);
+  SETREG (0xd6,0x00);
+  SETREG (0xd7,0x00);
+  SETREG (0xd8,0x00);
+  SETREG (0xd9,0x00);
+
+  /* memory layout
+  SETREG (0xe0,0x00);
+  SETREG (0xe1,0x48);
+  SETREG (0xe2,0x15);
+  SETREG (0xe3,0x90);
+  SETREG (0xe4,0x15);
+  SETREG (0xe5,0x91);
+  SETREG (0xe6,0x2a);
+  SETREG (0xe7,0xd9);
+  SETREG (0xe8,0x2a);
+  SETREG (0xe9,0xad);
+  SETREG (0xea,0x40);
+  SETREG (0xeb,0x22);
+  SETREG (0xec,0x40);
+  SETREG (0xed,0x23);
+  SETREG (0xee,0x55);
+  SETREG (0xef,0x6b);
+  SETREG (0xf0,0x55);
+  SETREG (0xf1,0x6c);
+  SETREG (0xf2,0x6a);
+  SETREG (0xf3,0xb4);
+  SETREG (0xf4,0x6a);
+  SETREG (0xf5,0xb5);
+  SETREG (0xf6,0x7f);
+  SETREG (0xf7,0xfd);*/
+
+  SETREG (0xf8,0x01);   /* other value is 0x05 */
+  SETREG (0xf9,0x00);
+  SETREG (0xfa,0x00);
+  SETREG (0xfb,0x00);
+  SETREG (0xfc,0x00);
+  SETREG (0xff,0x00);
+
+  /* fine tune upon device description */
+  dev->reg.find_reg(0x05).value &= ~REG05_DPIHW;
+  switch (sanei_genesys_find_sensor_any(dev).optical_res)
+    {
+    case 600:
+      dev->reg.find_reg(0x05).value |= REG05_DPIHW_600;
+      break;
+    case 1200:
+      dev->reg.find_reg(0x05).value |= REG05_DPIHW_1200;
+      break;
+    case 2400:
+      dev->reg.find_reg(0x05).value |= REG05_DPIHW_2400;
+      break;
+    case 4800:
+      dev->reg.find_reg(0x05).value |= REG05_DPIHW_4800;
+      break;
+    }
+
+  dev->calib_reg = dev->reg;
+
+  DBGCOMPLETED;
+}
+
+/**@brief send slope table for motor movement
+ * Send slope_table in machine byte order
+ * @param dev device to send slope table
+ * @param table_nr index of the slope table in ASIC memory
+ * Must be in the [0-4] range.
+ * @param slope_table pointer to 16 bit values array of the slope table
+ * @param steps number of elemnts in the slope table
+ */
+static SANE_Status
+gl124_send_slope_table (Genesys_Device * dev, int table_nr,
+			uint16_t * slope_table, int steps)
+{
+  SANE_Status status = SANE_STATUS_GOOD;
+  int i;
+  char msg[10000];
+
+  DBG (DBG_proc, "%s (table_nr = %d, steps = %d)\n", __func__,
+       table_nr, steps);
+
+  /* sanity check */
+  if(table_nr<0 || table_nr>4)
+    {
+      DBG (DBG_error, "%s: invalid table number %d!\n", __func__, table_nr);
+      return SANE_STATUS_INVAL;
+    }
+
+  std::vector<uint8_t> table(steps * 2);
+  for (i = 0; i < steps; i++)
+    {
+      table[i * 2] = slope_table[i] & 0xff;
+      table[i * 2 + 1] = slope_table[i] >> 8;
+    }
+
+  if (DBG_LEVEL >= DBG_io)
+    {
+      sprintf (msg, "write slope %d (%d)=", table_nr, steps);
+      for (i = 0; i < steps; i++)
+	{
+	  sprintf (msg+strlen(msg), ",%d", slope_table[i]);
+	}
+      DBG (DBG_io, "%s: %s\n", __func__, msg);
+    }
+
+  /* slope table addresses are fixed */
+  status = sanei_genesys_write_ahb(dev, 0x10000000 + 0x4000 * table_nr, steps * 2, table.data());
+  if (status != SANE_STATUS_GOOD)
+    {
+      DBG (DBG_error,
+	   "%s: write to AHB failed writing slope table %d (%s)\n",
+	   __func__, table_nr, sane_strstatus (status));
+    }
+
+  DBGCOMPLETED;
+  return status;
+}
+
+/** @brief * Set register values of 'special' ti type frontend
+ * Registers value are taken from the frontend register data
+ * set.
+ * @param dev device owning the AFE
+ * @param set flag AFE_INIT to specify the AFE must be reset before writing data
+ * */
+static SANE_Status
+gl124_set_ti_fe (Genesys_Device * dev, uint8_t set)
+{
+  SANE_Status status = SANE_STATUS_GOOD;
+  int i;
+
+  DBGSTART;
+  if (set == AFE_INIT)
+    {
+      DBG (DBG_proc, "%s: setting DAC %u\n", __func__, dev->model->dac_type);
+
+      dev->frontend = dev->frontend_initial;
+    }
+
+  /* start writing to DAC */
+  status = sanei_genesys_fe_write_data (dev, 0x00, 0x80);
+  if (status != SANE_STATUS_GOOD)
+    {
+      DBG (DBG_error, "%s: failed to write reg0: %s\n", __func__,
+	   sane_strstatus (status));
+      return status;
+    }
+
+  /* write values to analog frontend */
+  for (uint16_t addr = 0x01; addr < 0x04; addr++)
+    {
+      status = sanei_genesys_fe_write_data(dev, addr, dev->frontend.regs.get_value(addr));
+      if (status != SANE_STATUS_GOOD)
+	{
+          DBG(DBG_error, "%s: failed to write reg %d: %s\n", __func__, addr,
+              sane_strstatus(status));
+	  return status;
+	}
+    }
+
+  status = sanei_genesys_fe_write_data (dev, 0x04, 0x00);
+  if (status != SANE_STATUS_GOOD)
+    {
+      DBG (DBG_error, "%s: failed to write reg4: %s\n", __func__,
+	   sane_strstatus (status));
+      return status;
+    }
+
+  /* these are not really sign for this AFE */
+  for (i = 0; i < 3; i++)
+    {
+      status = sanei_genesys_fe_write_data(dev, 0x05 + i, dev->frontend.regs.get_value(0x24 + i));
+      if (status != SANE_STATUS_GOOD)
+	{
+	  DBG (DBG_error,
+	       "%s: failed to write reg %d: %s\n", __func__, i+5,
+	       sane_strstatus (status));
+	  return status;
+	}
+    }
+
+  /* close writing to DAC */
+  if(dev->model->dac_type == DAC_CANONLIDE120)
+    {
+      status = sanei_genesys_fe_write_data (dev, 0x00, 0x01);
+    }
+  else
+    {
+      status = sanei_genesys_fe_write_data (dev, 0x00, 0x11);
+    }
+  if (status != SANE_STATUS_GOOD)
+    {
+      DBG (DBG_error, "%s: failed to write reg0: %s\n", __func__,
+	   sane_strstatus (status));
+      return status;
+    }
+
+  DBGCOMPLETED;
+
+  return status;
+}
+
+
+/* Set values of analog frontend */
+static SANE_Status
+gl124_set_fe(Genesys_Device * dev, const Genesys_Sensor& sensor, uint8_t set)
+{
+    (void) sensor;
+  SANE_Status status = SANE_STATUS_GOOD;
+  uint8_t val;
+
+  DBG(DBG_proc, "%s (%s)\n", __func__, set == AFE_INIT ? "init" : set == AFE_SET ? "set" : set ==
+      AFE_POWER_SAVE ? "powersave" : "huh?");
+
+  if (set == AFE_INIT)
+    {
+      DBG(DBG_proc, "%s(): setting DAC %u\n", __func__, dev->model->dac_type);
+      dev->frontend = dev->frontend_initial;
+    }
+
+  RIE (sanei_genesys_read_register (dev, REG0A, &val));
+
+  /* route to correct analog FE */
+  switch ((val & REG0A_SIFSEL)>>REG0AS_SIFSEL)
+    {
+    case 3:
+      status=gl124_set_ti_fe (dev, set);
+      break;
+    case 0:
+    case 1:
+    case 2:
+    default:
+      DBG(DBG_error, "%s: unsupported analog FE 0x%02x\n", __func__, val);
+      status=SANE_STATUS_INVAL;
+      break;
+    }
+
+  DBGCOMPLETED;
+  return status;
+}
+
+
+/**@brief compute exposure to use
+ * compute the sensor exposure based on target resolution
+ * @param dev pointer to  device description
+ * @param xres sensor's required resolution
+ * @param half_ccd flag for half ccd mode
+ */
+static int gl124_compute_exposure(Genesys_Device *dev, int xres, int half_ccd)
+{
+  Sensor_Profile* sensor_profile = get_sensor_profile(dev->model->ccd_type, xres, half_ccd);
+  return sensor_profile->exposure;
+}
+
+
+static SANE_Status
+gl124_init_motor_regs_scan (Genesys_Device * dev,
+                            const Genesys_Sensor& sensor,
+                            Genesys_Register_Set * reg,
+                            unsigned int scan_exposure_time,
+			    float scan_yres,
+			    int scan_step_type,
+			    unsigned int scan_lines,
+			    unsigned int scan_dummy,
+			    unsigned int feed_steps,
+                            ScanColorMode scan_mode,
+                            unsigned int flags)
+{
+  SANE_Status status = SANE_STATUS_GOOD;
+  int use_fast_fed;
+  unsigned int lincnt, fast_dpi;
+  uint16_t scan_table[SLOPE_TABLE_SIZE];
+  uint16_t fast_table[SLOPE_TABLE_SIZE];
+  int scan_steps,fast_steps,factor;
+  unsigned int feedl,dist;
+  uint32_t z1, z2;
+  float yres;
+  int min_speed;
+  unsigned int linesel;
+
+  DBGSTART;
+  DBG(DBG_info, "%s : scan_exposure_time=%d, scan_yres=%g, scan_step_type=%d, scan_lines=%d, "
+      "scan_dummy=%d, feed_steps=%d, scan_mode=%d, flags=%x\n", __func__, scan_exposure_time,
+      scan_yres, scan_step_type, scan_lines, scan_dummy, feed_steps,
+      static_cast<unsigned>(scan_mode), flags);
+
+  /* we never use fast fed since we do manual feed for the scans */
+  use_fast_fed=0;
+  factor=1;
+
+  /* enforce motor minimal scan speed
+   * @TODO extend motor struct for this value */
+  if (scan_mode == ScanColorMode::COLOR_SINGLE_PASS)
+    {
+      min_speed = 900;
+    }
+  else
+    {
+      switch(dev->model->motor_type)
+        {
+          case MOTOR_CANONLIDE110:
+	    min_speed = 600;
+            break;
+          case MOTOR_CANONLIDE120:
+            min_speed = 900;
+            break;
+          default:
+            min_speed = 900;
+            break;
+        }
+    }
+
+  /* compute min_speed and linesel */
+  if(scan_yres<min_speed)
+    {
+      yres=min_speed;
+      linesel=yres/scan_yres-1;
+      /* limit case, we need a linesel > 0 */
+      if(linesel==0)
+        {
+          linesel=1;
+          yres=scan_yres*2;
+        }
+    }
+  else
+    {
+      yres=scan_yres;
+      linesel=0;
+    }
+
+  DBG (DBG_io2, "%s: final yres=%f, linesel=%d\n", __func__, yres, linesel);
+
+  lincnt=scan_lines*(linesel+1);
+  sanei_genesys_set_triple(reg,REG_LINCNT,lincnt);
+  DBG (DBG_io, "%s: lincnt=%d\n", __func__, lincnt);
+
+  /* compute register 02 value */
+    uint8_t r02 = REG02_NOTHOME;
+
+    if (use_fast_fed) {
+        r02 |= REG02_FASTFED;
+    } else {
+        r02 &= ~REG02_FASTFED;
+    }
+
+    if (flags & MOTOR_FLAG_AUTO_GO_HOME)
+        r02 |= REG02_AGOHOME;
+
+    if ((flags & MOTOR_FLAG_DISABLE_BUFFER_FULL_MOVE)
+            ||(yres>=sensor.optical_res))
+    {
+        r02 |= REG02_ACDCDIS;
+    }
+
+    reg->set8(REG02, r02);
+    sanei_genesys_set_motor_power(*reg, true);
+
+  /* SCANFED */
+  sanei_genesys_set_double(reg,REG_SCANFED,4);
+
+  /* scan and backtracking slope table */
+  sanei_genesys_slope_table(scan_table,
+                            &scan_steps,
+                            yres,
+                            scan_exposure_time,
+                            dev->motor.base_ydpi,
+                            scan_step_type,
+                            factor,
+                            dev->model->motor_type,
+                            motors);
+  RIE(gl124_send_slope_table (dev, SCAN_TABLE, scan_table, scan_steps));
+  RIE(gl124_send_slope_table (dev, BACKTRACK_TABLE, scan_table, scan_steps));
+
+  /* STEPNO */
+  sanei_genesys_set_double(reg,REG_STEPNO,scan_steps);
+
+  /* fast table */
+  fast_dpi=yres;
+
+  /*
+  if (scan_mode != ScanColorMode::COLOR_SINGLE_PASS)
+    {
+      fast_dpi*=3;
+    }
+    */
+  sanei_genesys_slope_table(fast_table,
+                            &fast_steps,
+                            fast_dpi,
+                            scan_exposure_time,
+                            dev->motor.base_ydpi,
+                            scan_step_type,
+                            factor,
+                            dev->model->motor_type,
+                            motors);
+  RIE(gl124_send_slope_table (dev, STOP_TABLE, fast_table, fast_steps));
+  RIE(gl124_send_slope_table (dev, FAST_TABLE, fast_table, fast_steps));
+
+  /* FASTNO */
+  sanei_genesys_set_double(reg,REG_FASTNO,fast_steps);
+
+  /* FSHDEC */
+  sanei_genesys_set_double(reg,REG_FSHDEC,fast_steps);
+
+  /* FMOVNO */
+  sanei_genesys_set_double(reg,REG_FMOVNO,fast_steps);
+
+  /* substract acceleration distance from feedl */
+  feedl=feed_steps;
+  feedl<<=scan_step_type;
+
+  dist = scan_steps;
+  if (flags & MOTOR_FLAG_FEED)
+    dist *=2;
+  if (use_fast_fed)
+    {
+        dist += fast_steps*2;
+    }
+  DBG (DBG_io2, "%s: acceleration distance=%d\n", __func__, dist);
+
+  /* get sure we don't use insane value */
+  if(dist<feedl)
+    feedl -= dist;
+  else
+    feedl = 0;
+
+  sanei_genesys_set_triple(reg,REG_FEEDL,feedl);
+  DBG (DBG_io, "%s: feedl=%d\n", __func__, feedl);
+
+  /* doesn't seem to matter that much */
+  sanei_genesys_calculate_zmode2 (use_fast_fed,
+				  scan_exposure_time,
+				  scan_table,
+				  scan_steps,
+				  feedl,
+                                  scan_steps,
+                                  &z1,
+                                  &z2);
+
+  sanei_genesys_set_triple(reg, REG_Z1MOD,z1);
+  DBG(DBG_info, "%s: z1 = %d\n", __func__, z1);
+
+  sanei_genesys_set_triple(reg, REG_Z2MOD, z2);
+  DBG(DBG_info, "%s: z2 = %d\n", __func__, z2);
+
+  /* LINESEL */
+  reg->set8_mask(REG1D, linesel, REG1D_LINESEL);
+  reg->set8(REGA0, (scan_step_type << REGA0S_STEPSEL) | (scan_step_type << REGA0S_FSTPSEL));
+
+  /* FMOVDEC */
+  sanei_genesys_set_double(reg,REG_FMOVDEC,fast_steps);
+
+  DBGCOMPLETED;
+  return SANE_STATUS_GOOD;
+}
+
+
+/** @brief copy sensor specific settings
+ * Set up register set for the given sensor resolution. Values are from the device table
+ * in genesys_devices.c for registers:
+ *       [0x16 ... 0x1d]
+ *       [0x52 ... 0x5e]
+ * Other come from the specific device sensor table in genesys_gl124.h:
+ *      0x18, 0x20, 0x61, 0x98 and
+ * @param dev device to set up
+ * @param regs register set to modify
+ * @param dpi resolution of the sensor during scan
+ * @param half_ccd flag for half ccd mode
+ * */
+static void gl124_setup_sensor(Genesys_Device * dev,
+                               const Genesys_Sensor& sensor,
+                               Genesys_Register_Set * regs, int dpi, int half_ccd)
+{
+  int dpihw;
+  uint32_t exp;
+
+  DBGSTART;
+
+    // we start at 6, 0-5 is a 16 bits cache for exposure
+    for (uint16_t addr = 0x16; addr < 0x1e; addr++) {
+        regs->set8(addr, sensor.custom_regs.get_value(addr));
+    }
+
+    // skip writing 5d,5e which is AFE address because
+    // they are not defined in register set */
+    for (uint16_t addr = 0x52; addr < 0x52 + 11; addr++) {
+        regs->set8(addr, sensor.custom_regs.get_value(addr));
+    }
+
+  /* set EXPDUMMY and CKxMAP */
+    dpihw = sanei_genesys_compute_dpihw(dev, sensor, dpi);
+    Sensor_Profile* sensor_profile = get_sensor_profile(dev->model->ccd_type, dpihw, half_ccd);
+
+    regs->set8(0x18, sensor_profile->reg18);
+    regs->set8(0x20, sensor_profile->reg20);
+    regs->set8(0x61, sensor_profile->reg61);
+    regs->set8(0x98, sensor_profile->reg98);
+    if (sensor_profile->reg16 != 0) {
+        regs->set8(0x16, sensor_profile->reg16);
+    }
+    if (sensor_profile->reg70 != 0) {
+        regs->set8(0x70, sensor_profile->reg70);
+    }
+
+
+  sanei_genesys_set_triple(regs,REG_SEGCNT,sensor_profile->segcnt);
+  sanei_genesys_set_double(regs,REG_TG0CNT,sensor_profile->tg0cnt);
+  sanei_genesys_set_double(regs,REG_EXPDMY,sensor_profile->expdummy);
+
+  /* if no calibration has been done, set default values for exposures */
+  exp = sensor.exposure.red;
+  if(exp==0)
+    {
+      exp=sensor_profile->expr;
+    }
+  sanei_genesys_set_triple(regs,REG_EXPR,exp);
+
+  exp =sensor.exposure.green;
+  if(exp==0)
+    {
+      exp=sensor_profile->expg;
+    }
+  sanei_genesys_set_triple(regs,REG_EXPG,exp);
+
+  exp = sensor.exposure.blue;
+  if(exp==0)
+    {
+      exp=sensor_profile->expb;
+    }
+  sanei_genesys_set_triple(regs,REG_EXPB,exp);
+
+  sanei_genesys_set_triple(regs,REG_CK1MAP,sensor_profile->ck1map);
+  sanei_genesys_set_triple(regs,REG_CK3MAP,sensor_profile->ck3map);
+  sanei_genesys_set_triple(regs,REG_CK4MAP,sensor_profile->ck4map);
+
+  /* order of the sub-segments */
+  dev->order=sensor_profile->order;
+
+  DBGCOMPLETED;
+}
+
+/** @brief setup optical related registers
+ * start and pixels are expressed in optical sensor resolution coordinate
+ * space.
+ * @param dev scanner device to use
+ * @param reg registers to set up
+ * @param exposure_time exposure time to use
+ * @param used_res scanning resolution used, may differ from
+ *        scan's one
+ * @param start logical start pixel coordinate
+ * @param pixels logical number of pixels to use
+ * @param channels number of color channels (currently 1 or 3)
+ * @param depth bit depth of the scan (1, 8 or 16)
+ * @param half_ccd SANE_TRUE if sensor's timings are such that x coordinates
+ *           must be halved
+ * @param color_filter color channel to use as gray data
+ * @param flags optical flags (@see )
+ * @return SANE_STATUS_GOOD if OK
+ */
+static SANE_Status
+gl124_init_optical_regs_scan (Genesys_Device * dev,
+                              const Genesys_Sensor& sensor,
+			      Genesys_Register_Set * reg,
+			      unsigned int exposure_time,
+			      int used_res,
+			      unsigned int start,
+			      unsigned int pixels,
+			      int channels,
+			      int depth,
+			      SANE_Bool half_ccd,
+                              ColorFilter color_filter,
+                              int flags)
+{
+  unsigned int words_per_line, segcnt;
+  unsigned int startx, endx, used_pixels, segnb;
+  unsigned int dpiset, cksel, dpihw, factor;
+  unsigned int bytes;
+  GenesysRegister *r;
+  SANE_Status status = SANE_STATUS_GOOD;
+  uint32_t expmax, exp;
+
+  DBG(DBG_proc, "%s :  exposure_time=%d, used_res=%d, start=%d, pixels=%d, channels=%d, depth=%d, "
+      "half_ccd=%d, flags=%x\n", __func__, exposure_time, used_res, start, pixels, channels, depth,
+      half_ccd, flags);
+
+  /* resolution is divided according to CKSEL */
+  r = sanei_genesys_get_address (reg, REG18);
+  cksel= (r->value & REG18_CKSEL)+1;
+  DBG (DBG_io2, "%s: cksel=%d\n", __func__, cksel);
+
+  /* to manage high resolution device while keeping good
+   * low resolution scanning speed, we make hardware dpi vary */
+  dpihw=sanei_genesys_compute_dpihw(dev, sensor, used_res * cksel);
+  factor=sensor.optical_res/dpihw;
+  DBG (DBG_io2, "%s: dpihw=%d (factor=%d)\n", __func__, dpihw, factor);
+
+  /* sensor parameters */
+  gl124_setup_sensor(dev, sensor, reg, dpihw, half_ccd);
+  dpiset = used_res * cksel;
+
+  /* start and end coordinate in optical dpi coordinates */
+  /* startx = start/cksel + sensor.dummy_pixel; XXX STEF XXX */
+  startx = start/cksel;
+  used_pixels=pixels/cksel;
+  endx = startx + used_pixels;
+
+  /* pixel coordinate factor correction when used dpihw is not maximal one */
+  startx/=factor;
+  endx/=factor;
+  used_pixels=endx-startx;
+
+  status = gl124_set_fe(dev, sensor, AFE_SET);
+  if (status != SANE_STATUS_GOOD)
+    {
+      DBG (DBG_error, "%s: failed to set frontend: %s\n", __func__,
+	   sane_strstatus (status));
+      return status;
+    }
+
+  /* enable shading */
+  r = sanei_genesys_get_address (reg, REG01);
+  r->value &= ~REG01_SCAN;
+  if ((flags & OPTICAL_FLAG_DISABLE_SHADING) ||
+      (dev->model->flags & GENESYS_FLAG_NO_CALIBRATION))
+    {
+      r->value &= ~REG01_DVDSET;
+    }
+  else
+    {
+      r->value |= REG01_DVDSET;
+    }
+  r->value &= ~REG01_SCAN;
+
+  r = sanei_genesys_get_address (reg, REG03);
+  if((dev->model->ccd_type!=CIS_CANONLIDE120)&&(used_res>=600))
+    {
+      r->value &= ~REG03_AVEENB;
+      DBG (DBG_io, "%s: disabling AVEENB\n", __func__);
+    }
+  else
+    {
+      r->value |= ~REG03_AVEENB;
+      DBG (DBG_io, "%s: enabling AVEENB\n", __func__);
+    }
+
+    sanei_genesys_set_lamp_power(dev, sensor, *reg, !(flags & OPTICAL_FLAG_DISABLE_LAMP));
+
+  /* BW threshold */
+  RIE (sanei_genesys_write_register (dev, REG114, dev->settings.threshold));
+  RIE (sanei_genesys_write_register (dev, REG115, dev->settings.threshold));
+
+  /* monochrome / color scan */
+  r = sanei_genesys_get_address (reg, REG04);
+  switch (depth)
+    {
+    case 1:
+      r->value &= ~REG04_BITSET;
+      r->value |= REG04_LINEART;
+      break;
+    case 8:
+      r->value &= ~(REG04_LINEART | REG04_BITSET);
+      break;
+    case 16:
+      r->value &= ~REG04_LINEART;
+      r->value |= REG04_BITSET;
+      break;
+    }
+
+  r->value &= ~REG04_FILTER;
+  if (channels == 1)
+    {
+      switch (color_filter)
+	{
+            case ColorFilter::RED:
+                r->value |= 0x10;
+                break;
+            case ColorFilter::BLUE:
+                r->value |= 0x30;
+                break;
+            case ColorFilter::GREEN:
+                r->value |= 0x20;
+                break;
+            default:
+                break; // should not happen
+	}
+    }
+
+  /* register 05 */
+  r = sanei_genesys_get_address (reg, REG05);
+
+  /* set up dpihw */
+  r->value &= ~REG05_DPIHW;
+  switch(dpihw)
+    {
+      case 600:
+        r->value |= REG05_DPIHW_600;
+        break;
+      case 1200:
+        r->value |= REG05_DPIHW_1200;
+        break;
+      case 2400:
+        r->value |= REG05_DPIHW_2400;
+        break;
+      case 4800:
+        r->value |= REG05_DPIHW_4800;
+        break;
+    }
+
+  /* enable gamma tables */
+  if (flags & OPTICAL_FLAG_DISABLE_GAMMA)
+    r->value &= ~REG05_GMMENB;
+  else
+    r->value |= REG05_GMMENB;
+
+  if(half_ccd)
+    {
+      sanei_genesys_set_double(reg,REG_DPISET,dpiset*2);
+      DBG (DBG_io2, "%s: dpiset used=%d\n", __func__, dpiset*2);
+    }
+  else
+    {
+      sanei_genesys_set_double(reg,REG_DPISET,dpiset);
+      DBG (DBG_io2, "%s: dpiset used=%d\n", __func__, dpiset);
+    }
+
+  r = sanei_genesys_get_address (reg, REG06);
+  r->value |= REG06_GAIN4;
+
+  /* CIS scanners can do true gray by setting LEDADD */
+  /* we set up LEDADD only when asked */
+  if (dev->model->is_cis == SANE_TRUE)
+    {
+      r = sanei_genesys_get_address (reg, REG60);
+      r->value &= ~REG60_LEDADD;
+      if (channels == 1 && (flags & OPTICAL_FLAG_ENABLE_LEDADD))
+	{
+	  r->value |= REG60_LEDADD;
+          sanei_genesys_get_triple(reg,REG_EXPR,&expmax);
+          sanei_genesys_get_triple(reg,REG_EXPG,&exp);
+          if(exp>expmax)
+            {
+              expmax=exp;
+            }
+          sanei_genesys_get_triple(reg,REG_EXPB,&exp);
+          if(exp>expmax)
+            {
+              expmax=exp;
+            }
+          sanei_genesys_set_triple(&dev->reg,REG_EXPR,expmax);
+          sanei_genesys_set_triple(&dev->reg,REG_EXPG,expmax);
+          sanei_genesys_set_triple(&dev->reg,REG_EXPB,expmax);
+	}
+      /* RGB weighting, REG_TRUER,G and B are to be set  */
+      r = sanei_genesys_get_address (reg, 0x01);
+      r->value &= ~REG01_TRUEGRAY;
+      if (channels == 1 && (flags & OPTICAL_FLAG_ENABLE_LEDADD))
+	{
+	  r->value |= REG01_TRUEGRAY;
+          sanei_genesys_write_register (dev, REG_TRUER, 0x80);
+          sanei_genesys_write_register (dev, REG_TRUEG, 0x80);
+          sanei_genesys_write_register (dev, REG_TRUEB, 0x80);
+	}
+    }
+
+  /* segment number */
+  r = sanei_genesys_get_address (reg, 0x98);
+  segnb = r->value & 0x0f;
+
+  sanei_genesys_set_triple(reg,REG_STRPIXEL,startx/segnb);
+  DBG (DBG_io2, "%s: strpixel used=%d\n", __func__, startx/segnb);
+  sanei_genesys_get_triple(reg,REG_SEGCNT,&segcnt);
+  if(endx/segnb==segcnt)
+    {
+      endx=0;
+    }
+  sanei_genesys_set_triple(reg,REG_ENDPIXEL,endx/segnb);
+  DBG (DBG_io2, "%s: endpixel used=%d\n", __func__, endx/segnb);
+
+  /* words(16bit) before gamma, conversion to 8 bit or lineart */
+  words_per_line = (used_pixels * dpiset) / dpihw;
+  bytes = depth / 8;
+  if (depth == 1)
+    {
+      words_per_line = (words_per_line >> 3) + ((words_per_line & 7) ? 1 : 0);
+    }
+  else
+    {
+      words_per_line *= bytes;
+    }
+
+  dev->bpl = words_per_line;
+  dev->cur = 0;
+  dev->skip = 0;
+  dev->len = dev->bpl/segnb;
+  dev->dist = dev->bpl/segnb;
+  dev->segnb = segnb;
+  dev->line_count = 0;
+  dev->line_interp = 0;
+
+  DBG (DBG_io2, "%s: used_pixels     =%d\n", __func__, used_pixels);
+  DBG (DBG_io2, "%s: pixels          =%d\n", __func__, pixels);
+  DBG (DBG_io2, "%s: depth           =%d\n", __func__, depth);
+  DBG (DBG_io2, "%s: dev->bpl        =%lu\n", __func__, (unsigned long)dev->bpl);
+  DBG (DBG_io2, "%s: dev->len        =%lu\n", __func__, (unsigned long)dev->len);
+  DBG (DBG_io2, "%s: dev->dist       =%lu\n", __func__, (unsigned long)dev->dist);
+  DBG (DBG_io2, "%s: dev->line_interp=%lu\n", __func__, (unsigned long)dev->line_interp);
+
+  words_per_line *= channels;
+  dev->wpl = words_per_line;
+
+  /* allocate buffer for odd/even pixels handling */
+    dev->oe_buffer.clear();
+    dev->oe_buffer.alloc(dev->wpl);
+
+  /* MAXWD is expressed in 2 words unit */
+  sanei_genesys_set_triple(reg,REG_MAXWD,(words_per_line));
+  DBG (DBG_io2, "%s: words_per_line used=%d\n", __func__, words_per_line);
+
+  sanei_genesys_set_triple(reg,REG_LPERIOD,exposure_time);
+  DBG (DBG_io2, "%s: exposure_time used=%d\n", __func__, exposure_time);
+
+  sanei_genesys_set_double(reg,REG_DUMMY,sensor.dummy_pixel);
+
+  DBGCOMPLETED;
+  return SANE_STATUS_GOOD;
+}
+
+/** set up registers for an actual scan
+ *
+ * this function sets up the scanner to scan in normal or single line mode
+ */
+static SANE_Status
+gl124_init_scan_regs(Genesys_Device * dev, const Genesys_Sensor& sensor, Genesys_Register_Set* reg,
+                     SetupParams& params)
+{
+    params.assert_valid();
+
+  int used_res;
+  int start, used_pixels;
+  int bytes_per_line;
+  int move;
+  unsigned int lincnt;
+  unsigned int oflags, mflags; /**> optical and motor flags */
+  int exposure_time;
+  int stagger;
+
+  int dummy = 0;
+  int slope_dpi = 0;
+  int scan_step_type = 1;
+  int max_shift;
+  size_t requested_buffer_size, read_buffer_size;
+
+  SANE_Bool half_ccd;                /* false: full CCD res is used, true, half max CCD res is used */
+  unsigned optical_res;
+  SANE_Status status = SANE_STATUS_GOOD;
+
+    DBG(DBG_info, "%s ", __func__);
+    debug_dump(DBG_info, params);
+
+  half_ccd=compute_half_ccd(sensor, params.xres);
+
+  /* optical_res */
+  optical_res = sensor.optical_res;
+  if (half_ccd)
+    optical_res /= 2;
+  DBG (DBG_info, "%s: optical_res=%d\n", __func__, optical_res);
+
+  /* stagger */
+  if ((!half_ccd) && (dev->model->flags & GENESYS_FLAG_STAGGERED_LINE))
+    stagger = (4 * params.yres) / dev->motor.base_ydpi;
+  else
+    stagger = 0;
+  DBG (DBG_info, "gl124_init_scan_regs : stagger=%d lines\n", stagger);
+
+  /** @brief compute used resolution */
+  if (params.flags & SCAN_FLAG_USE_OPTICAL_RES)
+    {
+      used_res = optical_res;
+    }
+  else
+    {
+      /* resolution is choosen from a fixed list and can be used directly,
+       * unless we have ydpi higher than sensor's maximum one */
+      if(params.xres>optical_res)
+        used_res=optical_res;
+      else
+        used_res = params.xres;
+    }
+
+  /* compute scan parameters values */
+  /* pixels are allways given at full optical resolution */
+  /* use detected left margin and fixed value */
+  /* start */
+  /* add x coordinates */
+  start = params.startx;
+
+  if (stagger > 0)
+    start |= 1;
+
+  /* compute correct pixels number */
+  used_pixels = (params.pixels * optical_res) / params.xres;
+  DBG (DBG_info, "%s: used_pixels=%d\n", __func__, used_pixels);
+
+  /* round up pixels number if needed */
+  if (used_pixels * params.xres < params.pixels * optical_res)
+    used_pixels++;
+
+  /* we want even number of pixels here */
+  if(used_pixels & 1)
+    used_pixels++;
+
+  /* slope_dpi */
+  /* cis color scan is effectively a gray scan with 3 gray lines per color line and a FILTER of 0 */
+  if (dev->model->is_cis)
+    slope_dpi = params.yres * params.channels;
+  else
+    slope_dpi = params.yres;
+
+  /* scan_step_type */
+  if(params.flags & SCAN_FLAG_FEEDING)
+    {
+      scan_step_type=0;
+      exposure_time=MOVE_EXPOSURE;
+    }
+  else
+    {
+      exposure_time = gl124_compute_exposure (dev, used_res, half_ccd);
+      scan_step_type = sanei_genesys_compute_step_type(motors, dev->model->motor_type, exposure_time);
+    }
+
+  DBG(DBG_info, "%s : exposure_time=%d pixels\n", __func__, exposure_time);
+  DBG(DBG_info, "%s : scan_step_type=%d\n", __func__, scan_step_type);
+
+  /*** optical parameters ***/
+  /* in case of dynamic lineart, we use an internal 8 bit gray scan
+   * to generate 1 lineart data */
+    if (params.flags & SCAN_FLAG_DYNAMIC_LINEART) {
+        params.depth = 8;
+    }
+
+  /* we enable true gray for cis scanners only, and just when doing
+   * scan since color calibration is OK for this mode
+   */
+  oflags = 0;
+  if (params.flags & SCAN_FLAG_DISABLE_SHADING)
+    oflags |= OPTICAL_FLAG_DISABLE_SHADING;
+  if (params.flags & SCAN_FLAG_DISABLE_GAMMA)
+    oflags |= OPTICAL_FLAG_DISABLE_GAMMA;
+  if (params.flags & SCAN_FLAG_DISABLE_LAMP)
+    oflags |= OPTICAL_FLAG_DISABLE_LAMP;
+  if (params.flags & SCAN_FLAG_CALIBRATION)
+    oflags |= OPTICAL_FLAG_DISABLE_DOUBLE;
+
+  if (dev->model->is_cis && dev->settings.true_gray)
+    {
+      oflags |= OPTICAL_FLAG_ENABLE_LEDADD;
+    }
+
+  /* now _LOGICAL_ optical values used are known, setup registers */
+  status = gl124_init_optical_regs_scan (dev,
+                                         sensor,
+					 reg,
+					 exposure_time,
+					 used_res,
+					 start,
+					 used_pixels,
+                                         params.channels,
+                                         params.depth,
+					 half_ccd,
+                                         params.color_filter,
+                                         oflags);
+  if (status != SANE_STATUS_GOOD)
+    return status;
+
+  /*** motor parameters ***/
+
+  /* max_shift */
+  max_shift=sanei_genesys_compute_max_shift(dev,params.channels,params.yres,params.flags);
+
+  /* lines to scan */
+  lincnt = params.lines + max_shift + stagger;
+
+  /* add tl_y to base movement */
+  move = params.starty;
+  DBG(DBG_info, "%s: move=%d steps\n", __func__, move);
+
+  mflags=0;
+  if(params.flags & SCAN_FLAG_DISABLE_BUFFER_FULL_MOVE)
+    mflags|=MOTOR_FLAG_DISABLE_BUFFER_FULL_MOVE;
+  if(params.flags & SCAN_FLAG_FEEDING)
+    mflags|=MOTOR_FLAG_FEED;
+
+  status = gl124_init_motor_regs_scan (dev, sensor,
+                                       reg,
+                                       exposure_time,
+                                       slope_dpi,
+                                       scan_step_type,
+                                       dev->model->is_cis ? lincnt * params.channels : lincnt,
+                                       dummy,
+                                       move,
+                                       params.scan_mode,
+                                       mflags);
+  if (status != SANE_STATUS_GOOD)
+    return status;
+
+  /*** prepares data reordering ***/
+
+  /* words_per_line */
+  bytes_per_line = (used_pixels * used_res) / optical_res;
+  bytes_per_line = (bytes_per_line * params.channels * params.depth) / 8;
+
+  /* since we don't have sheetfed scanners to handle,
+   * use huge read buffer */
+  /* TODO find the best size according to settings */
+  requested_buffer_size = 16 * bytes_per_line;
+
+  read_buffer_size =
+    2 * requested_buffer_size +
+    ((max_shift + stagger) * used_pixels * params.channels * params.depth) / 8;
+
+    dev->read_buffer.clear();
+    dev->read_buffer.alloc(read_buffer_size);
+
+    dev->lines_buffer.clear();
+    dev->lines_buffer.alloc(read_buffer_size);
+
+    dev->shrink_buffer.clear();
+    dev->shrink_buffer.alloc(requested_buffer_size);
+
+    dev->out_buffer.clear();
+    dev->out_buffer.alloc((8 * dev->settings.pixels * params.channels * params.depth) / 8);
+
+  dev->read_bytes_left = bytes_per_line * lincnt;
+
+  DBG(DBG_info, "%s: physical bytes to read = %lu\n", __func__, (u_long) dev->read_bytes_left);
+  dev->read_active = SANE_TRUE;
+
+
+  dev->current_setup.params = params;
+  dev->current_setup.pixels = (used_pixels * used_res) / optical_res;
+  DBG(DBG_info, "%s: current_setup.pixels=%d\n", __func__, dev->current_setup.pixels);
+  dev->current_setup.lines = lincnt;
+  dev->current_setup.depth = params.depth;
+  dev->current_setup.channels = params.channels;
+  dev->current_setup.exposure_time = exposure_time;
+  dev->current_setup.xres = used_res;
+  dev->current_setup.yres = params.yres;
+  dev->current_setup.ccd_size_divisor = half_ccd ? 2 : 1;
+  dev->current_setup.stagger = stagger;
+  dev->current_setup.max_shift = max_shift + stagger;
+
+  dev->total_bytes_read = 0;
+  if (params.depth == 1)
+    dev->total_bytes_to_read =
+      ((dev->settings.pixels * dev->settings.lines) / 8 +
+       (((dev->settings.pixels * dev->settings.lines) % 8) ? 1 : 0)) *
+      params.channels;
+  else
+    dev->total_bytes_to_read =
+      dev->settings.pixels * dev->settings.lines * params.channels * (params.depth / 8);
+
+  DBG(DBG_info, "%s: total bytes to send = %lu\n", __func__, (u_long) dev->total_bytes_to_read);
+
+  DBGCOMPLETED;
+  return SANE_STATUS_GOOD;
+}
+
+static void
+gl124_calculate_current_setup (Genesys_Device * dev, const Genesys_Sensor& sensor)
+{
+  int channels;
+  int depth;
+  int start;
+
+  int used_res;
+  int used_pixels;
+  unsigned int lincnt;
+  int exposure_time;
+  int stagger;
+  SANE_Bool half_ccd;
+
+  int max_shift, dpihw;
+
+  int optical_res;
+
+    DBG(DBG_info, "%s ", __func__);
+    debug_dump(DBG_info, dev->settings);
+
+  /* channels */
+  if (dev->settings.scan_mode == ScanColorMode::COLOR_SINGLE_PASS)
+    channels = 3;
+  else
+    channels = 1;
+
+  /* depth */
+  depth = dev->settings.depth;
+  if (dev->settings.scan_mode == ScanColorMode::LINEART)
+    depth = 1;
+
+  /* start */
+  start = SANE_UNFIX (dev->model->x_offset);
+  start += dev->settings.tl_x;
+  start = (start * sensor.optical_res) / MM_PER_INCH;
+
+    SetupParams params;
+    params.xres = dev->settings.xres;
+    params.yres = dev->settings.yres;
+    params.startx = start;
+    params.starty = 0; // not used
+    params.pixels = dev->settings.pixels;
+    params.lines = dev->settings.lines;
+    params.depth = depth;
+    params.channels = channels;
+    params.scan_method = dev->settings.scan_method;
+    params.scan_mode = dev->settings.scan_mode;
+    params.color_filter = dev->settings.color_filter;
+    params.flags = 0;
+
+  half_ccd=compute_half_ccd(sensor, params.xres);
+
+    DBG(DBG_info, "%s ", __func__);
+    debug_dump(DBG_info, params);
+
+  /* optical_res */
+  optical_res = sensor.optical_res;
+
+  if (params.xres <= (unsigned) optical_res)
+    used_res = params.xres;
+  else
+    used_res=optical_res;
+
+  /* compute scan parameters values */
+  /* pixels are allways given at half or full CCD optical resolution */
+  /* use detected left margin  and fixed value */
+
+  /* compute correct pixels number */
+  used_pixels = (params.pixels * optical_res) / params.xres;
+  DBG (DBG_info, "%s: used_pixels=%d\n", __func__, used_pixels);
+
+  /* exposure */
+  exposure_time = gl124_compute_exposure (dev, params.xres, half_ccd);
+  DBG (DBG_info, "%s : exposure_time=%d pixels\n", __func__, exposure_time);
+
+  /* max_shift */
+  max_shift=sanei_genesys_compute_max_shift(dev, params.channels, params.yres, 0);
+
+  /* compute hw dpi for sensor */
+  dpihw=sanei_genesys_compute_dpihw(dev, sensor,used_res);
+
+  Sensor_Profile* sensor_profile = get_sensor_profile(dev->model->ccd_type, dpihw, half_ccd);
+  dev->segnb=sensor_profile->reg98 & 0x0f;
+
+  /* stagger */
+  if ((!half_ccd) && (dev->model->flags & GENESYS_FLAG_STAGGERED_LINE))
+    stagger = (4 * params.yres) / dev->motor.base_ydpi;
+  else
+    stagger = 0;
+  DBG (DBG_info, "%s: stagger=%d lines\n", __func__, stagger);
+
+  /* lincnt */
+  lincnt = params.lines + max_shift + stagger;
+
+  dev->current_setup.params = params;
+  dev->current_setup.pixels = (used_pixels * used_res) / optical_res;
+  DBG (DBG_info, "%s: current_setup.pixels=%d\n", __func__, dev->current_setup.pixels);
+  dev->current_setup.lines = lincnt;
+  dev->current_setup.depth = params.depth;
+  dev->current_setup.channels = params.channels;
+  dev->current_setup.exposure_time = exposure_time;
+  dev->current_setup.xres = used_res;
+  dev->current_setup.yres = params.yres;
+  dev->current_setup.ccd_size_divisor = half_ccd ? 2 : 1;
+  dev->current_setup.stagger = stagger;
+  dev->current_setup.max_shift = max_shift + stagger;
+
+  DBGCOMPLETED;
+}
+
+/**
+ * for fast power saving methods only, like disabling certain amplifiers
+ * @param dev device to use
+ * @param enable true to set inot powersaving
+ * */
+static SANE_Status
+gl124_save_power (Genesys_Device * dev, SANE_Bool enable)
+{
+  DBG(DBG_proc, "%s: enable = %d\n", __func__, enable);
+  if (dev == NULL)
+    return SANE_STATUS_INVAL;
+
+  DBGCOMPLETED;
+  return SANE_STATUS_GOOD;
+}
+
+static SANE_Status
+gl124_set_powersaving (Genesys_Device * dev, int delay /* in minutes */ )
+{
+  GenesysRegister *r;
+
+  DBG(DBG_proc, "%s (delay = %d)\n", __func__, delay);
+
+  r = sanei_genesys_get_address (&dev->reg, REG03);
+  r->value &= ~0xf0;
+  if(delay<15)
+    {
+      r->value |= delay;
+    }
+  else
+    {
+      r->value |= 0x0f;
+    }
+
+  DBGCOMPLETED;
+  return SANE_STATUS_GOOD;
+}
+
+static SANE_Status
+gl124_start_action (Genesys_Device * dev)
+{
+  return sanei_genesys_write_register (dev, 0x0f, 0x01);
+}
+
+static SANE_Status
+gl124_stop_action (Genesys_Device * dev)
+{
+  SANE_Status status = SANE_STATUS_GOOD;
+  uint8_t val40, val;
+  unsigned int loop;
+
+  DBGSTART;
+
+  /* post scan gpio : without that HOMSNR is unreliable */
+  gl124_homsnr_gpio(dev);
+
+  status = sanei_genesys_get_status (dev, &val);
+  if (DBG_LEVEL >= DBG_io)
+    {
+      sanei_genesys_print_status (val);
+    }
+
+  status = sanei_genesys_read_register (dev, REG100, &val40);
+  if (status != SANE_STATUS_GOOD)
+    {
+      DBG(DBG_error, "%s: failed to read reg100: %s\n", __func__, sane_strstatus(status));
+      DBGCOMPLETED;
+      return status;
+    }
+
+  /* only stop action if needed */
+  if (!(val40 & REG100_DATAENB) && !(val40 & REG100_MOTMFLG))
+    {
+      DBG (DBG_info, "%s: already stopped\n", __func__);
+      DBGCOMPLETED;
+      return SANE_STATUS_GOOD;
+    }
+
+  /* ends scan */
+  val = dev->reg.get8(REG01);
+  val &= ~REG01_SCAN;
+  dev->reg.set8(REG01, val);
+  status = sanei_genesys_write_register (dev, REG01, val);
+  if (status != SANE_STATUS_GOOD)
+    {
+      DBG (DBG_error,
+	   "%s: failed to write register 01: %s\n", __func__,
+	   sane_strstatus (status));
+      return status;
+    }
+  sanei_genesys_sleep_ms(100);
+
+  loop = 10;
+  while (loop > 0)
+    {
+      status = sanei_genesys_get_status (dev, &val);
+      if (DBG_LEVEL >= DBG_io)
+	{
+	  sanei_genesys_print_status (val);
+	}
+      status = sanei_genesys_read_register (dev, REG100, &val40);
+      if (status != SANE_STATUS_GOOD)
+	{
+	  DBG (DBG_error,
+	       "%s: failed to read home sensor: %s\n", __func__,
+	       sane_strstatus (status));
+	  DBGCOMPLETED;
+	  return status;
+	}
+
+      /* if scanner is in command mode, we are done */
+      if (!(val40 & REG100_DATAENB) && !(val40 & REG100_MOTMFLG)
+	  && !(val & MOTORENB))
+	{
+	  DBGCOMPLETED;
+	  return SANE_STATUS_GOOD;
+	}
+
+      sanei_genesys_sleep_ms(100);
+      loop--;
+    }
+
+  DBGCOMPLETED;
+  return SANE_STATUS_IO_ERROR;
+}
+
+
+/** @brief setup GPIOs for scan
+ * Setup GPIO values to drive motor (or light) needed for the
+ * target resolution
+ * @param *dev device to set up
+ * @param resolution dpi of the target scan
+ * @return SANE_STATUS_GOOD unless REG32 cannot be read
+ */
+static SANE_Status
+gl124_setup_scan_gpio(Genesys_Device *dev, int resolution)
+{
+SANE_Status status = SANE_STATUS_GOOD;
+uint8_t val;
+
+  DBGSTART;
+  RIE (sanei_genesys_read_register (dev, REG32, &val));
+
+  /* LiDE 110, 210 and 220 cases */
+  if(dev->model->gpo_type != GPO_CANONLIDE120)
+    {
+      if(resolution>=dev->motor.base_ydpi/2)
+	{
+	  val &= 0xf7;
+	}
+      else if(resolution>=dev->motor.base_ydpi/4)
+	{
+	  val &= 0xef;
+	}
+      else
+	{
+	  val |= 0x10;
+	}
+    }
+  /* 120 : <=300 => 0x53 */
+  else
+    { /* base_ydpi is 4800 */
+      if(resolution<=300)
+	{
+	  val &= 0xf7;
+	}
+      else if(resolution<=600)
+	{
+	  val |= 0x08;
+	}
+      else if(resolution<=1200)
+	{
+	  val &= 0xef;
+	  val |= 0x08;
+	}
+      else
+	{
+	  val &= 0xf7;
+	}
+    }
+  val |= 0x02;
+  RIE (sanei_genesys_write_register (dev, REG32, val));
+  DBGCOMPLETED;
+  return SANE_STATUS_GOOD;
+}
+
+/* Send the low-level scan command */
+/* todo : is this that useful ? */
+static SANE_Status
+gl124_begin_scan (Genesys_Device * dev, const Genesys_Sensor& sensor, Genesys_Register_Set * reg,
+		  SANE_Bool start_motor)
+{
+    (void) sensor;
+
+  SANE_Status status = SANE_STATUS_GOOD;
+  uint8_t val;
+
+  DBGSTART;
+  if (reg == NULL)
+    return SANE_STATUS_INVAL;
+
+  /* set up GPIO for scan */
+  RIE(gl124_setup_scan_gpio(dev,dev->settings.yres));
+
+  /* clear scan and feed count */
+  RIE (sanei_genesys_write_register (dev, REG0D, REG0D_CLRLNCNT | REG0D_CLRMCNT));
+
+  /* enable scan and motor */
+  RIE (sanei_genesys_read_register (dev, REG01, &val));
+  val |= REG01_SCAN;
+  RIE (sanei_genesys_write_register (dev, REG01, val));
+
+  if (start_motor)
+    {
+      RIE (sanei_genesys_write_register (dev, REG0F, 1));
+    }
+  else
+    {
+      RIE (sanei_genesys_write_register (dev, REG0F, 0));
+    }
+
+  DBGCOMPLETED;
+  return status;
+}
+
+
+/* Send the stop scan command */
+static SANE_Status
+gl124_end_scan (Genesys_Device * dev, Genesys_Register_Set * reg,
+		SANE_Bool check_stop)
+{
+  SANE_Status status = SANE_STATUS_GOOD;
+
+  DBG(DBG_proc, "%s (check_stop = %d)\n", __func__, check_stop);
+  if (reg == NULL)
+    return SANE_STATUS_INVAL;
+
+  if (dev->model->is_sheetfed == SANE_TRUE)
+    {
+      status = SANE_STATUS_GOOD;
+    }
+  else                                /* flat bed scanners */
+    {
+      status = gl124_stop_action (dev);
+      if (status != SANE_STATUS_GOOD)
+	{
+          DBG(DBG_error, "%s: failed to stop: %s\n", __func__, sane_strstatus(status));
+	  return status;
+	}
+    }
+
+  DBGCOMPLETED;
+  return status;
+}
+
+
+/** rewind scan
+ * Move back by the same amount of distance than previous scan.
+ * @param dev device to rewind
+ * @returns SANE_STATUS_GOOD on success
+ */
+static
+SANE_Status gl124_rewind(Genesys_Device * dev)
+{
+  SANE_Status status = SANE_STATUS_GOOD;
+  uint8_t byte;
+
+  DBGSTART;
+
+  /* set motor reverse */
+  RIE (sanei_genesys_read_register (dev, 0x02, &byte));
+  byte |= 0x04;
+  RIE (sanei_genesys_write_register(dev, 0x02, byte));
+
+  const auto& sensor = sanei_genesys_find_sensor_any(dev);
+
+  /* and start scan, then wait completion */
+  RIE (gl124_begin_scan (dev, sensor, &dev->reg, SANE_TRUE));
+  do
+    {
+      sanei_genesys_sleep_ms(100);
+      RIE (sanei_genesys_read_register (dev, REG100, &byte));
+    }
+  while(byte & REG100_MOTMFLG);
+  RIE (gl124_end_scan (dev, &dev->reg, SANE_TRUE));
+
+  /* restore direction */
+  RIE (sanei_genesys_read_register (dev, 0x02, &byte));
+  byte &= 0xfb;
+  RIE (sanei_genesys_write_register(dev, 0x02, byte));
+  DBGCOMPLETED;
+  return SANE_STATUS_GOOD;
+}
+
+
+/** Park head
+ * Moves the slider to the home (top) position slowly
+ * @param dev device to park
+ * @param wait_until_home true to make the function waiting for head
+ * to be home before returning, if fals returne immediately
+ * @returns SANE_STATUS_GOO on success */
+static
+SANE_Status
+gl124_slow_back_home (Genesys_Device * dev, SANE_Bool wait_until_home)
+{
+  Genesys_Register_Set local_reg;
+  SANE_Status status = SANE_STATUS_GOOD;
+  GenesysRegister *r;
+  uint8_t val;
+  float resolution;
+  int loop = 0;
+
+  DBG(DBG_proc, "%s (wait_until_home = %d)\n", __func__, wait_until_home);
+
+  /* post scan gpio : without that HOMSNR is unreliable */
+  gl124_homsnr_gpio(dev);
+
+  /* first read gives HOME_SENSOR true */
+  status = sanei_genesys_get_status (dev, &val);
+  if (status != SANE_STATUS_GOOD)
+    {
+      DBG(DBG_error, "%s: failed to read home sensor: %s\n", __func__, sane_strstatus(status));
+      return status;
+    }
+  if (DBG_LEVEL >= DBG_io)
+    {
+      sanei_genesys_print_status (val);
+    }
+  sanei_genesys_sleep_ms(100);
+
+  /* second is reliable */
+  status = sanei_genesys_get_status (dev, &val);
+  if (status != SANE_STATUS_GOOD)
+    {
+      DBG(DBG_error, "%s: failed to read home sensor: %s\n", __func__, sane_strstatus(status));
+      return status;
+    }
+  if (DBG_LEVEL >= DBG_io)
+    {
+      sanei_genesys_print_status (val);
+    }
+
+  /* is sensor at home? */
+  if (val & HOMESNR)
+    {
+      DBG (DBG_info, "%s: already at home, completed\n", __func__);
+      dev->scanhead_position_in_steps = 0;
+      DBGCOMPLETED;
+      return SANE_STATUS_GOOD;
+    }
+
+  /* feed a little first */
+  if (dev->model->model_id == MODEL_CANON_LIDE_210)
+    {
+      status = gl124_feed (dev, 20, SANE_TRUE);
+      if (status != SANE_STATUS_GOOD)
+        {
+          DBG(DBG_error, "%s: failed to do initial feed: %s\n", __func__, sane_strstatus(status));
+          return status;
+        }
+    }
+
+  local_reg = dev->reg;
+  resolution=sanei_genesys_get_lowest_dpi(dev);
+
+  const auto& sensor = sanei_genesys_find_sensor_any(dev);
+
+    SetupParams params;
+    params.xres = resolution;
+    params.yres = resolution;
+    params.startx = 100;
+    params.starty = 30000;
+    params.pixels = 100;
+    params.lines = 100;
+    params.depth = 8;
+    params.channels = 1;
+    params.scan_method = dev->settings.scan_method;
+    params.scan_mode = ScanColorMode::GRAY;
+    params.color_filter = ColorFilter::RED;
+    params.flags = SCAN_FLAG_DISABLE_SHADING |
+                   SCAN_FLAG_DISABLE_GAMMA |
+                   SCAN_FLAG_IGNORE_LINE_DISTANCE;
+
+    status = gl124_init_scan_regs(dev, sensor, &local_reg, params);
+
+  if (status != SANE_STATUS_GOOD)
+    {
+      DBG(DBG_error, "%s: failed to set up registers: %s\n", __func__, sane_strstatus(status));
+      DBGCOMPLETED;
+      return status;
+    }
+
+  /* clear scan and feed count */
+  RIE (sanei_genesys_write_register (dev, REG0D, REG0D_CLRLNCNT | REG0D_CLRMCNT));
+
+  /* set up for reverse and no scan */
+  r = sanei_genesys_get_address(&local_reg, REG02);
+  r->value |= REG02_MTRREV;
+
+  RIE (dev->model->cmd_set->bulk_write_register(dev, local_reg));
+
+  RIE(gl124_setup_scan_gpio(dev,resolution));
+
+    try {
+        status = gl124_start_action (dev);
+    } catch (...) {
+        DBG(DBG_error, "%s: failed to start motor: %s\n", __func__, sane_strstatus(status));
+        try {
+            gl124_stop_action (dev);
+        } catch (...) {}
+        try {
+            // restore original registers
+            dev->model->cmd_set->bulk_write_register(dev, dev->reg);
+        } catch (...) {}
+        throw;
+    }
+    if (status != SANE_STATUS_GOOD) {
+        DBG(DBG_error, "%s: failed to start motor: %s\n", __func__, sane_strstatus(status));
+        try {
+            gl124_stop_action (dev);
+        } catch (...) {}
+        /* restore original registers */
+        dev->model->cmd_set->bulk_write_register(dev, dev->reg);
+        return status;
+    }
+
+  /* post scan gpio : without that HOMSNR is unreliable */
+  gl124_homsnr_gpio(dev);
+
+  if (wait_until_home)
+    {
+
+      while (loop < 300)        /* do not wait longer then 30 seconds */
+	{
+	  status = sanei_genesys_get_status (dev, &val);
+	  if (status != SANE_STATUS_GOOD)
+	    {
+	      DBG(DBG_error, "%s: failed to read home sensor: %s\n", __func__,
+		  sane_strstatus(status));
+	      return status;
+	    }
+
+	  if (val & HOMESNR)        /* home sensor */
+	    {
+	      DBG(DBG_info, "%s: reached home position\n", __func__);
+	      DBGCOMPLETED;
+              dev->scanhead_position_in_steps = 0;
+	      return SANE_STATUS_GOOD;
+	    }
+          sanei_genesys_sleep_ms(100);
+	  ++loop;
+	}
+
+      /* when we come here then the scanner needed too much time for this, so we better stop the motor */
+      gl124_stop_action (dev);
+      DBG(DBG_error, "%s: timeout while waiting for scanhead to go home\n", __func__);
+      return SANE_STATUS_IO_ERROR;
+    }
+
+  DBG(DBG_info, "%s: scanhead is still moving\n", __func__);
+  DBGCOMPLETED;
+  return SANE_STATUS_GOOD;
+}
+
+/** @brief moves the slider to steps at motor base dpi
+ * @param dev device to work on
+ * @param steps number of steps to move
+ * @param reverse true is moving backward
+ * */
+static SANE_Status
+gl124_feed (Genesys_Device * dev, unsigned int steps, int reverse)
+{
+  Genesys_Register_Set local_reg;
+  SANE_Status status = SANE_STATUS_GOOD;
+  GenesysRegister *r;
+  float resolution;
+  uint8_t val;
+
+  DBGSTART;
+  DBG (DBG_io, "%s: steps=%d\n", __func__, steps);
+
+  /* prepare local registers */
+  local_reg = dev->reg;
+
+  resolution=sanei_genesys_get_lowest_ydpi(dev);
+  const auto& sensor = sanei_genesys_find_sensor(dev, resolution);
+
+    SetupParams params;
+    params.xres = resolution;
+    params.yres = resolution;
+    params.startx = 0;
+    params.starty = steps;
+    params.pixels = 100;
+    params.lines = 3;
+    params.depth = 8;
+    params.channels = 3;
+    params.scan_method = dev->settings.scan_method;
+    params.scan_mode = ScanColorMode::COLOR_SINGLE_PASS;
+    params.color_filter = dev->settings.color_filter;
+    params.flags = SCAN_FLAG_DISABLE_SHADING |
+                   SCAN_FLAG_DISABLE_GAMMA |
+                   SCAN_FLAG_FEEDING |
+                   SCAN_FLAG_DISABLE_BUFFER_FULL_MOVE |
+                   SCAN_FLAG_IGNORE_LINE_DISTANCE;
+
+    status = gl124_init_scan_regs(dev, sensor, &local_reg, params);
+
+  if (status != SANE_STATUS_GOOD)
+    {
+      DBG (DBG_error, "%s: failed to set up registers: %s\n", __func__, sane_strstatus (status));
+      DBGCOMPLETED;
+      return status;
+    }
+
+  /* set exposure to zero */
+  sanei_genesys_set_triple(&local_reg,REG_EXPR,0);
+  sanei_genesys_set_triple(&local_reg,REG_EXPG,0);
+  sanei_genesys_set_triple(&local_reg,REG_EXPB,0);
+
+  /* clear scan and feed count */
+  RIE (sanei_genesys_write_register (dev, REG0D, REG0D_CLRLNCNT));
+  RIE (sanei_genesys_write_register (dev, REG0D, REG0D_CLRMCNT));
+
+  /* set up for no scan */
+  r = sanei_genesys_get_address (&local_reg, REG01);
+  r->value &= ~REG01_SCAN;
+
+  /* set up for reverse if needed */
+  if(reverse)
+    {
+      r = sanei_genesys_get_address (&local_reg, REG02);
+      r->value |= REG02_MTRREV;
+    }
+
+  /* send registers */
+  RIE (dev->model->cmd_set->bulk_write_register(dev, local_reg));
+
+  status = gl124_start_action (dev);
+  if (status != SANE_STATUS_GOOD)
+    {
+      DBG (DBG_error, "%s: failed to start motor: %s\n", __func__, sane_strstatus (status));
+      gl124_stop_action (dev);
+
+      /* restore original registers */
+      dev->model->cmd_set->bulk_write_register(dev, dev->reg);
+      return status;
+    }
+
+  /* wait until feed count reaches the required value, but do not
+   * exceed 30s */
+  do
+    {
+          status = sanei_genesys_get_status (dev, &val);
+    }
+  while (status == SANE_STATUS_GOOD && !(val & FEEDFSH));
+
+  /* then stop scanning */
+  RIE(gl124_stop_action (dev));
+
+  DBGCOMPLETED;
+  return SANE_STATUS_GOOD;
+}
+
+
+/* Automatically set top-left edge of the scan area by scanning a 200x200 pixels
+   area at 600 dpi from very top of scanner */
+static SANE_Status
+gl124_search_start_position (Genesys_Device * dev)
+{
+  int size;
+  SANE_Status status = SANE_STATUS_GOOD;
+  Genesys_Register_Set local_reg = dev->reg;
+  int steps;
+
+  int pixels = 600;
+  int dpi = 300;
+
+  DBGSTART;
+
+  /* sets for a 200 lines * 600 pixels */
+  /* normal scan with no shading */
+
+  // FIXME: the current approach of doing search only for one resolution does not work on scanners
+  // whith employ different sensors with potentially different settings.
+  auto& sensor = sanei_genesys_find_sensor_for_write(dev, dpi);
+
+    SetupParams params;
+    params.xres = dpi;
+    params.yres = dpi;
+    params.startx = 0;
+    params.starty = 0;        /*we should give a small offset here~60 steps */
+    params.pixels = 600;
+    params.lines = dev->model->search_lines;
+    params.depth = 8;
+    params.channels = 1;
+    params.scan_method = dev->settings.scan_method;
+    params.scan_mode = ScanColorMode::GRAY;
+    params.color_filter = ColorFilter::GREEN;
+    params.flags = SCAN_FLAG_DISABLE_SHADING |
+                   SCAN_FLAG_DISABLE_GAMMA |
+                   SCAN_FLAG_IGNORE_LINE_DISTANCE |
+                   SCAN_FLAG_DISABLE_BUFFER_FULL_MOVE;
+
+    status = gl124_init_scan_regs(dev, sensor, &local_reg, params);
+
+  if (status!=SANE_STATUS_GOOD)
+    {
+      DBG(DBG_error, "%s: failed to init scan registers: %s\n", __func__, sane_strstatus(status));
+      return status;
+    }
+
+  /* send to scanner */
+  status = dev->model->cmd_set->bulk_write_register(dev, local_reg);
+  if (status != SANE_STATUS_GOOD)
+    {
+      DBG(DBG_error, "%s: failed to bulk write registers: %s\n", __func__, sane_strstatus(status));
+      return status;
+    }
+
+  size = pixels * dev->model->search_lines;
+
+  std::vector<uint8_t> data(size);
+
+  status = gl124_begin_scan (dev, sensor, &local_reg, SANE_TRUE);
+  if (status != SANE_STATUS_GOOD)
+    {
+      DBG(DBG_error, "%s: failed to begin scan: %s\n", __func__, sane_strstatus(status));
+      return status;
+    }
+
+  /* waits for valid data */
+  do
+    sanei_genesys_test_buffer_empty (dev, &steps);
+  while (steps);
+
+  /* now we're on target, we can read data */
+  status = sanei_genesys_read_data_from_scanner (dev, data.data(), size);
+  if (status != SANE_STATUS_GOOD)
+    {
+      DBG(DBG_error, "%s: failed to read data: %s\n", __func__, sane_strstatus(status));
+      return status;
+    }
+
+  if (DBG_LEVEL >= DBG_data)
+    sanei_genesys_write_pnm_file("gl124_search_position.pnm", data.data(), 8, 1, pixels,
+                                 dev->model->search_lines);
+
+  status = gl124_end_scan (dev, &local_reg, SANE_TRUE);
+  if (status != SANE_STATUS_GOOD)
+    {
+      DBG(DBG_error, "%s: failed to end scan: %s\n", __func__, sane_strstatus(status));
+      return status;
+    }
+
+  /* update regs to copy ASIC internal state */
+  dev->reg = local_reg;
+
+  status =
+    sanei_genesys_search_reference_point (dev, sensor, data.data(), 0, dpi, pixels,
+					  dev->model->search_lines);
+  if (status != SANE_STATUS_GOOD)
+    {
+      DBG(DBG_error, "%s: failed to set search reference point: %s\n", __func__,
+          sane_strstatus(status));
+      return status;
+    }
+
+  DBGCOMPLETED;
+  return SANE_STATUS_GOOD;
+}
+
+/*
+ * sets up register for coarse gain calibration
+ * todo: check it for scanners using it */
+static SANE_Status
+gl124_init_regs_for_coarse_calibration(Genesys_Device* dev, const Genesys_Sensor& sensor,
+                                       Genesys_Register_Set& regs)
+{
+  SANE_Status status = SANE_STATUS_GOOD;
+  uint8_t channels;
+  uint8_t cksel;
+
+  DBGSTART;
+  cksel = (regs.find_reg(0x18).value & REG18_CKSEL) + 1;        /* clock speed = 1..4 clocks */
+
+  /* set line size */
+    if (dev->settings.scan_mode == ScanColorMode::COLOR_SINGLE_PASS) {
+        channels = 3;
+    } else {
+        channels = 1;
+    }
+
+    SetupParams params;
+    params.xres = dev->settings.xres;
+    params.yres = dev->settings.yres;
+    params.startx = 0;
+    params.starty = 0;
+    params.pixels = sensor.optical_res / cksel;
+    params.lines = 20;
+    params.depth = 16;
+    params.channels = channels;
+    params.scan_method = dev->settings.scan_method;
+    params.scan_mode = dev->settings.scan_mode;
+    params.color_filter = dev->settings.color_filter;
+    params.flags = SCAN_FLAG_DISABLE_SHADING |
+                   SCAN_FLAG_DISABLE_GAMMA |
+                   SCAN_FLAG_SINGLE_LINE |
+                   SCAN_FLAG_FEEDING |
+                   SCAN_FLAG_IGNORE_LINE_DISTANCE;
+
+    status = gl124_init_scan_regs(dev, sensor, &regs, params);
+
+  if (status != SANE_STATUS_GOOD)
+    {
+      DBG(DBG_error, "%s: failed to setup scan: %s\n", __func__, sane_strstatus(status));
+      return status;
+    }
+  sanei_genesys_set_motor_power(regs, false);
+
+  DBG(DBG_info, "%s: optical sensor res: %d dpi, actual res: %d\n", __func__,
+      sensor.optical_res / cksel, dev->settings.xres);
+
+  status = dev->model->cmd_set->bulk_write_register(dev, regs);
+  if (status != SANE_STATUS_GOOD)
+    {
+      DBG(DBG_error, "%s: failed to bulk write registers: %s\n", __func__, sane_strstatus(status));
+      return status;
+    }
+
+  DBGCOMPLETED;
+  return SANE_STATUS_GOOD;
+}
+
+
+/* init registers for shading calibration */
+/* shading calibration is done at dpihw */
+static SANE_Status
+gl124_init_regs_for_shading(Genesys_Device * dev, const Genesys_Sensor& sensor,
+                            Genesys_Register_Set& regs)
+{
+  SANE_Status status = SANE_STATUS_GOOD;
+  int move, resolution, dpihw, factor;
+
+  DBGSTART;
+
+  /* initial calibration reg values */
+  regs = dev->reg;
+
+  dev->calib_channels = 3;
+  dev->calib_lines = dev->model->shading_lines;
+  dpihw=sanei_genesys_compute_dpihw(dev, sensor, dev->settings.xres);
+  if(dpihw>=2400)
+    {
+      dev->calib_lines *= 2;
+    }
+  resolution=dpihw;
+
+  /* if half CCD mode, use half resolution */
+  if(compute_half_ccd(sensor, dev->settings.xres)==SANE_TRUE)
+    {
+      resolution /= 2;
+      dev->calib_lines /= 2;
+    }
+  dev->calib_resolution = resolution;
+  dev->calib_total_bytes_to_read = 0;
+  factor=sensor.optical_res/resolution;
+  dev->calib_pixels = sensor.sensor_pixels/factor;
+
+  /* distance to move to reach white target at high resolution */
+  move=0;
+  if(dev->settings.yres>=1200)
+    {
+      move = SANE_UNFIX (dev->model->y_offset_calib);
+      move = (move * (dev->motor.base_ydpi/4)) / MM_PER_INCH;
+    }
+  DBG (DBG_io, "%s: move=%d steps\n", __func__, move);
+
+    SetupParams params;
+    params.xres = resolution;
+    params.yres = resolution;
+    params.startx = 0;
+    params.starty = move;
+    params.pixels = dev->calib_pixels;
+    params.lines = dev->calib_lines;
+    params.depth = 16;
+    params.channels = dev->calib_channels;
+    params.scan_method = dev->settings.scan_method;
+    params.scan_mode = ScanColorMode::COLOR_SINGLE_PASS;
+    params.color_filter = ColorFilter::RED;
+    params.flags = SCAN_FLAG_DISABLE_SHADING |
+                   SCAN_FLAG_DISABLE_GAMMA |
+                   SCAN_FLAG_DISABLE_BUFFER_FULL_MOVE |
+                   SCAN_FLAG_IGNORE_LINE_DISTANCE;
+
+    status = gl124_init_scan_regs(dev, sensor, &regs, params);
+
+    sanei_genesys_set_motor_power(regs, false);
+
+  if (status != SANE_STATUS_GOOD)
+    {
+      DBG (DBG_error, "%s: failed to setup scan: %s\n", __func__,
+	   sane_strstatus (status));
+      return status;
+    }
+
+  dev->scanhead_position_in_steps += dev->calib_lines + move;
+
+  status = dev->model->cmd_set->bulk_write_register(dev, regs);
+  if (status != SANE_STATUS_GOOD)
+    {
+      DBG (DBG_error,
+	   "%s: failed to bulk write registers: %s\n", __func__,
+	   sane_strstatus (status));
+      return status;
+    }
+
+  DBGCOMPLETED;
+  return SANE_STATUS_GOOD;
+}
+
+static void gl124_wait_for_motor_stop(Genesys_Device* dev)
+{
+    DBG_HELPER(dbg);
+    uint8_t val40, val;
+
+    TIE(sanei_genesys_get_status(dev, &val));
+    TIE(sanei_genesys_read_register(dev, REG100, &val40));
+
+    if ((val & MOTORENB) == 0 && (val40 & REG100_MOTMFLG) == 0)
+        return;
+
+    do {
+        sanei_genesys_sleep_ms(10);
+        TIE(sanei_genesys_get_status(dev, &val));
+        TIE(sanei_genesys_read_register(dev, REG100, &val40));
+    } while ((val & MOTORENB) ||(val40 & REG100_MOTMFLG));
+    sanei_genesys_sleep_ms(50);
+}
+
+/** @brief set up registers for the actual scan
+ */
+static SANE_Status
+gl124_init_regs_for_scan (Genesys_Device * dev, const Genesys_Sensor& sensor)
+{
+  int channels;
+  int flags;
+  int depth;
+  float move;
+  int move_dpi;
+  float start;
+
+  SANE_Status status = SANE_STATUS_GOOD;
+
+    DBG(DBG_info, "%s ", __func__);
+    debug_dump(DBG_info, dev->settings);
+
+  /* channels */
+  if (dev->settings.scan_mode == ScanColorMode::COLOR_SINGLE_PASS)
+    channels = 3;
+  else
+    channels = 1;
+
+  /* depth */
+  depth = dev->settings.depth;
+  if (dev->settings.scan_mode == ScanColorMode::LINEART)
+    depth = 1;
+
+  /* y (motor) distance to move to reach scanned area */
+  move_dpi = dev->motor.base_ydpi/4;
+  move = SANE_UNFIX (dev->model->y_offset);
+  move += dev->settings.tl_y;
+  move = (move * move_dpi) / MM_PER_INCH;
+  DBG (DBG_info, "%s: move=%f steps\n", __func__, move);
+
+  if(channels*dev->settings.yres>=600 && move>700)
+    {
+      status = gl124_feed (dev, move-500, SANE_FALSE);
+      if (status != SANE_STATUS_GOOD)
+        {
+          DBG (DBG_error, "%s: failed to move to scan area\n",__func__);
+          return status;
+        }
+      move=500;
+    }
+  DBG(DBG_info, "%s: move=%f steps\n", __func__, move);
+
+  /* start */
+  start = SANE_UNFIX (dev->model->x_offset);
+  start += dev->settings.tl_x;
+  if(compute_half_ccd(sensor, dev->settings.xres)==SANE_TRUE)
+    {
+      start /=2;
+    }
+  start = (start * sensor.optical_res) / MM_PER_INCH;
+
+  flags = 0;
+
+  /* enable emulated lineart from gray data */
+  if(dev->settings.scan_mode == ScanColorMode::LINEART
+     && dev->settings.dynamic_lineart)
+    {
+      flags |= SCAN_FLAG_DYNAMIC_LINEART;
+    }
+
+    SetupParams params;
+    params.xres = dev->settings.xres;
+    params.yres = dev->settings.yres;
+    params.startx = start;
+    params.starty = move;
+    params.pixels = dev->settings.pixels;
+    params.lines = dev->settings.lines;
+    params.depth = depth;
+    params.channels = channels;
+    params.scan_method = dev->settings.scan_method;
+    params.scan_mode = dev->settings.scan_mode;
+    params.color_filter = dev->settings.color_filter;
+    params.flags = flags;
+
+    status = gl124_init_scan_regs(dev, sensor, &dev->reg, params);
+
+  if (status != SANE_STATUS_GOOD)
+    return status;
+
+  DBGCOMPLETED;
+  return SANE_STATUS_GOOD;
+}
+
+/**
+ * Send shading calibration data. The buffer is considered to always hold values
+ * for all the channels.
+ */
+static SANE_Status
+gl124_send_shading_data (Genesys_Device * dev, const Genesys_Sensor& sensor,
+                         uint8_t * data, int size)
+{
+  SANE_Status status = SANE_STATUS_GOOD;
+  uint32_t addr, length, strpixel ,endpixel, x, factor, segcnt, pixels, i;
+  uint32_t lines, channels;
+  uint16_t dpiset,dpihw;
+  uint8_t val,*ptr,*src;
+
+  DBGSTART;
+  DBG( DBG_io2, "%s: writing %d bytes of shading data\n",__func__,size);
+
+  /* logical size of a color as seen by generic code of the frontend */
+  length = (uint32_t) (size / 3);
+  sanei_genesys_get_triple(&dev->reg,REG_STRPIXEL,&strpixel);
+  sanei_genesys_get_triple(&dev->reg,REG_ENDPIXEL,&endpixel);
+  sanei_genesys_get_triple(&dev->reg,REG_SEGCNT,&segcnt);
+  if(endpixel==0)
+    {
+      endpixel=segcnt;
+    }
+  DBG( DBG_io2, "%s: STRPIXEL=%d, ENDPIXEL=%d, PIXELS=%d, SEGCNT=%d\n",__func__,strpixel,endpixel,endpixel-strpixel,segcnt);
+
+  /* compute deletion factor */
+  sanei_genesys_get_double(&dev->reg,REG_DPISET,&dpiset);
+  dpihw=sanei_genesys_compute_dpihw(dev, sensor, dpiset);
+  factor=dpihw/dpiset;
+  DBG( DBG_io2, "%s: factor=%d\n",__func__,factor);
+
+  /* binary data logging */
+  if(DBG_LEVEL>=DBG_data)
+    {
+      dev->binary=fopen("binary.pnm","wb");
+      sanei_genesys_get_triple(&dev->reg, REG_LINCNT, &lines);
+      channels=dev->current_setup.channels;
+      if(dev->binary!=NULL)
+        {
+          fprintf(dev->binary,"P5\n%d %d\n%d\n",(endpixel-strpixel)/factor*channels*dev->segnb,lines/channels,255);
+        }
+    }
+
+  /* turn pixel value into bytes 2x16 bits words */
+  strpixel*=2*2; /* 2 words of 2 bytes */
+  endpixel*=2*2;
+  segcnt*=2*2;
+  pixels=endpixel-strpixel;
+
+  DBG( DBG_io2, "%s: using chunks of %d bytes (%d shading data pixels)\n",__func__,length, length/4);
+  std::vector<uint8_t> buffer(pixels * dev->segnb, 0);
+
+  /* write actual red data */
+  for(i=0;i<3;i++)
+    {
+      /* copy data to work buffer and process it */
+          /* coefficent destination */
+      ptr = buffer.data();
+
+      /* iterate on both sensor segment */
+      for(x=0;x<pixels;x+=4*factor)
+        {
+          /* coefficient source */
+          src=data+x+strpixel+i*length;
+
+          /* iterate over all the segments */
+          switch(dev->segnb)
+            {
+            case 1:
+              ptr[0+pixels*0]=src[0+segcnt*0];
+              ptr[1+pixels*0]=src[1+segcnt*0];
+              ptr[2+pixels*0]=src[2+segcnt*0];
+              ptr[3+pixels*0]=src[3+segcnt*0];
+              break;
+            case 2:
+              ptr[0+pixels*0]=src[0+segcnt*0];
+              ptr[1+pixels*0]=src[1+segcnt*0];
+              ptr[2+pixels*0]=src[2+segcnt*0];
+              ptr[3+pixels*0]=src[3+segcnt*0];
+              ptr[0+pixels*1]=src[0+segcnt*1];
+              ptr[1+pixels*1]=src[1+segcnt*1];
+              ptr[2+pixels*1]=src[2+segcnt*1];
+              ptr[3+pixels*1]=src[3+segcnt*1];
+              break;
+            case 4:
+              ptr[0+pixels*0]=src[0+segcnt*0];
+              ptr[1+pixels*0]=src[1+segcnt*0];
+              ptr[2+pixels*0]=src[2+segcnt*0];
+              ptr[3+pixels*0]=src[3+segcnt*0];
+              ptr[0+pixels*1]=src[0+segcnt*2];
+              ptr[1+pixels*1]=src[1+segcnt*2];
+              ptr[2+pixels*1]=src[2+segcnt*2];
+              ptr[3+pixels*1]=src[3+segcnt*2];
+              ptr[0+pixels*2]=src[0+segcnt*1];
+              ptr[1+pixels*2]=src[1+segcnt*1];
+              ptr[2+pixels*2]=src[2+segcnt*1];
+              ptr[3+pixels*2]=src[3+segcnt*1];
+              ptr[0+pixels*3]=src[0+segcnt*3];
+              ptr[1+pixels*3]=src[1+segcnt*3];
+              ptr[2+pixels*3]=src[2+segcnt*3];
+              ptr[3+pixels*3]=src[3+segcnt*3];
+              break;
+            }
+
+          /* next shading coefficient */
+          ptr+=4;
+        }
+      RIE (sanei_genesys_read_register (dev, 0xd0+i, &val));
+      addr = val * 8192 + 0x10000000;
+      status = sanei_genesys_write_ahb(dev, addr, pixels*dev->segnb, buffer.data());
+      if (status != SANE_STATUS_GOOD)
+        {
+          DBG(DBG_error, "%s; write to AHB failed (%s)\n", __func__, sane_strstatus(status));
+          return status;
+        }
+    }
+
+  DBGCOMPLETED;
+
+  return status;
+}
+
+
+/** @brief move to calibration area
+ * This functions moves scanning head to calibration area
+ * by doing a 600 dpi scan
+ * @param dev scanner device
+ * @return SANE_STATUS_GOOD on success, else the error code
+ */
+static SANE_Status
+move_to_calibration_area (Genesys_Device * dev, const Genesys_Sensor& sensor,
+                          Genesys_Register_Set& regs)
+{
+  int pixels;
+  int size;
+  SANE_Status status = SANE_STATUS_GOOD;
+
+  DBGSTART;
+
+  pixels = (sensor.sensor_pixels*600)/sensor.optical_res;
+
+  /* initial calibration reg values */
+  regs = dev->reg;
+
+    SetupParams params;
+    params.xres = 600;
+    params.yres = 600;
+    params.startx = 0;
+    params.starty = 0;
+    params.pixels = pixels;
+    params.lines = 1;
+    params.depth = 8;
+    params.channels = 3;
+    params.scan_method = dev->settings.scan_method;
+    params.scan_mode = ScanColorMode::COLOR_SINGLE_PASS;
+    params.color_filter = dev->settings.color_filter;
+    params.flags = SCAN_FLAG_DISABLE_SHADING |
+                   SCAN_FLAG_DISABLE_GAMMA |
+                   SCAN_FLAG_SINGLE_LINE |
+                   SCAN_FLAG_IGNORE_LINE_DISTANCE;
+
+    status = gl124_init_scan_regs(dev, sensor, &regs, params);
+
+  if (status != SANE_STATUS_GOOD)
+    {
+      DBG (DBG_error, "%s: failed to setup scan: %s\n", __func__, sane_strstatus (status));
+      return status;
+    }
+
+  size = pixels * 3;
+  std::vector<uint8_t> line(size);
+
+  /* write registers and scan data */
+  RIE(dev->model->cmd_set->bulk_write_register(dev, regs));
+
+  DBG (DBG_info, "%s: starting line reading\n", __func__);
+  RIE(gl124_begin_scan (dev, sensor, &regs, SANE_TRUE));
+  RIE(sanei_genesys_read_data_from_scanner(dev, line.data(), size));
+
+  /* stop scanning */
+  RIE(gl124_stop_action (dev));
+
+  if (DBG_LEVEL >= DBG_data)
+    {
+      sanei_genesys_write_pnm_file("gl124_movetocalarea.pnm", line.data(), 8, 3, pixels, 1);
+    }
+
+  DBGCOMPLETED;
+  return status;
+}
+
+/* this function does the led calibration by scanning one line of the calibration
+   area below scanner's top on white strip.
+
+-needs working coarse/gain
+*/
+static SANE_Status
+gl124_led_calibration (Genesys_Device * dev, Genesys_Sensor& sensor, Genesys_Register_Set& regs)
+{
+  int num_pixels;
+  int total_size;
+  int resolution;
+  int dpihw;
+  int i, j;
+  SANE_Status status = SANE_STATUS_GOOD;
+  int val;
+  int channels, depth;
+  int avg[3];
+  int turn;
+  uint16_t exp[3],target;
+  SANE_Bool acceptable;
+  SANE_Bool half_ccd;
+
+  DBGSTART;
+
+  /* move to calibration area */
+  move_to_calibration_area(dev, sensor, regs);
+
+  /* offset calibration is always done in 16 bit depth color mode */
+  channels = 3;
+  depth=16;
+  dpihw=sanei_genesys_compute_dpihw(dev, sensor, dev->settings.xres);
+  half_ccd=compute_half_ccd(sensor, dev->settings.xres);
+  if(half_ccd==SANE_TRUE)
+    {
+      resolution = dpihw/2;
+    }
+  else
+    {
+      resolution = dpihw;
+    }
+  Sensor_Profile* sensor_profile = get_sensor_profile(dev->model->ccd_type, dpihw, half_ccd);
+  num_pixels = (sensor.sensor_pixels*resolution)/sensor.optical_res;
+
+  /* initial calibration reg values */
+  regs = dev->reg;
+
+    SetupParams params;
+    params.xres = resolution;
+    params.yres = resolution;
+    params.startx = 0;
+    params.starty = 0;
+    params.pixels = num_pixels;
+    params.lines = 1;
+    params.depth = depth;
+    params.channels = channels;
+    params.scan_method = dev->settings.scan_method;
+    params.scan_mode = ScanColorMode::COLOR_SINGLE_PASS;
+    params.color_filter = dev->settings.color_filter;
+    params.flags = SCAN_FLAG_DISABLE_SHADING |
+                   SCAN_FLAG_DISABLE_GAMMA |
+                   SCAN_FLAG_SINGLE_LINE |
+                   SCAN_FLAG_IGNORE_LINE_DISTANCE;
+
+    status = gl124_init_scan_regs(dev, sensor, &regs, params);
+
+  if (status != SANE_STATUS_GOOD)
+    {
+      DBG (DBG_error, "%s: failed to setup scan: %s\n", __func__, sane_strstatus (status));
+      return status;
+    }
+
+  total_size = num_pixels * channels * (depth/8) * 1;        /* colors * bytes_per_color * scan lines */
+  std::vector<uint8_t> line(total_size);
+
+  /* initial loop values and boundaries */
+  exp[0]=sensor_profile->expr;
+  exp[1]=sensor_profile->expg;
+  exp[2]=sensor_profile->expb;
+  target=sensor.gain_white_ref*256;
+
+  turn = 0;
+
+  /* no move during led calibration */
+  sanei_genesys_set_motor_power(regs, false);
+  do
+    {
+      /* set up exposure */
+      sanei_genesys_set_triple(&regs,REG_EXPR,exp[0]);
+      sanei_genesys_set_triple(&regs,REG_EXPG,exp[1]);
+      sanei_genesys_set_triple(&regs,REG_EXPB,exp[2]);
+
+      /* write registers and scan data */
+      RIE(dev->model->cmd_set->bulk_write_register(dev, regs));
+
+      DBG(DBG_info, "%s: starting line reading\n", __func__);
+      RIE(gl124_begin_scan (dev, sensor, &regs, SANE_TRUE));
+      RIE(sanei_genesys_read_data_from_scanner (dev, line.data(), total_size));
+
+      /* stop scanning */
+      RIE(gl124_stop_action (dev));
+
+      if (DBG_LEVEL >= DBG_data)
+	{
+          char fn[30];
+          snprintf(fn, 30, "gl124_led_%02d.pnm", turn);
+          sanei_genesys_write_pnm_file(fn, line.data(), depth, channels, num_pixels, 1);
+	}
+
+      /* compute average */
+      for (j = 0; j < channels; j++)
+	{
+	  avg[j] = 0;
+	  for (i = 0; i < num_pixels; i++)
+	    {
+	      if (dev->model->is_cis)
+		val =
+		  line[i * 2 + j * 2 * num_pixels + 1] * 256 +
+		  line[i * 2 + j * 2 * num_pixels];
+	      else
+		val =
+		  line[i * 2 * channels + 2 * j + 1] * 256 +
+		  line[i * 2 * channels + 2 * j];
+	      avg[j] += val;
+	    }
+
+	  avg[j] /= num_pixels;
+	}
+
+      DBG(DBG_info, "%s: average: %d,%d,%d\n", __func__, avg[0], avg[1], avg[2]);
+
+      /* check if exposure gives average within the boundaries */
+      acceptable = SANE_TRUE;
+      for(i=0;i<3;i++)
+        {
+          /* we accept +- 2% delta from target */
+          if(abs(avg[i]-target)>target/50)
+            {
+              exp[i]=(exp[i]*target)/avg[i];
+              acceptable = SANE_FALSE;
+            }
+        }
+
+      turn++;
+    }
+  while (!acceptable && turn < 100);
+
+  DBG(DBG_info, "%s: acceptable exposure: %d,%d,%d\n", __func__, exp[0], exp[1], exp[2]);
+
+  /* set these values as final ones for scan */
+  sanei_genesys_set_triple(&dev->reg,REG_EXPR,exp[0]);
+  sanei_genesys_set_triple(&dev->reg,REG_EXPG,exp[1]);
+  sanei_genesys_set_triple(&dev->reg,REG_EXPB,exp[2]);
+
+  /* store in this struct since it is the one used by cache calibration */
+  sensor.exposure.red = exp[0];
+  sensor.exposure.green = exp[1];
+  sensor.exposure.blue = exp[2];
+
+  DBGCOMPLETED;
+  return status;
+}
+
+/**
+ * average dark pixels of a 8 bits scan
+ */
+static int
+dark_average (uint8_t * data, unsigned int pixels, unsigned int lines,
+	      unsigned int channels, unsigned int black)
+{
+  unsigned int i, j, k, average, count;
+  unsigned int avg[3];
+  uint8_t val;
+
+  /* computes average value on black margin */
+  for (k = 0; k < channels; k++)
+    {
+      avg[k] = 0;
+      count = 0;
+      for (i = 0; i < lines; i++)
+	{
+	  for (j = 0; j < black; j++)
+	    {
+	      val = data[i * channels * pixels + j + k];
+	      avg[k] += val;
+	      count++;
+	    }
+	}
+      if (count)
+	avg[k] /= count;
+      DBG(DBG_info, "%s: avg[%d] = %d\n", __func__, k, avg[k]);
+    }
+  average = 0;
+  for (i = 0; i < channels; i++)
+    average += avg[i];
+  average /= channels;
+  DBG(DBG_info, "%s: average = %d\n", __func__, average);
+  return average;
+}
+
+
+static SANE_Status
+gl124_offset_calibration(Genesys_Device * dev, const Genesys_Sensor& sensor,
+                         Genesys_Register_Set& regs)
+{
+  SANE_Status status = SANE_STATUS_GOOD;
+  uint8_t reg0a;
+  unsigned int channels, bpp;
+  int pass = 0, avg, total_size;
+  int topavg, bottomavg, resolution, lines;
+  int top, bottom, black_pixels, pixels;
+
+  DBGSTART;
+
+  /* no gain nor offset for TI AFE */
+  RIE (sanei_genesys_read_register (dev, REG0A, &reg0a));
+  if(((reg0a & REG0A_SIFSEL)>>REG0AS_SIFSEL)==3)
+    {
+      DBGCOMPLETED;
+      return status;
+    }
+
+  /* offset calibration is always done in color mode */
+  channels = 3;
+  resolution=sensor.optical_res;
+  dev->calib_pixels = sensor.sensor_pixels;
+  lines=1;
+  bpp=8;
+  pixels= (sensor.sensor_pixels*resolution) / sensor.optical_res;
+  black_pixels = (sensor.black_pixels * resolution) / sensor.optical_res;
+  DBG(DBG_io2, "%s: black_pixels=%d\n", __func__, black_pixels);
+
+    SetupParams params;
+    params.xres = resolution;
+    params.yres = resolution;
+    params.startx = 0;
+    params.starty = 0;
+    params.pixels = pixels;
+    params.lines = lines;
+    params.depth = bpp;
+    params.channels = channels;
+    params.scan_method = dev->settings.scan_method;
+    params.scan_mode = ScanColorMode::COLOR_SINGLE_PASS;
+    params.color_filter = dev->settings.color_filter;
+    params.flags = SCAN_FLAG_DISABLE_SHADING |
+                   SCAN_FLAG_DISABLE_GAMMA |
+                   SCAN_FLAG_SINGLE_LINE |
+                   SCAN_FLAG_IGNORE_LINE_DISTANCE;
+
+    status = gl124_init_scan_regs(dev, sensor, &regs, params);
+
+  if (status != SANE_STATUS_GOOD)
+    {
+      DBG(DBG_error, "%s: failed to setup scan: %s\n", __func__, sane_strstatus(status));
+      return status;
+    }
+  sanei_genesys_set_motor_power(regs, false);
+
+  /* allocate memory for scans */
+  total_size = pixels * channels * lines * (bpp/8);        /* colors * bytes_per_color * scan lines */
+
+  std::vector<uint8_t> first_line(total_size);
+  std::vector<uint8_t> second_line(total_size);
+
+  /* init gain */
+  dev->frontend.set_gain(0, 0);
+  dev->frontend.set_gain(1, 0);
+  dev->frontend.set_gain(2, 0);
+
+  /* scan with no move */
+  bottom = 10;
+  dev->frontend.set_offset(0, bottom);
+  dev->frontend.set_offset(1, bottom);
+  dev->frontend.set_offset(2, bottom);
+
+  RIE(gl124_set_fe(dev, sensor, AFE_SET));
+  RIE(dev->model->cmd_set->bulk_write_register(dev, regs));
+  DBG(DBG_info, "%s: starting first line reading\n", __func__);
+  RIE(gl124_begin_scan(dev, sensor, &regs, SANE_TRUE));
+  RIE(sanei_genesys_read_data_from_scanner(dev, first_line.data(), total_size));
+  if (DBG_LEVEL >= DBG_data)
+   {
+      char title[30];
+      snprintf(title, 30, "gl124_offset%03d.pnm", bottom);
+      sanei_genesys_write_pnm_file(title, first_line.data(), bpp, channels, pixels, lines);
+   }
+
+  bottomavg = dark_average(first_line.data(), pixels, lines, channels, black_pixels);
+  DBG(DBG_io2, "%s: bottom avg=%d\n", __func__, bottomavg);
+
+  /* now top value */
+  top = 255;
+  dev->frontend.set_offset(0, top);
+  dev->frontend.set_offset(1, top);
+  dev->frontend.set_offset(2, top);
+  RIE(gl124_set_fe(dev, sensor, AFE_SET));
+  RIE(dev->model->cmd_set->bulk_write_register(dev, regs));
+  DBG(DBG_info, "%s: starting second line reading\n", __func__);
+  RIE(gl124_begin_scan(dev, sensor, &regs, SANE_TRUE));
+  RIE(sanei_genesys_read_data_from_scanner (dev, second_line.data(), total_size));
+
+  topavg = dark_average(second_line.data(), pixels, lines, channels, black_pixels);
+  DBG(DBG_io2, "%s: top avg=%d\n", __func__, topavg);
+
+  /* loop until acceptable level */
+  while ((pass < 32) && (top - bottom > 1))
+    {
+      pass++;
+
+      /* settings for new scan */
+      dev->frontend.set_offset(0, (top + bottom) / 2);
+      dev->frontend.set_offset(1, (top + bottom) / 2);
+      dev->frontend.set_offset(2, (top + bottom) / 2);
+
+      /* scan with no move */
+      RIE(gl124_set_fe(dev, sensor, AFE_SET));
+      RIE(dev->model->cmd_set->bulk_write_register(dev, regs));
+      DBG(DBG_info, "%s: starting second line reading\n", __func__);
+      RIE(gl124_begin_scan(dev, sensor, &regs, SANE_TRUE));
+      RIE(sanei_genesys_read_data_from_scanner(dev, second_line.data(), total_size));
+
+      if (DBG_LEVEL >= DBG_data)
+	{
+          char title[30];
+          snprintf(title, 30, "gl124_offset%03d.pnm", dev->frontend.get_offset(1));
+          sanei_genesys_write_pnm_file(title, second_line.data(), bpp, channels, pixels, lines);
+	}
+
+      avg = dark_average(second_line.data(), pixels, lines, channels, black_pixels);
+      DBG(DBG_info, "%s: avg=%d offset=%d\n", __func__, avg, dev->frontend.get_offset(1));
+
+      /* compute new boundaries */
+      if (topavg == avg)
+	{
+	  topavg = avg;
+          top = dev->frontend.get_offset(1);
+	}
+      else
+	{
+	  bottomavg = avg;
+          bottom = dev->frontend.get_offset(1);
+	}
+    }
+  DBG(DBG_info, "%s: offset=(%d,%d,%d)\n", __func__,
+      dev->frontend.get_offset(0),
+      dev->frontend.get_offset(1),
+      dev->frontend.get_offset(2));
+
+  DBGCOMPLETED;
+  return SANE_STATUS_GOOD;
+}
+
+
+/* alternative coarse gain calibration
+   this on uses the settings from offset_calibration and
+   uses only one scanline
+ */
+/*
+  with offset and coarse calibration we only want to get our input range into
+  a reasonable shape. the fine calibration of the upper and lower bounds will
+  be done with shading.
+ */
+static SANE_Status
+gl124_coarse_gain_calibration(Genesys_Device * dev, const Genesys_Sensor& sensor,
+                              Genesys_Register_Set& regs, int dpi)
+{
+  int pixels;
+  int total_size;
+  uint8_t reg0a;
+  int i, j, channels;
+  SANE_Status status = SANE_STATUS_GOOD;
+  int max[3];
+  float gain[3],coeff;
+  int val, code, lines;
+  int resolution;
+  int bpp;
+
+  DBG(DBG_proc, "%s: dpi = %d\n", __func__, dpi);
+
+  /* no gain nor offset for TI AFE */
+  RIE (sanei_genesys_read_register (dev, REG0A, &reg0a));
+  if(((reg0a & REG0A_SIFSEL)>>REG0AS_SIFSEL)==3)
+    {
+      DBGCOMPLETED;
+      return status;
+    }
+
+  /* coarse gain calibration is always done in color mode */
+  channels = 3;
+
+  /* follow CKSEL */
+  if(dev->settings.xres<sensor.optical_res)
+    {
+      coeff=0.9;
+      /*resolution=sensor.optical_res/2;*/
+      resolution=sensor.optical_res;
+    }
+  else
+    {
+      resolution=sensor.optical_res;
+      coeff=1.0;
+    }
+  lines=10;
+  bpp=8;
+  pixels = (sensor.sensor_pixels * resolution) / sensor.optical_res;
+
+    SetupParams params;
+    params.xres = resolution;
+    params.yres = resolution;
+    params.startx = 0;
+    params.starty = 0;
+    params.pixels = pixels;
+    params.lines = lines;
+    params.depth = bpp;
+    params.channels = channels;
+    params.scan_method = dev->settings.scan_method;
+    params.scan_mode = ScanColorMode::COLOR_SINGLE_PASS;
+    params.color_filter = dev->settings.color_filter;
+    params.flags = SCAN_FLAG_DISABLE_SHADING |
+                   SCAN_FLAG_DISABLE_GAMMA |
+                   SCAN_FLAG_SINGLE_LINE |
+                   SCAN_FLAG_IGNORE_LINE_DISTANCE;
+
+    try {
+        status = gl124_init_scan_regs(dev, sensor, &regs, params);
+    } catch (...) {
+        try {
+            sanei_genesys_set_motor_power(regs, false);
+        } catch (...) {}
+        throw;
+    }
+
+    sanei_genesys_set_motor_power(regs, false);
+
+  if (status != SANE_STATUS_GOOD)
+    {
+      DBG(DBG_error, "%s: failed to setup scan: %s\n", __func__, sane_strstatus(status));
+      return status;
+    }
+
+  RIE (dev->model->cmd_set->bulk_write_register(dev, regs));
+
+  total_size = pixels * channels * (16/bpp) * lines;
+
+  std::vector<uint8_t> line(total_size);
+
+  RIE(gl124_set_fe(dev, sensor, AFE_SET));
+  RIE(gl124_begin_scan(dev, sensor, &regs, SANE_TRUE));
+  RIE(sanei_genesys_read_data_from_scanner(dev, line.data(), total_size));
+
+  if (DBG_LEVEL >= DBG_data)
+    sanei_genesys_write_pnm_file("gl124_gain.pnm", line.data(), bpp, channels, pixels, lines);
+
+  /* average value on each channel */
+  for (j = 0; j < channels; j++)
+    {
+      max[j] = 0;
+      for (i = pixels/4; i < (pixels*3/4); i++)
+	{
+          if(bpp==16)
+            {
+	  if (dev->model->is_cis)
+	    val =
+	      line[i * 2 + j * 2 * pixels + 1] * 256 +
+	      line[i * 2 + j * 2 * pixels];
+	  else
+	    val =
+	      line[i * 2 * channels + 2 * j + 1] * 256 +
+	      line[i * 2 * channels + 2 * j];
+            }
+          else
+            {
+	  if (dev->model->is_cis)
+	    val = line[i + j * pixels];
+	  else
+	    val = line[i * channels + j];
+            }
+
+	    max[j] += val;
+	}
+      max[j] = max[j] / (pixels/2);
+
+      gain[j] = ((float) sensor.gain_white_ref*coeff) / max[j];
+
+      /* turn logical gain value into gain code, checking for overflow */
+      code = 283 - 208 / gain[j];
+      if (code > 255)
+	code = 255;
+      else if (code < 0)
+	code = 0;
+      dev->frontend.set_gain(j, code);
+
+      DBG(DBG_proc, "%s: channel %d, max=%d, gain = %f, setting:%d\n", __func__, j, max[j],
+          gain[j], dev->frontend.get_gain(j));
+    }
+
+    if (dev->model->is_cis) {
+        uint8_t gain0 = dev->frontend.get_gain(0);
+        if (gain0 > dev->frontend.get_gain(1)) {
+            gain0 = dev->frontend.get_gain(1);
+        }
+        if (gain0 > dev->frontend.get_gain(2)) {
+            gain0 = dev->frontend.get_gain(2);
+        }
+        dev->frontend.set_gain(0, gain0);
+        dev->frontend.set_gain(1, gain0);
+        dev->frontend.set_gain(2, gain0);
+    }
+
+    if (channels == 1) {
+        dev->frontend.set_gain(0, dev->frontend.get_gain(1));
+        dev->frontend.set_gain(2, dev->frontend.get_gain(1));
+    }
+
+  RIE (gl124_stop_action (dev));
+
+  status = gl124_slow_back_home (dev, SANE_TRUE);
+
+  DBGCOMPLETED;
+  return status;
+}
+
+/*
+ * wait for lamp warmup by scanning the same line until difference
+ * between 2 scans is below a threshold
+ */
+static SANE_Status
+gl124_init_regs_for_warmup (Genesys_Device * dev,
+                            const Genesys_Sensor& sensor,
+			    Genesys_Register_Set * reg,
+			    int *channels, int *total_size)
+{
+  int num_pixels;
+  SANE_Status status = SANE_STATUS_GOOD;
+
+  DBGSTART;
+  if (dev == NULL || reg == NULL || channels == NULL || total_size == NULL)
+    return SANE_STATUS_INVAL;
+
+  *channels=3;
+
+  *reg = dev->reg;
+
+    SetupParams params;
+    params.xres = sensor.optical_res;
+    params.yres = dev->motor.base_ydpi;
+    params.startx = sensor.sensor_pixels / 4;
+    params.starty = 0;
+    params.pixels = sensor.sensor_pixels / 2;
+    params.lines = 1;
+    params.depth = 8;
+    params.channels = *channels;
+    params.scan_method = dev->settings.scan_method;
+    params.scan_mode = ScanColorMode::COLOR_SINGLE_PASS;
+    params.color_filter = dev->settings.color_filter;
+    params.flags = SCAN_FLAG_DISABLE_SHADING |
+                   SCAN_FLAG_DISABLE_GAMMA |
+                   SCAN_FLAG_SINGLE_LINE |
+                   SCAN_FLAG_IGNORE_LINE_DISTANCE;
+
+    status = gl124_init_scan_regs(dev, sensor, reg, params);
+
+  if (status != SANE_STATUS_GOOD)
+    {
+      DBG(DBG_error, "%s: failed to setup scan: %s\n", __func__, sane_strstatus(status));
+      return status;
+    }
+
+  num_pixels = dev->current_setup.pixels;
+
+  *total_size = num_pixels * 3 * 1;        /* colors * bytes_per_color * scan lines */
+
+  sanei_genesys_set_motor_power(*reg, false);
+  RIE (dev->model->cmd_set->bulk_write_register(dev, *reg));
+
+  DBGCOMPLETED;
+  return SANE_STATUS_GOOD;
+}
+
+/** @brief default GPIO values
+ * set up GPIO/GPOE for idle state
+ * @param dev device to set up
+ * @return SANE_STATUS_GOOD unless a GPIO register cannot be written
+ */
+static SANE_Status
+gl124_init_gpio (Genesys_Device * dev)
+{
+  SANE_Status status = SANE_STATUS_GOOD;
+  int idx;
+
+  DBGSTART;
+
+  /* per model GPIO layout */
+  if (dev->model->model_id == MODEL_CANON_LIDE_110)
+    {
+      idx = 0;
+    }
+  else if (dev->model->model_id == MODEL_CANON_LIDE_120)
+    {
+      idx = 2;
+    }
+  else
+    {                                /* canon LiDE 210 and 220 case */
+      idx = 1;
+    }
+
+  RIE (sanei_genesys_write_register (dev, REG31, gpios[idx].r31));
+  RIE (sanei_genesys_write_register (dev, REG32, gpios[idx].r32));
+  RIE (sanei_genesys_write_register (dev, REG33, gpios[idx].r33));
+  RIE (sanei_genesys_write_register (dev, REG34, gpios[idx].r34));
+  RIE (sanei_genesys_write_register (dev, REG35, gpios[idx].r35));
+  RIE (sanei_genesys_write_register (dev, REG36, gpios[idx].r36));
+  RIE (sanei_genesys_write_register (dev, REG38, gpios[idx].r38));
+
+  DBGCOMPLETED;
+  return status;
+}
+
+/**
+ * set memory layout by filling values in dedicated registers
+ */
+static SANE_Status
+gl124_init_memory_layout (Genesys_Device * dev)
+{
+  SANE_Status status = SANE_STATUS_GOOD;
+  int idx = 0;
+
+  DBGSTART;
+
+  /* point to per model memory layout */
+  if (dev->model->model_id == MODEL_CANON_LIDE_110 ||dev->model->model_id == MODEL_CANON_LIDE_120)
+    {
+      idx = 0;
+    }
+  else
+    {                                /* canon LiDE 210 and 220 case */
+      idx = 1;
+    }
+
+  /* setup base address for shading data. */
+  /* values must be multiplied by 8192=0x4000 to give address on AHB */
+  /* R-Channel shading bank0 address setting for CIS */
+  sanei_genesys_write_register (dev, 0xd0, layouts[idx].rd0);
+  /* G-Channel shading bank0 address setting for CIS */
+  sanei_genesys_write_register (dev, 0xd1, layouts[idx].rd1);
+  /* B-Channel shading bank0 address setting for CIS */
+  sanei_genesys_write_register (dev, 0xd2, layouts[idx].rd2);
+
+  /* setup base address for scanned data. */
+  /* values must be multiplied by 1024*2=0x0800 to give address on AHB */
+  /* R-Channel ODD image buffer 0x0124->0x92000 */
+  /* size for each buffer is 0x16d*1k word */
+  sanei_genesys_write_register (dev, 0xe0, layouts[idx].re0);
+  sanei_genesys_write_register (dev, 0xe1, layouts[idx].re1);
+  /* R-Channel ODD image buffer end-address 0x0291->0x148800 => size=0xB6800*/
+  sanei_genesys_write_register (dev, 0xe2, layouts[idx].re2);
+  sanei_genesys_write_register (dev, 0xe3, layouts[idx].re3);
+
+  /* R-Channel EVEN image buffer 0x0292 */
+  sanei_genesys_write_register (dev, 0xe4, layouts[idx].re4);
+  sanei_genesys_write_register (dev, 0xe5, layouts[idx].re5);
+  /* R-Channel EVEN image buffer end-address 0x03ff*/
+  sanei_genesys_write_register (dev, 0xe6, layouts[idx].re6);
+  sanei_genesys_write_register (dev, 0xe7, layouts[idx].re7);
+
+  /* same for green, since CIS, same addresses */
+  sanei_genesys_write_register (dev, 0xe8, layouts[idx].re0);
+  sanei_genesys_write_register (dev, 0xe9, layouts[idx].re1);
+  sanei_genesys_write_register (dev, 0xea, layouts[idx].re2);
+  sanei_genesys_write_register (dev, 0xeb, layouts[idx].re3);
+  sanei_genesys_write_register (dev, 0xec, layouts[idx].re4);
+  sanei_genesys_write_register (dev, 0xed, layouts[idx].re5);
+  sanei_genesys_write_register (dev, 0xee, layouts[idx].re6);
+  sanei_genesys_write_register (dev, 0xef, layouts[idx].re7);
+
+/* same for blue, since CIS, same addresses */
+  sanei_genesys_write_register (dev, 0xf0, layouts[idx].re0);
+  sanei_genesys_write_register (dev, 0xf1, layouts[idx].re1);
+  sanei_genesys_write_register (dev, 0xf2, layouts[idx].re2);
+  sanei_genesys_write_register (dev, 0xf3, layouts[idx].re3);
+  sanei_genesys_write_register (dev, 0xf4, layouts[idx].re4);
+  sanei_genesys_write_register (dev, 0xf5, layouts[idx].re5);
+  sanei_genesys_write_register (dev, 0xf6, layouts[idx].re6);
+  sanei_genesys_write_register (dev, 0xf7, layouts[idx].re7);
+
+  DBGCOMPLETED;
+  return status;
+}
+
+/**
+ * initialize backend and ASIC : registers, motor tables, and gamma tables
+ * then ensure scanner's head is at home
+ */
+static SANE_Status
+gl124_init(Genesys_Device * dev)
+{
+  SANE_Status status = SANE_STATUS_GOOD;
+
+  DBG_INIT ();
+  DBGSTART;
+
+  status=sanei_genesys_asic_init(dev, 0);
+
+  DBGCOMPLETED;
+  return status;
+}
+
+
+/* *
+ * initialize ASIC from power on condition
+ */
+static SANE_Status
+gl124_boot (Genesys_Device * dev, SANE_Bool cold)
+{
+  SANE_Status status = SANE_STATUS_GOOD;
+  uint8_t val;
+
+  DBGSTART;
+
+  /* reset ASIC in case of cold boot */
+  if(cold)
+    {
+      RIE (sanei_genesys_write_register (dev, 0x0e, 0x01));
+      RIE (sanei_genesys_write_register (dev, 0x0e, 0x00));
+    }
+
+  /* enable GPOE 17 */
+  RIE (sanei_genesys_write_register (dev, 0x36, 0x01));
+
+  /* set GPIO 17 */
+  RIE (sanei_genesys_read_register (dev, 0x33, &val));
+  val |= 0x01;
+  RIE (sanei_genesys_write_register (dev, 0x33, val));
+
+  /* test CHKVER */
+  RIE (sanei_genesys_read_register (dev, REG100, &val));
+  if (val & REG100_CHKVER)
+    {
+      RIE (sanei_genesys_read_register (dev, 0x00, &val));
+      DBG(DBG_info, "%s: reported version for genesys chip is 0x%02x\n", __func__, val);
+    }
+
+  /* Set default values for registers */
+  gl124_init_registers (dev);
+
+  /* Write initial registers */
+  RIE (dev->model->cmd_set->bulk_write_register(dev, dev->reg));
+
+  /* tune reg 0B */
+  val = REG0B_30MHZ | REG0B_ENBDRAM | REG0B_64M;
+  RIE (sanei_genesys_write_register (dev, REG0B, val));
+  dev->reg.remove_reg(0x0b);
+
+  /* set up end access */
+  RIE (sanei_genesys_write_0x8c (dev, 0x10, 0x0b));
+  RIE (sanei_genesys_write_0x8c (dev, 0x13, 0x0e));
+
+  /* CIS_LINE */
+  SETREG (0x08, REG08_CIS_LINE);
+  RIE (sanei_genesys_write_register (dev, 0x08, dev->reg.find_reg(0x08).value));
+
+  /* setup gpio */
+  RIE (gl124_init_gpio (dev));
+
+  /* setup internal memory layout */
+  RIE (gl124_init_memory_layout (dev));
+
+  DBGCOMPLETED;
+  return SANE_STATUS_GOOD;
+}
+
+
+static SANE_Status
+gl124_update_hardware_sensors (Genesys_Scanner * s)
+{
+  /* do what is needed to get a new set of events, but try to not loose
+     any of them.
+   */
+  SANE_Status status = SANE_STATUS_GOOD;
+  uint8_t val=0;
+
+  RIE (sanei_genesys_read_register (s->dev, REG31, &val));
+
+  /* TODO : for the next scanner special case,
+   * add another per scanner button profile struct to avoid growing
+   * hard-coded button mapping here.
+   */
+  if((s->dev->model->gpo_type == GPO_CANONLIDE110)
+    ||(s->dev->model->gpo_type == GPO_CANONLIDE120))
+    {
+        s->buttons[BUTTON_SCAN_SW].write((val & 0x01) == 0);
+        s->buttons[BUTTON_FILE_SW].write((val & 0x08) == 0);
+        s->buttons[BUTTON_EMAIL_SW].write((val & 0x04) == 0);
+        s->buttons[BUTTON_COPY_SW].write((val & 0x02) == 0);
+    }
+  else
+    { /* LiDE 210 case */
+        s->buttons[BUTTON_EXTRA_SW].write((val & 0x01) == 0);
+        s->buttons[BUTTON_SCAN_SW].write((val & 0x02) == 0);
+        s->buttons[BUTTON_COPY_SW].write((val & 0x04) == 0);
+        s->buttons[BUTTON_EMAIL_SW].write((val & 0x08) == 0);
+        s->buttons[BUTTON_FILE_SW].write((val & 0x10) == 0);
+    }
+  return status;
+}
+
+
+/** the gl124 command set */
+static Genesys_Command_Set gl124_cmd_set = {
+  "gl124-generic",                /* the name of this set */
+
+  [](Genesys_Device* dev) -> bool { (void) dev; return true; },
+
+  gl124_init,
+  gl124_init_regs_for_warmup,
+  gl124_init_regs_for_coarse_calibration,
+  gl124_init_regs_for_shading,
+  gl124_init_regs_for_scan,
+
+  gl124_get_filter_bit,
+  gl124_get_lineart_bit,
+  gl124_get_bitset_bit,
+  gl124_get_gain4_bit,
+  gl124_get_fast_feed_bit,
+  gl124_test_buffer_empty_bit,
+  gl124_test_motor_flag_bit,
+
+  gl124_set_fe,
+  gl124_set_powersaving,
+  gl124_save_power,
+
+  gl124_begin_scan,
+  gl124_end_scan,
+
+  sanei_genesys_send_gamma_table,
+
+  gl124_search_start_position,
+
+  gl124_offset_calibration,
+  gl124_coarse_gain_calibration,
+  gl124_led_calibration,
+
+  gl124_wait_for_motor_stop,
+  gl124_slow_back_home,
+  gl124_rewind,
+
+  sanei_genesys_bulk_write_register,
+  NULL,
+  sanei_genesys_bulk_read_data,
+
+  gl124_update_hardware_sensors,
+
+  /* no sheetfed support for now */
+  NULL,
+  NULL,
+  NULL,
+  NULL,
+
+  sanei_genesys_is_compatible_calibration,
+  NULL,
+  gl124_send_shading_data,
+  gl124_calculate_current_setup,
+  gl124_boot
+};
+
+SANE_Status
+sanei_gl124_init_cmd_set (Genesys_Device * dev)
+{
+  dev->model->cmd_set = &gl124_cmd_set;
+  return SANE_STATUS_GOOD;
+}