summaryrefslogtreecommitdiff
path: root/backend/canon630u-common.c
blob: 4417141125ba112abc646f313c6ecaa93ce01f53 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
/*
   (c) 2001,2002 Nathan Rutman  nathan@gordian.com  10/17/01

   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.  
*/

/*
   Communication, calibration, and scanning with the Canon CanoScan FB630U
   flatbed scanner under linux.
   
   Reworked into SANE-compatible format.
   
   The usb-parallel port interface chip is GL640usb, on the far side of
   which is an LM9830 parallel-port scanner-on-a-chip.

   This code has not been tested on anything other than Linux/i386.
*/

#include <errno.h>
#include <fcntl.h>		/* open */
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>		/* usleep */
#include <time.h>
#include <math.h>               /* exp() */
#ifdef HAVE_OS2_H
#include <sys/types.h> 		/* mode_t */
#endif
#include <sys/stat.h>
#include "lm9830.h"

#define USB_TYPE_VENDOR                 (0x02 << 5)
#define USB_RECIP_DEVICE                0x00
#define USB_DIR_OUT                     0x00
#define USB_DIR_IN                      0x80

/* Assign status and verify a good return code */
#define CHK(A) {if( (status = A) != SANE_STATUS_GOOD ) { \
                 DBG( 1, "Failure on line of %s: %d\n", __FILE__, \
                      __LINE__ ); return A; }}


typedef SANE_Byte byte;


/*****************************************************
            GL640 communication primitives
   Provides I/O routines to Genesys Logic GL640USB USB-IEEE1284 parallel
   port bridge.  Used in HP3300c, Canon FB630u.
******************************************************/

/* Register codes for the bridge.  These are NOT the registers for the
   scanner chip on the other side of the bridge. */
typedef enum
{
  GL640_BULK_SETUP = 0x82,
  GL640_EPP_ADDR = 0x83,
  GL640_EPP_DATA_READ = 0x84,
  GL640_EPP_DATA_WRITE = 0x85,
  GL640_SPP_STATUS = 0x86,
  GL640_SPP_CONTROL = 0x87,
  GL640_SPP_DATA = 0x88,
  GL640_GPIO_OE = 0x89,
  GL640_GPIO_READ = 0x8a,
  GL640_GPIO_WRITE = 0x8b
}
GL640_Request;

/* Write to the usb-parallel port bridge. */
static SANE_Status
gl640WriteControl (int fd, GL640_Request req, byte * data, unsigned int size)
{
  SANE_Status status;
  status = sanei_usb_control_msg (fd,
				  /* rqttype */ USB_TYPE_VENDOR |
				  USB_RECIP_DEVICE | USB_DIR_OUT /*0x40? */ ,
				  /* rqt */ (size > 1) ? 0x04 : 0x0C,
				  /* val */ (SANE_Int) req,
				  /* ind */ 0,
				  /* len */ size,
				  /* dat */ data);
  if (status != SANE_STATUS_GOOD)
    DBG (1, "gl640WriteControl error\n");
  return status;
}


/* Read from the usb-parallel port bridge. */
static SANE_Status
gl640ReadControl (int fd, GL640_Request req, byte * data, unsigned int size)
{
  SANE_Status status;
  status = sanei_usb_control_msg (fd,
				  /* rqttype */ USB_TYPE_VENDOR |
				  USB_RECIP_DEVICE | USB_DIR_IN /*0xc0? */ ,
				  /* rqt */ (size > 1) ? 0x04 : 0x0C,
				  /* val */ (SANE_Int) req,
				  /* ind */ 0,
				  /* len */ size,
				  /* dat */ data);
  if (status != SANE_STATUS_GOOD)
    DBG (1, "gl640ReadControl error\n");
  return status;
}


/* Wrappers to read or write a single byte to the bridge */
static inline SANE_Status
gl640WriteReq (int fd, GL640_Request req, byte data)
{
  return gl640WriteControl (fd, req, &data, 1);
}

static inline SANE_Status
gl640ReadReq (int fd, GL640_Request req, byte * data)
{
  return gl640ReadControl (fd, req, data, 1);
}


/* Write USB bulk data 
   setup is an apparently scanner-specific sequence:
   {(0=read, 1=write), 0x00, 0x00, 0x00, sizelo, sizehi, 0x00, 0x00}
   hp3400: setup[1] = 0x01
   fb630u: setup[2] = 0x80
*/
static SANE_Status
gl640WriteBulk (int fd, byte * setup, byte * data, size_t size)
{
  SANE_Status status;
  setup[0] = 1;
  setup[4] = (size) & 0xFF;
  setup[5] = (size >> 8) & 0xFF;

  CHK (gl640WriteControl (fd, GL640_BULK_SETUP, setup, 8));

  status = sanei_usb_write_bulk (fd, data, &size);
  if (status != SANE_STATUS_GOOD)
    DBG (1, "gl640WriteBulk error\n");

  return status;
}


/* Read USB bulk data 
   setup is an apparently scanner-specific sequence:
   {(0=read, 1=write), 0x00, 0x00, 0x00, sizelo, sizehi, 0x00, 0x00}
   fb630u: setup[2] = 0x80
*/
static SANE_Status
gl640ReadBulk (int fd, byte * setup, byte * data, size_t size)
{
  SANE_Status status;
  setup[0] = 0;
  setup[4] = (size) & 0xFF;
  setup[5] = (size >> 8) & 0xFF;

  CHK (gl640WriteControl (fd, GL640_BULK_SETUP, setup, 8));

  status = sanei_usb_read_bulk (fd, data, &size);
  if (status != SANE_STATUS_GOOD)
    DBG (1, "gl640ReadBulk error\n");

  return status;
}


/*****************************************************
            LM9830 communication primitives
	    parallel-port scanner-on-a-chip.
******************************************************/

/* write 1 byte to a LM9830 register address */
static SANE_Status
write_byte (int fd, byte addr, byte val)
{
  SANE_Status status;
  DBG (14, "write_byte(fd, 0x%02x, 0x%02x);\n", addr, val);
  CHK (gl640WriteReq (fd, GL640_EPP_ADDR, addr));
  CHK (gl640WriteReq (fd, GL640_EPP_DATA_WRITE, val));
  return status;
}


/* read 1 byte from a LM9830 register address */
static SANE_Status
read_byte (int fd, byte addr, byte * val)
{
  SANE_Status status;
  CHK (gl640WriteReq (fd, GL640_EPP_ADDR, addr));
  CHK (gl640ReadReq (fd, GL640_EPP_DATA_READ, val));
  DBG (14, "read_byte(fd, 0x%02x, &result); /* got %02x */\n", addr, *val);
  return status;
}


static byte bulk_setup_data[] = { 0, 0, 0x80, 0, 0, 0, 0, 0 };

/* Bulk write */
static SANE_Status
write_bulk (int fd, unsigned int addr, void *src, size_t count)
{
  SANE_Status status;

  DBG (13, "write_bulk(fd, 0x%02x, buf, 0x%04lx);\n", addr, (u_long) count);

  if (!src)
    {
      DBG (1, "write_bulk: bad src\n");
      return SANE_STATUS_INVAL;
    }

  /* destination address */
  CHK (gl640WriteReq (fd, GL640_EPP_ADDR, addr));
  /* write */
  CHK (gl640WriteBulk (fd, bulk_setup_data, src, count));
  return status;
}


/* Bulk read */
static SANE_Status
read_bulk (int fd, unsigned int addr, void *dst, size_t count)
{
  SANE_Status status;

  DBG (13, "read_bulk(fd, 0x%02x, buf, 0x%04lx);\n", addr, (u_long) count);

  if (!dst)
    {
      DBG (1, "read_bulk: bad dest\n");
      return SANE_STATUS_INVAL;
    }

  /* destination address */
  CHK (gl640WriteReq (fd, GL640_EPP_ADDR, addr));
  /* read */
  CHK (gl640ReadBulk (fd, bulk_setup_data, dst, count));
  return status;
}



/*****************************************************
            useful macro routines
******************************************************/

/* write a 16-bit int to two sequential registers */
static SANE_Status
write_word (int fd, unsigned int addr, unsigned int data)
{
  SANE_Status status;
  /* MSB */
  CHK (write_byte (fd, addr, (data >> 8) & 0xff));
  /* LSB */
  CHK (write_byte (fd, addr + 1, data & 0xff));
  return status;
}


/* write multiple bytes, one at a time (non-bulk) */
static SANE_Status
write_many (int fd, unsigned int addr, void *src, size_t count)
{
  SANE_Status status;
  size_t i;

  DBG (14, "multi write %lu\n", (u_long) count);
  for (i = 0; i < count; i++)
    {
      DBG (15, " %04lx:%02x", (u_long) (addr + i), ((byte *) src)[i]);
      status = write_byte (fd, addr + i, ((byte *) src)[i]);
      if (status != SANE_STATUS_GOOD)
	{
	  DBG (15, "\n");
	  return status;
	}
    }
  DBG (15, "\n");
  return SANE_STATUS_GOOD;
}


/* read multiple bytes, one at a time (non-bulk) */
static SANE_Status
read_many (int fd, unsigned int addr, void *dst, size_t count)
{
  SANE_Status status;
  size_t i;
  byte val;

  DBG (14, "multi read %lu\n", (u_long) count);
  for (i = 0; i < count; i++)
    {
      status = read_byte (fd, addr + i, &val);
      ((byte *) dst)[i] = val;
      DBG (15, " %04lx:%02x", (u_long) (addr + i), ((byte *) dst)[i]);
      /* on err, return number of success */
      if (status != SANE_STATUS_GOOD)
	{
	  DBG (15, "\n");
	  return status;
	}
    }
  DBG (15, "\n");
  return SANE_STATUS_GOOD;
}


/* Poll addr until result & mask = val */
static int
read_poll_flag (int fd,
		unsigned int addr, unsigned int mask, unsigned int val)
{
  SANE_Status status;
  byte result = 0;
  time_t start_time = time (NULL);

  DBG (12, "read_poll_flag...\n");
  do
    {
      status = read_byte (fd, addr, &result);
      if (status != SANE_STATUS_GOOD)
	return -1;
      /* Give it a minute */
      if ((time (NULL) - start_time) > 60)
	{
	  DBG (1, "read_poll_flag: timed out (%d)\n", result);
	  return -1;
	}
      usleep (100000);
    }
  while ((result & mask) != val);
  return result;
}


/* Keep reading addr until results >= min */
static int
read_poll_min (int fd, unsigned int addr, unsigned int min)
{
  SANE_Status status;
  byte result;
  time_t start_time = time (NULL);

  DBG (12, "waiting...\n");
  do
    {
      status = read_byte (fd, addr, &result);
      if (status != SANE_STATUS_GOOD)
	return -1;
      /* Give it a minute */
      if ((time (NULL) - start_time) > 60)
	{
	  DBG (1, "read_poll_min: timed out (%d < %d)\n", result, min);
	  return -1;
	}
      /* no sleep here, or calibration gets unhappy. */
    }
  while (result < min);
  return result;
}


/* Bulk read "ks" kilobytes + "remainder" bytes of data, to a buffer if the
   buffer is valid. */
static int
read_bulk_size (int fd, int ks, int remainder, byte * dest, int destsize)
{
  byte *buf;
  int bytes = (ks - 1) * 1024 + remainder;
  int dropdata = ((dest == 0) || (destsize < bytes));

  if (bytes < 0)
    {
      DBG (1, "read_bulk_size: invalid size %02x (%d)\n", ks, bytes);
      return -1;
    }
  if (destsize && (destsize < bytes))
    {
      DBG (3, "read_bulk_size: more data than buffer (%d/%d)\n",
	   destsize, bytes);
      bytes = destsize;
    }

  if (bytes == 0)
    return 0;

  if (dropdata)
    {
      buf = malloc (bytes);
      DBG (3, " ignoring data ");
    }
  else
    buf = dest;

  read_bulk (fd, 0x00, buf, bytes);

  if (dropdata)
    free (buf);
  return bytes;
}



/*****************************************************

            fb630u calibration and scan

******************************************************/

/* data structures and constants */

typedef struct CANON_Handle
{
  int fd;			/* scanner fd */
  int x1, x2, y1, y2;		/* in pixels, 600 dpi */
  int width, height;		/* at scan resolution */
  int resolution;		/* dpi */
  char *fname;			/* output file name */
  FILE *fp;			/* output file pointer (for reading) */
  char *buf, *ptr;		/* data buffer */
  unsigned char gain;		/* static analog gain, 0 - 31 */
  double gamma;		        /* gamma correction */
  int flags;
#define FLG_GRAY	0x01	/* grayscale */
#define FLG_FORCE_CAL	0x02	/* force calibration */
#define FLG_BUF		0x04	/* save scan to buffer instead of file */
#define FLG_NO_INTERLEAVE 0x08	/* don't interleave r,g,b pixels; leave them 
				   in row format */
#define FLG_PPM_HEADER	0x10	/* include PPM header in scan file */
}
CANON_Handle;


/* offset/gain calibration file name */
#define CAL_FILE_OGN "/tmp/canon.cal"

/* at 600 dpi */
#define CANON_MAX_WIDTH    5100	/* 8.5in */
/* this may not be right */
#define CANON_MAX_HEIGHT   7000	/* 11.66in */

/* scanline end-of-line data byte, returned after each r,g,b segment,
   specific to the FB630u */
#define SCANLINE_END	0x0c


static const byte seq002[] =
  { /*r08 */ 0x04, /*300 dpi */ 0x1a, 0x00, 0x0d, 0x4c, 0x2f, 0x00, 0x01,
/*r10 */ 0x07, 0x04, 0x05, 0x06, 0x07, 0x00, 0x00, 0x00, 0x03, 0x00, 0x00, 0x00, 0x03, 0x25, 0x00,
0x4b, /*r20 */ 0x15, 0xe0, /*data px start */ 0x00, 0x4b, /*data px end */ 0x14, 0x37, 0x15, 0x00 };

static const byte seq003[] =
  { 0x02, 0x00, 0x00, /*lights out */ 0x03, 0xff, 0x00, 0x01, 0x03, 0xff,
0x00, 0x01, 0x03, 0xff, 0x00, 0x01, 0x00, 0x00, 0x00, 0x01, 0x01, 0x01, 0x00, 0x00, 0x00, 0x00, 0x06,
0x1d, 0x00, 0x13, 0x04, 0x1a, 0x01, 0x04, 0x00, 0x00, 0x00, 0x00, 0x57, 0x02, 0x00, 0x3c, 0x35, 0x94,
0x00, 0x10, 0x08, 0x3f, 0x2b, 0x91, 0x00, 0x00, 0x01, 0x00, 0x80, 0x00 };


/* Scanner init, called at calibration and scan time.  Returns 1 if this
   was the first time the scanner was plugged in, 0 afterward, and
   -1 on error. */
static int
init (int fd)
{
  byte result, rv;

  if (gl640WriteReq (fd, GL640_GPIO_OE, 0x71) != SANE_STATUS_GOOD) { 
      DBG(1, "Initial write request failed.\n");
      return -1;
  }
  /* Gets 0x04 or 0x05 first run, gets 0x64 subsequent runs. */
  if (gl640ReadReq (fd, GL640_GPIO_READ, &rv) != SANE_STATUS_GOOD) {
      DBG(1, "Initial read request failed.\n");
      return -1;
  }
  gl640WriteReq (fd, GL640_GPIO_OE, 0x70);

  DBG (2, "init query: %x\n", rv);
  if (rv != 0x64)
    {
      gl640WriteReq (fd, GL640_GPIO_WRITE, 0x00);
      gl640WriteReq (fd, GL640_GPIO_WRITE, 0x40);
    }

  gl640WriteReq (fd, GL640_SPP_DATA, 0x99);
  gl640WriteReq (fd, GL640_SPP_DATA, 0x66);
  gl640WriteReq (fd, GL640_SPP_DATA, 0xcc);
  gl640WriteReq (fd, GL640_SPP_DATA, 0x33);
  /* parallel port setting */
  write_byte (fd, PARALLEL_PORT, 0x06);
  /* sensor control settings */
  write_byte (fd, 0x0b, 0x0d);
  write_byte (fd, 0x0c, 0x4c);
  write_byte (fd, 0x0d, 0x2f);
  read_byte (fd, 0x0b, &result);	/* wants 0d */
  read_byte (fd, 0x0c, &result);	/* wants 4c */
  read_byte (fd, 0x0d, &result);	/* wants 2f */
  /* parallel port noise filter */
  write_byte (fd, 0x70, 0x73);

  DBG (2, "init post-reset: %x\n", rv);
  /* Returns 1 if this was the first time the scanner was plugged in. */
  return (rv != 0x64);
}


/* Turn off the lamps */
static void
lights_out (int fd)
{
  write_word (fd, LAMP_R_ON, 0x3fff);
  write_word (fd, LAMP_R_OFF, 0x0001);
  write_word (fd, LAMP_G_ON, 0x3fff);
  write_word (fd, LAMP_G_OFF, 0x0001);
  write_word (fd, LAMP_B_ON, 0x3fff);
  write_word (fd, LAMP_B_OFF, 0x0001);
}


/* Do the scan and save the resulting image as r,g,b interleaved PPM
   file.  */
static SANE_Status
do_scan (CANON_Handle * s)
{
  SANE_Status status = SANE_STATUS_GOOD;
  int numbytes, datasize, level = 0, line = 0, pixel = 0;
  byte *buf, *ptr, *redptr;
  FILE *fp;

#define BUFSIZE 0xf000
  buf = malloc (BUFSIZE);
  if (!buf)
    return SANE_STATUS_NO_MEM;

  if (s->flags & FLG_BUF)
    {
      /* read the whole thing into buf */
      if (!s->buf)
	return SANE_STATUS_NO_MEM;
      s->ptr = s->buf;
      fp = NULL;
    }
  else
    {
      fp = fopen (s->fname, "w");
      if (!fp)
	{
	  free (buf);
	  DBG (1, "err:%s when opening %s\n", strerror (errno), s->fname);
	  return SANE_STATUS_IO_ERROR;
	}
    }
  if (fp && (s->flags & FLG_PPM_HEADER))
    /* PPM format header */
    fprintf (fp, "P6\n%d %d\n255\n", s->width, s->height);

  /* lights off */
  write_byte (s->fd, COMMAND, 0x08);
  /* lights on */
  write_byte (s->fd, COMMAND, 0x00);
  /* begin scan */
  write_byte (s->fd, COMMAND, 0x03);

  ptr = redptr = buf;
  while (line < s->height)
    {
      datasize = read_poll_min (s->fd, IMAGE_DATA_AVAIL, 2);
      if (datasize < 0)
	{
	  DBG (1, "no data\n");
	  break;
	}
      DBG (12, "scan line %d %dk\n", line, datasize - 1);
      /* Read may cause scan head to move */
      numbytes = read_bulk_size (s->fd, datasize, 0, ptr, BUFSIZE - level);
      if (numbytes < 0)
	{
	  status = SANE_STATUS_INVAL;
	  break;
	}
      /* Data coming back is "width" bytes Red data followed by 0x0c,
         width bytes Green, 0x0c, width bytes Blue, 0x0c, repeat for
         "height" lines. */
      if (s->flags & FLG_NO_INTERLEAVE)
	{
	  /* number of full lines */
	  line += (numbytes + level) / (s->width * 3);
	  /* remainder (partial line) */
	  level = (numbytes + level) % (s->width * 3);
	  /* but if last line, don't store extra */
	  if (line >= s->height)
	    numbytes -= (line - s->height) * s->width * 3 + level;
	  if (fp)
	    fwrite (buf, 1, numbytes, fp);
	  else
	    {
	      memcpy (s->ptr, buf, numbytes);
	      s->ptr += numbytes;
	    }
	}
      else
	{
	  /* Contorsions to convert data from line-by-line RGB to
	     byte-by-byte RGB, without reading in the whole buffer first.
	     We use the sliding window redptr with the temp buffer buf. */
	  ptr += numbytes;	/* point to the end of data */
	  /* while we have RGB triple data */
	  while (redptr + s->width + s->width <= ptr)
	    {
	      if (*redptr == SCANLINE_END)
		DBG (13, "-%d- ", pixel);
	      if (fp)
		{
		  /* for PPM binary (P6), 3-byte RGB pixel */
		  fwrite (redptr, 1, 1, fp);	/* Red */
		  fwrite (redptr + s->width, 1, 1, fp);	/* Green */
		  fwrite (redptr + s->width + s->width, 1, 1, fp);	/* Blue */
		  /* for PPM ascii (P3)
		     fprintf(fp, "%3d %3d %3d\n",  *redptr, 
		     *(redptr + s->width),
		     *(redptr + s->width + s->width));
		   */
		}
	      else
		{
		  /* R */ *s->ptr = *redptr;
		  s->ptr++;
		  /* G */ *s->ptr = *(redptr + s->width);
		  s->ptr++;
		  /* B */ *s->ptr = *(redptr + s->width + s->width);
		  s->ptr++;
		}
	      redptr++;
	      pixel++;
	      if (pixel && !(pixel % s->width))
		{
		  /* end of a line, move redptr to the next Red section */
		  line++;
		  redptr += s->width + s->width;
#if 0
		  /* progress */
		  printf ("%2d%%\r", line * 100 / s->height);
		  fflush (stdout);
#endif
		  /* don't record any extra */
		  if (line >= s->height)
		    break;
		}
	    }
	  /* keep the extra around for next time */
	  level = ptr - redptr;
	  if (level < 0)
	    level = 0;
	  memmove (buf, redptr, level);
	  ptr = buf + level;
	  redptr = buf;
	}
    }

  if (fp)
    {
      fclose (fp);
      DBG (6, "created scan file %s\n", s->fname);
    }
  free (buf);
  DBG (6, "%d lines, %d pixels, %d extra bytes\n", line, pixel, level);

  /* motor off */
  write_byte (s->fd, COMMAND, 0x00);

  return status;
}


static int
wait_for_return (int fd)
{
  return read_poll_flag (fd, STATUS, STATUS_HOME, STATUS_HOME);
}


static SANE_Status compute_ogn (char *calfilename);


/* This is the calibration rountine Win2k goes through when the scanner is
   first plugged in.
   Original usb trace from Win2k with USBSnoopy ("usb sniffer for w2k"
   http://benoit.papillault.free.fr/speedtouch/sniff-2000.en.php3)
 */
static int
plugin_cal (CANON_Handle * s)
{
  SANE_Status status;
  unsigned int temp;
  byte result;
  byte *buf;
  int fd = s->fd;

  DBG (6, "Calibrating\n");

  /* reserved? */
  read_byte (fd, 0x69, &result);	/* wants 02 */

  /* parallel port setting */
  write_byte (fd, PARALLEL_PORT, 0x06);

  write_many (fd, 0x08, (byte *) seq002, sizeof (seq002));
  /* addr 0x28 isn't written */
  write_many (fd, 0x29, (byte *) seq003, sizeof (seq003));
  /* Verification */
  buf = malloc (0x400);
  read_many (fd, 0x08, buf, sizeof (seq002));
  if (memcmp (seq002, buf, sizeof (seq002)))
    DBG (1, "seq002 verification error\n");
  /* addr 0x28 isn't read */
  read_many (fd, 0x29, buf, sizeof (seq003));
  if (memcmp (seq003, buf, sizeof (seq003)))
    DBG (1, "seq003 verification error\n");

  /* parallel port noise filter */
  write_byte (fd, 0x70, 0x73);

  lights_out (fd);

  /* Home motor */
  read_byte (fd, STATUS, &result);	/* wants 2f or 2d */
  if (!(result & STATUS_HOME) /*0x2d */ )
    write_byte (fd, COMMAND, 0x02);

  wait_for_return (fd);

  /* Motor forward */
  write_byte (fd, COMMAND, 0x01);
  usleep (600000);
  read_byte (fd, STATUS, &result);	/* wants 0c or 2c */
  read_byte (fd, STATUS, &result);	/* wants 0c */
  /* Return home */
  write_byte (fd, COMMAND, 0x02);

  /* Gamma tables */
  /* Linear gamma */
  for (temp = 0; temp < 0x0400; temp++)
    buf[temp] = temp / 4;
  /* Gamma Red */
  write_byte (fd, DATAPORT_TARGET, DP_R | DP_GAMMA);
  write_word (fd, DATAPORT_ADDR, DP_WRITE);
  write_bulk (fd, DATAPORT, buf, 0x0400);
  /* Gamma Green */
  write_byte (fd, DATAPORT_TARGET, DP_G | DP_GAMMA);
  write_word (fd, DATAPORT_ADDR, DP_WRITE);
  write_bulk (fd, DATAPORT, buf, 0x0400);
  /* Gamma Blue */
  write_byte (fd, DATAPORT_TARGET, DP_B | DP_GAMMA);
  write_word (fd, DATAPORT_ADDR, DP_WRITE);
  write_bulk (fd, DATAPORT, buf, 0x0400);

  /* Read back gamma tables.  I suppose I should check results... */
  /* Gamma Red */
  write_byte (fd, DATAPORT_TARGET, DP_R | DP_GAMMA);
  write_word (fd, DATAPORT_ADDR, DP_READ);
  read_bulk (fd, DATAPORT, buf, 0x0400);
  /* Gamma Green */
  write_byte (fd, DATAPORT_TARGET, DP_G | DP_GAMMA);
  write_word (fd, DATAPORT_ADDR, DP_READ);
  read_bulk (fd, DATAPORT, buf, 0x0400);
  /* Gamma Blue */
  write_byte (fd, DATAPORT_TARGET, DP_B | DP_GAMMA);
  write_word (fd, DATAPORT_ADDR, DP_READ);
  read_bulk (fd, DATAPORT, buf, 0x0400);
  free (buf);

  /* Make sure STATUS_HOME */
  read_byte (fd, STATUS, &result);	/* wants 0e */
  /* stepper forward */
  write_byte (fd, COMMAND, 0x01);
  read_byte (fd, STATUS, &result);	/* wants 0c */
  /* not sure if this rigid read/write pattern is required */
  read_byte (fd, CLOCK_DIV, &result);	/* wants 04 */
  write_byte (fd, CLOCK_DIV, 0x04);
  read_byte (fd, STEP_SIZE, &result);	/* wants 04 */
  write_byte (fd, STEP_SIZE, 0x3f);
  read_byte (fd, 0x47, &result);	/* wants 1a */
  write_byte (fd, 0x47, 0xff);
  read_byte (fd, FAST_STEP, &result);	/* wants 01 */
  write_byte (fd, FAST_STEP, 0x01);
  read_byte (fd, 0x49, &result);	/* wants 04 */
  write_byte (fd, 0x49, 0x04);
  read_byte (fd, SKIP_STEPS, &result);	/* wants 00 */
  write_byte (fd, SKIP_STEPS, 0x00);
  read_byte (fd, 0x4b, &result);	/* wants 00 */
  write_byte (fd, 0x4b, 0xc8);
  read_byte (fd, BUFFER_LIMIT, &result);	/* wants 57 */
  write_byte (fd, BUFFER_LIMIT, 0x04);
  read_byte (fd, BUFFER_RESUME, &result);	/* wants 02 */
  write_byte (fd, BUFFER_RESUME, 0x02);
  read_byte (fd, REVERSE_STEPS, &result);	/* wants 00 */
  write_byte (fd, REVERSE_STEPS, 0x00);
  write_byte (fd, STEP_PWM, 0x1f);

  /* Reset motor */
  write_byte (fd, COMMAND, 0x08);
  write_byte (fd, COMMAND, 0x00);
  /* Scan */
  write_byte (fd, COMMAND, 0x03);
  /* Wants 02 or 03, gets a bunch of 0's first */
  read_poll_min (fd, IMAGE_DATA_AVAIL, 2);
  write_byte (fd, COMMAND, 0x00);

  write_byte (fd, STEP_PWM, 0x3f);
  write_byte (fd, CLOCK_DIV, 0x04);
  /* 300 dpi */
  write_word (fd, STEP_SIZE, 0x041a);
  write_word (fd, FAST_STEP, 0x0104);
  /* Don't skip the black/white calibration area at the bottom of the
     scanner. */
  write_word (fd, SKIP_STEPS, 0x0000);
  write_byte (fd, BUFFER_LIMIT, 0x57);
  write_byte (fd, BUFFER_RESUME, 0x02);
  write_byte (fd, REVERSE_STEPS, 0x00);
  write_byte (fd, BUFFER_LIMIT, 0x09);
  write_byte (fd, STEP_PWM, 0x1f);
  read_byte (fd, MICROSTEP, &result);	/* wants 13, active */
  write_byte (fd, MICROSTEP, 0x03 /* tristate */ );

  /* Calibration data taken under 3 different lighting conditions */
  /* dark */
  write_word (fd, LAMP_R_ON, 0x0017);
  write_word (fd, LAMP_R_OFF, 0x0100);
  write_word (fd, LAMP_G_ON, 0x0017);
  write_word (fd, LAMP_G_OFF, 0x0100);
  write_word (fd, LAMP_B_ON, 0x0017);
  write_word (fd, LAMP_B_OFF, 0x0100);
  /* coming in, we've got 300dpi,
     data px start : 0x004b
     data px end  : 0x1437 for a total of 5100(13ec) 600-dpi pixels, 
     (8.5 inches) or 2550 300-dpi pixels (7653 bytes). 
     Interestingly, the scan head never moves, no matter how many rows
     are read. */
  s->width = 2551;
  s->height = 1;
  s->flags = FLG_BUF | FLG_NO_INTERLEAVE;
  s->buf = malloc (s->width * s->height * 3);
  /* FIXME do something with this data */
  CHK (do_scan (s));

  /* Lighting */
  /* medium */
  write_word (fd, LAMP_R_ON, 0x0017);
  write_word (fd, LAMP_R_OFF, 0x0200);
  write_word (fd, LAMP_G_ON, 0x0017);
  write_word (fd, LAMP_G_OFF, 0x01d7 /* also 01db */ );
  write_word (fd, LAMP_B_ON, 0x0017);
  write_word (fd, LAMP_B_OFF, 0x01af /* also 01b2 */ );
  /* FIXME do something with this data */
  CHK (do_scan (s));

  /* Lighting */
  /* bright */
  write_word (fd, LAMP_R_ON, 0x0017);
  write_word (fd, LAMP_R_OFF, 0x0e8e /* also 1040 */ );
  write_word (fd, LAMP_G_ON, 0x0017);
  write_word (fd, LAMP_G_OFF, 0x0753 /* also 0718 */ );
  write_word (fd, LAMP_B_ON, 0x0017);
  write_word (fd, LAMP_B_OFF, 0x03f8 /* also 040d */ );
  /* FIXME do something with this data */
  CHK (do_scan (s));
  free (s->buf);
  s->buf = NULL;

  /* The trace gets a little iffy from here on out since the log files
     are missing different urb's.  This is kind of a puzzled-out
     compilation. */

  write_byte (fd, MICROSTEP, 0x13 /* pins active */ );
  write_byte (fd, STEP_PWM, 0x3f);
  read_byte (fd, STATUS, &result);	/* wants 0c */

  /* Stepper home */
  write_byte (fd, COMMAND, 0x02);
  /* Step size */
  write_word (fd, STEP_SIZE, 0x041a /* 300 dpi */ );
  /* Skip steps */
  write_word (fd, SKIP_STEPS, 0x0000);
  /* Pause buffer levels */
  write_byte (fd, BUFFER_LIMIT, 0x57);
  /* Resume buffer levels */
  write_byte (fd, BUFFER_RESUME, 0x02);

  wait_for_return (fd);
  /* stepper forward small */
  write_byte (fd, COMMAND, 0x01);
  read_byte (fd, STATUS, &result);	/* wants 0c */
  usleep (200000);
  write_byte (fd, STEP_PWM, 0x1f);

  /* Read in cal strip at bottom of scanner (to adjust gain/offset
     tables.  Note that this isn't the brightest lighting condition.)
     At 300 dpi: black rows 0-25; white rows 30-75; beginning
     of glass 90.
     This produces 574k of data, so save it to a temp file. */
  if (!s->fname)
    {
      DBG (1, "No temp filename!\n");
      s->fname = strdup ("/tmp/cal.XXXXXX");
      mktemp (s->fname);
    }
  s->width = 2551;
  s->height = 75;
  s->flags = FLG_PPM_HEADER | FLG_NO_INTERLEAVE;
  CHK (do_scan (s));
  compute_ogn (s->fname);
  unlink (s->fname);

  write_byte (fd, STEP_PWM, 0x3f);
  /* stepper home */
  write_byte (fd, COMMAND, 0x02);

  /* discard the remaining data */
  read_byte (fd, IMAGE_DATA_AVAIL, &result);	/* wants 42,4c */
  if (result > 1)
    {
      read_bulk_size (fd, result, 0, 0, 0);
      DBG (11, "read %dk extra\n", result);
    }
  read_byte (fd, 0x69, &result);	/* wants 02 */
  write_byte (fd, 0x69, 0x0a);

  lights_out (fd);
  init (fd);

#if 0
  /* Repeatedly send this every 1 second.  Button scan?  FIXME */
  gl640ReadReq (fd, GL640_GPIO_READ, &result);	/* wants 00 */
#endif

  return 0;
}


/* The number of regions in the calibration strip (black & white). */
#define NREGIONS 2

/* Compute the offset/gain table from the calibration strip.  This is
   somewhat more complicated than necessary because I don't hard-code the
   strip widths; I try to figure out the regions based on the scan data.
   Theoretically, the region-finder should work for any number of distinct
   regions (but there are only 2 on this scanner.) 
   This produces the CAL_FILE_OGN file, the final offset/gain table. */
static SANE_Status
compute_ogn (char *calfilename)
{
  byte *linebuf, *oldline, *newline;
  mode_t oldmask;
  FILE *fp;
  int width, height, nlines = 0, region = -1, i, transition = 1, badcnt;
  int pct;
  int reglines[NREGIONS];
  float *avg;
  float max_range[3], tmp1, tmp2;

  fp = fopen (calfilename, "r");
  if (!fp)
    {
      DBG (1, "open %s\n", calfilename);
      return SANE_STATUS_EOF;
    }
  fscanf (fp, "P6 %d %d %*d ", &width, &height);
  DBG (12, "cal file %s %dx%d\n", calfilename, width, height);
  width = width * 3;		/* 1 byte each of r, g, b */
  /* make a buffer holding 2 lines of data */
  linebuf = calloc (width * 2, sizeof (linebuf[0]));
  /* first line is data read buffer */
  newline = linebuf;
  /* second line is a temporary holding spot in case the next line read
     is the black/white transition, in which case we'll disregard this
     one. */
  oldline = linebuf + width;
  /* column averages per region */
  avg = calloc (width * NREGIONS, sizeof (avg[0]));

  while (nlines < height)
    {
      if (fread (newline, 1, width, fp) != (size_t) width)
	break;
      nlines++;
      /* Check if new line is majorly different than old.
         Criteria is 10 pixels differing by more than 10%. */
      badcnt = 0;
      for (i = 0; i < width; i++)
	{
	  pct = newline[i] - oldline[i];
	  /* Fix by M.Reinelt <reinelt@eunet.at>
	   * do NOT use 10% (think of a dark area with
	   * oldline=4 and newline=5, which is a change of 20% !!
	   * Use an absolute difference of 10 as criteria
	   */
	  if (pct < -10 || pct > 10)
	    {
	      badcnt++;
	      DBG (16, "pix%d[%d/%d] ", i, newline[i], oldline[i]);
	    }
	}
      DBG (13, "line %d changed %d\n", nlines, badcnt);
      if ((badcnt > 10) || (nlines == height))
	{
	  /* End of region.  Lines are different or end of data. */
	  transition++;
	  if (transition == 1)
	    DBG (12, "Region %d lines %d-%d\n",
		 region, nlines - reglines[region], nlines - 1);
	}
      else
	{
	  /* Lines are similar, so still in region.  */
	  if (transition)
	    {
	      /* There was just a transition, so this is the start of a
	         new region. */
	      region++;
	      if (region >= NREGIONS)
		/* Too many regions detected.  Err below. */
		break;
	      transition = 0;
	      reglines[region] = 0;
	    }
	  /* Add oldline to the current region's average */
	  for (i = 0; i < width; i++)
	    avg[i + region * width] += oldline[i];
	  reglines[region]++;
	}
      /* And newline becomes old */
      memcpy (oldline, newline, width);
    }
  fclose (fp);
  free (linebuf);
  region++;			/* now call it number of regions instead of index */
  DBG (11, "read %d lines as %d regions\n", nlines, region);

  /* Check to see if we screwed up */
  if (region != NREGIONS)
    {
      DBG (1, "Warning: gain/offset compute failed.\n"
	   "Found %d regions instead of %d.\n", region, NREGIONS);
      for (i = 0; i < region; i++)
	DBG (1, "   Region %d: %d lines\n",
	     i, (i >= NREGIONS) ? -1 : reglines[i]);
      free (avg);
      return SANE_STATUS_UNSUPPORTED;
    }

  /* Now we've got regions and sums.  Find averages and range. */
  max_range[0] = max_range[1] = max_range[2] = 0.0;
  for (i = 0; i < width; i++)
    {
      /* Convert sums to averages */
      /* black region */
      tmp1 = avg[i] /= reglines[0];
      /* white region */
      tmp2 = avg[i + width] /= reglines[1];
      /* Track largest range for each color.
         If image is interleaved, use 'i%3', if not, 'i/(width/3)' */
      if ((tmp2 - tmp1) > max_range[i / (width / 3)])
	{
	  max_range[i / (width / 3)] = tmp2 - tmp1;
	  DBG (14, "max %d@%d %f-%f=%f\n",
	       i / (width / 3), i, tmp2, tmp1, tmp2 - tmp1);
	}
    }
  DBG (13, "max range r %f\n", max_range[0]);
  DBG (13, "max range g %f\n", max_range[1]);
  DBG (13, "max range b %f\n", max_range[2]);

  /* Set umask to world r/w so other users can overwrite common cal... */
  oldmask = umask (0);
  fp = fopen (CAL_FILE_OGN, "w");
  /* ... and set it back. */
  umask (oldmask);
  if (!fp)
    {
      DBG (1, "open " CAL_FILE_OGN);
      free (avg);
      return SANE_STATUS_IO_ERROR;
    }

  /* Finally, compute offset and gain */
  for (i = 0; i < width; i++)
    {
      int gain, offset;
      byte ogn[2];

      /* skip line termination flags */
      if (!((i + 1) % (width / 3)))
	{
	  DBG (13, "skip scanline EOL %d/%d\n", i, width);
	  continue;
	}

      /* Gain multiplier: 
         255 : 1.5 times brighter
         511 : 2 times brighter
         1023: 3 times brighter */
#if 1
      /* Original gain/offset */
      gain = 512 * ((max_range[i / (width / 3)] /
		     (avg[i + width] - avg[i])) - 1);
      offset = avg[i];
#else
      /* This doesn't work for some people.  For instance, a negative
         offset would be bad.  */

      /* Enhanced offset and gain calculation by M.Reinelt <reinelt@eunet.at>
       * These expressions were found by an iterative calibration process, 
       * by changing gain and offset values for every pixel until the desired
       * values for black and white were reached, and finding an approximation 
       * formula.
       * Note that offset is linear, but gain isn't!
       */
      offset = (double)3.53 * avg[i] - 125;
      gain = (double)3861.0 * exp(-0.0168 * (avg[i + width] - avg[i]));
#endif

      DBG (14, "%d wht=%f blk=%f diff=%f gain=%d offset=%d\n", i,
	   avg[i + width], avg[i], avg[i + width] - avg[i], gain, offset);
      /* 10-bit gain, 6-bit offset (subtractor) in two bytes */
      ogn[0] = (byte) (((offset << 2) + (gain >> 8)) & 0xFF);
      ogn[1] = (byte) (gain & 0xFF);
      fwrite (ogn, sizeof (byte), 2, fp);
      /* Annoyingly, we seem to use ogn data at 600dpi, while we scanned
         at 300, so double our file.  Much easier than doubling at the
         read. */
      fwrite (ogn, sizeof (byte), 2, fp);
    }

  fclose (fp);
  free (avg);
  return SANE_STATUS_GOOD;
}

static int
check_ogn_file (void)
{
  FILE *fp;
  fp = fopen (CAL_FILE_OGN, "r");
  if (fp)
    {
      fclose (fp);
      return 1;
    }
  return 0;
}

/* Load or fake the offset/gain table */
static void
install_ogn (int fd)
{
  int temp;
  byte *buf;
  FILE *fp;

  /* 8.5in at 600dpi = 5104 pixels in scan head
     10-bit gain + 6-bit offset = 2 bytes per pixel, so 10208 bytes */
  buf = malloc (10208);

  fp = fopen (CAL_FILE_OGN, "r");
  if (fp)
    {
      fread (buf, 2, 5100, fp);
      /* screw the last 4 pixels */
    }
  else
    {
      /* Make up the gain/offset data. */
#define GAIN 256		/* 1.5x */
#define OFFSET 0
      for (temp = 0; temp < 10208; temp += 2)
	{
	  buf[temp] = (byte) ((OFFSET << 2) + (GAIN >> 8));
	  buf[temp + 1] = (byte) (GAIN & 0xFF);
	}
    }
  /* Gain/offset table (r,g,b) */
  write_byte (fd, DATAPORT_TARGET, DP_R | DP_OFFSET);
  write_word (fd, DATAPORT_ADDR, DP_WRITE);
  write_bulk (fd, DATAPORT, buf, 10208);
  if (fp)
    fread (buf, 2, 5100, fp);
  write_byte (fd, DATAPORT_TARGET, DP_G | DP_OFFSET);
  write_word (fd, DATAPORT_ADDR, DP_WRITE);
  write_bulk (fd, DATAPORT, buf, 10208);
  if (fp)
    {
      fread (buf, 2, 5100, fp);
      fclose (fp);
    }
  write_byte (fd, DATAPORT_TARGET, DP_B | DP_OFFSET);
  write_word (fd, DATAPORT_ADDR, DP_WRITE);
  write_bulk (fd, DATAPORT, buf, 10208);

  free (buf);
  return;
}


/* Scan sequence */
/* resolution is 75,150,300,600,1200
   scan coordinates in 600-dpi pixels */
static SANE_Status
scan (CANON_Handle * opt)
{
  SANE_Status status;
  const int left_edge = 0x004b;	/* Just for my scanner, or is this
				   universal?  Calibrate? */
  int temp;
  int fd = opt->fd;
  byte result;
  byte *buf;

  /* Check status. (not in w2k driver) */
  read_byte (fd, STATUS, &result);	/* wants 2f or 2d */
  if (!(result & STATUS_HOME) /*0x2d */ )
    return SANE_STATUS_DEVICE_BUSY;
  /* or force it to return? 
     write_byte(fd, COMMAND, 0x02); 
     wait_for_return(fd);
   */

  /* reserved? */
  read_byte (fd, 0x69, &result);	/* wants 0a */

  read_byte (fd, STATUS, &result);	/* wants 0e */
  read_byte (fd, PAPER_SENSOR, &result);	/* wants 2b */
  write_byte (fd, PAPER_SENSOR, 0x2b);
  /* Color mode:
     1-Channel Line Rate Color 0x15.
     1-Channel Grayscale 0x14 (and we skip some of these tables) */
  write_byte (fd, COLOR_MODE, 0x15);

  /* install the offset/gain table */
  install_ogn (fd);

  read_byte (fd, STATUS, &result);	/* wants 0e */
  /* move forward to "glass 0" */
  write_byte (fd, COMMAND, 0x01);
  read_byte (fd, STATUS, &result);	/* wants 0c */

  /* create gamma table */
  buf = malloc (0x400);
  for (temp = 0; temp < 0x0400; temp++)
    /* gamma calculation by M.Reinelt <reinelt@eunet.at> */
    buf[temp] = (double) 255.0 * exp(log((temp + 0.5) / 1023.0) / opt->gamma)
	+ 0.5;

  /* Gamma R, write and verify */
  write_byte (fd, DATAPORT_TARGET, DP_R | DP_GAMMA);
  write_word (fd, DATAPORT_ADDR, DP_WRITE);
  write_bulk (fd, DATAPORT, buf, 0x0400);
  write_byte (fd, DATAPORT_TARGET, DP_R | DP_GAMMA);
  write_word (fd, DATAPORT_ADDR, DP_READ);
  read_bulk (fd, DATAPORT, buf, 0x0400);
  /* Gamma G */
  write_byte (fd, DATAPORT_TARGET, DP_G | DP_GAMMA);
  write_word (fd, DATAPORT_ADDR, DP_WRITE);
  write_bulk (fd, DATAPORT, buf, 0x0400);
  write_byte (fd, DATAPORT_TARGET, DP_G | DP_GAMMA);
  write_word (fd, DATAPORT_ADDR, DP_READ);
  read_bulk (fd, DATAPORT, buf, 0x0400);
  /* Gamma B */
  write_byte (fd, DATAPORT_TARGET, DP_B | DP_GAMMA);
  write_word (fd, DATAPORT_ADDR, DP_WRITE);
  write_bulk (fd, DATAPORT, buf, 0x0400);
  write_byte (fd, DATAPORT_TARGET, DP_B | DP_GAMMA);
  write_word (fd, DATAPORT_ADDR, DP_READ);
  read_bulk (fd, DATAPORT, buf, 0x0400);
  free (buf);

  write_byte (fd, CLOCK_DIV, 0x04);
  /* Resolution: dpi 75(ie) 100,150(1c) 200,300(1a) 600,1200(18) */
  switch (opt->resolution)
    {
    case 150:
      write_byte (fd, 0x09, 0x1c);
      break;
    case 300:
      write_byte (fd, 0x09, 0x1a);
      break;
    case 600:
    case 1200:
      /* actually 600 dpi horiz max */
      write_byte (fd, 0x09, 0x18);
      break;
    default:			/* 75 */
      write_byte (fd, 0x09, 0x1e);
      opt->resolution = 75;
    }

  write_word (fd, ACTIVE_PX_START, left_edge);
  /* Data pixel start.  Measured at 600dpi regardless of
     scan resolution.  0-position is 0x004b */
  write_word (fd, DATA_PX_START, left_edge + opt->x1);
  /* Data pixel end.  Measured at 600dpi regardless of scan
     resolution. */
  write_word (fd, DATA_PX_END, left_edge + opt->x2);
  /* greyscale has 14,03, different lights */
  write_byte (fd, COLOR_MODE, 0x15);
  write_byte (fd, 0x29, 0x02);
  /* Lights */
  write_word (fd, LAMP_R_ON, 0x0017);
  /* "Hi-low color" selection from windows driver.  low(1437) hi(1481) */
  write_word (fd, LAMP_R_OFF, 0x1437);
  write_word (fd, LAMP_G_ON, 0x0017);
  write_word (fd, LAMP_G_OFF, 0x094e);
  write_word (fd, LAMP_B_ON, 0x0017);
  write_word (fd, LAMP_B_OFF, 0x0543);

  /* Analog static offset R,G,B.  Greyscale has 0,0,0 */
  write_byte (fd, 0x38, 0x3f);
  write_byte (fd, 0x39, 0x3f);
  write_byte (fd, 0x3a, 0x3f);
  /* Analog static gain R,G,B (normally 0x01) */
  write_byte (fd, 0x3b, opt->gain);
  write_byte (fd, 0x3c, opt->gain);
  write_byte (fd, 0x3d, opt->gain);
  /* Digital gain/offset settings.  Greyscale has 0 */
  write_byte (fd, 0x3e, 0x1a);

  {
    /* Stepper motion setup. */
    int stepsize, faststep = 0x0104, reverse = 0x28, phase, pwm = 0x1f;
    switch (opt->resolution)
      {
      case 75:
	stepsize = 0x0106;
	faststep = 0x0106;
	reverse = 0;
	phase = 0x39a8;
	pwm = 0x3f;
	break;
      case 150:
	stepsize = 0x020d;
	phase = 0x3198;
	break;
      case 300:
	stepsize = 0x041a;
	phase = 0x2184;
	break;
      case 600:
	stepsize = 0x0835;
	phase = 0x0074;
	break;
      case 1200:
	/* 1200 dpi y only, x is 600 dpi */
	stepsize = 0x106b;
	phase = 0x41ac;
	break;
      default:
	DBG (1, "BAD RESOLUTION");
	return SANE_STATUS_UNSUPPORTED;
      }

    write_word (fd, STEP_SIZE, stepsize);
    write_word (fd, FAST_STEP, faststep);
    /* There sounds like a weird step disjoint at the end of skipsteps
       at 75dpi, so I think that's why skipsteps=0 at 75dpi in the
       Windows driver.  It still works at the normal 0x017a though. */
    /* cal strip is 0x17a steps, plus 2 300dpi microsteps per pixel */
    write_word (fd, SKIP_STEPS, 0x017a /* cal strip */  + opt->y1 * 2);
    /* FIXME could be 0x57, why not? */
    write_byte (fd, BUFFER_LIMIT, 0x20);
    write_byte (fd, BUFFER_RESUME, 0x02);
    write_byte (fd, REVERSE_STEPS, reverse);
    /* motor resume phasing */
    write_word (fd, 0x52, phase);
    write_byte (fd, STEP_PWM, pwm);
  }

  read_byte (fd, PAPER_SENSOR, &result);	/* wants 2b */
  write_byte (fd, PAPER_SENSOR, 0x0b);

  opt->width = (opt->x2 - opt->x1) * opt->resolution / 600 + 1;
  opt->height = (opt->y2 - opt->y1) * opt->resolution / 600;
  opt->flags = 0;
  DBG (1, "width=%d height=%d dpi=%d\n", opt->width, opt->height,
       opt->resolution);
  CHK (do_scan (opt));

  read_byte (fd, PAPER_SENSOR, &result);	/* wants 0b */
  write_byte (fd, PAPER_SENSOR, 0x2b);
  write_byte (fd, STEP_PWM, 0x3f);

  lights_out (fd);
  /* home */
  write_byte (fd, COMMAND, 0x02);

  return status;
}


static SANE_Status
CANON_set_scan_parameters (CANON_Handle * scan,
			   const int forceCal,
			   const int gray,
			   const int left,
			   const int top,
			   const int right,
			   const int bottom, 
			   const int res, 
			   const int gain, 
			   const double gamma)
{
  DBG (2, "CANON_set_scan_parameters:\n");
  DBG (2, "cal   = %d\n", forceCal);
  DBG (2, "gray  = %d (ignored)\n", gray);
  DBG (2, "res   = %d\n", res);
  DBG (2, "gain  = %d\n", gain);
  DBG (2, "gamma = %f\n", gamma);
  DBG (2, "in 600dpi pixels:\n");
  DBG (2, "left  = %d, top    = %d\n", left, top);
  DBG (2, "right = %d, bottom = %d\n", right, bottom);

  /* Validate the input parameters */
  if ((left < 0) || (right > CANON_MAX_WIDTH))
    return SANE_STATUS_INVAL;

  if ((top < 0) || (bottom > CANON_MAX_HEIGHT))
    return SANE_STATUS_INVAL;

  if (((right - left) < 10) || ((bottom - top) < 10))
    return SANE_STATUS_INVAL;

  if ((res != 75) && (res != 150) && (res != 300)
      && (res != 600) && (res != 1200))
    return SANE_STATUS_INVAL;

  if ((gain < 0) || (gain > 64))
    return SANE_STATUS_INVAL;

  if (gamma <= 0.0)
    return SANE_STATUS_INVAL;

  /* Store params */
  scan->resolution = res;
  scan->x1 = left;
  scan->x2 = right - /* subtract 1 pixel */ 600 / scan->resolution;
  scan->y1 = top;
  scan->y2 = bottom;
  scan->gain = gain;
  scan->gamma = gamma;
  scan->flags = forceCal ? FLG_FORCE_CAL : 0;

  return SANE_STATUS_GOOD;
}


static SANE_Status
CANON_close_device (CANON_Handle * scan)
{
  DBG (3, "CANON_close_device:\n");
  sanei_usb_close (scan->fd);
  return SANE_STATUS_GOOD;
}


static SANE_Status
CANON_open_device (CANON_Handle * scan, const char *dev)
{
  SANE_Word vendor;
  SANE_Word product;
  SANE_Status res;

  DBG (3, "CANON_open_device: `%s'\n", dev);

  scan->fname = NULL;
  scan->fp = NULL;
  scan->flags = 0;

  res = sanei_usb_open (dev, &scan->fd);
  if (res != SANE_STATUS_GOOD)
    {
      DBG (1, "CANON_open_device: couldn't open device `%s': %s\n", dev,
	   sane_strstatus (res));
      return res;
    }

#ifndef NO_AUTODETECT
  /* We have opened the device. Check that it is a USB scanner. */
  if (sanei_usb_get_vendor_product (scan->fd, &vendor, &product) !=
      SANE_STATUS_GOOD)
    {
      DBG (1, "CANON_open_device: sanei_usb_get_vendor_product failed\n");
      /* This is not a USB scanner, or SANE or the OS doesn't support it. */
      sanei_usb_close (scan->fd);
      scan->fd = -1;
      return SANE_STATUS_UNSUPPORTED;
    }

  /* Make sure we have a CANON scanner */
  if ((vendor != 0x04a9) || (product != 0x2204))
    {
      DBG (1, "CANON_open_device: incorrect vendor/product (0x%x/0x%x)\n",
	   vendor, product);
      sanei_usb_close (scan->fd);
      scan->fd = -1;
      return SANE_STATUS_UNSUPPORTED;
    }
#endif

  return SANE_STATUS_GOOD;
}


static const char *
CANON_get_device_name (CANON_Handle * scanner)
{
  scanner = scanner;		/* Eliminate warning about unused parameters */
  return "Canoscan FB630U";
}


static SANE_Status
CANON_finish_scan (CANON_Handle * scanner)
{
  DBG (3, "CANON_finish_scan:\n");
  if (scanner->fp)
    fclose (scanner->fp);
  scanner->fp = NULL;

  /* remove temp file */
  if (scanner->fname)
    {
      DBG (4, "removing temp file %s\n", scanner->fname);
      unlink (scanner->fname);
      free (scanner->fname);
    }
  scanner->fname = NULL;

  return SANE_STATUS_GOOD;
}


static SANE_Status
CANON_start_scan (CANON_Handle * scanner)
{
  int rv;
  SANE_Status status;
  DBG (3, "CANON_start_scan called\n");

  /* choose a temp file name for scan data */
  scanner->fname = strdup ("/tmp/scan.XXXXXX");
  if (!mktemp (scanner->fname))
    return SANE_STATUS_IO_ERROR;

  /* calibrate if needed */
  rv = init (scanner->fd);
  if (rv < 0) {
      DBG(1, "Can't talk on USB.\n");
      return SANE_STATUS_IO_ERROR;
  }
  if ((rv == 1)
      || !check_ogn_file () 
      || (scanner->flags & FLG_FORCE_CAL)) {
      plugin_cal (scanner);
      wait_for_return (scanner->fd);
  }
  
  /* scan */
  if ((status = scan (scanner)) != SANE_STATUS_GOOD)
    {
      CANON_finish_scan (scanner);
      return status;
    }

  /* read the temp file back out */
  scanner->fp = fopen (scanner->fname, "r");
  DBG (4, "reading %s\n", scanner->fname);
  if (!scanner->fp)
    {
      DBG (1, "open %s", scanner->fname);
      return SANE_STATUS_IO_ERROR;
    }
  return SANE_STATUS_GOOD;
}


static SANE_Status
CANON_read (CANON_Handle * scanner, SANE_Byte * data,
	    SANE_Int max_length, SANE_Int * length)
{
  SANE_Status status;
  int red_len;

  DBG (5, "CANON_read called\n");
  if (!scanner->fp)
    return SANE_STATUS_INVAL;
  red_len = fread (data, 1, max_length, scanner->fp);
  /* return some data */
  if (red_len > 0)
    {
      *length = red_len;
      DBG (5, "CANON_read returned (%d/%d)\n", *length, max_length);
      return SANE_STATUS_GOOD;
    }

  /* EOF or file err */
  *length = 0;
  if (feof (scanner->fp))
    {
      DBG (4, "EOF\n");
      status = SANE_STATUS_EOF;
    }
  else
    {
      DBG (4, "IO ERR\n");
      status = SANE_STATUS_IO_ERROR;
    }

  CANON_finish_scan (scanner);
  DBG (5, "CANON_read returned (%d/%d)\n", *length, max_length);
  return status;
}