aboutsummaryrefslogtreecommitdiff
path: root/drivers/media/video/bw-qcam.c
blob: f09df9dffaae50d3db2ac887757e53d4fb2ff61d (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
/*
 *    QuickCam Driver For Video4Linux.
 *
 *	Video4Linux conversion work by Alan Cox.
 *	Parport compatibility by Phil Blundell.
 *	Busy loop avoidance by Mark Cooke.
 *
 *    Module parameters:
 *
 *	maxpoll=<1 - 5000>
 *
 *	  When polling the QuickCam for a response, busy-wait for a
 *	  maximum of this many loops. The default of 250 gives little
 *	  impact on interactive response.
 *
 *	  NOTE: If this parameter is set too high, the processor
 *		will busy wait until this loop times out, and then
 *		slowly poll for a further 5 seconds before failing
 *		the transaction. You have been warned.
 *
 *	yieldlines=<1 - 250>
 *
 *	  When acquiring a frame from the camera, the data gathering
 *	  loop will yield back to the scheduler after completing
 *	  this many lines. The default of 4 provides a trade-off
 *	  between increased frame acquisition time and impact on
 *	  interactive response.
 */

/* qcam-lib.c -- Library for programming with the Connectix QuickCam.
 * See the included documentation for usage instructions and details
 * of the protocol involved. */


/* Version 0.5, August 4, 1996 */
/* Version 0.7, August 27, 1996 */
/* Version 0.9, November 17, 1996 */


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

Copyright (C) 1996 by Scott Laird

Permission is hereby granted, free of charge, to any person obtaining
a copy of this software and associated documentation files (the
"Software"), to deal in the Software without restriction, including
without limitation the rights to use, copy, modify, merge, publish,
distribute, sublicense, and/or sell copies of the Software, and to
permit persons to whom the Software is furnished to do so, subject to
the following conditions:

The above copyright notice and this permission notice shall be
included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
IN NO EVENT SHALL SCOTT LAIRD BE LIABLE FOR ANY CLAIM, DAMAGES OR
OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
OTHER DEALINGS IN THE SOFTWARE.

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

#include <linux/module.h>
#include <linux/delay.h>
#include <linux/errno.h>
#include <linux/fs.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/mm.h>
#include <linux/parport.h>
#include <linux/sched.h>
#include <linux/videodev2.h>
#include <linux/mutex.h>
#include <asm/uaccess.h>
#include <media/v4l2-common.h>
#include <media/v4l2-ioctl.h>
#include <media/v4l2-device.h>

/* One from column A... */
#define QC_NOTSET 0
#define QC_UNIDIR 1
#define QC_BIDIR  2
#define QC_SERIAL 3

/* ... and one from column B */
#define QC_ANY          0x00
#define QC_FORCE_UNIDIR 0x10
#define QC_FORCE_BIDIR  0x20
#define QC_FORCE_SERIAL 0x30
/* in the port_mode member */

#define QC_MODE_MASK    0x07
#define QC_FORCE_MASK   0x70

#define MAX_HEIGHT 243
#define MAX_WIDTH 336

/* Bit fields for status flags */
#define QC_PARAM_CHANGE	0x01 /* Camera status change has occurred */

struct qcam {
	struct v4l2_device v4l2_dev;
	struct video_device vdev;
	struct pardevice *pdev;
	struct parport *pport;
	struct mutex lock;
	int width, height;
	int bpp;
	int mode;
	int contrast, brightness, whitebal;
	int port_mode;
	int transfer_scale;
	int top, left;
	int status;
	unsigned int saved_bits;
	unsigned long in_use;
};

static unsigned int maxpoll = 250;   /* Maximum busy-loop count for qcam I/O */
static unsigned int yieldlines = 4;  /* Yield after this many during capture */
static int video_nr = -1;
static unsigned int force_init;		/* Whether to probe aggressively */

module_param(maxpoll, int, 0);
module_param(yieldlines, int, 0);
module_param(video_nr, int, 0);

/* Set force_init=1 to avoid detection by polling status register and
 * immediately attempt to initialize qcam */
module_param(force_init, int, 0);

#define MAX_CAMS 4
static struct qcam *qcams[MAX_CAMS];
static unsigned int num_cams;

static inline int read_lpstatus(struct qcam *q)
{
	return parport_read_status(q->pport);
}

static inline int read_lpdata(struct qcam *q)
{
	return parport_read_data(q->pport);
}

static inline void write_lpdata(struct qcam *q, int d)
{
	parport_write_data(q->pport, d);
}

static void write_lpcontrol(struct qcam *q, int d)
{
	if (d & 0x20) {
		/* Set bidirectional mode to reverse (data in) */
		parport_data_reverse(q->pport);
	} else {
		/* Set bidirectional mode to forward (data out) */
		parport_data_forward(q->pport);
	}

	/* Now issue the regular port command, but strip out the
	 * direction flag */
	d &= ~0x20;
	parport_write_control(q->pport, d);
}


/* qc_waithand busy-waits for a handshake signal from the QuickCam.
 * Almost all communication with the camera requires handshaking. */

static int qc_waithand(struct qcam *q, int val)
{
	int status;
	int runs = 0;

	if (val) {
		while (!((status = read_lpstatus(q)) & 8)) {
			/* 1000 is enough spins on the I/O for all normal
			   cases, at that point we start to poll slowly
			   until the camera wakes up. However, we are
			   busy blocked until the camera responds, so
			   setting it lower is much better for interactive
			   response. */

			if (runs++ > maxpoll)
				msleep_interruptible(5);
			if (runs > (maxpoll + 1000)) /* 5 seconds */
				return -1;
		}
	} else {
		while (((status = read_lpstatus(q)) & 8)) {
			/* 1000 is enough spins on the I/O for all normal
			   cases, at that point we start to poll slowly
			   until the camera wakes up. However, we are
			   busy blocked until the camera responds, so
			   setting it lower is much better for interactive
			   response. */

			if (runs++ > maxpoll)
				msleep_interruptible(5);
			if (runs++ > (maxpoll + 1000)) /* 5 seconds */
				return -1;
		}
	}

	return status;
}

/* Waithand2 is used when the qcam is in bidirectional mode, and the
 * handshaking signal is CamRdy2 (bit 0 of data reg) instead of CamRdy1
 * (bit 3 of status register).  It also returns the last value read,
 * since this data is useful. */

static unsigned int qc_waithand2(struct qcam *q, int val)
{
	unsigned int status;
	int runs = 0;

	do {
		status = read_lpdata(q);
		/* 1000 is enough spins on the I/O for all normal
		   cases, at that point we start to poll slowly
		   until the camera wakes up. However, we are
		   busy blocked until the camera responds, so
		   setting it lower is much better for interactive
		   response. */

		if (runs++ > maxpoll)
			msleep_interruptible(5);
		if (runs++ > (maxpoll + 1000)) /* 5 seconds */
			return 0;
	} while ((status & 1) != val);

	return status;
}

/* qc_command is probably a bit of a misnomer -- it's used to send
 * bytes *to* the camera.  Generally, these bytes are either commands
 * or arguments to commands, so the name fits, but it still bugs me a
 * bit.  See the documentation for a list of commands. */

static int qc_command(struct qcam *q, int command)
{
	int n1, n2;
	int cmd;

	write_lpdata(q, command);
	write_lpcontrol(q, 6);

	n1 = qc_waithand(q, 1);

	write_lpcontrol(q, 0xe);
	n2 = qc_waithand(q, 0);

	cmd = (n1 & 0xf0) | ((n2 & 0xf0) >> 4);
	return cmd;
}

static int qc_readparam(struct qcam *q)
{
	int n1, n2;
	int cmd;

	write_lpcontrol(q, 6);
	n1 = qc_waithand(q, 1);

	write_lpcontrol(q, 0xe);
	n2 = qc_waithand(q, 0);

	cmd = (n1 & 0xf0) | ((n2 & 0xf0) >> 4);
	return cmd;
}


/* Try to detect a QuickCam.  It appears to flash the upper 4 bits of
   the status register at 5-10 Hz.  This is only used in the autoprobe
   code.  Be aware that this isn't the way Connectix detects the
   camera (they send a reset and try to handshake), but this should be
   almost completely safe, while their method screws up my printer if
   I plug it in before the camera. */

static int qc_detect(struct qcam *q)
{
	int reg, lastreg;
	int count = 0;
	int i;

	if (force_init)
		return 1;

	lastreg = reg = read_lpstatus(q) & 0xf0;

	for (i = 0; i < 500; i++) {
		reg = read_lpstatus(q) & 0xf0;
		if (reg != lastreg)
			count++;
		lastreg = reg;
		mdelay(2);
	}


#if 0
	/* Force camera detection during testing. Sometimes the camera
	   won't be flashing these bits. Possibly unloading the module
	   in the middle of a grab? Or some timeout condition?
	   I've seen this parameter as low as 19 on my 450Mhz box - mpc */
	printk(KERN_DEBUG "Debugging: QCam detection counter <30-200 counts as detected>: %d\n", count);
	return 1;
#endif

	/* Be (even more) liberal in what you accept...  */

	if (count > 20 && count < 400) {
		return 1;	/* found */
	} else {
		printk(KERN_ERR "No Quickcam found on port %s\n",
				q->pport->name);
		printk(KERN_DEBUG "Quickcam detection counter: %u\n", count);
		return 0;	/* not found */
	}
}

/* Decide which scan mode to use.  There's no real requirement that
 * the scanmode match the resolution in q->height and q-> width -- the
 * camera takes the picture at the resolution specified in the
 * "scanmode" and then returns the image at the resolution specified
 * with the resolution commands.  If the scan is bigger than the
 * requested resolution, the upper-left hand corner of the scan is
 * returned.  If the scan is smaller, then the rest of the image
 * returned contains garbage. */

static int qc_setscanmode(struct qcam *q)
{
	int old_mode = q->mode;

	switch (q->transfer_scale) {
	case 1:
		q->mode = 0;
		break;
	case 2:
		q->mode = 4;
		break;
	case 4:
		q->mode = 8;
		break;
	}

	switch (q->bpp) {
	case 4:
		break;
	case 6:
		q->mode += 2;
		break;
	}

	switch (q->port_mode & QC_MODE_MASK) {
	case QC_BIDIR:
		q->mode += 1;
		break;
	case QC_NOTSET:
	case QC_UNIDIR:
		break;
	}

	if (q->mode != old_mode)
		q->status |= QC_PARAM_CHANGE;

	return 0;
}


/* Reset the QuickCam.  This uses the same sequence the Windows
 * QuickPic program uses.  Someone with a bi-directional port should
 * check that bi-directional mode is detected right, and then
 * implement bi-directional mode in qc_readbyte(). */

static void qc_reset(struct qcam *q)
{
	switch (q->port_mode & QC_FORCE_MASK) {
	case QC_FORCE_UNIDIR:
		q->port_mode = (q->port_mode & ~QC_MODE_MASK) | QC_UNIDIR;
		break;

	case QC_FORCE_BIDIR:
		q->port_mode = (q->port_mode & ~QC_MODE_MASK) | QC_BIDIR;
		break;

	case QC_ANY:
		write_lpcontrol(q, 0x20);
		write_lpdata(q, 0x75);

		if (read_lpdata(q) != 0x75)
			q->port_mode = (q->port_mode & ~QC_MODE_MASK) | QC_BIDIR;
		else
			q->port_mode = (q->port_mode & ~QC_MODE_MASK) | QC_UNIDIR;
		break;
	}

	write_lpcontrol(q, 0xb);
	udelay(250);
	write_lpcontrol(q, 0xe);
	qc_setscanmode(q);		/* in case port_mode changed */
}



/* Reset the QuickCam and program for brightness, contrast,
 * white-balance, and resolution. */

static void qc_set(struct qcam *q)
{
	int val;
	int val2;

	qc_reset(q);

	/* Set the brightness.  Yes, this is repetitive, but it works.
	 * Shorter versions seem to fail subtly.  Feel free to try :-). */
	/* I think the problem was in qc_command, not here -- bls */

	qc_command(q, 0xb);
	qc_command(q, q->brightness);

	val = q->height / q->transfer_scale;
	qc_command(q, 0x11);
	qc_command(q, val);
	if ((q->port_mode & QC_MODE_MASK) == QC_UNIDIR && q->bpp == 6) {
		/* The normal "transfers per line" calculation doesn't seem to work
		   as expected here (and yet it works fine in qc_scan).  No idea
		   why this case is the odd man out.  Fortunately, Laird's original
		   working version gives me a good way to guess at working values.
		   -- bls */
		val = q->width;
		val2 = q->transfer_scale * 4;
	} else {
		val = q->width * q->bpp;
		val2 = (((q->port_mode & QC_MODE_MASK) == QC_BIDIR) ? 24 : 8) *
			q->transfer_scale;
	}
	val = DIV_ROUND_UP(val, val2);
	qc_command(q, 0x13);
	qc_command(q, val);

	/* Setting top and left -- bls */
	qc_command(q, 0xd);
	qc_command(q, q->top);
	qc_command(q, 0xf);
	qc_command(q, q->left / 2);

	qc_command(q, 0x19);
	qc_command(q, q->contrast);
	qc_command(q, 0x1f);
	qc_command(q, q->whitebal);

	/* Clear flag that we must update the grabbing parameters on the camera
	   before we grab the next frame */
	q->status &= (~QC_PARAM_CHANGE);
}

/* Qc_readbytes reads some bytes from the QC and puts them in
   the supplied buffer.  It returns the number of bytes read,
   or -1 on error. */

static inline int qc_readbytes(struct qcam *q, char buffer[])
{
	int ret = 1;
	unsigned int hi, lo;
	unsigned int hi2, lo2;
	static int state;

	if (buffer == NULL) {
		state = 0;
		return 0;
	}

	switch (q->port_mode & QC_MODE_MASK) {
	case QC_BIDIR:		/* Bi-directional Port */
		write_lpcontrol(q, 0x26);
		lo = (qc_waithand2(q, 1) >> 1);
		hi = (read_lpstatus(q) >> 3) & 0x1f;
		write_lpcontrol(q, 0x2e);
		lo2 = (qc_waithand2(q, 0) >> 1);
		hi2 = (read_lpstatus(q) >> 3) & 0x1f;
		switch (q->bpp) {
		case 4:
			buffer[0] = lo & 0xf;
			buffer[1] = ((lo & 0x70) >> 4) | ((hi & 1) << 3);
			buffer[2] = (hi & 0x1e) >> 1;
			buffer[3] = lo2 & 0xf;
			buffer[4] = ((lo2 & 0x70) >> 4) | ((hi2 & 1) << 3);
			buffer[5] = (hi2 & 0x1e) >> 1;
			ret = 6;
			break;
		case 6:
			buffer[0] = lo & 0x3f;
			buffer[1] = ((lo & 0x40) >> 6) | (hi << 1);
			buffer[2] = lo2 & 0x3f;
			buffer[3] = ((lo2 & 0x40) >> 6) | (hi2 << 1);
			ret = 4;
			break;
		}
		break;

	case QC_UNIDIR:	/* Unidirectional Port */
		write_lpcontrol(q, 6);
		lo = (qc_waithand(q, 1) & 0xf0) >> 4;
		write_lpcontrol(q, 0xe);
		hi = (qc_waithand(q, 0) & 0xf0) >> 4;

		switch (q->bpp) {
		case 4:
			buffer[0] = lo;
			buffer[1] = hi;
			ret = 2;
			break;
		case 6:
			switch (state) {
			case 0:
				buffer[0] = (lo << 2) | ((hi & 0xc) >> 2);
				q->saved_bits = (hi & 3) << 4;
				state = 1;
				ret = 1;
				break;
			case 1:
				buffer[0] = lo | q->saved_bits;
				q->saved_bits = hi << 2;
				state = 2;
				ret = 1;
				break;
			case 2:
				buffer[0] = ((lo & 0xc) >> 2) | q->saved_bits;
				buffer[1] = ((lo & 3) << 4) | hi;
				state = 0;
				ret = 2;
				break;
			}
			break;
		}
		break;
	}
	return ret;
}

/* requests a scan from the camera.  It sends the correct instructions
 * to the camera and then reads back the correct number of bytes.  In
 * previous versions of this routine the return structure contained
 * the raw output from the camera, and there was a 'qc_convertscan'
 * function that converted that to a useful format.  In version 0.3 I
 * rolled qc_convertscan into qc_scan and now I only return the
 * converted scan.  The format is just an one-dimensional array of
 * characters, one for each pixel, with 0=black up to n=white, where
 * n=2^(bit depth)-1.  Ask me for more details if you don't understand
 * this. */

static long qc_capture(struct qcam *q, char __user *buf, unsigned long len)
{
	int i, j, k, yield;
	int bytes;
	int linestotrans, transperline;
	int divisor;
	int pixels_per_line;
	int pixels_read = 0;
	int got = 0;
	char buffer[6];
	int  shift = 8 - q->bpp;
	char invert;

	if (q->mode == -1)
		return -ENXIO;

	qc_command(q, 0x7);
	qc_command(q, q->mode);

	if ((q->port_mode & QC_MODE_MASK) == QC_BIDIR) {
		write_lpcontrol(q, 0x2e);	/* turn port around */
		write_lpcontrol(q, 0x26);
		qc_waithand(q, 1);
		write_lpcontrol(q, 0x2e);
		qc_waithand(q, 0);
	}

	/* strange -- should be 15:63 below, but 4bpp is odd */
	invert = (q->bpp == 4) ? 16 : 63;

	linestotrans = q->height / q->transfer_scale;
	pixels_per_line = q->width / q->transfer_scale;
	transperline = q->width * q->bpp;
	divisor = (((q->port_mode & QC_MODE_MASK) == QC_BIDIR) ? 24 : 8) *
		q->transfer_scale;
	transperline = DIV_ROUND_UP(transperline, divisor);

	for (i = 0, yield = yieldlines; i < linestotrans; i++) {
		for (pixels_read = j = 0; j < transperline; j++) {
			bytes = qc_readbytes(q, buffer);
			for (k = 0; k < bytes && (pixels_read + k) < pixels_per_line; k++) {
				int o;
				if (buffer[k] == 0 && invert == 16) {
					/* 4bpp is odd (again) -- inverter is 16, not 15, but output
					   must be 0-15 -- bls */
					buffer[k] = 16;
				}
				o = i * pixels_per_line + pixels_read + k;
				if (o < len) {
					got++;
					put_user((invert - buffer[k]) << shift, buf + o);
				}
			}
			pixels_read += bytes;
		}
		qc_readbytes(q, NULL);	/* reset state machine */

		/* Grabbing an entire frame from the quickcam is a lengthy
		   process. We don't (usually) want to busy-block the
		   processor for the entire frame. yieldlines is a module
		   parameter. If we yield every line, the minimum frame
		   time will be 240 / 200 = 1.2 seconds. The compile-time
		   default is to yield every 4 lines. */
		if (i >= yield) {
			msleep_interruptible(5);
			yield = i + yieldlines;
		}
	}

	if ((q->port_mode & QC_MODE_MASK) == QC_BIDIR) {
		write_lpcontrol(q, 2);
		write_lpcontrol(q, 6);
		udelay(3);
		write_lpcontrol(q, 0xe);
	}
	if (got < len)
		return got;
	return len;
}

/*
 *	Video4linux interfacing
 */

static int qcam_querycap(struct file *file, void  *priv,
					struct v4l2_capability *vcap)
{
	struct qcam *qcam = video_drvdata(file);

	strlcpy(vcap->driver, qcam->v4l2_dev.name, sizeof(vcap->driver));
	strlcpy(vcap->card, "B&W Quickcam", sizeof(vcap->card));
	strlcpy(vcap->bus_info, "parport", sizeof(vcap->bus_info));
	vcap->capabilities = V4L2_CAP_VIDEO_CAPTURE | V4L2_CAP_READWRITE;
	return 0;
}

static int qcam_enum_input(struct file *file, void *fh, struct v4l2_input *vin)
{
	if (vin->index > 0)
		return -EINVAL;
	strlcpy(vin->name, "Camera", sizeof(vin->name));
	vin->type = V4L2_INPUT_TYPE_CAMERA;
	vin->audioset = 0;
	vin->tuner = 0;
	vin->std = 0;
	vin->status = 0;
	return 0;
}

static int qcam_g_input(struct file *file, void *fh, unsigned int *inp)
{
	*inp = 0;
	return 0;
}

static int qcam_s_input(struct file *file, void *fh, unsigned int inp)
{
	return (inp > 0) ? -EINVAL : 0;
}

static int qcam_queryctrl(struct file *file, void *priv,
					struct v4l2_queryctrl *qc)
{
	switch (qc->id) {
	case V4L2_CID_BRIGHTNESS:
		return v4l2_ctrl_query_fill(qc, 0, 255, 1, 180);
	case V4L2_CID_CONTRAST:
		return v4l2_ctrl_query_fill(qc, 0, 255, 1, 192);
	case V4L2_CID_GAMMA:
		return v4l2_ctrl_query_fill(qc, 0, 255, 1, 105);
	}
	return -EINVAL;
}

static int qcam_g_ctrl(struct file *file, void *priv,
					struct v4l2_control *ctrl)
{
	struct qcam *qcam = video_drvdata(file);
	int ret = 0;

	switch (ctrl->id) {
	case V4L2_CID_BRIGHTNESS:
		ctrl->value = qcam->brightness;
		break;
	case V4L2_CID_CONTRAST:
		ctrl->value = qcam->contrast;
		break;
	case V4L2_CID_GAMMA:
		ctrl->value = qcam->whitebal;
		break;
	default:
		ret = -EINVAL;
		break;
	}
	return ret;
}

static int qcam_s_ctrl(struct file *file, void *priv,
					struct v4l2_control *ctrl)
{
	struct qcam *qcam = video_drvdata(file);
	int ret = 0;

	mutex_lock(&qcam->lock);
	switch (ctrl->id) {
	case V4L2_CID_BRIGHTNESS:
		qcam->brightness = ctrl->value;
		break;
	case V4L2_CID_CONTRAST:
		qcam->contrast = ctrl->value;
		break;
	case V4L2_CID_GAMMA:
		qcam->whitebal = ctrl->value;
		break;
	default:
		ret = -EINVAL;
		break;
	}
	if (ret == 0) {
		qc_setscanmode(qcam);
		qcam->status |= QC_PARAM_CHANGE;
	}
	mutex_unlock(&qcam->lock);
	return ret;
}

static int qcam_g_fmt_vid_cap(struct file *file, void *fh, struct v4l2_format *fmt)
{
	struct qcam *qcam = video_drvdata(file);
	struct v4l2_pix_format *pix = &fmt->fmt.pix;

	pix->width = qcam->width / qcam->transfer_scale;
	pix->height = qcam->height / qcam->transfer_scale;
	pix->pixelformat = (qcam->bpp == 4) ? V4L2_PIX_FMT_Y4 : V4L2_PIX_FMT_Y6;
	pix->field = V4L2_FIELD_NONE;
	pix->bytesperline = qcam->width;
	pix->sizeimage = qcam->width * qcam->height;
	/* Just a guess */
	pix->colorspace = V4L2_COLORSPACE_SRGB;
	return 0;
}

static int qcam_try_fmt_vid_cap(struct file *file, void *fh, struct v4l2_format *fmt)
{
	struct v4l2_pix_format *pix = &fmt->fmt.pix;

	if (pix->height <= 60 || pix->width <= 80) {
		pix->height = 60;
		pix->width = 80;
	} else if (pix->height <= 120 || pix->width <= 160) {
		pix->height = 120;
		pix->width = 160;
	} else {
		pix->height = 240;
		pix->width = 320;
	}
	if (pix->pixelformat != V4L2_PIX_FMT_Y4 &&
	    pix->pixelformat != V4L2_PIX_FMT_Y6)
		pix->pixelformat = V4L2_PIX_FMT_Y4;
	pix->field = V4L2_FIELD_NONE;
	pix->bytesperline = pix->width;
	pix->sizeimage = pix->width * pix->height;
	/* Just a guess */
	pix->colorspace = V4L2_COLORSPACE_SRGB;
	return 0;
}

static int qcam_s_fmt_vid_cap(struct file *file, void *fh, struct v4l2_format *fmt)
{
	struct qcam *qcam = video_drvdata(file);
	struct v4l2_pix_format *pix = &fmt->fmt.pix;
	int ret = qcam_try_fmt_vid_cap(file, fh, fmt);

	if (ret)
		return ret;
	qcam->width = 320;
	qcam->height = 240;
	if (pix->height == 60)
		qcam->transfer_scale = 4;
	else if (pix->height == 120)
		qcam->transfer_scale = 2;
	else
		qcam->transfer_scale = 1;
	if (pix->pixelformat == V4L2_PIX_FMT_Y6)
		qcam->bpp = 6;
	else
		qcam->bpp = 4;

	mutex_lock(&qcam->lock);
	qc_setscanmode(qcam);
	/* We must update the camera before we grab. We could
	   just have changed the grab size */
	qcam->status |= QC_PARAM_CHANGE;
	mutex_unlock(&qcam->lock);
	return 0;
}

static int qcam_enum_fmt_vid_cap(struct file *file, void *fh, struct v4l2_fmtdesc *fmt)
{
	static struct v4l2_fmtdesc formats[] = {
		{ 0, 0, 0,
		  "4-Bit Monochrome", V4L2_PIX_FMT_Y4,
		  { 0, 0, 0, 0 }
		},
		{ 0, 0, 0,
		  "6-Bit Monochrome", V4L2_PIX_FMT_Y6,
		  { 0, 0, 0, 0 }
		},
	};
	enum v4l2_buf_type type = fmt->type;

	if (fmt->index > 1)
		return -EINVAL;

	*fmt = formats[fmt->index];
	fmt->type = type;
	return 0;
}

static ssize_t qcam_read(struct file *file, char __user *buf,
		size_t count, loff_t *ppos)
{
	struct qcam *qcam = video_drvdata(file);
	int len;
	parport_claim_or_block(qcam->pdev);

	mutex_lock(&qcam->lock);

	qc_reset(qcam);

	/* Update the camera parameters if we need to */
	if (qcam->status & QC_PARAM_CHANGE)
		qc_set(qcam);

	len = qc_capture(qcam, buf, count);

	mutex_unlock(&qcam->lock);

	parport_release(qcam->pdev);
	return len;
}

static const struct v4l2_file_operations qcam_fops = {
	.owner		= THIS_MODULE,
	.unlocked_ioctl = video_ioctl2,
	.read		= qcam_read,
};

static const struct v4l2_ioctl_ops qcam_ioctl_ops = {
	.vidioc_querycap    		    = qcam_querycap,
	.vidioc_g_input      		    = qcam_g_input,
	.vidioc_s_input      		    = qcam_s_input,
	.vidioc_enum_input   		    = qcam_enum_input,
	.vidioc_queryctrl 		    = qcam_queryctrl,
	.vidioc_g_ctrl  		    = qcam_g_ctrl,
	.vidioc_s_ctrl 			    = qcam_s_ctrl,
	.vidioc_enum_fmt_vid_cap 	    = qcam_enum_fmt_vid_cap,
	.vidioc_g_fmt_vid_cap 		    = qcam_g_fmt_vid_cap,
	.vidioc_s_fmt_vid_cap  		    = qcam_s_fmt_vid_cap,
	.vidioc_try_fmt_vid_cap  	    = qcam_try_fmt_vid_cap,
};

/* Initialize the QuickCam driver control structure.  This is where
 * defaults are set for people who don't have a config file.*/

static struct qcam *qcam_init(struct parport *port)
{
	struct qcam *qcam;
	struct v4l2_device *v4l2_dev;

	qcam = kzalloc(sizeof(struct qcam), GFP_KERNEL);
	if (qcam == NULL)
		return NULL;

	v4l2_dev = &qcam->v4l2_dev;
	strlcpy(v4l2_dev->name, "bw-qcam", sizeof(v4l2_dev->name));

	if (v4l2_device_register(NULL, v4l2_dev) < 0) {
		v4l2_err(v4l2_dev, "Could not register v4l2_device\n");
		kfree(qcam);
		return NULL;
	}

	qcam->pport = port;
	qcam->pdev = parport_register_device(port, "bw-qcam", NULL, NULL,
			NULL, 0, NULL);
	if (qcam->pdev == NULL) {
		v4l2_err(v4l2_dev, "couldn't register for %s.\n", port->name);
		kfree(qcam);
		return NULL;
	}

	strlcpy(qcam->vdev.name, "Connectix QuickCam", sizeof(qcam->vdev.name));
	qcam->vdev.v4l2_dev = v4l2_dev;
	qcam->vdev.fops = &qcam_fops;
	qcam->vdev.ioctl_ops = &qcam_ioctl_ops;
	qcam->vdev.release = video_device_release_empty;
	video_set_drvdata(&qcam->vdev, qcam);

	mutex_init(&qcam->lock);

	qcam->port_mode = (QC_ANY | QC_NOTSET);
	qcam->width = 320;
	qcam->height = 240;
	qcam->bpp = 4;
	qcam->transfer_scale = 2;
	qcam->contrast = 192;
	qcam->brightness = 180;
	qcam->whitebal = 105;
	qcam->top = 1;
	qcam->left = 14;
	qcam->mode = -1;
	qcam->status = QC_PARAM_CHANGE;
	return qcam;
}

static int qc_calibrate(struct qcam *q)
{
	/*
	 *	Bugfix by Hanno Mueller hmueller@kabel.de, Mai 21 96
	 *	The white balance is an individual value for each
	 *	quickcam.
	 */

	int value;
	int count = 0;

	qc_command(q, 27);	/* AutoAdjustOffset */
	qc_command(q, 0);	/* Dummy Parameter, ignored by the camera */

	/* GetOffset (33) will read 255 until autocalibration */
	/* is finished. After that, a value of 1-254 will be */
	/* returned. */

	do {
		qc_command(q, 33);
		value = qc_readparam(q);
		mdelay(1);
		schedule();
		count++;
	} while (value == 0xff && count < 2048);

	q->whitebal = value;
	return value;
}

static int init_bwqcam(struct parport *port)
{
	struct qcam *qcam;

	if (num_cams == MAX_CAMS) {
		printk(KERN_ERR "Too many Quickcams (max %d)\n", MAX_CAMS);
		return -ENOSPC;
	}

	qcam = qcam_init(port);
	if (qcam == NULL)
		return -ENODEV;

	parport_claim_or_block(qcam->pdev);

	qc_reset(qcam);

	if (qc_detect(qcam) == 0) {
		parport_release(qcam->pdev);
		parport_unregister_device(qcam->pdev);
		kfree(qcam);
		return -ENODEV;
	}
	qc_calibrate(qcam);

	parport_release(qcam->pdev);

	v4l2_info(&qcam->v4l2_dev, "Connectix Quickcam on %s\n", qcam->pport->name);

	if (video_register_device(&qcam->vdev, VFL_TYPE_GRABBER, video_nr) < 0) {
		parport_unregister_device(qcam->pdev);
		kfree(qcam);
		return -ENODEV;
	}

	qcams[num_cams++] = qcam;

	return 0;
}

static void close_bwqcam(struct qcam *qcam)
{
	video_unregister_device(&qcam->vdev);
	parport_unregister_device(qcam->pdev);
	kfree(qcam);
}

/* The parport parameter controls which parports will be scanned.
 * Scanning all parports causes some printers to print a garbage page.
 *       -- March 14, 1999  Billy Donahue <billy@escape.com> */
#ifdef MODULE
static char *parport[MAX_CAMS] = { NULL, };
module_param_array(parport, charp, NULL, 0);
#endif

static int accept_bwqcam(struct parport *port)
{
#ifdef MODULE
	int n;

	if (parport[0] && strncmp(parport[0], "auto", 4) != 0) {
		/* user gave parport parameters */
		for (n = 0; n < MAX_CAMS && parport[n]; n++) {
			char *ep;
			unsigned long r;
			r = simple_strtoul(parport[n], &ep, 0);
			if (ep == parport[n]) {
				printk(KERN_ERR
					"bw-qcam: bad port specifier \"%s\"\n",
					parport[n]);
				continue;
			}
			if (r == port->number)
				return 1;
		}
		return 0;
	}
#endif
	return 1;
}

static void bwqcam_attach(struct parport *port)
{
	if (accept_bwqcam(port))
		init_bwqcam(port);
}

static void bwqcam_detach(struct parport *port)
{
	int i;
	for (i = 0; i < num_cams; i++) {
		struct qcam *qcam = qcams[i];
		if (qcam && qcam->pdev->port == port) {
			qcams[i] = NULL;
			close_bwqcam(qcam);
		}
	}
}

static struct parport_driver bwqcam_driver = {
	.name	= "bw-qcam",
	.attach	= bwqcam_attach,
	.detach	= bwqcam_detach,
};

static void __exit exit_bw_qcams(void)
{
	parport_unregister_driver(&bwqcam_driver);
}

static int __init init_bw_qcams(void)
{
#ifdef MODULE
	/* Do some sanity checks on the module parameters. */
	if (maxpoll > 5000) {
		printk(KERN_INFO "Connectix Quickcam max-poll was above 5000. Using 5000.\n");
		maxpoll = 5000;
	}

	if (yieldlines < 1) {
		printk(KERN_INFO "Connectix Quickcam yieldlines was less than 1. Using 1.\n");
		yieldlines = 1;
	}
#endif
	return parport_register_driver(&bwqcam_driver);
}

module_init(init_bw_qcams);
module_exit(exit_bw_qcams);

MODULE_LICENSE("GPL");
MODULE_VERSION("0.0.3");