summaryrefslogtreecommitdiffstats
path: root/drivers/media/v4l2-core/v4l2-common.c
blob: f995dd31151d0cc36bce91110e8ca3c0443c0138 (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
/*
 *	Video for Linux Two
 *
 *	A generic video device interface for the LINUX operating system
 *	using a set of device structures/vectors for low level operations.
 *
 *	This file replaces the videodev.c file that comes with the
 *	regular kernel distribution.
 *
 *	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.
 *
 * Author:	Bill Dirks <bill@thedirks.org>
 *		based on code by Alan Cox, <alan@cymru.net>
 *
 */

/*
 * Video capture interface for Linux
 *
 *	A generic video device interface for the LINUX operating system
 *	using a set of device structures/vectors for low level operations.
 *
 *		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.
 *
 * Author:	Alan Cox, <alan@lxorguk.ukuu.org.uk>
 *
 * Fixes:
 */

/*
 * Video4linux 1/2 integration by Justin Schoeman
 * <justin@suntiger.ee.up.ac.za>
 * 2.4 PROCFS support ported from 2.4 kernels by
 *  Iñaki García Etxebarria <garetxe@euskalnet.net>
 * Makefile fix by "W. Michael Petullo" <mike@flyn.org>
 * 2.4 devfs support ported from 2.4 kernels by
 *  Dan Merillat <dan@merillat.org>
 * Added Gerd Knorrs v4l1 enhancements (Justin Schoeman)
 */

#include <linux/module.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/string.h>
#include <linux/errno.h>
#include <linux/i2c.h>
#if defined(CONFIG_SPI)
#include <linux/spi/spi.h>
#endif
#include <asm/uaccess.h>
#include <asm/pgtable.h>
#include <asm/io.h>
#include <asm/div64.h>
#include <media/v4l2-common.h>
#include <media/v4l2-device.h>
#include <media/v4l2-ctrls.h>
#include <media/v4l2-chip-ident.h>

#include <linux/videodev2.h>

MODULE_AUTHOR("Bill Dirks, Justin Schoeman, Gerd Knorr");
MODULE_DESCRIPTION("misc helper functions for v4l2 device drivers");
MODULE_LICENSE("GPL");

/*
 *
 *	V 4 L 2   D R I V E R   H E L P E R   A P I
 *
 */

/*
 *  Video Standard Operations (contributed by Michael Schimek)
 */

/* Helper functions for control handling			     */

/* Check for correctness of the ctrl's value based on the data from
   struct v4l2_queryctrl and the available menu items. Note that
   menu_items may be NULL, in that case it is ignored. */
int v4l2_ctrl_check(struct v4l2_ext_control *ctrl, struct v4l2_queryctrl *qctrl,
		const char * const *menu_items)
{
	if (qctrl->flags & V4L2_CTRL_FLAG_DISABLED)
		return -EINVAL;
	if (qctrl->flags & V4L2_CTRL_FLAG_GRABBED)
		return -EBUSY;
	if (qctrl->type == V4L2_CTRL_TYPE_STRING)
		return 0;
	if (qctrl->type == V4L2_CTRL_TYPE_BUTTON ||
	    qctrl->type == V4L2_CTRL_TYPE_INTEGER64 ||
	    qctrl->type == V4L2_CTRL_TYPE_CTRL_CLASS)
		return 0;
	if (ctrl->value < qctrl->minimum || ctrl->value > qctrl->maximum)
		return -ERANGE;
	if (qctrl->type == V4L2_CTRL_TYPE_MENU && menu_items != NULL) {
		if (menu_items[ctrl->value] == NULL ||
		    menu_items[ctrl->value][0] == '\0')
			return -EINVAL;
	}
	if (qctrl->type == V4L2_CTRL_TYPE_BITMASK &&
			(ctrl->value & ~qctrl->maximum))
		return -ERANGE;
	return 0;
}
EXPORT_SYMBOL(v4l2_ctrl_check);

/* Fill in a struct v4l2_queryctrl */
int v4l2_ctrl_query_fill(struct v4l2_queryctrl *qctrl, s32 min, s32 max, s32 step, s32 def)
{
	const char *name;

	v4l2_ctrl_fill(qctrl->id, &name, &qctrl->type,
		       &min, &max, &step, &def, &qctrl->flags);

	if (name == NULL)
		return -EINVAL;

	qctrl->minimum = min;
	qctrl->maximum = max;
	qctrl->step = step;
	qctrl->default_value = def;
	qctrl->reserved[0] = qctrl->reserved[1] = 0;
	strlcpy(qctrl->name, name, sizeof(qctrl->name));
	return 0;
}
EXPORT_SYMBOL(v4l2_ctrl_query_fill);

/* Fill in a struct v4l2_querymenu based on the struct v4l2_queryctrl and
   the menu. The qctrl pointer may be NULL, in which case it is ignored.
   If menu_items is NULL, then the menu items are retrieved using
   v4l2_ctrl_get_menu. */
int v4l2_ctrl_query_menu(struct v4l2_querymenu *qmenu, struct v4l2_queryctrl *qctrl,
	       const char * const *menu_items)
{
	int i;

	qmenu->reserved = 0;
	if (menu_items == NULL)
		menu_items = v4l2_ctrl_get_menu(qmenu->id);
	if (menu_items == NULL ||
	    (qctrl && (qmenu->index < qctrl->minimum || qmenu->index > qctrl->maximum)))
		return -EINVAL;
	for (i = 0; i < qmenu->index && menu_items[i]; i++) ;
	if (menu_items[i] == NULL || menu_items[i][0] == '\0')
		return -EINVAL;
	strlcpy(qmenu->name, menu_items[qmenu->index], sizeof(qmenu->name));
	return 0;
}
EXPORT_SYMBOL(v4l2_ctrl_query_menu);

/* Fill in a struct v4l2_querymenu based on the specified array of valid
   menu items (terminated by V4L2_CTRL_MENU_IDS_END).
   Use this if there are 'holes' in the list of valid menu items. */
int v4l2_ctrl_query_menu_valid_items(struct v4l2_querymenu *qmenu, const u32 *ids)
{
	const char * const *menu_items = v4l2_ctrl_get_menu(qmenu->id);

	qmenu->reserved = 0;
	if (menu_items == NULL || ids == NULL)
		return -EINVAL;
	while (*ids != V4L2_CTRL_MENU_IDS_END) {
		if (*ids++ == qmenu->index) {
			strlcpy(qmenu->name, menu_items[qmenu->index],
					sizeof(qmenu->name));
			return 0;
		}
	}
	return -EINVAL;
}
EXPORT_SYMBOL(v4l2_ctrl_query_menu_valid_items);

/* ctrl_classes points to an array of u32 pointers, the last element is
   a NULL pointer. Each u32 array is a 0-terminated array of control IDs.
   Each array must be sorted low to high and belong to the same control
   class. The array of u32 pointers must also be sorted, from low class IDs
   to high class IDs.

   This function returns the first ID that follows after the given ID.
   When no more controls are available 0 is returned. */
u32 v4l2_ctrl_next(const u32 * const * ctrl_classes, u32 id)
{
	u32 ctrl_class = V4L2_CTRL_ID2CLASS(id);
	const u32 *pctrl;

	if (ctrl_classes == NULL)
		return 0;

	/* if no query is desired, then check if the ID is part of ctrl_classes */
	if ((id & V4L2_CTRL_FLAG_NEXT_CTRL) == 0) {
		/* find class */
		while (*ctrl_classes && V4L2_CTRL_ID2CLASS(**ctrl_classes) != ctrl_class)
			ctrl_classes++;
		if (*ctrl_classes == NULL)
			return 0;
		pctrl = *ctrl_classes;
		/* find control ID */
		while (*pctrl && *pctrl != id) pctrl++;
		return *pctrl ? id : 0;
	}
	id &= V4L2_CTRL_ID_MASK;
	id++;	/* select next control */
	/* find first class that matches (or is greater than) the class of
	   the ID */
	while (*ctrl_classes && V4L2_CTRL_ID2CLASS(**ctrl_classes) < ctrl_class)
		ctrl_classes++;
	/* no more classes */
	if (*ctrl_classes == NULL)
		return 0;
	pctrl = *ctrl_classes;
	/* find first ctrl within the class that is >= ID */
	while (*pctrl && *pctrl < id) pctrl++;
	if (*pctrl)
		return *pctrl;
	/* we are at the end of the controls of the current class. */
	/* continue with next class if available */
	ctrl_classes++;
	if (*ctrl_classes == NULL)
		return 0;
	return **ctrl_classes;
}
EXPORT_SYMBOL(v4l2_ctrl_next);

int v4l2_chip_match_host(const struct v4l2_dbg_match *match)
{
	switch (match->type) {
	case V4L2_CHIP_MATCH_HOST:
		return match->addr == 0;
	default:
		return 0;
	}
}
EXPORT_SYMBOL(v4l2_chip_match_host);

#if defined(CONFIG_I2C) || (defined(CONFIG_I2C_MODULE) && defined(MODULE))
int v4l2_chip_match_i2c_client(struct i2c_client *c, const struct v4l2_dbg_match *match)
{
	int len;

	if (c == NULL || match == NULL)
		return 0;

	switch (match->type) {
	case V4L2_CHIP_MATCH_I2C_DRIVER:
		if (c->driver == NULL || c->driver->driver.name == NULL)
			return 0;
		len = strlen(c->driver->driver.name);
		/* legacy drivers have a ' suffix, don't try to match that */
		if (len && c->driver->driver.name[len - 1] == '\'')
			len--;
		return len && !strncmp(c->driver->driver.name, match->name, len);
	case V4L2_CHIP_MATCH_I2C_ADDR:
		return c->addr == match->addr;
	default:
		return 0;
	}
}
EXPORT_SYMBOL(v4l2_chip_match_i2c_client);

int v4l2_chip_ident_i2c_client(struct i2c_client *c, struct v4l2_dbg_chip_ident *chip,
		u32 ident, u32 revision)
{
	if (!v4l2_chip_match_i2c_client(c, &chip->match))
		return 0;
	if (chip->ident == V4L2_IDENT_NONE) {
		chip->ident = ident;
		chip->revision = revision;
	}
	else {
		chip->ident = V4L2_IDENT_AMBIGUOUS;
		chip->revision = 0;
	}
	return 0;
}
EXPORT_SYMBOL(v4l2_chip_ident_i2c_client);

/* ----------------------------------------------------------------- */

/* I2C Helper functions */


void v4l2_i2c_subdev_init(struct v4l2_subdev *sd, struct i2c_client *client,
		const struct v4l2_subdev_ops *ops)
{
	v4l2_subdev_init(sd, ops);
	sd->flags |= V4L2_SUBDEV_FL_IS_I2C;
	/* the owner is the same as the i2c_client's driver owner */
	sd->owner = client->driver->driver.owner;
	/* i2c_client and v4l2_subdev point to one another */
	v4l2_set_subdevdata(sd, client);
	i2c_set_clientdata(client, sd);
	/* initialize name */
	snprintf(sd->name, sizeof(sd->name), "%s %d-%04x",
		client->driver->driver.name, i2c_adapter_id(client->adapter),
		client->addr);
}
EXPORT_SYMBOL_GPL(v4l2_i2c_subdev_init);



/* Load an i2c sub-device. */
struct v4l2_subdev *v4l2_i2c_new_subdev_board(struct v4l2_device *v4l2_dev,
		struct i2c_adapter *adapter, struct i2c_board_info *info,
		const unsigned short *probe_addrs)
{
	struct v4l2_subdev *sd = NULL;
	struct i2c_client *client;

	BUG_ON(!v4l2_dev);

	request_module(I2C_MODULE_PREFIX "%s", info->type);

	/* Create the i2c client */
	if (info->addr == 0 && probe_addrs)
		client = i2c_new_probed_device(adapter, info, probe_addrs,
					       NULL);
	else
		client = i2c_new_device(adapter, info);

	/* Note: by loading the module first we are certain that c->driver
	   will be set if the driver was found. If the module was not loaded
	   first, then the i2c core tries to delay-load the module for us,
	   and then c->driver is still NULL until the module is finally
	   loaded. This delay-load mechanism doesn't work if other drivers
	   want to use the i2c device, so explicitly loading the module
	   is the best alternative. */
	if (client == NULL || client->driver == NULL)
		goto error;

	/* Lock the module so we can safely get the v4l2_subdev pointer */
	if (!try_module_get(client->driver->driver.owner))
		goto error;
	sd = i2c_get_clientdata(client);

	/* Register with the v4l2_device which increases the module's
	   use count as well. */
	if (v4l2_device_register_subdev(v4l2_dev, sd))
		sd = NULL;
	/* Decrease the module use count to match the first try_module_get. */
	module_put(client->driver->driver.owner);

error:
	/* If we have a client but no subdev, then something went wrong and
	   we must unregister the client. */
	if (client && sd == NULL)
		i2c_unregister_device(client);
	return sd;
}
EXPORT_SYMBOL_GPL(v4l2_i2c_new_subdev_board);

struct v4l2_subdev *v4l2_i2c_new_subdev(struct v4l2_device *v4l2_dev,
		struct i2c_adapter *adapter, const char *client_type,
		u8 addr, const unsigned short *probe_addrs)
{
	struct i2c_board_info info;

	/* Setup the i2c board info with the device type and
	   the device address. */
	memset(&info, 0, sizeof(info));
	strlcpy(info.type, client_type, sizeof(info.type));
	info.addr = addr;

	return v4l2_i2c_new_subdev_board(v4l2_dev, adapter, &info, probe_addrs);
}
EXPORT_SYMBOL_GPL(v4l2_i2c_new_subdev);

/* Return i2c client address of v4l2_subdev. */
unsigned short v4l2_i2c_subdev_addr(struct v4l2_subdev *sd)
{
	struct i2c_client *client = v4l2_get_subdevdata(sd);

	return client ? client->addr : I2C_CLIENT_END;
}
EXPORT_SYMBOL_GPL(v4l2_i2c_subdev_addr);

/* Return a list of I2C tuner addresses to probe. Use only if the tuner
   addresses are unknown. */
const unsigned short *v4l2_i2c_tuner_addrs(enum v4l2_i2c_tuner_type type)
{
	static const unsigned short radio_addrs[] = {
#if defined(CONFIG_MEDIA_TUNER_TEA5761) || defined(CONFIG_MEDIA_TUNER_TEA5761_MODULE)
		0x10,
#endif
		0x60,
		I2C_CLIENT_END
	};
	static const unsigned short demod_addrs[] = {
		0x42, 0x43, 0x4a, 0x4b,
		I2C_CLIENT_END
	};
	static const unsigned short tv_addrs[] = {
		0x42, 0x43, 0x4a, 0x4b,		/* tda8290 */
		0x60, 0x61, 0x62, 0x63, 0x64,
		I2C_CLIENT_END
	};

	switch (type) {
	case ADDRS_RADIO:
		return radio_addrs;
	case ADDRS_DEMOD:
		return demod_addrs;
	case ADDRS_TV:
		return tv_addrs;
	case ADDRS_TV_WITH_DEMOD:
		return tv_addrs + 4;
	}
	return NULL;
}
EXPORT_SYMBOL_GPL(v4l2_i2c_tuner_addrs);

#endif /* defined(CONFIG_I2C) */

#if defined(CONFIG_SPI)

/* Load an spi sub-device. */

void v4l2_spi_subdev_init(struct v4l2_subdev *sd, struct spi_device *spi,
		const struct v4l2_subdev_ops *ops)
{
	v4l2_subdev_init(sd, ops);
	sd->flags |= V4L2_SUBDEV_FL_IS_SPI;
	/* the owner is the same as the spi_device's driver owner */
	sd->owner = spi->dev.driver->owner;
	/* spi_device and v4l2_subdev point to one another */
	v4l2_set_subdevdata(sd, spi);
	spi_set_drvdata(spi, sd);
	/* initialize name */
	strlcpy(sd->name, spi->dev.driver->name, sizeof(sd->name));
}
EXPORT_SYMBOL_GPL(v4l2_spi_subdev_init);

struct v4l2_subdev *v4l2_spi_new_subdev(struct v4l2_device *v4l2_dev,
		struct spi_master *master, struct spi_board_info *info)
{
	struct v4l2_subdev *sd = NULL;
	struct spi_device *spi = NULL;

	BUG_ON(!v4l2_dev);

	if (info->modalias[0])
		request_module(info->modalias);

	spi = spi_new_device(master, info);

	if (spi == NULL || spi->dev.driver == NULL)
		goto error;

	if (!try_module_get(spi->dev.driver->owner))
		goto error;

	sd = spi_get_drvdata(spi);

	/* Register with the v4l2_device which increases the module's
	   use count as well. */
	if (v4l2_device_register_subdev(v4l2_dev, sd))
		sd = NULL;

	/* Decrease the module use count to match the first try_module_get. */
	module_put(spi->dev.driver->owner);

error:
	/* If we have a client but no subdev, then something went wrong and
	   we must unregister the client. */
	if (spi && sd == NULL)
		spi_unregister_device(spi);

	return sd;
}
EXPORT_SYMBOL_GPL(v4l2_spi_new_subdev);

#endif /* defined(CONFIG_SPI) */

/* Clamp x to be between min and max, aligned to a multiple of 2^align.  min
 * and max don't have to be aligned, but there must be at least one valid
 * value.  E.g., min=17,max=31,align=4 is not allowed as there are no multiples
 * of 16 between 17 and 31.  */
static unsigned int clamp_align(unsigned int x, unsigned int min,
				unsigned int max, unsigned int align)
{
	/* Bits that must be zero to be aligned */
	unsigned int mask = ~((1 << align) - 1);

	/* Round to nearest aligned value */
	if (align)
		x = (x + (1 << (align - 1))) & mask;

	/* Clamp to aligned value of min and max */
	if (x < min)
		x = (min + ~mask) & mask;
	else if (x > max)
		x = max & mask;

	return x;
}

/* Bound an image to have a width between wmin and wmax, and height between
 * hmin and hmax, inclusive.  Additionally, the width will be a multiple of
 * 2^walign, the height will be a multiple of 2^halign, and the overall size
 * (width*height) will be a multiple of 2^salign.  The image may be shrunk
 * or enlarged to fit the alignment constraints.
 *
 * The width or height maximum must not be smaller than the corresponding
 * minimum.  The alignments must not be so high there are no possible image
 * sizes within the allowed bounds.  wmin and hmin must be at least 1
 * (don't use 0).  If you don't care about a certain alignment, specify 0,
 * as 2^0 is 1 and one byte alignment is equivalent to no alignment.  If
 * you only want to adjust downward, specify a maximum that's the same as
 * the initial value.
 */
void v4l_bound_align_image(u32 *w, unsigned int wmin, unsigned int wmax,
			   unsigned int walign,
			   u32 *h, unsigned int hmin, unsigned int hmax,
			   unsigned int halign, unsigned int salign)
{
	*w = clamp_align(*w, wmin, wmax, walign);
	*h = clamp_align(*h, hmin, hmax, halign);

	/* Usually we don't need to align the size and are done now. */
	if (!salign)
		return;

	/* How much alignment do we have? */
	walign = __ffs(*w);
	halign = __ffs(*h);
	/* Enough to satisfy the image alignment? */
	if (walign + halign < salign) {
		/* Max walign where there is still a valid width */
		unsigned int wmaxa = __fls(wmax ^ (wmin - 1));
		/* Max halign where there is still a valid height */
		unsigned int hmaxa = __fls(hmax ^ (hmin - 1));

		/* up the smaller alignment until we have enough */
		do {
			if (halign >= hmaxa ||
			    (walign <= halign && walign < wmaxa)) {
				*w = clamp_align(*w, wmin, wmax, walign + 1);
				walign = __ffs(*w);
			} else {
				*h = clamp_align(*h, hmin, hmax, halign + 1);
				halign = __ffs(*h);
			}
		} while (halign + walign < salign);
	}
}
EXPORT_SYMBOL_GPL(v4l_bound_align_image);

/**
 * v4l_fill_dv_preset_info - fill description of a digital video preset
 * @preset - preset value
 * @info - pointer to struct v4l2_dv_enum_preset
 *
 * drivers can use this helper function to fill description of dv preset
 * in info.
 */
int v4l_fill_dv_preset_info(u32 preset, struct v4l2_dv_enum_preset *info)
{
	static const struct v4l2_dv_preset_info {
		u16 width;
		u16 height;
		const char *name;
	} dv_presets[] = {
		{ 0, 0, "Invalid" },		/* V4L2_DV_INVALID */
		{ 720,  480, "480p@59.94" },	/* V4L2_DV_480P59_94 */
		{ 720,  576, "576p@50" },	/* V4L2_DV_576P50 */
		{ 1280, 720, "720p@24" },	/* V4L2_DV_720P24 */
		{ 1280, 720, "720p@25" },	/* V4L2_DV_720P25 */
		{ 1280, 720, "720p@30" },	/* V4L2_DV_720P30 */
		{ 1280, 720, "720p@50" },	/* V4L2_DV_720P50 */
		{ 1280, 720, "720p@59.94" },	/* V4L2_DV_720P59_94 */
		{ 1280, 720, "720p@60" },	/* V4L2_DV_720P60 */
		{ 1920, 1080, "1080i@29.97" },	/* V4L2_DV_1080I29_97 */
		{ 1920, 1080, "1080i@30" },	/* V4L2_DV_1080I30 */
		{ 1920, 1080, "1080i@25" },	/* V4L2_DV_1080I25 */
		{ 1920, 1080, "1080i@50" },	/* V4L2_DV_1080I50 */
		{ 1920, 1080, "1080i@60" },	/* V4L2_DV_1080I60 */
		{ 1920, 1080, "1080p@24" },	/* V4L2_DV_1080P24 */
		{ 1920, 1080, "1080p@25" },	/* V4L2_DV_1080P25 */
		{ 1920, 1080, "1080p@30" },	/* V4L2_DV_1080P30 */
		{ 1920, 1080, "1080p@50" },	/* V4L2_DV_1080P50 */
		{ 1920, 1080, "1080p@60" },	/* V4L2_DV_1080P60 */
	};

	if (info == NULL || preset >= ARRAY_SIZE(dv_presets))
		return -EINVAL;

	info->preset = preset;
	info->width = dv_presets[preset].width;
	info->height = dv_presets[preset].height;
	strlcpy(info->name, dv_presets[preset].name, sizeof(info->name));
	return 0;
}
EXPORT_SYMBOL_GPL(v4l_fill_dv_preset_info);

/**
 * v4l_match_dv_timings - check if two timings match
 * @t1 - compare this v4l2_dv_timings struct...
 * @t2 - with this struct.
 * @pclock_delta - the allowed pixelclock deviation.
 *
 * Compare t1 with t2 with a given margin of error for the pixelclock.
 */
bool v4l_match_dv_timings(const struct v4l2_dv_timings *t1,
			  const struct v4l2_dv_timings *t2,
			  unsigned pclock_delta)
{
	if (t1->type != t2->type || t1->type != V4L2_DV_BT_656_1120)
		return false;
	if (t1->bt.width == t2->bt.width &&
	    t1->bt.height == t2->bt.height &&
	    t1->bt.interlaced == t2->bt.interlaced &&
	    t1->bt.polarities == t2->bt.polarities &&
	    t1->bt.pixelclock >= t2->bt.pixelclock - pclock_delta &&
	    t1->bt.pixelclock <= t2->bt.pixelclock + pclock_delta &&
	    t1->bt.hfrontporch == t2->bt.hfrontporch &&
	    t1->bt.vfrontporch == t2->bt.vfrontporch &&
	    t1->bt.vsync == t2->bt.vsync &&
	    t1->bt.vbackporch == t2->bt.vbackporch &&
	    (!t1->bt.interlaced ||
		(t1->bt.il_vfrontporch == t2->bt.il_vfrontporch &&
		 t1->bt.il_vsync == t2->bt.il_vsync &&
		 t1->bt.il_vbackporch == t2->bt.il_vbackporch)))
		return true;
	return false;
}
EXPORT_SYMBOL_GPL(v4l_match_dv_timings);

/*
 * CVT defines
 * Based on Coordinated Video Timings Standard
 * version 1.1 September 10, 2003
 */

#define CVT_PXL_CLK_GRAN	250000	/* pixel clock granularity */

/* Normal blanking */
#define CVT_MIN_V_BPORCH	7	/* lines */
#define CVT_MIN_V_PORCH_RND	3	/* lines */
#define CVT_MIN_VSYNC_BP	550	/* min time of vsync + back porch (us) */

/* Normal blanking for CVT uses GTF to calculate horizontal blanking */
#define CVT_CELL_GRAN		8	/* character cell granularity */
#define CVT_M			600	/* blanking formula gradient */
#define CVT_C			40	/* blanking formula offset */
#define CVT_K			128	/* blanking formula scaling factor */
#define CVT_J			20	/* blanking formula scaling factor */
#define CVT_C_PRIME (((CVT_C - CVT_J) * CVT_K / 256) + CVT_J)
#define CVT_M_PRIME (CVT_K * CVT_M / 256)

/* Reduced Blanking */
#define CVT_RB_MIN_V_BPORCH    7       /* lines  */
#define CVT_RB_V_FPORCH        3       /* lines  */
#define CVT_RB_MIN_V_BLANK   460     /* us     */
#define CVT_RB_H_SYNC         32       /* pixels */
#define CVT_RB_H_BPORCH       80       /* pixels */
#define CVT_RB_H_BLANK       160       /* pixels */

/** v4l2_detect_cvt - detect if the given timings follow the CVT standard
 * @frame_height - the total height of the frame (including blanking) in lines.
 * @hfreq - the horizontal frequency in Hz.
 * @vsync - the height of the vertical sync in lines.
 * @polarities - the horizontal and vertical polarities (same as struct
 *		v4l2_bt_timings polarities).
 * @fmt - the resulting timings.
 *
 * This function will attempt to detect if the given values correspond to a
 * valid CVT format. If so, then it will return true, and fmt will be filled
 * in with the found CVT timings.
 */
bool v4l2_detect_cvt(unsigned frame_height, unsigned hfreq, unsigned vsync,
		u32 polarities, struct v4l2_dv_timings *fmt)
{
	int  v_fp, v_bp, h_fp, h_bp, hsync;
	int  frame_width, image_height, image_width;
	bool reduced_blanking;
	unsigned pix_clk;

	if (vsync < 4 || vsync > 7)
		return false;

	if (polarities == V4L2_DV_VSYNC_POS_POL)
		reduced_blanking = false;
	else if (polarities == V4L2_DV_HSYNC_POS_POL)
		reduced_blanking = true;
	else
		return false;

	/* Vertical */
	if (reduced_blanking) {
		v_fp = CVT_RB_V_FPORCH;
		v_bp = (CVT_RB_MIN_V_BLANK * hfreq + 999999) / 1000000;
		v_bp -= vsync + v_fp;

		if (v_bp < CVT_RB_MIN_V_BPORCH)
			v_bp = CVT_RB_MIN_V_BPORCH;
	} else {
		v_fp = CVT_MIN_V_PORCH_RND;
		v_bp = (CVT_MIN_VSYNC_BP * hfreq + 999999) / 1000000 - vsync;

		if (v_bp < CVT_MIN_V_BPORCH)
			v_bp = CVT_MIN_V_BPORCH;
	}
	image_height = (frame_height - v_fp - vsync - v_bp + 1) & ~0x1;

	/* Aspect ratio based on vsync */
	switch (vsync) {
	case 4:
		image_width = (image_height * 4) / 3;
		break;
	case 5:
		image_width = (image_height * 16) / 9;
		break;
	case 6:
		image_width = (image_height * 16) / 10;
		break;
	case 7:
		/* special case */
		if (image_height == 1024)
			image_width = (image_height * 5) / 4;
		else if (image_height == 768)
			image_width = (image_height * 15) / 9;
		else
			return false;
		break;
	default:
		return false;
	}

	image_width = image_width & ~7;

	/* Horizontal */
	if (reduced_blanking) {
		pix_clk = (image_width + CVT_RB_H_BLANK) * hfreq;
		pix_clk = (pix_clk / CVT_PXL_CLK_GRAN) * CVT_PXL_CLK_GRAN;

		h_bp = CVT_RB_H_BPORCH;
		hsync = CVT_RB_H_SYNC;
		h_fp = CVT_RB_H_BLANK - h_bp - hsync;

		frame_width = image_width + CVT_RB_H_BLANK;
	} else {
		int h_blank;
		unsigned ideal_duty_cycle = CVT_C_PRIME - (CVT_M_PRIME * 1000) / hfreq;

		h_blank = (image_width * ideal_duty_cycle + (100 - ideal_duty_cycle) / 2) /
						(100 - ideal_duty_cycle);
		h_blank = h_blank - h_blank % (2 * CVT_CELL_GRAN);

		if (h_blank * 100 / image_width < 20) {
			h_blank = image_width / 5;
			h_blank = (h_blank + 0x7) & ~0x7;
		}

		pix_clk = (image_width + h_blank) * hfreq;
		pix_clk = (pix_clk / CVT_PXL_CLK_GRAN) * CVT_PXL_CLK_GRAN;

		h_bp = h_blank / 2;
		frame_width = image_width + h_blank;

		hsync = (frame_width * 8 + 50) / 100;
		hsync = hsync - hsync % CVT_CELL_GRAN;
		h_fp = h_blank - hsync - h_bp;
	}

	fmt->bt.polarities = polarities;
	fmt->bt.width = image_width;
	fmt->bt.height = image_height;
	fmt->bt.hfrontporch = h_fp;
	fmt->bt.vfrontporch = v_fp;
	fmt->bt.hsync = hsync;
	fmt->bt.vsync = vsync;
	fmt->bt.hbackporch = frame_width - image_width - h_fp - hsync;
	fmt->bt.vbackporch = frame_height - image_height - v_fp - vsync;
	fmt->bt.pixelclock = pix_clk;
	fmt->bt.standards = V4L2_DV_BT_STD_CVT;
	if (reduced_blanking)
		fmt->bt.flags |= V4L2_DV_FL_REDUCED_BLANKING;
	return true;
}
EXPORT_SYMBOL_GPL(v4l2_detect_cvt);

/*
 * GTF defines
 * Based on Generalized Timing Formula Standard
 * Version 1.1 September 2, 1999
 */

#define GTF_PXL_CLK_GRAN	250000	/* pixel clock granularity */

#define GTF_MIN_VSYNC_BP	550	/* min time of vsync + back porch (us) */
#define GTF_V_FP		1	/* vertical front porch (lines) */
#define GTF_CELL_GRAN		8	/* character cell granularity */

/* Default */
#define GTF_D_M			600	/* blanking formula gradient */
#define GTF_D_C			40	/* blanking formula offset */
#define GTF_D_K			128	/* blanking formula scaling factor */
#define GTF_D_J			20	/* blanking formula scaling factor */
#define GTF_D_C_PRIME ((((GTF_D_C - GTF_D_J) * GTF_D_K) / 256) + GTF_D_J)
#define GTF_D_M_PRIME ((GTF_D_K * GTF_D_M) / 256)

/* Secondary */
#define GTF_S_M			3600	/* blanking formula gradient */
#define GTF_S_C			40	/* blanking formula offset */
#define GTF_S_K			128	/* blanking formula scaling factor */
#define GTF_S_J			35	/* blanking formula scaling factor */
#define GTF_S_C_PRIME ((((GTF_S_C - GTF_S_J) * GTF_S_K) / 256) + GTF_S_J)
#define GTF_S_M_PRIME ((GTF_S_K * GTF_S_M) / 256)

/** v4l2_detect_gtf - detect if the given timings follow the GTF standard
 * @frame_height - the total height of the frame (including blanking) in lines.
 * @hfreq - the horizontal frequency in Hz.
 * @vsync - the height of the vertical sync in lines.
 * @polarities - the horizontal and vertical polarities (same as struct
 *		v4l2_bt_timings polarities).
 * @aspect - preferred aspect ratio. GTF has no method of determining the
 *		aspect ratio in order to derive the image width from the
 *		image height, so it has to be passed explicitly. Usually
 *		the native screen aspect ratio is used for this. If it
 *		is not filled in correctly, then 16:9 will be assumed.
 * @fmt - the resulting timings.
 *
 * This function will attempt to detect if the given values correspond to a
 * valid GTF format. If so, then it will return true, and fmt will be filled
 * in with the found GTF timings.
 */
bool v4l2_detect_gtf(unsigned frame_height,
		unsigned hfreq,
		unsigned vsync,
		u32 polarities,
		struct v4l2_fract aspect,
		struct v4l2_dv_timings *fmt)
{
	int pix_clk;
	int  v_fp, v_bp, h_fp, h_bp, hsync;
	int frame_width, image_height, image_width;
	bool default_gtf;
	int h_blank;

	if (vsync != 3)
		return false;

	if (polarities == V4L2_DV_VSYNC_POS_POL)
		default_gtf = true;
	else if (polarities == V4L2_DV_HSYNC_POS_POL)
		default_gtf = false;
	else
		return false;

	/* Vertical */
	v_fp = GTF_V_FP;
	v_bp = (GTF_MIN_VSYNC_BP * hfreq + 999999) / 1000000 - vsync;
	image_height = (frame_height - v_fp - vsync - v_bp + 1) & ~0x1;

	if (aspect.numerator == 0 || aspect.denominator == 0) {
		aspect.numerator = 16;
		aspect.denominator = 9;
	}
	image_width = ((image_height * aspect.numerator) / aspect.denominator);

	/* Horizontal */
	if (default_gtf)
		h_blank = ((image_width * GTF_D_C_PRIME * hfreq) -
					(image_width * GTF_D_M_PRIME * 1000) +
			(hfreq * (100 - GTF_D_C_PRIME) + GTF_D_M_PRIME * 1000) / 2) /
			(hfreq * (100 - GTF_D_C_PRIME) + GTF_D_M_PRIME * 1000);
	else
		h_blank = ((image_width * GTF_S_C_PRIME * hfreq) -
					(image_width * GTF_S_M_PRIME * 1000) +
			(hfreq * (100 - GTF_S_C_PRIME) + GTF_S_M_PRIME * 1000) / 2) /
			(hfreq * (100 - GTF_S_C_PRIME) + GTF_S_M_PRIME * 1000);

	h_blank = h_blank - h_blank % (2 * GTF_CELL_GRAN);
	frame_width = image_width + h_blank;

	pix_clk = (image_width + h_blank) * hfreq;
	pix_clk = pix_clk / GTF_PXL_CLK_GRAN * GTF_PXL_CLK_GRAN;

	hsync = (frame_width * 8 + 50) / 100;
	hsync = hsync - hsync % GTF_CELL_GRAN;

	h_fp = h_blank / 2 - hsync;
	h_bp = h_blank / 2;

	fmt->bt.polarities = polarities;
	fmt->bt.width = image_width;
	fmt->bt.height = image_height;
	fmt->bt.hfrontporch = h_fp;
	fmt->bt.vfrontporch = v_fp;
	fmt->bt.hsync = hsync;
	fmt->bt.vsync = vsync;
	fmt->bt.hbackporch = frame_width - image_width - h_fp - hsync;
	fmt->bt.vbackporch = frame_height - image_height - v_fp - vsync;
	fmt->bt.pixelclock = pix_clk;
	fmt->bt.standards = V4L2_DV_BT_STD_GTF;
	if (!default_gtf)
		fmt->bt.flags |= V4L2_DV_FL_REDUCED_BLANKING;
	return true;
}
EXPORT_SYMBOL_GPL(v4l2_detect_gtf);

/** v4l2_calc_aspect_ratio - calculate the aspect ratio based on bytes
 *	0x15 and 0x16 from the EDID.
 * @hor_landscape - byte 0x15 from the EDID.
 * @vert_portrait - byte 0x16 from the EDID.
 *
 * Determines the aspect ratio from the EDID.
 * See VESA Enhanced EDID standard, release A, rev 2, section 3.6.2:
 * "Horizontal and Vertical Screen Size or Aspect Ratio"
 */
struct v4l2_fract v4l2_calc_aspect_ratio(u8 hor_landscape, u8 vert_portrait)
{
	struct v4l2_fract aspect = { 16, 9 };
	u32 tmp;
	u8 ratio;

	/* Nothing filled in, fallback to 16:9 */
	if (!hor_landscape && !vert_portrait)
		return aspect;
	/* Both filled in, so they are interpreted as the screen size in cm */
	if (hor_landscape && vert_portrait) {
		aspect.numerator = hor_landscape;
		aspect.denominator = vert_portrait;
		return aspect;
	}
	/* Only one is filled in, so interpret them as a ratio:
	   (val + 99) / 100 */
	ratio = hor_landscape | vert_portrait;
	/* Change some rounded values into the exact aspect ratio */
	if (ratio == 79) {
		aspect.numerator = 16;
		aspect.denominator = 9;
	} else if (ratio == 34) {
		aspect.numerator = 4;
		aspect.numerator = 3;
	} else if (ratio == 68) {
		aspect.numerator = 15;
		aspect.numerator = 9;
	} else {
		aspect.numerator = hor_landscape + 99;
		aspect.denominator = 100;
	}
	if (hor_landscape)
		return aspect;
	/* The aspect ratio is for portrait, so swap numerator and denominator */
	tmp = aspect.denominator;
	aspect.denominator = aspect.numerator;
	aspect.numerator = tmp;
	return aspect;
}
EXPORT_SYMBOL_GPL(v4l2_calc_aspect_ratio);

const struct v4l2_frmsize_discrete *v4l2_find_nearest_format(
		const struct v4l2_discrete_probe *probe,
		s32 width, s32 height)
{
	int i;
	u32 error, min_error = UINT_MAX;
	const struct v4l2_frmsize_discrete *size, *best = NULL;

	if (!probe)
		return best;

	for (i = 0, size = probe->sizes; i < probe->num_sizes; i++, size++) {
		error = abs(size->width - width) + abs(size->height - height);
		if (error < min_error) {
			min_error = error;
			best = size;
		}
		if (!error)
			break;
	}

	return best;
}
EXPORT_SYMBOL_GPL(v4l2_find_nearest_format);