summaryrefslogtreecommitdiffstats
path: root/drivers/media/usb/em28xx/em28xx-i2c.c
blob: 6458682bc6e250b7513be2d6f4a457eaa2ed23f3 (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
// SPDX-License-Identifier: GPL-2.0+
//
// em28xx-i2c.c - driver for Empia EM2800/EM2820/2840 USB video capture devices
//
// Copyright (C) 2005 Ludovico Cavedon <cavedon@sssup.it>
//		      Markus Rechberger <mrechberger@gmail.com>
//		      Mauro Carvalho Chehab <mchehab@kernel.org>
//		      Sascha Sommer <saschasommer@freenet.de>
// Copyright (C) 2013 Frank Schäfer <fschaefer.oss@googlemail.com>
//
// 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.

#include "em28xx.h"

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/usb.h>
#include <linux/i2c.h>
#include <linux/jiffies.h>

#include "tuner-xc2028.h"
#include <media/v4l2-common.h>
#include <media/tuner.h>

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

static unsigned int i2c_scan;
module_param(i2c_scan, int, 0444);
MODULE_PARM_DESC(i2c_scan, "scan i2c bus at insmod time");

static unsigned int i2c_debug;
module_param(i2c_debug, int, 0644);
MODULE_PARM_DESC(i2c_debug, "i2c debug message level (1: normal debug, 2: show I2C transfers)");

#define dprintk(level, fmt, arg...) do {				\
	if (i2c_debug > level)						\
		dev_printk(KERN_DEBUG, &dev->intf->dev,			\
			   "i2c: %s: " fmt, __func__, ## arg);		\
} while (0)

/*
 * Time in msecs to wait for i2c xfers to finish.
 * 35ms is the maximum time a SMBUS device could wait when
 * clock stretching is used. As the transfer itself will take
 * some time to happen, set it to 35 ms.
 *
 * Ok, I2C doesn't specify any limit. So, eventually, we may need
 * to increase this timeout.
 */
#define EM28XX_I2C_XFER_TIMEOUT         35 /* ms */

static int em28xx_i2c_timeout(struct em28xx *dev)
{
	int time = EM28XX_I2C_XFER_TIMEOUT;

	switch (dev->i2c_speed & 0x03) {
	case EM28XX_I2C_FREQ_25_KHZ:
		time += 4;		/* Assume 4 ms for transfers */
		break;
	case EM28XX_I2C_FREQ_100_KHZ:
	case EM28XX_I2C_FREQ_400_KHZ:
		time += 1;		/* Assume 1 ms for transfers */
		break;
	default: /* EM28XX_I2C_FREQ_1_5_MHZ */
		break;
	}

	return msecs_to_jiffies(time);
}

/*
 * em2800_i2c_send_bytes()
 * send up to 4 bytes to the em2800 i2c device
 */
static int em2800_i2c_send_bytes(struct em28xx *dev, u8 addr, u8 *buf, u16 len)
{
	unsigned long timeout = jiffies + em28xx_i2c_timeout(dev);
	int ret;
	u8 b2[6];

	if (len < 1 || len > 4)
		return -EOPNOTSUPP;

	b2[5] = 0x80 + len - 1;
	b2[4] = addr;
	b2[3] = buf[0];
	if (len > 1)
		b2[2] = buf[1];
	if (len > 2)
		b2[1] = buf[2];
	if (len > 3)
		b2[0] = buf[3];

	/* trigger write */
	ret = dev->em28xx_write_regs(dev, 4 - len, &b2[4 - len], 2 + len);
	if (ret != 2 + len) {
		dev_warn(&dev->intf->dev,
			 "failed to trigger write to i2c address 0x%x (error=%i)\n",
			    addr, ret);
		return (ret < 0) ? ret : -EIO;
	}
	/* wait for completion */
	while (time_is_after_jiffies(timeout)) {
		ret = dev->em28xx_read_reg(dev, 0x05);
		if (ret == 0x80 + len - 1)
			return len;
		if (ret == 0x94 + len - 1) {
			dprintk(1, "R05 returned 0x%02x: I2C ACK error\n", ret);
			return -ENXIO;
		}
		if (ret < 0) {
			dev_warn(&dev->intf->dev,
				 "failed to get i2c transfer status from bridge register (error=%i)\n",
				ret);
			return ret;
		}
		usleep_range(5000, 6000);
	}
	dprintk(0, "write to i2c device at 0x%x timed out\n", addr);
	return -ETIMEDOUT;
}

/*
 * em2800_i2c_recv_bytes()
 * read up to 4 bytes from the em2800 i2c device
 */
static int em2800_i2c_recv_bytes(struct em28xx *dev, u8 addr, u8 *buf, u16 len)
{
	unsigned long timeout = jiffies + em28xx_i2c_timeout(dev);
	u8 buf2[4];
	int ret;
	int i;

	if (len < 1 || len > 4)
		return -EOPNOTSUPP;

	/* trigger read */
	buf2[1] = 0x84 + len - 1;
	buf2[0] = addr;
	ret = dev->em28xx_write_regs(dev, 0x04, buf2, 2);
	if (ret != 2) {
		dev_warn(&dev->intf->dev,
			 "failed to trigger read from i2c address 0x%x (error=%i)\n",
			 addr, ret);
		return (ret < 0) ? ret : -EIO;
	}

	/* wait for completion */
	while (time_is_after_jiffies(timeout)) {
		ret = dev->em28xx_read_reg(dev, 0x05);
		if (ret == 0x84 + len - 1)
			break;
		if (ret == 0x94 + len - 1) {
			dprintk(1, "R05 returned 0x%02x: I2C ACK error\n",
				ret);
			return -ENXIO;
		}
		if (ret < 0) {
			dev_warn(&dev->intf->dev,
				 "failed to get i2c transfer status from bridge register (error=%i)\n",
				 ret);
			return ret;
		}
		usleep_range(5000, 6000);
	}
	if (ret != 0x84 + len - 1)
		dprintk(0, "read from i2c device at 0x%x timed out\n", addr);

	/* get the received message */
	ret = dev->em28xx_read_reg_req_len(dev, 0x00, 4 - len, buf2, len);
	if (ret != len) {
		dev_warn(&dev->intf->dev,
			 "reading from i2c device at 0x%x failed: couldn't get the received message from the bridge (error=%i)\n",
			 addr, ret);
		return (ret < 0) ? ret : -EIO;
	}
	for (i = 0; i < len; i++)
		buf[i] = buf2[len - 1 - i];

	return ret;
}

/*
 * em2800_i2c_check_for_device()
 * check if there is an i2c device at the supplied address
 */
static int em2800_i2c_check_for_device(struct em28xx *dev, u8 addr)
{
	u8 buf;
	int ret;

	ret = em2800_i2c_recv_bytes(dev, addr, &buf, 1);
	if (ret == 1)
		return 0;
	return (ret < 0) ? ret : -EIO;
}

/*
 * em28xx_i2c_send_bytes()
 */
static int em28xx_i2c_send_bytes(struct em28xx *dev, u16 addr, u8 *buf,
				 u16 len, int stop)
{
	unsigned long timeout = jiffies + em28xx_i2c_timeout(dev);
	int ret;

	if (len < 1 || len > 64)
		return -EOPNOTSUPP;
	/*
	 * NOTE: limited by the USB ctrl message constraints
	 * Zero length reads always succeed, even if no device is connected
	 */

	/* Write to i2c device */
	ret = dev->em28xx_write_regs_req(dev, stop ? 2 : 3, addr, buf, len);
	if (ret != len) {
		if (ret < 0) {
			dev_warn(&dev->intf->dev,
				 "writing to i2c device at 0x%x failed (error=%i)\n",
				 addr, ret);
			return ret;
		}
		dev_warn(&dev->intf->dev,
			 "%i bytes write to i2c device at 0x%x requested, but %i bytes written\n",
				len, addr, ret);
		return -EIO;
	}

	/* wait for completion */
	while (time_is_after_jiffies(timeout)) {
		ret = dev->em28xx_read_reg(dev, 0x05);
		if (ret == 0) /* success */
			return len;
		if (ret == 0x10) {
			dprintk(1, "I2C ACK error on writing to addr 0x%02x\n",
				addr);
			return -ENXIO;
		}
		if (ret < 0) {
			dev_warn(&dev->intf->dev,
				 "failed to get i2c transfer status from bridge register (error=%i)\n",
				 ret);
			return ret;
		}
		usleep_range(5000, 6000);
		/*
		 * NOTE: do we really have to wait for success ?
		 * Never seen anything else than 0x00 or 0x10
		 * (even with high payload) ...
		 */
	}

	if (ret == 0x02 || ret == 0x04) {
		/* NOTE: these errors seem to be related to clock stretching */
		dprintk(0,
			"write to i2c device at 0x%x timed out (status=%i)\n",
			addr, ret);
		return -ETIMEDOUT;
	}

	dev_warn(&dev->intf->dev,
		 "write to i2c device at 0x%x failed with unknown error (status=%i)\n",
		 addr, ret);
	return -EIO;
}

/*
 * em28xx_i2c_recv_bytes()
 * read a byte from the i2c device
 */
static int em28xx_i2c_recv_bytes(struct em28xx *dev, u16 addr, u8 *buf, u16 len)
{
	int ret;

	if (len < 1 || len > 64)
		return -EOPNOTSUPP;
	/*
	 * NOTE: limited by the USB ctrl message constraints
	 * Zero length reads always succeed, even if no device is connected
	 */

	/* Read data from i2c device */
	ret = dev->em28xx_read_reg_req_len(dev, 2, addr, buf, len);
	if (ret < 0) {
		dev_warn(&dev->intf->dev,
			 "reading from i2c device at 0x%x failed (error=%i)\n",
			 addr, ret);
		return ret;
	}
	/*
	 * NOTE: some devices with two i2c busses have the bad habit to return 0
	 * bytes if we are on bus B AND there was no write attempt to the
	 * specified slave address before AND no device is present at the
	 * requested slave address.
	 * Anyway, the next check will fail with -ENXIO in this case, so avoid
	 * spamming the system log on device probing and do nothing here.
	 */

	/* Check success of the i2c operation */
	ret = dev->em28xx_read_reg(dev, 0x05);
	if (ret == 0) /* success */
		return len;
	if (ret < 0) {
		dev_warn(&dev->intf->dev,
			 "failed to get i2c transfer status from bridge register (error=%i)\n",
			 ret);
		return ret;
	}
	if (ret == 0x10) {
		dprintk(1, "I2C ACK error on writing to addr 0x%02x\n",
			addr);
		return -ENXIO;
	}

	if (ret == 0x02 || ret == 0x04) {
		/* NOTE: these errors seem to be related to clock stretching */
		dprintk(0,
			"write to i2c device at 0x%x timed out (status=%i)\n",
			addr, ret);
		return -ETIMEDOUT;
	}

	dev_warn(&dev->intf->dev,
		 "write to i2c device at 0x%x failed with unknown error (status=%i)\n",
		 addr, ret);
	return -EIO;
}

/*
 * em28xx_i2c_check_for_device()
 * check if there is a i2c_device at the supplied address
 */
static int em28xx_i2c_check_for_device(struct em28xx *dev, u16 addr)
{
	int ret;
	u8 buf;

	ret = em28xx_i2c_recv_bytes(dev, addr, &buf, 1);
	if (ret == 1)
		return 0;
	return (ret < 0) ? ret : -EIO;
}

/*
 * em25xx_bus_B_send_bytes
 * write bytes to the i2c device
 */
static int em25xx_bus_B_send_bytes(struct em28xx *dev, u16 addr, u8 *buf,
				   u16 len)
{
	int ret;

	if (len < 1 || len > 64)
		return -EOPNOTSUPP;
	/*
	 * NOTE: limited by the USB ctrl message constraints
	 * Zero length reads always succeed, even if no device is connected
	 */

	/* Set register and write value */
	ret = dev->em28xx_write_regs_req(dev, 0x06, addr, buf, len);
	if (ret != len) {
		if (ret < 0) {
			dev_warn(&dev->intf->dev,
				 "writing to i2c device at 0x%x failed (error=%i)\n",
				 addr, ret);
			return ret;
		}

		dev_warn(&dev->intf->dev,
			 "%i bytes write to i2c device at 0x%x requested, but %i bytes written\n",
			 len, addr, ret);
		return -EIO;
	}
	/* Check success */
	ret = dev->em28xx_read_reg_req(dev, 0x08, 0x0000);
	/*
	 * NOTE: the only error we've seen so far is
	 * 0x01 when the slave device is not present
	 */
	if (!ret)
		return len;

	if (ret > 0) {
		dprintk(1, "Bus B R08 returned 0x%02x: I2C ACK error\n", ret);
		return -ENXIO;
	}

	return ret;
	/*
	 * NOTE: With chip types (other chip IDs) which actually don't support
	 * this operation, it seems to succeed ALWAYS ! (even if there is no
	 * slave device or even no second i2c bus provided)
	 */
}

/*
 * em25xx_bus_B_recv_bytes
 * read bytes from the i2c device
 */
static int em25xx_bus_B_recv_bytes(struct em28xx *dev, u16 addr, u8 *buf,
				   u16 len)
{
	int ret;

	if (len < 1 || len > 64)
		return -EOPNOTSUPP;
	/*
	 * NOTE: limited by the USB ctrl message constraints
	 * Zero length reads always succeed, even if no device is connected
	 */

	/* Read value */
	ret = dev->em28xx_read_reg_req_len(dev, 0x06, addr, buf, len);
	if (ret < 0) {
		dev_warn(&dev->intf->dev,
			 "reading from i2c device at 0x%x failed (error=%i)\n",
			 addr, ret);
		return ret;
	}
	/*
	 * NOTE: some devices with two i2c busses have the bad habit to return 0
	 * bytes if we are on bus B AND there was no write attempt to the
	 * specified slave address before AND no device is present at the
	 * requested slave address.
	 * Anyway, the next check will fail with -ENXIO in this case, so avoid
	 * spamming the system log on device probing and do nothing here.
	 */

	/* Check success */
	ret = dev->em28xx_read_reg_req(dev, 0x08, 0x0000);
	/*
	 * NOTE: the only error we've seen so far is
	 * 0x01 when the slave device is not present
	 */
	if (!ret)
		return len;

	if (ret > 0) {
		dprintk(1, "Bus B R08 returned 0x%02x: I2C ACK error\n", ret);
		return -ENXIO;
	}

	return ret;
	/*
	 * NOTE: With chip types (other chip IDs) which actually don't support
	 * this operation, it seems to succeed ALWAYS ! (even if there is no
	 * slave device or even no second i2c bus provided)
	 */
}

/*
 * em25xx_bus_B_check_for_device()
 * check if there is a i2c device at the supplied address
 */
static int em25xx_bus_B_check_for_device(struct em28xx *dev, u16 addr)
{
	u8 buf;
	int ret;

	ret = em25xx_bus_B_recv_bytes(dev, addr, &buf, 1);
	if (ret < 0)
		return ret;

	return 0;
	/*
	 * NOTE: With chips which do not support this operation,
	 * it seems to succeed ALWAYS ! (even if no device connected)
	 */
}

static inline int i2c_check_for_device(struct em28xx_i2c_bus *i2c_bus, u16 addr)
{
	struct em28xx *dev = i2c_bus->dev;
	int rc = -EOPNOTSUPP;

	if (i2c_bus->algo_type == EM28XX_I2C_ALGO_EM28XX)
		rc = em28xx_i2c_check_for_device(dev, addr);
	else if (i2c_bus->algo_type == EM28XX_I2C_ALGO_EM2800)
		rc = em2800_i2c_check_for_device(dev, addr);
	else if (i2c_bus->algo_type == EM28XX_I2C_ALGO_EM25XX_BUS_B)
		rc = em25xx_bus_B_check_for_device(dev, addr);
	return rc;
}

static inline int i2c_recv_bytes(struct em28xx_i2c_bus *i2c_bus,
				 struct i2c_msg msg)
{
	struct em28xx *dev = i2c_bus->dev;
	u16 addr = msg.addr << 1;
	int rc = -EOPNOTSUPP;

	if (i2c_bus->algo_type == EM28XX_I2C_ALGO_EM28XX)
		rc = em28xx_i2c_recv_bytes(dev, addr, msg.buf, msg.len);
	else if (i2c_bus->algo_type == EM28XX_I2C_ALGO_EM2800)
		rc = em2800_i2c_recv_bytes(dev, addr, msg.buf, msg.len);
	else if (i2c_bus->algo_type == EM28XX_I2C_ALGO_EM25XX_BUS_B)
		rc = em25xx_bus_B_recv_bytes(dev, addr, msg.buf, msg.len);
	return rc;
}

static inline int i2c_send_bytes(struct em28xx_i2c_bus *i2c_bus,
				 struct i2c_msg msg, int stop)
{
	struct em28xx *dev = i2c_bus->dev;
	u16 addr = msg.addr << 1;
	int rc = -EOPNOTSUPP;

	if (i2c_bus->algo_type == EM28XX_I2C_ALGO_EM28XX)
		rc = em28xx_i2c_send_bytes(dev, addr, msg.buf, msg.len, stop);
	else if (i2c_bus->algo_type == EM28XX_I2C_ALGO_EM2800)
		rc = em2800_i2c_send_bytes(dev, addr, msg.buf, msg.len);
	else if (i2c_bus->algo_type == EM28XX_I2C_ALGO_EM25XX_BUS_B)
		rc = em25xx_bus_B_send_bytes(dev, addr, msg.buf, msg.len);
	return rc;
}

/*
 * em28xx_i2c_xfer()
 * the main i2c transfer function
 */
static int em28xx_i2c_xfer(struct i2c_adapter *i2c_adap,
			   struct i2c_msg msgs[], int num)
{
	struct em28xx_i2c_bus *i2c_bus = i2c_adap->algo_data;
	struct em28xx *dev = i2c_bus->dev;
	unsigned int bus = i2c_bus->bus;
	int addr, rc, i;
	u8 reg;

	/*
	 * prevent i2c xfer attempts after device is disconnected
	 * some fe's try to do i2c writes/reads from their release
	 * interfaces when called in disconnect path
	 */
	if (dev->disconnected)
		return -ENODEV;

	if (!rt_mutex_trylock(&dev->i2c_bus_lock))
		return -EAGAIN;

	/* Switch I2C bus if needed */
	if (bus != dev->cur_i2c_bus &&
	    i2c_bus->algo_type == EM28XX_I2C_ALGO_EM28XX) {
		if (bus == 1)
			reg = EM2874_I2C_SECONDARY_BUS_SELECT;
		else
			reg = 0;
		em28xx_write_reg_bits(dev, EM28XX_R06_I2C_CLK, reg,
				      EM2874_I2C_SECONDARY_BUS_SELECT);
		dev->cur_i2c_bus = bus;
	}

	if (num <= 0) {
		rt_mutex_unlock(&dev->i2c_bus_lock);
		return 0;
	}
	for (i = 0; i < num; i++) {
		addr = msgs[i].addr << 1;
		if (!msgs[i].len) {
			/*
			 * no len: check only for device presence
			 * This code is only called during device probe.
			 */
			rc = i2c_check_for_device(i2c_bus, addr);

			if (rc == -ENXIO)
				rc = -ENODEV;
		} else if (msgs[i].flags & I2C_M_RD) {
			/* read bytes */
			rc = i2c_recv_bytes(i2c_bus, msgs[i]);
		} else {
			/* write bytes */
			rc = i2c_send_bytes(i2c_bus, msgs[i], i == num - 1);
		}

		if (rc < 0)
			goto error;

		dprintk(2, "%s %s addr=%02x len=%d: %*ph\n",
			(msgs[i].flags & I2C_M_RD) ? "read" : "write",
			i == num - 1 ? "stop" : "nonstop",
			addr, msgs[i].len,
			msgs[i].len, msgs[i].buf);
	}

	rt_mutex_unlock(&dev->i2c_bus_lock);
	return num;

error:
	dprintk(2, "%s %s addr=%02x len=%d: %sERROR: %i\n",
		(msgs[i].flags & I2C_M_RD) ? "read" : "write",
		i == num - 1 ? "stop" : "nonstop",
		addr, msgs[i].len,
		(rc == -ENODEV) ? "no device " : "",
		rc);

	rt_mutex_unlock(&dev->i2c_bus_lock);
	return rc;
}

/*
 * based on linux/sunrpc/svcauth.h and linux/hash.h
 * The original hash function returns a different value, if arch is x86_64
 * or i386.
 */
static inline unsigned long em28xx_hash_mem(char *buf, int length, int bits)
{
	unsigned long hash = 0;
	unsigned long l = 0;
	int len = 0;
	unsigned char c;

	do {
		if (len == length) {
			c = (char)len;
			len = -1;
		} else {
			c = *buf++;
		}
		l = (l << 8) | c;
		len++;
		if ((len & (32 / 8 - 1)) == 0)
			hash = ((hash ^ l) * 0x9e370001UL);
	} while (len);

	return (hash >> (32 - bits)) & 0xffffffffUL;
}

/*
 * Helper function to read data blocks from i2c clients with 8 or 16 bit
 * address width, 8 bit register width and auto incrementation been activated
 */
static int em28xx_i2c_read_block(struct em28xx *dev, unsigned int bus, u16 addr,
				 bool addr_w16, u16 len, u8 *data)
{
	int remain = len, rsize, rsize_max, ret;
	u8 buf[2];

	/* Sanity check */
	if (addr + remain > (addr_w16 * 0xff00 + 0xff + 1))
		return -EINVAL;
	/* Select address */
	buf[0] = addr >> 8;
	buf[1] = addr & 0xff;
	ret = i2c_master_send(&dev->i2c_client[bus],
			      buf + !addr_w16, 1 + addr_w16);
	if (ret < 0)
		return ret;
	/* Read data */
	if (dev->board.is_em2800)
		rsize_max = 4;
	else
		rsize_max = 64;
	while (remain > 0) {
		if (remain > rsize_max)
			rsize = rsize_max;
		else
			rsize = remain;

		ret = i2c_master_recv(&dev->i2c_client[bus], data, rsize);
		if (ret < 0)
			return ret;

		remain -= rsize;
		data += rsize;
	}

	return len;
}

static int em28xx_i2c_eeprom(struct em28xx *dev, unsigned int bus,
			     u8 **eedata, u16 *eedata_len)
{
	const u16 len = 256;
	/*
	 * FIXME common length/size for bytes to read, to display, hash
	 * calculation and returned device dataset. Simplifies the code a lot,
	 * but we might have to deal with multiple sizes in the future !
	 */
	int err;
	struct em28xx_eeprom *dev_config;
	u8 buf, *data;

	*eedata = NULL;
	*eedata_len = 0;

	/* EEPROM is always on i2c bus 0 on all known devices. */

	dev->i2c_client[bus].addr = 0xa0 >> 1;

	/* Check if board has eeprom */
	err = i2c_master_recv(&dev->i2c_client[bus], &buf, 0);
	if (err < 0) {
		dev_info(&dev->intf->dev, "board has no eeprom\n");
		return -ENODEV;
	}

	data = kzalloc(len, GFP_KERNEL);
	if (!data)
		return -ENOMEM;

	/* Read EEPROM content */
	err = em28xx_i2c_read_block(dev, bus, 0x0000,
				    dev->eeprom_addrwidth_16bit,
				    len, data);
	if (err != len) {
		dev_err(&dev->intf->dev,
			"failed to read eeprom (err=%d)\n", err);
		goto error;
	}

	if (i2c_debug) {
		/* Display eeprom content */
		print_hex_dump(KERN_DEBUG, "em28xx eeprom ", DUMP_PREFIX_OFFSET,
			       16, 1, data, len, true);

		if (dev->eeprom_addrwidth_16bit)
			dev_info(&dev->intf->dev,
				 "eeprom %06x: ... (skipped)\n", 256);
	}

	if (dev->eeprom_addrwidth_16bit &&
	    data[0] == 0x26 && data[3] == 0x00) {
		/* new eeprom format; size 4-64kb */
		u16 mc_start;
		u16 hwconf_offset;

		dev->hash = em28xx_hash_mem(data, len, 32);
		mc_start = (data[1] << 8) + 4;	/* usually 0x0004 */

		dev_info(&dev->intf->dev,
			 "EEPROM ID = %4ph, EEPROM hash = 0x%08lx\n",
			 data, dev->hash);
		dev_info(&dev->intf->dev,
			 "EEPROM info:\n");
		dev_info(&dev->intf->dev,
			 "\tmicrocode start address = 0x%04x, boot configuration = 0x%02x\n",
			 mc_start, data[2]);
		/*
		 * boot configuration (address 0x0002):
		 * [0]   microcode download speed: 1 = 400 kHz; 0 = 100 kHz
		 * [1]   always selects 12 kb RAM
		 * [2]   USB device speed: 1 = force Full Speed; 0 = auto detect
		 * [4]   1 = force fast mode and no suspend for device testing
		 * [5:7] USB PHY tuning registers; determined by device
		 *       characterization
		 */

		/*
		 * Read hardware config dataset offset from address
		 * (microcode start + 46)
		 */
		err = em28xx_i2c_read_block(dev, bus, mc_start + 46, 1, 2,
					    data);
		if (err != 2) {
			dev_err(&dev->intf->dev,
				"failed to read hardware configuration data from eeprom (err=%d)\n",
				err);
			goto error;
		}

		/* Calculate hardware config dataset start address */
		hwconf_offset = mc_start + data[0] + (data[1] << 8);

		/* Read hardware config dataset */
		/*
		 * NOTE: the microcode copy can be multiple pages long, but
		 * we assume the hardware config dataset is the same as in
		 * the old eeprom and not longer than 256 bytes.
		 * tveeprom is currently also limited to 256 bytes.
		 */
		err = em28xx_i2c_read_block(dev, bus, hwconf_offset, 1, len,
					    data);
		if (err != len) {
			dev_err(&dev->intf->dev,
				"failed to read hardware configuration data from eeprom (err=%d)\n",
				err);
			goto error;
		}

		/* Verify hardware config dataset */
		/* NOTE: not all devices provide this type of dataset */
		if (data[0] != 0x1a || data[1] != 0xeb ||
		    data[2] != 0x67 || data[3] != 0x95) {
			dev_info(&dev->intf->dev,
				 "\tno hardware configuration dataset found in eeprom\n");
			kfree(data);
			return 0;
		}

		/*
		 * TODO: decrypt eeprom data for camera bridges
		 * (em25xx, em276x+)
		 */

	} else if (!dev->eeprom_addrwidth_16bit &&
		   data[0] == 0x1a && data[1] == 0xeb &&
		   data[2] == 0x67 && data[3] == 0x95) {
		dev->hash = em28xx_hash_mem(data, len, 32);
		dev_info(&dev->intf->dev,
			 "EEPROM ID = %4ph, EEPROM hash = 0x%08lx\n",
			 data, dev->hash);
		dev_info(&dev->intf->dev,
			 "EEPROM info:\n");
	} else {
		dev_info(&dev->intf->dev,
			 "unknown eeprom format or eeprom corrupted !\n");
		err = -ENODEV;
		goto error;
	}

	*eedata = data;
	*eedata_len = len;
	dev_config = (void *)*eedata;

	switch (le16_to_cpu(dev_config->chip_conf) >> 4 & 0x3) {
	case 0:
		dev_info(&dev->intf->dev, "\tNo audio on board.\n");
		break;
	case 1:
		dev_info(&dev->intf->dev, "\tAC97 audio (5 sample rates)\n");
		break;
	case 2:
		if (dev->chip_id < CHIP_ID_EM2860)
			dev_info(&dev->intf->dev,
				 "\tI2S audio, sample rate=32k\n");
		else
			dev_info(&dev->intf->dev,
				 "\tI2S audio, 3 sample rates\n");
		break;
	case 3:
		if (dev->chip_id < CHIP_ID_EM2860)
			dev_info(&dev->intf->dev,
				 "\tI2S audio, 3 sample rates\n");
		else
			dev_info(&dev->intf->dev,
				 "\tI2S audio, 5 sample rates\n");
		break;
	}

	if (le16_to_cpu(dev_config->chip_conf) & 1 << 3)
		dev_info(&dev->intf->dev, "\tUSB Remote wakeup capable\n");

	if (le16_to_cpu(dev_config->chip_conf) & 1 << 2)
		dev_info(&dev->intf->dev, "\tUSB Self power capable\n");

	switch (le16_to_cpu(dev_config->chip_conf) & 0x3) {
	case 0:
		dev_info(&dev->intf->dev, "\t500mA max power\n");
		break;
	case 1:
		dev_info(&dev->intf->dev, "\t400mA max power\n");
		break;
	case 2:
		dev_info(&dev->intf->dev, "\t300mA max power\n");
		break;
	case 3:
		dev_info(&dev->intf->dev, "\t200mA max power\n");
		break;
	}
	dev_info(&dev->intf->dev,
		 "\tTable at offset 0x%02x, strings=0x%04x, 0x%04x, 0x%04x\n",
		 dev_config->string_idx_table,
		 le16_to_cpu(dev_config->string1),
		 le16_to_cpu(dev_config->string2),
		 le16_to_cpu(dev_config->string3));

	return 0;

error:
	kfree(data);
	return err;
}

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

/*
 * functionality()
 */
static u32 functionality(struct i2c_adapter *i2c_adap)
{
	struct em28xx_i2c_bus *i2c_bus = i2c_adap->algo_data;

	if (i2c_bus->algo_type == EM28XX_I2C_ALGO_EM28XX ||
	    i2c_bus->algo_type == EM28XX_I2C_ALGO_EM25XX_BUS_B) {
		return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
	} else if (i2c_bus->algo_type == EM28XX_I2C_ALGO_EM2800)  {
		return (I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL) &
			~I2C_FUNC_SMBUS_WRITE_BLOCK_DATA;
	}

	WARN(1, "Unknown i2c bus algorithm.\n");
	return 0;
}

static const struct i2c_algorithm em28xx_algo = {
	.master_xfer   = em28xx_i2c_xfer,
	.functionality = functionality,
};

static const struct i2c_adapter em28xx_adap_template = {
	.owner = THIS_MODULE,
	.name = "em28xx",
	.algo = &em28xx_algo,
};

static const struct i2c_client em28xx_client_template = {
	.name = "em28xx internal",
};

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

/*
 * i2c_devs
 * incomplete list of known devices
 */
static char *i2c_devs[128] = {
	[0x1c >> 1] = "lgdt330x",
	[0x3e >> 1] = "remote IR sensor",
	[0x4a >> 1] = "saa7113h",
	[0x52 >> 1] = "drxk",
	[0x60 >> 1] = "remote IR sensor",
	[0x8e >> 1] = "remote IR sensor",
	[0x86 >> 1] = "tda9887",
	[0x80 >> 1] = "msp34xx",
	[0x88 >> 1] = "msp34xx",
	[0xa0 >> 1] = "eeprom",
	[0xb0 >> 1] = "tda9874",
	[0xb8 >> 1] = "tvp5150a",
	[0xba >> 1] = "webcam sensor or tvp5150a",
	[0xc0 >> 1] = "tuner (analog)",
	[0xc2 >> 1] = "tuner (analog)",
	[0xc4 >> 1] = "tuner (analog)",
	[0xc6 >> 1] = "tuner (analog)",
};

/*
 * do_i2c_scan()
 * check i2c address range for devices
 */
void em28xx_do_i2c_scan(struct em28xx *dev, unsigned int bus)
{
	u8 i2c_devicelist[128];
	unsigned char buf;
	int i, rc;

	memset(i2c_devicelist, 0, ARRAY_SIZE(i2c_devicelist));

	for (i = 0; i < ARRAY_SIZE(i2c_devs); i++) {
		dev->i2c_client[bus].addr = i;
		rc = i2c_master_recv(&dev->i2c_client[bus], &buf, 0);
		if (rc < 0)
			continue;
		i2c_devicelist[i] = i;
		dev_info(&dev->intf->dev,
			 "found i2c device @ 0x%x on bus %d [%s]\n",
			 i << 1, bus, i2c_devs[i] ? i2c_devs[i] : "???");
	}

	if (bus == dev->def_i2c_bus)
		dev->i2c_hash = em28xx_hash_mem(i2c_devicelist,
						ARRAY_SIZE(i2c_devicelist), 32);
}

/*
 * em28xx_i2c_register()
 * register i2c bus
 */
int em28xx_i2c_register(struct em28xx *dev, unsigned int bus,
			enum em28xx_i2c_algo_type algo_type)
{
	int retval;

	if (WARN_ON(!dev->em28xx_write_regs || !dev->em28xx_read_reg ||
		    !dev->em28xx_write_regs_req || !dev->em28xx_read_reg_req))
		return -ENODEV;

	if (bus >= NUM_I2C_BUSES)
		return -ENODEV;

	dev->i2c_adap[bus] = em28xx_adap_template;
	dev->i2c_adap[bus].dev.parent = &dev->intf->dev;
	strcpy(dev->i2c_adap[bus].name, dev_name(&dev->intf->dev));

	dev->i2c_bus[bus].bus = bus;
	dev->i2c_bus[bus].algo_type = algo_type;
	dev->i2c_bus[bus].dev = dev;
	dev->i2c_adap[bus].algo_data = &dev->i2c_bus[bus];

	retval = i2c_add_adapter(&dev->i2c_adap[bus]);
	if (retval < 0) {
		dev_err(&dev->intf->dev,
			"%s: i2c_add_adapter failed! retval [%d]\n",
			__func__, retval);
		return retval;
	}

	dev->i2c_client[bus] = em28xx_client_template;
	dev->i2c_client[bus].adapter = &dev->i2c_adap[bus];

	/* Up to now, all eeproms are at bus 0 */
	if (!bus) {
		retval = em28xx_i2c_eeprom(dev, bus,
					   &dev->eedata, &dev->eedata_len);
		if (retval < 0 && retval != -ENODEV) {
			dev_err(&dev->intf->dev,
				"%s: em28xx_i2_eeprom failed! retval [%d]\n",
				__func__, retval);
		}
	}

	if (i2c_scan)
		em28xx_do_i2c_scan(dev, bus);

	return 0;
}

/*
 * em28xx_i2c_unregister()
 * unregister i2c_bus
 */
int em28xx_i2c_unregister(struct em28xx *dev, unsigned int bus)
{
	if (bus >= NUM_I2C_BUSES)
		return -ENODEV;

	i2c_del_adapter(&dev->i2c_adap[bus]);
	return 0;
}