summaryrefslogtreecommitdiff
path: root/drivers/media/video/saa5246a.c
blob: 8f117bd50b8636faa47101932abffdcf6f67cc00 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
/*
 * Driver for the SAA5246A or SAA5281 Teletext (=Videotext) decoder chips from
 * Philips.
 *
 * Only capturing of Teletext pages is tested. The videotext chips also have a
 * TV output but my hardware doesn't use it. For this reason this driver does
 * not support changing any TV display settings.
 *
 * Copyright (C) 2004 Michael Geng <linux@MichaelGeng.de>
 *
 * Derived from
 *
 * saa5249 driver
 * Copyright (C) 1998 Richard Guenther
 * <richard.guenther@student.uni-tuebingen.de>
 *
 * with changes by
 * Alan Cox <alan@lxorguk.ukuu.org.uk>
 *
 * and
 *
 * vtx.c
 * Copyright (C) 1994-97 Martin Buck  <martin-2.buck@student.uni-ulm.de>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307,
 * USA.
 */

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/init.h>
#include <linux/i2c.h>
#include <linux/smp_lock.h>
#include <linux/mutex.h>
#include <linux/videotext.h>
#include <linux/videodev.h>
#include <media/v4l2-common.h>
#include <media/v4l2-ioctl.h>
#include <media/v4l2-i2c-drv-legacy.h>

MODULE_AUTHOR("Michael Geng <linux@MichaelGeng.de>");
MODULE_DESCRIPTION("Philips SAA5246A, SAA5281 Teletext decoder driver");
MODULE_LICENSE("GPL");

#define MAJOR_VERSION 1		/* driver major version number */
#define MINOR_VERSION 8		/* driver minor version number */

/* Number of DAUs = number of pages that can be searched at the same time. */
#define NUM_DAUS 4

#define NUM_ROWS_PER_PAGE 40

/* first column is 0 (not 1) */
#define POS_TIME_START 32
#define POS_TIME_END 39

#define POS_HEADER_START 7
#define POS_HEADER_END 31

/* Returns 'true' if the part of the videotext page described with req contains
   (at least parts of) the time field */
#define REQ_CONTAINS_TIME(p_req) \
	((p_req)->start <= POS_TIME_END && \
	 (p_req)->end   >= POS_TIME_START)

/* Returns 'true' if the part of the videotext page described with req contains
   (at least parts of) the page header */
#define REQ_CONTAINS_HEADER(p_req) \
	((p_req)->start <= POS_HEADER_END && \
	 (p_req)->end   >= POS_HEADER_START)

/*****************************************************************************/
/* Mode register numbers of the SAA5246A				     */
/*****************************************************************************/
#define SAA5246A_REGISTER_R0    0
#define SAA5246A_REGISTER_R1    1
#define SAA5246A_REGISTER_R2    2
#define SAA5246A_REGISTER_R3    3
#define SAA5246A_REGISTER_R4    4
#define SAA5246A_REGISTER_R5    5
#define SAA5246A_REGISTER_R6    6
#define SAA5246A_REGISTER_R7    7
#define SAA5246A_REGISTER_R8    8
#define SAA5246A_REGISTER_R9    9
#define SAA5246A_REGISTER_R10  10
#define SAA5246A_REGISTER_R11  11
#define SAA5246A_REGISTER_R11B 11

/* SAA5246A mode registers often autoincrement to the next register.
   Therefore we use variable argument lists. The following macro indicates
   the end of a command list. */
#define COMMAND_END (-1)

/*****************************************************************************/
/* Contents of the mode registers of the SAA5246A			     */
/*****************************************************************************/
/* Register R0 (Advanced Control) */
#define R0_SELECT_R11					   0x00
#define R0_SELECT_R11B					   0x01

#define R0_PLL_TIME_CONSTANT_LONG			   0x00
#define R0_PLL_TIME_CONSTANT_SHORT			   0x02

#define R0_ENABLE_nODD_EVEN_OUTPUT			   0x00
#define R0_DISABLE_nODD_EVEN_OUTPUT			   0x04

#define R0_ENABLE_HDR_POLL				   0x00
#define R0_DISABLE_HDR_POLL				   0x10

#define R0_DO_NOT_FORCE_nODD_EVEN_LOW_IF_PICTURE_DISPLAYED 0x00
#define R0_FORCE_nODD_EVEN_LOW_IF_PICTURE_DISPLAYED	   0x20

#define R0_NO_FREE_RUN_PLL				   0x00
#define R0_FREE_RUN_PLL					   0x40

#define R0_NO_AUTOMATIC_FASTEXT_PROMPT			   0x00
#define R0_AUTOMATIC_FASTEXT_PROMPT			   0x80

/* Register R1 (Mode) */
#define R1_INTERLACED_312_AND_HALF_312_AND_HALF_LINES	   0x00
#define R1_NON_INTERLACED_312_313_LINES			   0x01
#define R1_NON_INTERLACED_312_312_LINES			   0x02
#define R1_FFB_LEADING_EDGE_IN_FIRST_BROAD_PULSE	   0x03
#define R1_FFB_LEADING_EDGE_IN_SECOND_BROAD_PULSE	   0x07

#define R1_DEW						   0x00
#define R1_FULL_FIELD					   0x08

#define R1_EXTENDED_PACKET_DISABLE			   0x00
#define R1_EXTENDED_PACKET_ENABLE			   0x10

#define R1_DAUS_ALL_ON					   0x00
#define R1_DAUS_ALL_OFF					   0x20

#define R1_7_BITS_PLUS_PARITY				   0x00
#define R1_8_BITS_NO_PARITY				   0x40

#define R1_VCS_TO_SCS					   0x00
#define R1_NO_VCS_TO_SCS				   0x80

/* Register R2 (Page request address) */
#define R2_IN_R3_SELECT_PAGE_HUNDREDS			   0x00
#define R2_IN_R3_SELECT_PAGE_TENS			   0x01
#define R2_IN_R3_SELECT_PAGE_UNITS			   0x02
#define R2_IN_R3_SELECT_HOURS_TENS			   0x03
#define R2_IN_R3_SELECT_HOURS_UNITS			   0x04
#define R2_IN_R3_SELECT_MINUTES_TENS			   0x05
#define R2_IN_R3_SELECT_MINUTES_UNITS			   0x06

#define R2_DAU_0					   0x00
#define R2_DAU_1					   0x10
#define R2_DAU_2					   0x20
#define R2_DAU_3					   0x30

#define R2_BANK_0					   0x00
#define R2_BANK 1					   0x40

#define R2_HAMMING_CHECK_ON				   0x80
#define R2_HAMMING_CHECK_OFF				   0x00

/* Register R3 (Page request data) */
#define R3_PAGE_HUNDREDS_0				   0x00
#define R3_PAGE_HUNDREDS_1				   0x01
#define R3_PAGE_HUNDREDS_2				   0x02
#define R3_PAGE_HUNDREDS_3				   0x03
#define R3_PAGE_HUNDREDS_4				   0x04
#define R3_PAGE_HUNDREDS_5				   0x05
#define R3_PAGE_HUNDREDS_6				   0x06
#define R3_PAGE_HUNDREDS_7				   0x07

#define R3_HOLD_PAGE					   0x00
#define R3_UPDATE_PAGE					   0x08

#define R3_PAGE_HUNDREDS_DO_NOT_CARE			   0x00
#define R3_PAGE_HUNDREDS_DO_CARE			   0x10

#define R3_PAGE_TENS_DO_NOT_CARE			   0x00
#define R3_PAGE_TENS_DO_CARE				   0x10

#define R3_PAGE_UNITS_DO_NOT_CARE			   0x00
#define R3_PAGE_UNITS_DO_CARE				   0x10

#define R3_HOURS_TENS_DO_NOT_CARE			   0x00
#define R3_HOURS_TENS_DO_CARE				   0x10

#define R3_HOURS_UNITS_DO_NOT_CARE			   0x00
#define R3_HOURS_UNITS_DO_CARE				   0x10

#define R3_MINUTES_TENS_DO_NOT_CARE			   0x00
#define R3_MINUTES_TENS_DO_CARE				   0x10

#define R3_MINUTES_UNITS_DO_NOT_CARE			   0x00
#define R3_MINUTES_UNITS_DO_CARE			   0x10

/* Register R4 (Display chapter) */
#define R4_DISPLAY_PAGE_0				   0x00
#define R4_DISPLAY_PAGE_1				   0x01
#define R4_DISPLAY_PAGE_2				   0x02
#define R4_DISPLAY_PAGE_3				   0x03
#define R4_DISPLAY_PAGE_4				   0x04
#define R4_DISPLAY_PAGE_5				   0x05
#define R4_DISPLAY_PAGE_6				   0x06
#define R4_DISPLAY_PAGE_7				   0x07

/* Register R5 (Normal display control) */
#define R5_PICTURE_INSIDE_BOXING_OFF			   0x00
#define R5_PICTURE_INSIDE_BOXING_ON			   0x01

#define R5_PICTURE_OUTSIDE_BOXING_OFF			   0x00
#define R5_PICTURE_OUTSIDE_BOXING_ON			   0x02

#define R5_TEXT_INSIDE_BOXING_OFF			   0x00
#define R5_TEXT_INSIDE_BOXING_ON			   0x04

#define R5_TEXT_OUTSIDE_BOXING_OFF			   0x00
#define R5_TEXT_OUTSIDE_BOXING_ON			   0x08

#define R5_CONTRAST_REDUCTION_INSIDE_BOXING_OFF		   0x00
#define R5_CONTRAST_REDUCTION_INSIDE_BOXING_ON		   0x10

#define R5_CONTRAST_REDUCTION_OUTSIDE_BOXING_OFF	   0x00
#define R5_CONTRAST_REDUCTION_OUTSIDE_BOXING_ON		   0x20

#define R5_BACKGROUND_COLOR_INSIDE_BOXING_OFF		   0x00
#define R5_BACKGROUND_COLOR_INSIDE_BOXING_ON		   0x40

#define R5_BACKGROUND_COLOR_OUTSIDE_BOXING_OFF		   0x00
#define R5_BACKGROUND_COLOR_OUTSIDE_BOXING_ON		   0x80

/* Register R6 (Newsflash display) */
#define R6_NEWSFLASH_PICTURE_INSIDE_BOXING_OFF		   0x00
#define R6_NEWSFLASH_PICTURE_INSIDE_BOXING_ON		   0x01

#define R6_NEWSFLASH_PICTURE_OUTSIDE_BOXING_OFF		   0x00
#define R6_NEWSFLASH_PICTURE_OUTSIDE_BOXING_ON		   0x02

#define R6_NEWSFLASH_TEXT_INSIDE_BOXING_OFF		   0x00
#define R6_NEWSFLASH_TEXT_INSIDE_BOXING_ON		   0x04

#define R6_NEWSFLASH_TEXT_OUTSIDE_BOXING_OFF		   0x00
#define R6_NEWSFLASH_TEXT_OUTSIDE_BOXING_ON		   0x08

#define R6_NEWSFLASH_CONTRAST_REDUCTION_INSIDE_BOXING_OFF  0x00
#define R6_NEWSFLASH_CONTRAST_REDUCTION_INSIDE_BOXING_ON   0x10

#define R6_NEWSFLASH_CONTRAST_REDUCTION_OUTSIDE_BOXING_OFF 0x00
#define R6_NEWSFLASH_CONTRAST_REDUCTION_OUTSIDE_BOXING_ON  0x20

#define R6_NEWSFLASH_BACKGROUND_COLOR_INSIDE_BOXING_OFF    0x00
#define R6_NEWSFLASH_BACKGROUND_COLOR_INSIDE_BOXING_ON	   0x40

#define R6_NEWSFLASH_BACKGROUND_COLOR_OUTSIDE_BOXING_OFF   0x00
#define R6_NEWSFLASH_BACKGROUND_COLOR_OUTSIDE_BOXING_ON    0x80

/* Register R7 (Display mode) */
#define R7_BOX_OFF_ROW_0				   0x00
#define R7_BOX_ON_ROW_0					   0x01

#define R7_BOX_OFF_ROW_1_TO_23				   0x00
#define R7_BOX_ON_ROW_1_TO_23				   0x02

#define R7_BOX_OFF_ROW_24				   0x00
#define R7_BOX_ON_ROW_24				   0x04

#define R7_SINGLE_HEIGHT				   0x00
#define R7_DOUBLE_HEIGHT				   0x08

#define R7_TOP_HALF					   0x00
#define R7_BOTTOM_HALF					   0x10

#define R7_REVEAL_OFF					   0x00
#define R7_REVEAL_ON					   0x20

#define R7_CURSER_OFF					   0x00
#define R7_CURSER_ON					   0x40

#define R7_STATUS_BOTTOM				   0x00
#define R7_STATUS_TOP					   0x80

/* Register R8 (Active chapter) */
#define R8_ACTIVE_CHAPTER_0				   0x00
#define R8_ACTIVE_CHAPTER_1				   0x01
#define R8_ACTIVE_CHAPTER_2				   0x02
#define R8_ACTIVE_CHAPTER_3				   0x03
#define R8_ACTIVE_CHAPTER_4				   0x04
#define R8_ACTIVE_CHAPTER_5				   0x05
#define R8_ACTIVE_CHAPTER_6				   0x06
#define R8_ACTIVE_CHAPTER_7				   0x07

#define R8_CLEAR_MEMORY					   0x08
#define R8_DO_NOT_CLEAR_MEMORY				   0x00

/* Register R9 (Curser row) */
#define R9_CURSER_ROW_0					   0x00
#define R9_CURSER_ROW_1					   0x01
#define R9_CURSER_ROW_2					   0x02
#define R9_CURSER_ROW_25				   0x19

/* Register R10 (Curser column) */
#define R10_CURSER_COLUMN_0				   0x00
#define R10_CURSER_COLUMN_6				   0x06
#define R10_CURSER_COLUMN_8				   0x08

/*****************************************************************************/
/* Row 25 control data in column 0 to 9					     */
/*****************************************************************************/
#define ROW25_COLUMN0_PAGE_UNITS			   0x0F

#define ROW25_COLUMN1_PAGE_TENS				   0x0F

#define ROW25_COLUMN2_MINUTES_UNITS			   0x0F

#define ROW25_COLUMN3_MINUTES_TENS			   0x07
#define ROW25_COLUMN3_DELETE_PAGE			   0x08

#define ROW25_COLUMN4_HOUR_UNITS			   0x0F

#define ROW25_COLUMN5_HOUR_TENS				   0x03
#define ROW25_COLUMN5_INSERT_HEADLINE			   0x04
#define ROW25_COLUMN5_INSERT_SUBTITLE			   0x08

#define ROW25_COLUMN6_SUPPRESS_HEADER			   0x01
#define ROW25_COLUMN6_UPDATE_PAGE			   0x02
#define ROW25_COLUMN6_INTERRUPTED_SEQUENCE		   0x04
#define ROW25_COLUMN6_SUPPRESS_DISPLAY			   0x08

#define ROW25_COLUMN7_SERIAL_MODE			   0x01
#define ROW25_COLUMN7_CHARACTER_SET			   0x0E

#define ROW25_COLUMN8_PAGE_HUNDREDS			   0x07
#define ROW25_COLUMN8_PAGE_NOT_FOUND			   0x10

#define ROW25_COLUMN9_PAGE_BEING_LOOKED_FOR		   0x20

#define ROW25_COLUMN0_TO_7_HAMMING_ERROR		   0x10

/*****************************************************************************/
/* Helper macros for extracting page, hour and minute digits		     */
/*****************************************************************************/
/* BYTE_POS  0 is at row 0, column 0,
   BYTE_POS  1 is at row 0, column 1,
   BYTE_POS 40 is at row 1, column 0, (with NUM_ROWS_PER_PAGE = 40)
   BYTE_POS 41 is at row 1, column 1, (with NUM_ROWS_PER_PAGE = 40),
   ... */
#define ROW(BYTE_POS)    (BYTE_POS / NUM_ROWS_PER_PAGE)
#define COLUMN(BYTE_POS) (BYTE_POS % NUM_ROWS_PER_PAGE)

/*****************************************************************************/
/* Helper macros for extracting page, hour and minute digits		     */
/*****************************************************************************/
/* Macros for extracting hundreds, tens and units of a page number which
   must be in the range 0 ... 0x799.
   Note that page is coded in hexadecimal, i.e. 0x123 means page 123.
   page 0x.. means page 8.. */
#define HUNDREDS_OF_PAGE(page) (((page) / 0x100) & 0x7)
#define TENS_OF_PAGE(page)     (((page) / 0x10)  & 0xF)
#define UNITS_OF_PAGE(page)     ((page) & 0xF)

/* Macros for extracting tens and units of a hour information which
   must be in the range 0 ... 0x24.
   Note that hour is coded in hexadecimal, i.e. 0x12 means 12 hours */
#define TENS_OF_HOUR(hour)  ((hour) / 0x10)
#define UNITS_OF_HOUR(hour) ((hour) & 0xF)

/* Macros for extracting tens and units of a minute information which
   must be in the range 0 ... 0x59.
   Note that minute is coded in hexadecimal, i.e. 0x12 means 12 minutes */
#define TENS_OF_MINUTE(minute)  ((minute) / 0x10)
#define UNITS_OF_MINUTE(minute) ((minute) & 0xF)

#define HOUR_MAX   0x23
#define MINUTE_MAX 0x59
#define PAGE_MAX   0x8FF


struct saa5246a_device
{
	u8     pgbuf[NUM_DAUS][VTX_VIRTUALSIZE];
	int    is_searching[NUM_DAUS];
	struct i2c_client *client;
	unsigned long in_use;
	struct mutex lock;
};

static struct video_device saa_template;	/* Declared near bottom */

/*
 *	I2C interfaces
 */

static int i2c_sendbuf(struct saa5246a_device *t, int reg, int count, u8 *data)
{
	char buf[64];

	buf[0] = reg;
	memcpy(buf+1, data, count);

	if(i2c_master_send(t->client, buf, count+1)==count+1)
		return 0;
	return -1;
}

static int i2c_senddata(struct saa5246a_device *t, ...)
{
	unsigned char buf[64];
	int v;
	int ct = 0;
	va_list argp;
	va_start(argp, t);

	while ((v = va_arg(argp, int)) != -1)
		buf[ct++] = v;

	va_end(argp);
	return i2c_sendbuf(t, buf[0], ct-1, buf+1);
}

/* Get count number of bytes from I²C-device at address adr, store them in buf.
 * Start & stop handshaking is done by this routine, ack will be sent after the
 * last byte to inhibit further sending of data. If uaccess is 'true', data is
 * written to user-space with put_user. Returns -1 if I²C-device didn't send
 * acknowledge, 0 otherwise
 */
static int i2c_getdata(struct saa5246a_device *t, int count, u8 *buf)
{
	if(i2c_master_recv(t->client, buf, count)!=count)
		return -1;
	return 0;
}

/* When a page is found then the not FOUND bit in one of the status registers
 * of the SAA5264A chip is cleared. Unfortunately this bit is not set
 * automatically when a new page is requested. Instead this function must be
 * called after a page has been requested.
 *
 * Return value: 0 if successful
 */
static int saa5246a_clear_found_bit(struct saa5246a_device *t,
	unsigned char dau_no)
{
	unsigned char row_25_column_8;

	if (i2c_senddata(t, SAA5246A_REGISTER_R8,

		dau_no |
		R8_DO_NOT_CLEAR_MEMORY,

		R9_CURSER_ROW_25,

		R10_CURSER_COLUMN_8,

		COMMAND_END) ||
		i2c_getdata(t, 1, &row_25_column_8))
	{
		return -EIO;
	}
	row_25_column_8 |= ROW25_COLUMN8_PAGE_NOT_FOUND;
	if (i2c_senddata(t, SAA5246A_REGISTER_R8,

		dau_no |
		R8_DO_NOT_CLEAR_MEMORY,

		R9_CURSER_ROW_25,

		R10_CURSER_COLUMN_8,

		row_25_column_8,

		COMMAND_END))
	{
		return -EIO;
	}

	return 0;
}

/* Requests one videotext page as described in req. The fields of req are
 * checked and an error is returned if something is invalid.
 *
 * Return value: 0 if successful
 */
static int saa5246a_request_page(struct saa5246a_device *t,
    vtx_pagereq_t *req)
{
	if (req->pagemask < 0 || req->pagemask >= PGMASK_MAX)
		return -EINVAL;
	if (req->pagemask & PGMASK_PAGE)
		if (req->page < 0 || req->page > PAGE_MAX)
			return -EINVAL;
	if (req->pagemask & PGMASK_HOUR)
		if (req->hour < 0 || req->hour > HOUR_MAX)
			return -EINVAL;
	if (req->pagemask & PGMASK_MINUTE)
		if (req->minute < 0 || req->minute > MINUTE_MAX)
			return -EINVAL;
	if (req->pgbuf < 0 || req->pgbuf >= NUM_DAUS)
		return -EINVAL;

	if (i2c_senddata(t, SAA5246A_REGISTER_R2,

		R2_IN_R3_SELECT_PAGE_HUNDREDS |
		req->pgbuf << 4 |
		R2_BANK_0 |
		R2_HAMMING_CHECK_OFF,

		HUNDREDS_OF_PAGE(req->page) |
		R3_HOLD_PAGE |
		(req->pagemask & PG_HUND ?
			R3_PAGE_HUNDREDS_DO_CARE :
			R3_PAGE_HUNDREDS_DO_NOT_CARE),

		TENS_OF_PAGE(req->page) |
		(req->pagemask & PG_TEN ?
			R3_PAGE_TENS_DO_CARE :
			R3_PAGE_TENS_DO_NOT_CARE),

		UNITS_OF_PAGE(req->page) |
		(req->pagemask & PG_UNIT ?
			R3_PAGE_UNITS_DO_CARE :
			R3_PAGE_UNITS_DO_NOT_CARE),

		TENS_OF_HOUR(req->hour) |
		(req->pagemask & HR_TEN ?
			R3_HOURS_TENS_DO_CARE :
			R3_HOURS_TENS_DO_NOT_CARE),

		UNITS_OF_HOUR(req->hour) |
		(req->pagemask & HR_UNIT ?
			R3_HOURS_UNITS_DO_CARE :
			R3_HOURS_UNITS_DO_NOT_CARE),

		TENS_OF_MINUTE(req->minute) |
		(req->pagemask & MIN_TEN ?
			R3_MINUTES_TENS_DO_CARE :
			R3_MINUTES_TENS_DO_NOT_CARE),

		UNITS_OF_MINUTE(req->minute) |
		(req->pagemask & MIN_UNIT ?
			R3_MINUTES_UNITS_DO_CARE :
			R3_MINUTES_UNITS_DO_NOT_CARE),

		COMMAND_END) || i2c_senddata(t, SAA5246A_REGISTER_R2,

		R2_IN_R3_SELECT_PAGE_HUNDREDS |
		req->pgbuf << 4 |
		R2_BANK_0 |
		R2_HAMMING_CHECK_OFF,

		HUNDREDS_OF_PAGE(req->page) |
		R3_UPDATE_PAGE |
		(req->pagemask & PG_HUND ?
			R3_PAGE_HUNDREDS_DO_CARE :
			R3_PAGE_HUNDREDS_DO_NOT_CARE),

		COMMAND_END))
	{
		return -EIO;
	}

	t->is_searching[req->pgbuf] = true;
	return 0;
}

/* This routine decodes the page number from the infobits contained in line 25.
 *
 * Parameters:
 * infobits: must be bits 0 to 9 of column 25
 *
 * Return value: page number coded in hexadecimal, i. e. page 123 is coded 0x123
 */
static inline int saa5246a_extract_pagenum_from_infobits(
    unsigned char infobits[10])
{
	int page_hundreds, page_tens, page_units;

	page_units    = infobits[0] & ROW25_COLUMN0_PAGE_UNITS;
	page_tens     = infobits[1] & ROW25_COLUMN1_PAGE_TENS;
	page_hundreds = infobits[8] & ROW25_COLUMN8_PAGE_HUNDREDS;

	/* page 0x.. means page 8.. */
	if (page_hundreds == 0)
		page_hundreds = 8;

	return((page_hundreds << 8) | (page_tens << 4) | page_units);
}

/* Decodes the hour from the infobits contained in line 25.
 *
 * Parameters:
 * infobits: must be bits 0 to 9 of column 25
 *
 * Return: hour coded in hexadecimal, i. e. 12h is coded 0x12
 */
static inline int saa5246a_extract_hour_from_infobits(
    unsigned char infobits[10])
{
	int hour_tens, hour_units;

	hour_units = infobits[4] & ROW25_COLUMN4_HOUR_UNITS;
	hour_tens  = infobits[5] & ROW25_COLUMN5_HOUR_TENS;

	return((hour_tens << 4) | hour_units);
}

/* Decodes the minutes from the infobits contained in line 25.
 *
 * Parameters:
 * infobits: must be bits 0 to 9 of column 25
 *
 * Return: minutes coded in hexadecimal, i. e. 10min is coded 0x10
 */
static inline int saa5246a_extract_minutes_from_infobits(
    unsigned char infobits[10])
{
	int minutes_tens, minutes_units;

	minutes_units = infobits[2] & ROW25_COLUMN2_MINUTES_UNITS;
	minutes_tens  = infobits[3] & ROW25_COLUMN3_MINUTES_TENS;

	return((minutes_tens << 4) | minutes_units);
}

/* Reads the status bits contained in the first 10 columns of the first line
 * and extracts the information into info.
 *
 * Return value: 0 if successful
 */
static inline int saa5246a_get_status(struct saa5246a_device *t,
    vtx_pageinfo_t *info, unsigned char dau_no)
{
	unsigned char infobits[10];
	int column;

	if (dau_no >= NUM_DAUS)
		return -EINVAL;

	if (i2c_senddata(t, SAA5246A_REGISTER_R8,

		dau_no |
		R8_DO_NOT_CLEAR_MEMORY,

		R9_CURSER_ROW_25,

		R10_CURSER_COLUMN_0,

		COMMAND_END) ||
		i2c_getdata(t, 10, infobits))
	{
		return -EIO;
	}

	info->pagenum = saa5246a_extract_pagenum_from_infobits(infobits);
	info->hour    = saa5246a_extract_hour_from_infobits(infobits);
	info->minute  = saa5246a_extract_minutes_from_infobits(infobits);
	info->charset = ((infobits[7] & ROW25_COLUMN7_CHARACTER_SET) >> 1);
	info->delete = !!(infobits[3] & ROW25_COLUMN3_DELETE_PAGE);
	info->headline = !!(infobits[5] & ROW25_COLUMN5_INSERT_HEADLINE);
	info->subtitle = !!(infobits[5] & ROW25_COLUMN5_INSERT_SUBTITLE);
	info->supp_header = !!(infobits[6] & ROW25_COLUMN6_SUPPRESS_HEADER);
	info->update = !!(infobits[6] & ROW25_COLUMN6_UPDATE_PAGE);
	info->inter_seq = !!(infobits[6] & ROW25_COLUMN6_INTERRUPTED_SEQUENCE);
	info->dis_disp = !!(infobits[6] & ROW25_COLUMN6_SUPPRESS_DISPLAY);
	info->serial = !!(infobits[7] & ROW25_COLUMN7_SERIAL_MODE);
	info->notfound = !!(infobits[8] & ROW25_COLUMN8_PAGE_NOT_FOUND);
	info->pblf = !!(infobits[9] & ROW25_COLUMN9_PAGE_BEING_LOOKED_FOR);
	info->hamming = 0;
	for (column = 0; column <= 7; column++) {
		if (infobits[column] & ROW25_COLUMN0_TO_7_HAMMING_ERROR) {
			info->hamming = 1;
			break;
		}
	}
	if (!info->hamming && !info->notfound)
		t->is_searching[dau_no] = false;
	return 0;
}

/* Reads 1 videotext page buffer of the SAA5246A.
 *
 * req is used both as input and as output. It contains information which part
 * must be read. The videotext page is copied into req->buffer.
 *
 * Return value: 0 if successful
 */
static inline int saa5246a_get_page(struct saa5246a_device *t,
	vtx_pagereq_t *req)
{
	int start, end, size;
	char *buf;
	int err;

	if (req->pgbuf < 0 || req->pgbuf >= NUM_DAUS ||
	    req->start < 0 || req->start > req->end || req->end >= VTX_PAGESIZE)
		return -EINVAL;

	buf = kmalloc(VTX_PAGESIZE, GFP_KERNEL);
	if (!buf)
		return -ENOMEM;

	/* Read "normal" part of page */
	err = -EIO;

	end = min(req->end, VTX_PAGESIZE - 1);
	if (i2c_senddata(t, SAA5246A_REGISTER_R8,
			req->pgbuf | R8_DO_NOT_CLEAR_MEMORY,
			ROW(req->start), COLUMN(req->start), COMMAND_END))
		goto out;
	if (i2c_getdata(t, end - req->start + 1, buf))
		goto out;
	err = -EFAULT;
	if (copy_to_user(req->buffer, buf, end - req->start + 1))
		goto out;

	/* Always get the time from buffer 4, since this stupid SAA5246A only
	 * updates the currently displayed buffer...
	 */
	if (REQ_CONTAINS_TIME(req)) {
		start = max(req->start, POS_TIME_START);
		end   = min(req->end,   POS_TIME_END);
		size = end - start + 1;
		err = -EINVAL;
		if (size < 0)
			goto out;
		err = -EIO;
		if (i2c_senddata(t, SAA5246A_REGISTER_R8,
				R8_ACTIVE_CHAPTER_4 | R8_DO_NOT_CLEAR_MEMORY,
				R9_CURSER_ROW_0, start, COMMAND_END))
			goto out;
		if (i2c_getdata(t, size, buf))
			goto out;
		err = -EFAULT;
		if (copy_to_user(req->buffer + start - req->start, buf, size))
			goto out;
	}
	/* Insert the header from buffer 4 only, if acquisition circuit is still searching for a page */
	if (REQ_CONTAINS_HEADER(req) && t->is_searching[req->pgbuf]) {
		start = max(req->start, POS_HEADER_START);
		end   = min(req->end,   POS_HEADER_END);
		size = end - start + 1;
		err = -EINVAL;
		if (size < 0)
			goto out;
		err = -EIO;
		if (i2c_senddata(t, SAA5246A_REGISTER_R8,
				R8_ACTIVE_CHAPTER_4 | R8_DO_NOT_CLEAR_MEMORY,
				R9_CURSER_ROW_0, start, COMMAND_END))
			goto out;
		if (i2c_getdata(t, end - start + 1, buf))
			goto out;
		err = -EFAULT;
		if (copy_to_user(req->buffer + start - req->start, buf, size))
			goto out;
	}
	err = 0;
out:
	kfree(buf);
	return err;
}

/* Stops the acquisition circuit given in dau_no. The page buffer associated
 * with this acquisition circuit will no more be updated. The other daus are
 * not affected.
 *
 * Return value: 0 if successful
 */
static inline int saa5246a_stop_dau(struct saa5246a_device *t,
    unsigned char dau_no)
{
	if (dau_no >= NUM_DAUS)
		return -EINVAL;
	if (i2c_senddata(t, SAA5246A_REGISTER_R2,

		R2_IN_R3_SELECT_PAGE_HUNDREDS |
		dau_no << 4 |
		R2_BANK_0 |
		R2_HAMMING_CHECK_OFF,

		R3_PAGE_HUNDREDS_0 |
		R3_HOLD_PAGE |
		R3_PAGE_HUNDREDS_DO_NOT_CARE,

		COMMAND_END))
	{
		return -EIO;
	}
	t->is_searching[dau_no] = false;
	return 0;
}

/*  Handles ioctls defined in videotext.h
 *
 *  Returns 0 if successful
 */
static long do_saa5246a_ioctl(struct file *file, unsigned int cmd, void *arg)
{
	struct saa5246a_device *t = video_drvdata(file);

	switch(cmd)
	{
		case VTXIOCGETINFO:
		{
			vtx_info_t *info = arg;

			info->version_major = MAJOR_VERSION;
			info->version_minor = MINOR_VERSION;
			info->numpages = NUM_DAUS;
			return 0;
		}

		case VTXIOCCLRPAGE:
		{
			vtx_pagereq_t *req = arg;

			if (req->pgbuf < 0 || req->pgbuf >= NUM_DAUS)
				return -EINVAL;
			memset(t->pgbuf[req->pgbuf], ' ', sizeof(t->pgbuf[0]));
			return 0;
		}

		case VTXIOCCLRFOUND:
		{
			vtx_pagereq_t *req = arg;

			if (req->pgbuf < 0 || req->pgbuf >= NUM_DAUS)
				return -EINVAL;
			return(saa5246a_clear_found_bit(t, req->pgbuf));
		}

		case VTXIOCPAGEREQ:
		{
			vtx_pagereq_t *req = arg;

			return(saa5246a_request_page(t, req));
		}

		case VTXIOCGETSTAT:
		{
			vtx_pagereq_t *req = arg;
			vtx_pageinfo_t info;
			int rval;

			if ((rval = saa5246a_get_status(t, &info, req->pgbuf)))
				return rval;
			if(copy_to_user(req->buffer, &info,
				sizeof(vtx_pageinfo_t)))
				return -EFAULT;
			return 0;
		}

		case VTXIOCGETPAGE:
		{
			vtx_pagereq_t *req = arg;

			return(saa5246a_get_page(t, req));
		}

		case VTXIOCSTOPDAU:
		{
			vtx_pagereq_t *req = arg;

			return(saa5246a_stop_dau(t, req->pgbuf));
		}

		case VTXIOCPUTPAGE:
		case VTXIOCSETDISP:
		case VTXIOCPUTSTAT:
			return 0;

		case VTXIOCCLRCACHE:
		{
			return 0;
		}

		case VTXIOCSETVIRT:
		{
			/* I do not know what "virtual mode" means */
			return 0;
		}
	}
	return -EINVAL;
}

/*
 * Translates old vtx IOCTLs to new ones
 *
 * This keeps new kernel versions compatible with old userspace programs.
 */
static inline unsigned int vtx_fix_command(unsigned int cmd)
{
	switch (cmd) {
	case VTXIOCGETINFO_OLD:
		cmd = VTXIOCGETINFO;
		break;
	case VTXIOCCLRPAGE_OLD:
		cmd = VTXIOCCLRPAGE;
		break;
	case VTXIOCCLRFOUND_OLD:
		cmd = VTXIOCCLRFOUND;
		break;
	case VTXIOCPAGEREQ_OLD:
		cmd = VTXIOCPAGEREQ;
		break;
	case VTXIOCGETSTAT_OLD:
		cmd = VTXIOCGETSTAT;
		break;
	case VTXIOCGETPAGE_OLD:
		cmd = VTXIOCGETPAGE;
		break;
	case VTXIOCSTOPDAU_OLD:
		cmd = VTXIOCSTOPDAU;
		break;
	case VTXIOCPUTPAGE_OLD:
		cmd = VTXIOCPUTPAGE;
		break;
	case VTXIOCSETDISP_OLD:
		cmd = VTXIOCSETDISP;
		break;
	case VTXIOCPUTSTAT_OLD:
		cmd = VTXIOCPUTSTAT;
		break;
	case VTXIOCCLRCACHE_OLD:
		cmd = VTXIOCCLRCACHE;
		break;
	case VTXIOCSETVIRT_OLD:
		cmd = VTXIOCSETVIRT;
		break;
	}
	return cmd;
}

/*
 *	Handle the locking
 */
static long saa5246a_ioctl(struct file *file,
			 unsigned int cmd, unsigned long arg)
{
	struct saa5246a_device *t = video_drvdata(file);
	long err;

	cmd = vtx_fix_command(cmd);
	mutex_lock(&t->lock);
	err = video_usercopy(file, cmd, arg, do_saa5246a_ioctl);
	mutex_unlock(&t->lock);
	return err;
}

static int saa5246a_open(struct file *file)
{
	struct saa5246a_device *t = video_drvdata(file);

	if (t->client == NULL)
		return -ENODEV;

	if (test_and_set_bit(0, &t->in_use))
		return -EBUSY;

	if (i2c_senddata(t, SAA5246A_REGISTER_R0,
		R0_SELECT_R11 |
		R0_PLL_TIME_CONSTANT_LONG |
		R0_ENABLE_nODD_EVEN_OUTPUT |
		R0_ENABLE_HDR_POLL |
		R0_DO_NOT_FORCE_nODD_EVEN_LOW_IF_PICTURE_DISPLAYED |
		R0_NO_FREE_RUN_PLL |
		R0_NO_AUTOMATIC_FASTEXT_PROMPT,

		R1_NON_INTERLACED_312_312_LINES |
		R1_DEW |
		R1_EXTENDED_PACKET_DISABLE |
		R1_DAUS_ALL_ON |
		R1_8_BITS_NO_PARITY |
		R1_VCS_TO_SCS,

		COMMAND_END) ||
		i2c_senddata(t, SAA5246A_REGISTER_R4,

		/* We do not care much for the TV display but nevertheless we
		 * need the currently displayed page later because only on that
		 * page the time is updated. */
		R4_DISPLAY_PAGE_4,

		COMMAND_END))
	{
		clear_bit(0, &t->in_use);
		return -EIO;
	}
	return 0;
}

static int saa5246a_release(struct file *file)
{
	struct saa5246a_device *t = video_drvdata(file);

	/* Stop all acquisition circuits. */
	i2c_senddata(t, SAA5246A_REGISTER_R1,

		R1_INTERLACED_312_AND_HALF_312_AND_HALF_LINES |
		R1_DEW |
		R1_EXTENDED_PACKET_DISABLE |
		R1_DAUS_ALL_OFF |
		R1_8_BITS_NO_PARITY |
		R1_VCS_TO_SCS,

		COMMAND_END);
	clear_bit(0, &t->in_use);
	return 0;
}

static const struct v4l2_file_operations saa_fops = {
	.owner	 = THIS_MODULE,
	.open	 = saa5246a_open,
	.release = saa5246a_release,
	.ioctl	 = saa5246a_ioctl,
};

static struct video_device saa_template =
{
	.name	  = "saa5246a",
	.fops	  = &saa_fops,
	.release  = video_device_release,
	.minor    = -1,
};

/* Addresses to scan */
static unsigned short normal_i2c[] = { 0x22 >> 1, I2C_CLIENT_END };

I2C_CLIENT_INSMOD;

static int saa5246a_probe(struct i2c_client *client,
			const struct i2c_device_id *id)
{
	int pgbuf;
	int err;
	struct video_device *vd;
	struct saa5246a_device *t;

	v4l_info(client, "chip found @ 0x%x (%s)\n",
			client->addr << 1, client->adapter->name);
	v4l_info(client, "VideoText version %d.%d\n",
			MAJOR_VERSION, MINOR_VERSION);
	t = kzalloc(sizeof(*t), GFP_KERNEL);
	if (t == NULL)
		return -ENOMEM;
	mutex_init(&t->lock);

	/* Now create a video4linux device */
	vd = video_device_alloc();
	if (vd == NULL) {
		kfree(t);
		return -ENOMEM;
	}
	i2c_set_clientdata(client, vd);
	memcpy(vd, &saa_template, sizeof(*vd));

	for (pgbuf = 0; pgbuf < NUM_DAUS; pgbuf++) {
		memset(t->pgbuf[pgbuf], ' ', sizeof(t->pgbuf[0]));
		t->is_searching[pgbuf] = false;
	}
	video_set_drvdata(vd, t);

	/* Register it */
	err = video_register_device(vd, VFL_TYPE_VTX, -1);
	if (err < 0) {
		kfree(t);
		video_device_release(vd);
		return err;
	}
	t->client = client;
	return 0;
}

static int saa5246a_remove(struct i2c_client *client)
{
	struct video_device *vd = i2c_get_clientdata(client);

	video_unregister_device(vd);
	kfree(video_get_drvdata(vd));
	return 0;
}

static const struct i2c_device_id saa5246a_id[] = {
	{ "saa5246a", 0 },
	{ }
};
MODULE_DEVICE_TABLE(i2c, saa5246a_id);

static struct v4l2_i2c_driver_data v4l2_i2c_data = {
	.name = "saa5246a",
	.probe = saa5246a_probe,
	.remove = saa5246a_remove,
	.id_table = saa5246a_id,
};