drivers/media/rc/ir-sanyo-decoder.c

   1 /* ir-sanyo-decoder.c - handle SANYO IR Pulse/Space protocol
   2  *
   3  * Copyright (C) 2011 by Mauro Carvalho Chehab
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  *  it under the terms of the GNU General Public License as published by
   7  *  the Free Software Foundation version 2 of the License.
   8  *
   9  *  This program is distributed in the hope that it will be useful,
  10  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  *  GNU General Public License for more details.
  13  *
  14  * This protocol uses the NEC protocol timings. However, data is formatted as:
  15  *      13 bits Custom Code
  16  *      13 bits NOT(Custom Code)
  17  *      8 bits Key data
  18  *      8 bits NOT(Key data)
  19  *
  20  * According with LIRC, this protocol is used on Sanyo, Aiwa and Chinon
  21  * Information for this protocol is available at the Sanyo LC7461 datasheet.
  22  */
  23
  24 #include <linux/module.h>
  25 #include <linux/bitrev.h>
  26 #include "rc-core-priv.h"
  27
  28 #define SANYO_NBITS             (13+13+8+8)
  29 #define SANYO_UNIT              562500  /* ns */
  30 #define SANYO_HEADER_PULSE      (16  * SANYO_UNIT)
  31 #define SANYO_HEADER_SPACE      (8   * SANYO_UNIT)
  32 #define SANYO_BIT_PULSE         (1   * SANYO_UNIT)
  33 #define SANYO_BIT_0_SPACE       (1   * SANYO_UNIT)
  34 #define SANYO_BIT_1_SPACE       (3   * SANYO_UNIT)
  35 #define SANYO_REPEAT_SPACE      (150 * SANYO_UNIT)
  36 #define SANYO_TRAILER_PULSE     (1   * SANYO_UNIT)
  37 #define SANYO_TRAILER_SPACE     (10  * SANYO_UNIT)      /* in fact, 42 */
  38
  39 enum sanyo_state {
  40         STATE_INACTIVE,
  41         STATE_HEADER_SPACE,
  42         STATE_BIT_PULSE,
  43         STATE_BIT_SPACE,
  44         STATE_TRAILER_PULSE,
  45         STATE_TRAILER_SPACE,
  46 };
  47
  48 /**
  49  * ir_sanyo_decode() - Decode one SANYO pulse or space
  50  * @dev:        the struct rc_dev descriptor of the device
  51  * @duration:   the struct ir_raw_event descriptor of the pulse/space
  52  *
  53  * This function returns -EINVAL if the pulse violates the state machine
  54  */
  55 static int ir_sanyo_decode(struct rc_dev *dev, struct ir_raw_event ev)
  56 {
  57         struct sanyo_dec *data = &dev->raw->sanyo;
  58         u32 scancode;
  59         u16 address;
  60         u8 command, not_command;
  61
  62         if (!is_timing_event(ev)) {
  63                 if (ev.reset) {
  64                         IR_dprintk(1, "SANYO event reset received. reset to state 0\n");
  65                         data->state = STATE_INACTIVE;
  66                 }
  67                 return 0;
  68         }
  69
  70         IR_dprintk(2, "SANYO decode started at state %d (%uus %s)\n",
  71                    data->state, TO_US(ev.duration), TO_STR(ev.pulse));
  72
  73         switch (data->state) {
  74
  75         case STATE_INACTIVE:
  76                 if (!ev.pulse)
  77                         break;
  78
  79                 if (eq_margin(ev.duration, SANYO_HEADER_PULSE, SANYO_UNIT / 2)) {
  80                         data->count = 0;
  81                         data->state = STATE_HEADER_SPACE;
  82                         return 0;
  83                 }
  84                 break;
  85
  86
  87         case STATE_HEADER_SPACE:
  88                 if (ev.pulse)
  89                         break;
  90
  91                 if (eq_margin(ev.duration, SANYO_HEADER_SPACE, SANYO_UNIT / 2)) {
  92                         data->state = STATE_BIT_PULSE;
  93                         return 0;
  94                 }
  95
  96                 break;
  97
  98         case STATE_BIT_PULSE:
  99                 if (!ev.pulse)
 100                         break;
 101
 102                 if (!eq_margin(ev.duration, SANYO_BIT_PULSE, SANYO_UNIT / 2))
 103                         break;
 104
 105                 data->state = STATE_BIT_SPACE;
 106                 return 0;
 107
 108         case STATE_BIT_SPACE:
 109                 if (ev.pulse)
 110                         break;
 111
 112                 if (!data->count && geq_margin(ev.duration, SANYO_REPEAT_SPACE, SANYO_UNIT / 2)) {
 113                         rc_repeat(dev);
 114                         IR_dprintk(1, "SANYO repeat last key\n");
 115                         data->state = STATE_INACTIVE;
 116                         return 0;
 117                 }
 118
 119                 data->bits <<= 1;
 120                 if (eq_margin(ev.duration, SANYO_BIT_1_SPACE, SANYO_UNIT / 2))
 121                         data->bits |= 1;
 122                 else if (!eq_margin(ev.duration, SANYO_BIT_0_SPACE, SANYO_UNIT / 2))
 123                         break;
 124                 data->count++;
 125
 126                 if (data->count == SANYO_NBITS)
 127                         data->state = STATE_TRAILER_PULSE;
 128                 else
 129                         data->state = STATE_BIT_PULSE;
 130
 131                 return 0;
 132
 133         case STATE_TRAILER_PULSE:
 134                 if (!ev.pulse)
 135                         break;
 136
 137                 if (!eq_margin(ev.duration, SANYO_TRAILER_PULSE, SANYO_UNIT / 2))
 138                         break;
 139
 140                 data->state = STATE_TRAILER_SPACE;
 141                 return 0;
 142
 143         case STATE_TRAILER_SPACE:
 144                 if (ev.pulse)
 145                         break;
 146
 147                 if (!geq_margin(ev.duration, SANYO_TRAILER_SPACE, SANYO_UNIT / 2))
 148                         break;
 149
 150                 address     = bitrev16((data->bits >> 29) & 0x1fff) >> 3;
 151                 /* not_address = bitrev16((data->bits >> 16) & 0x1fff) >> 3; */
 152                 command     = bitrev8((data->bits >>  8) & 0xff);
 153                 not_command = bitrev8((data->bits >>  0) & 0xff);
 154
 155                 if ((command ^ not_command) != 0xff) {
 156                         IR_dprintk(1, "SANYO checksum error: received 0x%08Lx\n",
 157                                    data->bits);
 158                         data->state = STATE_INACTIVE;
 159                         return 0;
 160                 }
 161
 162                 scancode = address << 8 | command;
 163                 IR_dprintk(1, "SANYO scancode: 0x%06x\n", scancode);
 164                 rc_keydown(dev, RC_PROTO_SANYO, scancode, 0);
 165                 data->state = STATE_INACTIVE;
 166                 return 0;
 167         }
 168
 169         IR_dprintk(1, "SANYO decode failed at count %d state %d (%uus %s)\n",
 170                    data->count, data->state, TO_US(ev.duration), TO_STR(ev.pulse));
 171         data->state = STATE_INACTIVE;
 172         return -EINVAL;
 173 }
 174
 175 static const struct ir_raw_timings_pd ir_sanyo_timings = {
 176         .header_pulse  = SANYO_HEADER_PULSE,
 177         .header_space  = SANYO_HEADER_SPACE,
 178         .bit_pulse     = SANYO_BIT_PULSE,
 179         .bit_space[0]  = SANYO_BIT_0_SPACE,
 180         .bit_space[1]  = SANYO_BIT_1_SPACE,
 181         .trailer_pulse = SANYO_TRAILER_PULSE,
 182         .trailer_space = SANYO_TRAILER_SPACE,
 183         .msb_first     = 1,
 184 };
 185
 186 /**
 187  * ir_sanyo_encode() - Encode a scancode as a stream of raw events
 188  *
 189  * @protocol:   protocol to encode
 190  * @scancode:   scancode to encode
 191  * @events:     array of raw ir events to write into
 192  * @max:        maximum size of @events
 193  *
 194  * Returns:     The number of events written.
 195  *              -ENOBUFS if there isn't enough space in the array to fit the
 196  *              encoding. In this case all @max events will have been written.
 197  */
 198 static int ir_sanyo_encode(enum rc_proto protocol, u32 scancode,
 199                            struct ir_raw_event *events, unsigned int max)
 200 {
 201         struct ir_raw_event *e = events;
 202         int ret;
 203         u64 raw;
 204
 205         raw = ((u64)(bitrev16(scancode >> 8) & 0xfff8) << (8 + 8 + 13 - 3)) |
 206               ((u64)(bitrev16(~scancode >> 8) & 0xfff8) << (8 + 8 +  0 - 3)) |
 207               ((bitrev8(scancode) & 0xff) << 8) |
 208               (bitrev8(~scancode) & 0xff);
 209
 210         ret = ir_raw_gen_pd(&e, max, &ir_sanyo_timings, SANYO_NBITS, raw);
 211         if (ret < 0)
 212                 return ret;
 213
 214         return e - events;
 215 }
 216
 217 static struct ir_raw_handler sanyo_handler = {
 218         .protocols      = RC_PROTO_BIT_SANYO,
 219         .decode         = ir_sanyo_decode,
 220         .encode         = ir_sanyo_encode,
 221 };
 222
 223 static int __init ir_sanyo_decode_init(void)
 224 {
 225         ir_raw_handler_register(&sanyo_handler);
 226
 227         printk(KERN_INFO "IR SANYO protocol handler initialized\n");
 228         return 0;
 229 }
 230
 231 static void __exit ir_sanyo_decode_exit(void)
 232 {
 233         ir_raw_handler_unregister(&sanyo_handler);
 234 }
 235
 236 module_init(ir_sanyo_decode_init);
 237 module_exit(ir_sanyo_decode_exit);
 238
 239 MODULE_LICENSE("GPL");
 240 MODULE_AUTHOR("Mauro Carvalho Chehab");
 241 MODULE_AUTHOR("Red Hat Inc. (http://www.redhat.com)");
 242 MODULE_DESCRIPTION("SANYO IR protocol decoder");