LXR linux/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 <mchehab@redhat.com>
   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
  39enum 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 */
  55static 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        u8 address, command, not_command;
  60
  61        if (!(dev->raw->enabled_protocols & RC_BIT_SANYO))
  62                return 0;
  63
  64        if (!is_timing_event(ev)) {
  65                if (ev.reset) {
  66                        IR_dprintk(1, "SANYO event reset received. reset to state 0\n");
  67                        data->state = STATE_INACTIVE;
  68                }
  69                return 0;
  70        }
  71
  72        IR_dprintk(2, "SANYO decode started at state %d (%uus %s)\n",
  73                   data->state, TO_US(ev.duration), TO_STR(ev.pulse));
  74
  75        switch (data->state) {
  76
  77        case STATE_INACTIVE:
  78                if (!ev.pulse)
  79                        break;
  80
  81                if (eq_margin(ev.duration, SANYO_HEADER_PULSE, SANYO_UNIT / 2)) {
  82                        data->count = 0;
  83                        data->state = STATE_HEADER_SPACE;
  84                        return 0;
  85                }
  86                break;
  87
  88
  89        case STATE_HEADER_SPACE:
  90                if (ev.pulse)
  91                        break;
  92
  93                if (eq_margin(ev.duration, SANYO_HEADER_SPACE, SANYO_UNIT / 2)) {
  94                        data->state = STATE_BIT_PULSE;
  95                        return 0;
  96                }
  97
  98                break;
  99
 100        case STATE_BIT_PULSE:
 101                if (!ev.pulse)
 102                        break;
 103
 104                if (!eq_margin(ev.duration, SANYO_BIT_PULSE, SANYO_UNIT / 2))
 105                        break;
 106
 107                data->state = STATE_BIT_SPACE;
 108                return 0;
 109
 110        case STATE_BIT_SPACE:
 111                if (ev.pulse)
 112                        break;
 113
 114                if (!data->count && geq_margin(ev.duration, SANYO_REPEAT_SPACE, SANYO_UNIT / 2)) {
 115                        if (!dev->keypressed) {
 116                                IR_dprintk(1, "SANYO discarding last key repeat: event after key up\n");
 117                        } else {
 118                                rc_repeat(dev);
 119                                IR_dprintk(1, "SANYO repeat last key\n");
 120                                data->state = STATE_INACTIVE;
 121                        }
 122                        return 0;
 123                }
 124
 125                data->bits <<= 1;
 126                if (eq_margin(ev.duration, SANYO_BIT_1_SPACE, SANYO_UNIT / 2))
 127                        data->bits |= 1;
 128                else if (!eq_margin(ev.duration, SANYO_BIT_0_SPACE, SANYO_UNIT / 2))
 129                        break;
 130                data->count++;
 131
 132                if (data->count == SANYO_NBITS)
 133                        data->state = STATE_TRAILER_PULSE;
 134                else
 135                        data->state = STATE_BIT_PULSE;
 136
 137                return 0;
 138
 139        case STATE_TRAILER_PULSE:
 140                if (!ev.pulse)
 141                        break;
 142
 143                if (!eq_margin(ev.duration, SANYO_TRAILER_PULSE, SANYO_UNIT / 2))
 144                        break;
 145
 146                data->state = STATE_TRAILER_SPACE;
 147                return 0;
 148
 149        case STATE_TRAILER_SPACE:
 150                if (ev.pulse)
 151                        break;
 152
 153                if (!geq_margin(ev.duration, SANYO_TRAILER_SPACE, SANYO_UNIT / 2))
 154                        break;
 155
 156                address     = bitrev16((data->bits >> 29) & 0x1fff) >> 3;
 157                /* not_address = bitrev16((data->bits >> 16) & 0x1fff) >> 3; */
 158                command     = bitrev8((data->bits >>  8) & 0xff);
 159                not_command = bitrev8((data->bits >>  0) & 0xff);
 160
 161                if ((command ^ not_command) != 0xff) {
 162                        IR_dprintk(1, "SANYO checksum error: received 0x%08Lx\n",
 163                                   data->bits);
 164                        data->state = STATE_INACTIVE;
 165                        return 0;
 166                }
 167
 168                scancode = address << 8 | command;
 169                IR_dprintk(1, "SANYO scancode: 0x%06x\n", scancode);
 170                rc_keydown(dev, scancode, 0);
 171                data->state = STATE_INACTIVE;
 172                return 0;
 173        }
 174
 175        IR_dprintk(1, "SANYO decode failed at count %d state %d (%uus %s)\n",
 176                   data->count, data->state, TO_US(ev.duration), TO_STR(ev.pulse));
 177        data->state = STATE_INACTIVE;
 178        return -EINVAL;
 179}
 180
 181static struct ir_raw_handler sanyo_handler = {
 182        .protocols      = RC_BIT_SANYO,
 183        .decode         = ir_sanyo_decode,
 184};
 185
 186static int __init ir_sanyo_decode_init(void)
 187{
 188        ir_raw_handler_register(&sanyo_handler);
 189
 190        printk(KERN_INFO "IR SANYO protocol handler initialized\n");
 191        return 0;
 192}
 193
 194static void __exit ir_sanyo_decode_exit(void)
 195{
 196        ir_raw_handler_unregister(&sanyo_handler);
 197}
 198
 199module_init(ir_sanyo_decode_init);
 200module_exit(ir_sanyo_decode_exit);
 201
 202MODULE_LICENSE("GPL");
 203MODULE_AUTHOR("Mauro Carvalho Chehab <mchehab@redhat.com>");
 204MODULE_AUTHOR("Red Hat Inc. (http://www.redhat.com)");
 205MODULE_DESCRIPTION("SANYO IR protocol decoder");
 206