LXR linux/drivers/media/rc/ir-sony-decoder.c

   1/* ir-sony-decoder.c - handle Sony IR Pulse/Space protocol
   2 *
   3 * Copyright (C) 2010 by David Härdeman <david@hardeman.nu>
   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
  15#include <linux/bitrev.h>
  16#include <linux/module.h>
  17#include "rc-core-priv.h"
  18
  19#define SONY_UNIT               600000 /* ns */
  20#define SONY_HEADER_PULSE       (4 * SONY_UNIT)
  21#define SONY_HEADER_SPACE       (1 * SONY_UNIT)
  22#define SONY_BIT_0_PULSE        (1 * SONY_UNIT)
  23#define SONY_BIT_1_PULSE        (2 * SONY_UNIT)
  24#define SONY_BIT_SPACE          (1 * SONY_UNIT)
  25#define SONY_TRAILER_SPACE      (10 * SONY_UNIT) /* minimum */
  26
  27enum sony_state {
  28        STATE_INACTIVE,
  29        STATE_HEADER_SPACE,
  30        STATE_BIT_PULSE,
  31        STATE_BIT_SPACE,
  32        STATE_FINISHED,
  33};
  34
  35/**
  36 * ir_sony_decode() - Decode one Sony pulse or space
  37 * @dev:        the struct rc_dev descriptor of the device
  38 * @ev:         the struct ir_raw_event descriptor of the pulse/space
  39 *
  40 * This function returns -EINVAL if the pulse violates the state machine
  41 */
  42static int ir_sony_decode(struct rc_dev *dev, struct ir_raw_event ev)
  43{
  44        struct sony_dec *data = &dev->raw->sony;
  45        enum rc_type protocol;
  46        u32 scancode;
  47        u8 device, subdevice, function;
  48
  49        if (!(dev->enabled_protocols &
  50              (RC_BIT_SONY12 | RC_BIT_SONY15 | RC_BIT_SONY20)))
  51                return 0;
  52
  53        if (!is_timing_event(ev)) {
  54                if (ev.reset)
  55                        data->state = STATE_INACTIVE;
  56                return 0;
  57        }
  58
  59        if (!geq_margin(ev.duration, SONY_UNIT, SONY_UNIT / 2))
  60                goto out;
  61
  62        IR_dprintk(2, "Sony decode started at state %d (%uus %s)\n",
  63                   data->state, TO_US(ev.duration), TO_STR(ev.pulse));
  64
  65        switch (data->state) {
  66
  67        case STATE_INACTIVE:
  68                if (!ev.pulse)
  69                        break;
  70
  71                if (!eq_margin(ev.duration, SONY_HEADER_PULSE, SONY_UNIT / 2))
  72                        break;
  73
  74                data->count = 0;
  75                data->state = STATE_HEADER_SPACE;
  76                return 0;
  77
  78        case STATE_HEADER_SPACE:
  79                if (ev.pulse)
  80                        break;
  81
  82                if (!eq_margin(ev.duration, SONY_HEADER_SPACE, SONY_UNIT / 2))
  83                        break;
  84
  85                data->state = STATE_BIT_PULSE;
  86                return 0;
  87
  88        case STATE_BIT_PULSE:
  89                if (!ev.pulse)
  90                        break;
  91
  92                data->bits <<= 1;
  93                if (eq_margin(ev.duration, SONY_BIT_1_PULSE, SONY_UNIT / 2))
  94                        data->bits |= 1;
  95                else if (!eq_margin(ev.duration, SONY_BIT_0_PULSE, SONY_UNIT / 2))
  96                        break;
  97
  98                data->count++;
  99                data->state = STATE_BIT_SPACE;
 100                return 0;
 101
 102        case STATE_BIT_SPACE:
 103                if (ev.pulse)
 104                        break;
 105
 106                if (!geq_margin(ev.duration, SONY_BIT_SPACE, SONY_UNIT / 2))
 107                        break;
 108
 109                decrease_duration(&ev, SONY_BIT_SPACE);
 110
 111                if (!geq_margin(ev.duration, SONY_UNIT, SONY_UNIT / 2)) {
 112                        data->state = STATE_BIT_PULSE;
 113                        return 0;
 114                }
 115
 116                data->state = STATE_FINISHED;
 117                /* Fall through */
 118
 119        case STATE_FINISHED:
 120                if (ev.pulse)
 121                        break;
 122
 123                if (!geq_margin(ev.duration, SONY_TRAILER_SPACE, SONY_UNIT / 2))
 124                        break;
 125
 126                switch (data->count) {
 127                case 12:
 128                        if (!(dev->enabled_protocols & RC_BIT_SONY12))
 129                                goto finish_state_machine;
 130
 131                        device    = bitrev8((data->bits <<  3) & 0xF8);
 132                        subdevice = 0;
 133                        function  = bitrev8((data->bits >>  4) & 0xFE);
 134                        protocol = RC_TYPE_SONY12;
 135                        break;
 136                case 15:
 137                        if (!(dev->enabled_protocols & RC_BIT_SONY15))
 138                                goto finish_state_machine;
 139
 140                        device    = bitrev8((data->bits >>  0) & 0xFF);
 141                        subdevice = 0;
 142                        function  = bitrev8((data->bits >>  7) & 0xFE);
 143                        protocol = RC_TYPE_SONY15;
 144                        break;
 145                case 20:
 146                        if (!(dev->enabled_protocols & RC_BIT_SONY20))
 147                                goto finish_state_machine;
 148
 149                        device    = bitrev8((data->bits >>  5) & 0xF8);
 150                        subdevice = bitrev8((data->bits >>  0) & 0xFF);
 151                        function  = bitrev8((data->bits >> 12) & 0xFE);
 152                        protocol = RC_TYPE_SONY20;
 153                        break;
 154                default:
 155                        IR_dprintk(1, "Sony invalid bitcount %u\n", data->count);
 156                        goto out;
 157                }
 158
 159                scancode = device << 16 | subdevice << 8 | function;
 160                IR_dprintk(1, "Sony(%u) scancode 0x%05x\n", data->count, scancode);
 161                rc_keydown(dev, protocol, scancode, 0);
 162                goto finish_state_machine;
 163        }
 164
 165out:
 166        IR_dprintk(1, "Sony decode failed at state %d (%uus %s)\n",
 167                   data->state, TO_US(ev.duration), TO_STR(ev.pulse));
 168        data->state = STATE_INACTIVE;
 169        return -EINVAL;
 170
 171finish_state_machine:
 172        data->state = STATE_INACTIVE;
 173        return 0;
 174}
 175
 176static struct ir_raw_handler sony_handler = {
 177        .protocols      = RC_BIT_SONY12 | RC_BIT_SONY15 | RC_BIT_SONY20,
 178        .decode         = ir_sony_decode,
 179};
 180
 181static int __init ir_sony_decode_init(void)
 182{
 183        ir_raw_handler_register(&sony_handler);
 184
 185        printk(KERN_INFO "IR Sony protocol handler initialized\n");
 186        return 0;
 187}
 188
 189static void __exit ir_sony_decode_exit(void)
 190{
 191        ir_raw_handler_unregister(&sony_handler);
 192}
 193
 194module_init(ir_sony_decode_init);
 195module_exit(ir_sony_decode_exit);
 196
 197MODULE_LICENSE("GPL");
 198MODULE_AUTHOR("David Härdeman <david@hardeman.nu>");
 199MODULE_DESCRIPTION("Sony IR protocol decoder");
 200