linux/drivers/media/rc/ir-sony-decoder.c
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   1/* ir-sony-decoder.c - handle Sony IR Pulse/Space protocol
   2 *
   3 * Copyright (C) 2010 by David H\xC3\xA4rdeman <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        u32 scancode;
  46        u8 device, subdevice, function;
  47
  48        if (!(dev->raw->enabled_protocols & RC_TYPE_SONY))
  49                return 0;
  50
  51        if (!is_timing_event(ev)) {
  52                if (ev.reset)
  53                        data->state = STATE_INACTIVE;
  54                return 0;
  55        }
  56
  57        if (!geq_margin(ev.duration, SONY_UNIT, SONY_UNIT / 2))
  58                goto out;
  59
  60        IR_dprintk(2, "Sony decode started at state %d (%uus %s)\n",
  61                   data->state, TO_US(ev.duration), TO_STR(ev.pulse));
  62
  63        switch (data->state) {
  64
  65        case STATE_INACTIVE:
  66                if (!ev.pulse)
  67                        break;
  68
  69                if (!eq_margin(ev.duration, SONY_HEADER_PULSE, SONY_UNIT / 2))
  70                        break;
  71
  72                data->count = 0;
  73                data->state = STATE_HEADER_SPACE;
  74                return 0;
  75
  76        case STATE_HEADER_SPACE:
  77                if (ev.pulse)
  78                        break;
  79
  80                if (!eq_margin(ev.duration, SONY_HEADER_SPACE, SONY_UNIT / 2))
  81                        break;
  82
  83                data->state = STATE_BIT_PULSE;
  84                return 0;
  85
  86        case STATE_BIT_PULSE:
  87                if (!ev.pulse)
  88                        break;
  89
  90                data->bits <<= 1;
  91                if (eq_margin(ev.duration, SONY_BIT_1_PULSE, SONY_UNIT / 2))
  92                        data->bits |= 1;
  93                else if (!eq_margin(ev.duration, SONY_BIT_0_PULSE, SONY_UNIT / 2))
  94                        break;
  95
  96                data->count++;
  97                data->state = STATE_BIT_SPACE;
  98                return 0;
  99
 100        case STATE_BIT_SPACE:
 101                if (ev.pulse)
 102                        break;
 103
 104                if (!geq_margin(ev.duration, SONY_BIT_SPACE, SONY_UNIT / 2))
 105                        break;
 106
 107                decrease_duration(&ev, SONY_BIT_SPACE);
 108
 109                if (!geq_margin(ev.duration, SONY_UNIT, SONY_UNIT / 2)) {
 110                        data->state = STATE_BIT_PULSE;
 111                        return 0;
 112                }
 113
 114                data->state = STATE_FINISHED;
 115                /* Fall through */
 116
 117        case STATE_FINISHED:
 118                if (ev.pulse)
 119                        break;
 120
 121                if (!geq_margin(ev.duration, SONY_TRAILER_SPACE, SONY_UNIT / 2))
 122                        break;
 123
 124                switch (data->count) {
 125                case 12:
 126                        device    = bitrev8((data->bits <<  3) & 0xF8);
 127                        subdevice = 0;
 128                        function  = bitrev8((data->bits >>  4) & 0xFE);
 129                        break;
 130                case 15:
 131                        device    = bitrev8((data->bits >>  0) & 0xFF);
 132                        subdevice = 0;
 133                        function  = bitrev8((data->bits >>  7) & 0xFD);
 134                        break;
 135                case 20:
 136                        device    = bitrev8((data->bits >>  5) & 0xF8);
 137                        subdevice = bitrev8((data->bits >>  0) & 0xFF);
 138                        function  = bitrev8((data->bits >> 12) & 0xFE);
 139                        break;
 140                default:
 141                        IR_dprintk(1, "Sony invalid bitcount %u\n", data->count);
 142                        goto out;
 143                }
 144
 145                scancode = device << 16 | subdevice << 8 | function;
 146                IR_dprintk(1, "Sony(%u) scancode 0x%05x\n", data->count, scancode);
 147                rc_keydown(dev, scancode, 0);
 148                data->state = STATE_INACTIVE;
 149                return 0;
 150        }
 151
 152out:
 153        IR_dprintk(1, "Sony decode failed at state %d (%uus %s)\n",
 154                   data->state, TO_US(ev.duration), TO_STR(ev.pulse));
 155        data->state = STATE_INACTIVE;
 156        return -EINVAL;
 157}
 158
 159static struct ir_raw_handler sony_handler = {
 160        .protocols      = RC_TYPE_SONY,
 161        .decode         = ir_sony_decode,
 162};
 163
 164static int __init ir_sony_decode_init(void)
 165{
 166        ir_raw_handler_register(&sony_handler);
 167
 168        printk(KERN_INFO "IR Sony protocol handler initialized\n");
 169        return 0;
 170}
 171
 172static void __exit ir_sony_decode_exit(void)
 173{
 174        ir_raw_handler_unregister(&sony_handler);
 175}
 176
 177module_init(ir_sony_decode_init);
 178module_exit(ir_sony_decode_exit);
 179
 180MODULE_LICENSE("GPL");
 181MODULE_AUTHOR("David H\xC3\xA4rdeman <david@hardeman.nu>");
 182MODULE_DESCRIPTION("Sony IR protocol decoder");
 183