kernel/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
  27 enum 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  */
  42 static 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                                 data->state = STATE_INACTIVE;
 130                                 return 0;
 131                         }
 132                         device    = bitrev8((data->bits <<  3) & 0xF8);
 133                         subdevice = 0;
 134                         function  = bitrev8((data->bits >>  4) & 0xFE);
 135                         protocol = RC_TYPE_SONY12;
 136                         break;
 137                 case 15:
 138                         if (!(dev->enabled_protocols & RC_BIT_SONY15)) {
 139                                 data->state = STATE_INACTIVE;
 140                                 return 0;
 141                         }
 142                         device    = bitrev8((data->bits >>  0) & 0xFF);
 143                         subdevice = 0;
 144                         function  = bitrev8((data->bits >>  7) & 0xFE);
 145                         protocol = RC_TYPE_SONY15;
 146                         break;
 147                 case 20:
 148                         if (!(dev->enabled_protocols & RC_BIT_SONY20)) {
 149                                 data->state = STATE_INACTIVE;
 150                                 return 0;
 151                         }
 152                         device    = bitrev8((data->bits >>  5) & 0xF8);
 153                         subdevice = bitrev8((data->bits >>  0) & 0xFF);
 154                         function  = bitrev8((data->bits >> 12) & 0xFE);
 155                         protocol = RC_TYPE_SONY20;
 156                         break;
 157                 default:
 158                         IR_dprintk(1, "Sony invalid bitcount %u\n", data->count);
 159                         goto out;
 160                 }
 161
 162                 scancode = device << 16 | subdevice << 8 | function;
 163                 IR_dprintk(1, "Sony(%u) scancode 0x%05x\n", data->count, scancode);
 164                 rc_keydown(dev, protocol, scancode, 0);
 165                 data->state = STATE_INACTIVE;
 166                 return 0;
 167         }
 168
 169 out:
 170         IR_dprintk(1, "Sony decode failed at state %d (%uus %s)\n",
 171                    data->state, TO_US(ev.duration), TO_STR(ev.pulse));
 172         data->state = STATE_INACTIVE;
 173         return -EINVAL;
 174 }
 175
 176 static struct ir_raw_handler sony_handler = {
 177         .protocols      = RC_BIT_SONY12 | RC_BIT_SONY15 | RC_BIT_SONY20,
 178         .decode         = ir_sony_decode,
 179 };
 180
 181 static 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
 189 static void __exit ir_sony_decode_exit(void)
 190 {
 191         ir_raw_handler_unregister(&sony_handler);
 192 }
 193
 194 module_init(ir_sony_decode_init);
 195 module_exit(ir_sony_decode_exit);
 196
 197 MODULE_LICENSE("GPL");
 198 MODULE_AUTHOR("David Härdeman <david@hardeman.nu>");
 199 MODULE_DESCRIPTION("Sony IR protocol decoder");