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 (!is_timing_event(ev)) {
  50                 if (ev.reset)
  51                         data->state = STATE_INACTIVE;
  52                 return 0;
  53         }
  54
  55         if (!geq_margin(ev.duration, SONY_UNIT, SONY_UNIT / 2))
  56                 goto out;
  57
  58         IR_dprintk(2, "Sony decode started at state %d (%uus %s)\n",
  59                    data->state, TO_US(ev.duration), TO_STR(ev.pulse));
  60
  61         switch (data->state) {
  62
  63         case STATE_INACTIVE:
  64                 if (!ev.pulse)
  65                         break;
  66
  67                 if (!eq_margin(ev.duration, SONY_HEADER_PULSE, SONY_UNIT / 2))
  68                         break;
  69
  70                 data->count = 0;
  71                 data->state = STATE_HEADER_SPACE;
  72                 return 0;
  73
  74         case STATE_HEADER_SPACE:
  75                 if (ev.pulse)
  76                         break;
  77
  78                 if (!eq_margin(ev.duration, SONY_HEADER_SPACE, SONY_UNIT / 2))
  79                         break;
  80
  81                 data->state = STATE_BIT_PULSE;
  82                 return 0;
  83
  84         case STATE_BIT_PULSE:
  85                 if (!ev.pulse)
  86                         break;
  87
  88                 data->bits <<= 1;
  89                 if (eq_margin(ev.duration, SONY_BIT_1_PULSE, SONY_UNIT / 2))
  90                         data->bits |= 1;
  91                 else if (!eq_margin(ev.duration, SONY_BIT_0_PULSE, SONY_UNIT / 2))
  92                         break;
  93
  94                 data->count++;
  95                 data->state = STATE_BIT_SPACE;
  96                 return 0;
  97
  98         case STATE_BIT_SPACE:
  99                 if (ev.pulse)
 100                         break;
 101
 102                 if (!geq_margin(ev.duration, SONY_BIT_SPACE, SONY_UNIT / 2))
 103                         break;
 104
 105                 decrease_duration(&ev, SONY_BIT_SPACE);
 106
 107                 if (!geq_margin(ev.duration, SONY_UNIT, SONY_UNIT / 2)) {
 108                         data->state = STATE_BIT_PULSE;
 109                         return 0;
 110                 }
 111
 112                 data->state = STATE_FINISHED;
 113                 /* Fall through */
 114
 115         case STATE_FINISHED:
 116                 if (ev.pulse)
 117                         break;
 118
 119                 if (!geq_margin(ev.duration, SONY_TRAILER_SPACE, SONY_UNIT / 2))
 120                         break;
 121
 122                 switch (data->count) {
 123                 case 12:
 124                         if (!(dev->enabled_protocols & RC_BIT_SONY12))
 125                                 goto finish_state_machine;
 126
 127                         device    = bitrev8((data->bits <<  3) & 0xF8);
 128                         subdevice = 0;
 129                         function  = bitrev8((data->bits >>  4) & 0xFE);
 130                         protocol = RC_TYPE_SONY12;
 131                         break;
 132                 case 15:
 133                         if (!(dev->enabled_protocols & RC_BIT_SONY15))
 134                                 goto finish_state_machine;
 135
 136                         device    = bitrev8((data->bits >>  0) & 0xFF);
 137                         subdevice = 0;
 138                         function  = bitrev8((data->bits >>  7) & 0xFE);
 139                         protocol = RC_TYPE_SONY15;
 140                         break;
 141                 case 20:
 142                         if (!(dev->enabled_protocols & RC_BIT_SONY20))
 143                                 goto finish_state_machine;
 144
 145                         device    = bitrev8((data->bits >>  5) & 0xF8);
 146                         subdevice = bitrev8((data->bits >>  0) & 0xFF);
 147                         function  = bitrev8((data->bits >> 12) & 0xFE);
 148                         protocol = RC_TYPE_SONY20;
 149                         break;
 150                 default:
 151                         IR_dprintk(1, "Sony invalid bitcount %u\n", data->count);
 152                         goto out;
 153                 }
 154
 155                 scancode = device << 16 | subdevice << 8 | function;
 156                 IR_dprintk(1, "Sony(%u) scancode 0x%05x\n", data->count, scancode);
 157                 rc_keydown(dev, protocol, scancode, 0);
 158                 goto finish_state_machine;
 159         }
 160
 161 out:
 162         IR_dprintk(1, "Sony decode failed at state %d (%uus %s)\n",
 163                    data->state, TO_US(ev.duration), TO_STR(ev.pulse));
 164         data->state = STATE_INACTIVE;
 165         return -EINVAL;
 166
 167 finish_state_machine:
 168         data->state = STATE_INACTIVE;
 169         return 0;
 170 }
 171
 172 static struct ir_raw_handler sony_handler = {
 173         .protocols      = RC_BIT_SONY12 | RC_BIT_SONY15 | RC_BIT_SONY20,
 174         .decode         = ir_sony_decode,
 175 };
 176
 177 static int __init ir_sony_decode_init(void)
 178 {
 179         ir_raw_handler_register(&sony_handler);
 180
 181         printk(KERN_INFO "IR Sony protocol handler initialized\n");
 182         return 0;
 183 }
 184
 185 static void __exit ir_sony_decode_exit(void)
 186 {
 187         ir_raw_handler_unregister(&sony_handler);
 188 }
 189
 190 module_init(ir_sony_decode_init);
 191 module_exit(ir_sony_decode_exit);
 192
 193 MODULE_LICENSE("GPL");
 194 MODULE_AUTHOR("David Härdeman <david@hardeman.nu>");
 195 MODULE_DESCRIPTION("Sony IR protocol decoder");