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_proto 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         dev_dbg(&dev->dev, "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_PROTO_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_PROTO_SONY12;
 131                         break;
 132                 case 15:
 133                         if (!(dev->enabled_protocols & RC_PROTO_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_PROTO_SONY15;
 140                         break;
 141                 case 20:
 142                         if (!(dev->enabled_protocols & RC_PROTO_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_PROTO_SONY20;
 149                         break;
 150                 default:
 151                         dev_dbg(&dev->dev, "Sony invalid bitcount %u\n",
 152                                 data->count);
 153                         goto out;
 154                 }
 155
 156                 scancode = device << 16 | subdevice << 8 | function;
 157                 dev_dbg(&dev->dev, "Sony(%u) scancode 0x%05x\n", data->count,
 158                         scancode);
 159                 rc_keydown(dev, protocol, scancode, 0);
 160                 goto finish_state_machine;
 161         }
 162
 163 out:
 164         dev_dbg(&dev->dev, "Sony decode failed at state %d (%uus %s)\n",
 165                 data->state, TO_US(ev.duration), TO_STR(ev.pulse));
 166         data->state = STATE_INACTIVE;
 167         return -EINVAL;
 168
 169 finish_state_machine:
 170         data->state = STATE_INACTIVE;
 171         return 0;
 172 }
 173
 174 static const struct ir_raw_timings_pl ir_sony_timings = {
 175         .header_pulse  = SONY_HEADER_PULSE,
 176         .bit_space     = SONY_BIT_SPACE,
 177         .bit_pulse[0]  = SONY_BIT_0_PULSE,
 178         .bit_pulse[1]  = SONY_BIT_1_PULSE,
 179         .trailer_space = SONY_TRAILER_SPACE + SONY_BIT_SPACE,
 180         .msb_first     = 0,
 181 };
 182
 183 /**
 184  * ir_sony_encode() - Encode a scancode as a stream of raw events
 185  *
 186  * @protocol:   protocol to encode
 187  * @scancode:   scancode to encode
 188  * @events:     array of raw ir events to write into
 189  * @max:        maximum size of @events
 190  *
 191  * Returns:     The number of events written.
 192  *              -ENOBUFS if there isn't enough space in the array to fit the
 193  *              encoding. In this case all @max events will have been written.
 194  */
 195 static int ir_sony_encode(enum rc_proto protocol, u32 scancode,
 196                           struct ir_raw_event *events, unsigned int max)
 197 {
 198         struct ir_raw_event *e = events;
 199         u32 raw, len;
 200         int ret;
 201
 202         if (protocol == RC_PROTO_SONY12) {
 203                 raw = (scancode & 0x7f) | ((scancode & 0x1f0000) >> 9);
 204                 len = 12;
 205         } else if (protocol == RC_PROTO_SONY15) {
 206                 raw = (scancode & 0x7f) | ((scancode & 0xff0000) >> 9);
 207                 len = 15;
 208         } else {
 209                 raw = (scancode & 0x7f) | ((scancode & 0x1f0000) >> 9) |
 210                        ((scancode & 0xff00) << 4);
 211                 len = 20;
 212         }
 213
 214         ret = ir_raw_gen_pl(&e, max, &ir_sony_timings, len, raw);
 215         if (ret < 0)
 216                 return ret;
 217
 218         return e - events;
 219 }
 220
 221 static struct ir_raw_handler sony_handler = {
 222         .protocols      = RC_PROTO_BIT_SONY12 | RC_PROTO_BIT_SONY15 |
 223                                                         RC_PROTO_BIT_SONY20,
 224         .decode         = ir_sony_decode,
 225         .encode         = ir_sony_encode,
 226         .carrier        = 40000,
 227         .min_timeout    = SONY_TRAILER_SPACE,
 228 };
 229
 230 static int __init ir_sony_decode_init(void)
 231 {
 232         ir_raw_handler_register(&sony_handler);
 233
 234         printk(KERN_INFO "IR Sony protocol handler initialized\n");
 235         return 0;
 236 }
 237
 238 static void __exit ir_sony_decode_exit(void)
 239 {
 240         ir_raw_handler_unregister(&sony_handler);
 241 }
 242
 243 module_init(ir_sony_decode_init);
 244 module_exit(ir_sony_decode_exit);
 245
 246 MODULE_LICENSE("GPL");
 247 MODULE_AUTHOR("David Härdeman <david@hardeman.nu>");
 248 MODULE_DESCRIPTION("Sony IR protocol decoder");