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