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         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) & 0xFE);
 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
 152 out:
 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
 159 static struct ir_raw_handler sony_handler = {
 160         .protocols      = RC_TYPE_SONY,
 161         .decode         = ir_sony_decode,
 162 };
 163
 164 static 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
 172 static void __exit ir_sony_decode_exit(void)
 173 {
 174         ir_raw_handler_unregister(&sony_handler);
 175 }
 176
 177 module_init(ir_sony_decode_init);
 178 module_exit(ir_sony_decode_exit);
 179
 180 MODULE_LICENSE("GPL");
 181 MODULE_AUTHOR("David Härdeman <david@hardeman.nu>");
 182 MODULE_DESCRIPTION("Sony IR protocol decoder");