drivers/media/rc/ir-sanyo-decoder.c

   1 /* ir-sanyo-decoder.c - handle SANYO IR Pulse/Space protocol
   2  *
   3  * Copyright (C) 2011 by Mauro Carvalho Chehab
   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  * This protocol uses the NEC protocol timings. However, data is formatted as:
  15  *      13 bits Custom Code
  16  *      13 bits NOT(Custom Code)
  17  *      8 bits Key data
  18  *      8 bits NOT(Key data)
  19  *
  20  * According with LIRC, this protocol is used on Sanyo, Aiwa and Chinon
  21  * Information for this protocol is available at the Sanyo LC7461 datasheet.
  22  */
  23
  24 #include <linux/module.h>
  25 #include <linux/bitrev.h>
  26 #include "rc-core-priv.h"
  27
  28 #define SANYO_NBITS             (13+13+8+8)
  29 #define SANYO_UNIT              562500  /* ns */
  30 #define SANYO_HEADER_PULSE      (16  * SANYO_UNIT)
  31 #define SANYO_HEADER_SPACE      (8   * SANYO_UNIT)
  32 #define SANYO_BIT_PULSE         (1   * SANYO_UNIT)
  33 #define SANYO_BIT_0_SPACE       (1   * SANYO_UNIT)
  34 #define SANYO_BIT_1_SPACE       (3   * SANYO_UNIT)
  35 #define SANYO_REPEAT_SPACE      (150 * SANYO_UNIT)
  36 #define SANYO_TRAILER_PULSE     (1   * SANYO_UNIT)
  37 #define SANYO_TRAILER_SPACE     (10  * SANYO_UNIT)      /* in fact, 42 */
  38
  39 enum sanyo_state {
  40         STATE_INACTIVE,
  41         STATE_HEADER_SPACE,
  42         STATE_BIT_PULSE,
  43         STATE_BIT_SPACE,
  44         STATE_TRAILER_PULSE,
  45         STATE_TRAILER_SPACE,
  46 };
  47
  48 /**
  49  * ir_sanyo_decode() - Decode one SANYO pulse or space
  50  * @dev:        the struct rc_dev descriptor of the device
  51  * @duration:   the struct ir_raw_event descriptor of the pulse/space
  52  *
  53  * This function returns -EINVAL if the pulse violates the state machine
  54  */
  55 static int ir_sanyo_decode(struct rc_dev *dev, struct ir_raw_event ev)
  56 {
  57         struct sanyo_dec *data = &dev->raw->sanyo;
  58         u32 scancode;
  59         u16 address;
  60         u8 command, not_command;
  61
  62         if (!is_timing_event(ev)) {
  63                 if (ev.reset) {
  64                         IR_dprintk(1, "SANYO event reset received. reset to state 0\n");
  65                         data->state = STATE_INACTIVE;
  66                 }
  67                 return 0;
  68         }
  69
  70         IR_dprintk(2, "SANYO decode started at state %d (%uus %s)\n",
  71                    data->state, TO_US(ev.duration), TO_STR(ev.pulse));
  72
  73         switch (data->state) {
  74
  75         case STATE_INACTIVE:
  76                 if (!ev.pulse)
  77                         break;
  78
  79                 if (eq_margin(ev.duration, SANYO_HEADER_PULSE, SANYO_UNIT / 2)) {
  80                         data->count = 0;
  81                         data->state = STATE_HEADER_SPACE;
  82                         return 0;
  83                 }
  84                 break;
  85
  86
  87         case STATE_HEADER_SPACE:
  88                 if (ev.pulse)
  89                         break;
  90
  91                 if (eq_margin(ev.duration, SANYO_HEADER_SPACE, SANYO_UNIT / 2)) {
  92                         data->state = STATE_BIT_PULSE;
  93                         return 0;
  94                 }
  95
  96                 break;
  97
  98         case STATE_BIT_PULSE:
  99                 if (!ev.pulse)
 100                         break;
 101
 102                 if (!eq_margin(ev.duration, SANYO_BIT_PULSE, SANYO_UNIT / 2))
 103                         break;
 104
 105                 data->state = STATE_BIT_SPACE;
 106                 return 0;
 107
 108         case STATE_BIT_SPACE:
 109                 if (ev.pulse)
 110                         break;
 111
 112                 if (!data->count && geq_margin(ev.duration, SANYO_REPEAT_SPACE, SANYO_UNIT / 2)) {
 113                         if (!dev->keypressed) {
 114                                 IR_dprintk(1, "SANYO discarding last key repeat: event after key up\n");
 115                         } else {
 116                                 rc_repeat(dev);
 117                                 IR_dprintk(1, "SANYO repeat last key\n");
 118                                 data->state = STATE_INACTIVE;
 119                         }
 120                         return 0;
 121                 }
 122
 123                 data->bits <<= 1;
 124                 if (eq_margin(ev.duration, SANYO_BIT_1_SPACE, SANYO_UNIT / 2))
 125                         data->bits |= 1;
 126                 else if (!eq_margin(ev.duration, SANYO_BIT_0_SPACE, SANYO_UNIT / 2))
 127                         break;
 128                 data->count++;
 129
 130                 if (data->count == SANYO_NBITS)
 131                         data->state = STATE_TRAILER_PULSE;
 132                 else
 133                         data->state = STATE_BIT_PULSE;
 134
 135                 return 0;
 136
 137         case STATE_TRAILER_PULSE:
 138                 if (!ev.pulse)
 139                         break;
 140
 141                 if (!eq_margin(ev.duration, SANYO_TRAILER_PULSE, SANYO_UNIT / 2))
 142                         break;
 143
 144                 data->state = STATE_TRAILER_SPACE;
 145                 return 0;
 146
 147         case STATE_TRAILER_SPACE:
 148                 if (ev.pulse)
 149                         break;
 150
 151                 if (!geq_margin(ev.duration, SANYO_TRAILER_SPACE, SANYO_UNIT / 2))
 152                         break;
 153
 154                 address     = bitrev16((data->bits >> 29) & 0x1fff) >> 3;
 155                 /* not_address = bitrev16((data->bits >> 16) & 0x1fff) >> 3; */
 156                 command     = bitrev8((data->bits >>  8) & 0xff);
 157                 not_command = bitrev8((data->bits >>  0) & 0xff);
 158
 159                 if ((command ^ not_command) != 0xff) {
 160                         IR_dprintk(1, "SANYO checksum error: received 0x%08Lx\n",
 161                                    data->bits);
 162                         data->state = STATE_INACTIVE;
 163                         return 0;
 164                 }
 165
 166                 scancode = address << 8 | command;
 167                 IR_dprintk(1, "SANYO scancode: 0x%06x\n", scancode);
 168                 rc_keydown(dev, RC_TYPE_SANYO, scancode, 0);
 169                 data->state = STATE_INACTIVE;
 170                 return 0;
 171         }
 172
 173         IR_dprintk(1, "SANYO decode failed at count %d state %d (%uus %s)\n",
 174                    data->count, data->state, TO_US(ev.duration), TO_STR(ev.pulse));
 175         data->state = STATE_INACTIVE;
 176         return -EINVAL;
 177 }
 178
 179 static struct ir_raw_handler sanyo_handler = {
 180         .protocols      = RC_BIT_SANYO,
 181         .decode         = ir_sanyo_decode,
 182 };
 183
 184 static int __init ir_sanyo_decode_init(void)
 185 {
 186         ir_raw_handler_register(&sanyo_handler);
 187
 188         printk(KERN_INFO "IR SANYO protocol handler initialized\n");
 189         return 0;
 190 }
 191
 192 static void __exit ir_sanyo_decode_exit(void)
 193 {
 194         ir_raw_handler_unregister(&sanyo_handler);
 195 }
 196
 197 module_init(ir_sanyo_decode_init);
 198 module_exit(ir_sanyo_decode_exit);
 199
 200 MODULE_LICENSE("GPL");
 201 MODULE_AUTHOR("Mauro Carvalho Chehab");
 202 MODULE_AUTHOR("Red Hat Inc. (http://www.redhat.com)");
 203 MODULE_DESCRIPTION("SANYO IR protocol decoder");