kernel/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         u8 address, command, not_command;
  60
  61         if (!(dev->enabled_protocols & RC_BIT_SANYO))
  62                 return 0;
  63
  64         if (!is_timing_event(ev)) {
  65                 if (ev.reset) {
  66                         IR_dprintk(1, "SANYO event reset received. reset to state 0\n");
  67                         data->state = STATE_INACTIVE;
  68                 }
  69                 return 0;
  70         }
  71
  72         IR_dprintk(2, "SANYO decode started at state %d (%uus %s)\n",
  73                    data->state, TO_US(ev.duration), TO_STR(ev.pulse));
  74
  75         switch (data->state) {
  76
  77         case STATE_INACTIVE:
  78                 if (!ev.pulse)
  79                         break;
  80
  81                 if (eq_margin(ev.duration, SANYO_HEADER_PULSE, SANYO_UNIT / 2)) {
  82                         data->count = 0;
  83                         data->state = STATE_HEADER_SPACE;
  84                         return 0;
  85                 }
  86                 break;
  87
  88
  89         case STATE_HEADER_SPACE:
  90                 if (ev.pulse)
  91                         break;
  92
  93                 if (eq_margin(ev.duration, SANYO_HEADER_SPACE, SANYO_UNIT / 2)) {
  94                         data->state = STATE_BIT_PULSE;
  95                         return 0;
  96                 }
  97
  98                 break;
  99
 100         case STATE_BIT_PULSE:
 101                 if (!ev.pulse)
 102                         break;
 103
 104                 if (!eq_margin(ev.duration, SANYO_BIT_PULSE, SANYO_UNIT / 2))
 105                         break;
 106
 107                 data->state = STATE_BIT_SPACE;
 108                 return 0;
 109
 110         case STATE_BIT_SPACE:
 111                 if (ev.pulse)
 112                         break;
 113
 114                 if (!data->count && geq_margin(ev.duration, SANYO_REPEAT_SPACE, SANYO_UNIT / 2)) {
 115                         if (!dev->keypressed) {
 116                                 IR_dprintk(1, "SANYO discarding last key repeat: event after key up\n");
 117                         } else {
 118                                 rc_repeat(dev);
 119                                 IR_dprintk(1, "SANYO repeat last key\n");
 120                                 data->state = STATE_INACTIVE;
 121                         }
 122                         return 0;
 123                 }
 124
 125                 data->bits <<= 1;
 126                 if (eq_margin(ev.duration, SANYO_BIT_1_SPACE, SANYO_UNIT / 2))
 127                         data->bits |= 1;
 128                 else if (!eq_margin(ev.duration, SANYO_BIT_0_SPACE, SANYO_UNIT / 2))
 129                         break;
 130                 data->count++;
 131
 132                 if (data->count == SANYO_NBITS)
 133                         data->state = STATE_TRAILER_PULSE;
 134                 else
 135                         data->state = STATE_BIT_PULSE;
 136
 137                 return 0;
 138
 139         case STATE_TRAILER_PULSE:
 140                 if (!ev.pulse)
 141                         break;
 142
 143                 if (!eq_margin(ev.duration, SANYO_TRAILER_PULSE, SANYO_UNIT / 2))
 144                         break;
 145
 146                 data->state = STATE_TRAILER_SPACE;
 147                 return 0;
 148
 149         case STATE_TRAILER_SPACE:
 150                 if (ev.pulse)
 151                         break;
 152
 153                 if (!geq_margin(ev.duration, SANYO_TRAILER_SPACE, SANYO_UNIT / 2))
 154                         break;
 155
 156                 address     = bitrev16((data->bits >> 29) & 0x1fff) >> 3;
 157                 /* not_address = bitrev16((data->bits >> 16) & 0x1fff) >> 3; */
 158                 command     = bitrev8((data->bits >>  8) & 0xff);
 159                 not_command = bitrev8((data->bits >>  0) & 0xff);
 160
 161                 if ((command ^ not_command) != 0xff) {
 162                         IR_dprintk(1, "SANYO checksum error: received 0x%08Lx\n",
 163                                    data->bits);
 164                         data->state = STATE_INACTIVE;
 165                         return 0;
 166                 }
 167
 168                 scancode = address << 8 | command;
 169                 IR_dprintk(1, "SANYO scancode: 0x%06x\n", scancode);
 170                 rc_keydown(dev, RC_TYPE_SANYO, scancode, 0);
 171                 data->state = STATE_INACTIVE;
 172                 return 0;
 173         }
 174
 175         IR_dprintk(1, "SANYO decode failed at count %d state %d (%uus %s)\n",
 176                    data->count, data->state, TO_US(ev.duration), TO_STR(ev.pulse));
 177         data->state = STATE_INACTIVE;
 178         return -EINVAL;
 179 }
 180
 181 static struct ir_raw_handler sanyo_handler = {
 182         .protocols      = RC_BIT_SANYO,
 183         .decode         = ir_sanyo_decode,
 184 };
 185
 186 static int __init ir_sanyo_decode_init(void)
 187 {
 188         ir_raw_handler_register(&sanyo_handler);
 189
 190         printk(KERN_INFO "IR SANYO protocol handler initialized\n");
 191         return 0;
 192 }
 193
 194 static void __exit ir_sanyo_decode_exit(void)
 195 {
 196         ir_raw_handler_unregister(&sanyo_handler);
 197 }
 198
 199 module_init(ir_sanyo_decode_init);
 200 module_exit(ir_sanyo_decode_exit);
 201
 202 MODULE_LICENSE("GPL");
 203 MODULE_AUTHOR("Mauro Carvalho Chehab");
 204 MODULE_AUTHOR("Red Hat Inc. (http://www.redhat.com)");
 205 MODULE_DESCRIPTION("SANYO IR protocol decoder");