drivers/media/rc/img-ir/img-ir-nec.c

   1 /*
   2  * ImgTec IR Decoder setup for NEC protocol.
   3  *
   4  * Copyright 2010-2014 Imagination Technologies Ltd.
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by the
   8  * Free Software Foundation; either version 2 of the License, or (at your
   9  * option) any later version.
  10  */
  11
  12 #include "img-ir-hw.h"
  13 #include <linux/bitrev.h>
  14
  15 /* Convert NEC data to a scancode */
  16 static int img_ir_nec_scancode(int len, u64 raw, u64 enabled_protocols,
  17                                struct img_ir_scancode_req *request)
  18 {
  19         unsigned int addr, addr_inv, data, data_inv;
  20         /* a repeat code has no data */
  21         if (!len)
  22                 return IMG_IR_REPEATCODE;
  23         if (len != 32)
  24                 return -EINVAL;
  25         /* raw encoding: ddDDaaAA */
  26         addr     = (raw >>  0) & 0xff;
  27         addr_inv = (raw >>  8) & 0xff;
  28         data     = (raw >> 16) & 0xff;
  29         data_inv = (raw >> 24) & 0xff;
  30         if ((data_inv ^ data) != 0xff) {
  31                 /* 32-bit NEC (used by Apple and TiVo remotes) */
  32                 /* scan encoding: as transmitted, MSBit = first received bit */
  33                 request->scancode = bitrev8(addr)     << 24 |
  34                                 bitrev8(addr_inv) << 16 |
  35                                 bitrev8(data)     <<  8 |
  36                                 bitrev8(data_inv);
  37                 request->protocol = RC_TYPE_NEC32;
  38         } else if ((addr_inv ^ addr) != 0xff) {
  39                 /* Extended NEC */
  40                 /* scan encoding: AAaaDD */
  41                 request->scancode = addr     << 16 |
  42                                 addr_inv <<  8 |
  43                                 data;
  44                 request->protocol = RC_TYPE_NECX;
  45         } else {
  46                 /* Normal NEC */
  47                 /* scan encoding: AADD */
  48                 request->scancode = addr << 8 |
  49                                 data;
  50                 request->protocol = RC_TYPE_NEC;
  51         }
  52         return IMG_IR_SCANCODE;
  53 }
  54
  55 /* Convert NEC scancode to NEC data filter */
  56 static int img_ir_nec_filter(const struct rc_scancode_filter *in,
  57                              struct img_ir_filter *out, u64 protocols)
  58 {
  59         unsigned int addr, addr_inv, data, data_inv;
  60         unsigned int addr_m, addr_inv_m, data_m, data_inv_m;
  61
  62         data       = in->data & 0xff;
  63         data_m     = in->mask & 0xff;
  64
  65         if ((in->data | in->mask) & 0xff000000) {
  66                 /* 32-bit NEC (used by Apple and TiVo remotes) */
  67                 /* scan encoding: as transmitted, MSBit = first received bit */
  68                 addr       = bitrev8(in->data >> 24);
  69                 addr_m     = bitrev8(in->mask >> 24);
  70                 addr_inv   = bitrev8(in->data >> 16);
  71                 addr_inv_m = bitrev8(in->mask >> 16);
  72                 data       = bitrev8(in->data >>  8);
  73                 data_m     = bitrev8(in->mask >>  8);
  74                 data_inv   = bitrev8(in->data >>  0);
  75                 data_inv_m = bitrev8(in->mask >>  0);
  76         } else if ((in->data | in->mask) & 0x00ff0000) {
  77                 /* Extended NEC */
  78                 /* scan encoding AAaaDD */
  79                 addr       = (in->data >> 16) & 0xff;
  80                 addr_m     = (in->mask >> 16) & 0xff;
  81                 addr_inv   = (in->data >>  8) & 0xff;
  82                 addr_inv_m = (in->mask >>  8) & 0xff;
  83                 data_inv   = data ^ 0xff;
  84                 data_inv_m = data_m;
  85         } else {
  86                 /* Normal NEC */
  87                 /* scan encoding: AADD */
  88                 addr       = (in->data >>  8) & 0xff;
  89                 addr_m     = (in->mask >>  8) & 0xff;
  90                 addr_inv   = addr ^ 0xff;
  91                 addr_inv_m = addr_m;
  92                 data_inv   = data ^ 0xff;
  93                 data_inv_m = data_m;
  94         }
  95
  96         /* raw encoding: ddDDaaAA */
  97         out->data = data_inv << 24 |
  98                     data     << 16 |
  99                     addr_inv <<  8 |
 100                     addr;
 101         out->mask = data_inv_m << 24 |
 102                     data_m     << 16 |
 103                     addr_inv_m <<  8 |
 104                     addr_m;
 105         return 0;
 106 }
 107
 108 /*
 109  * NEC decoder
 110  * See also http://www.sbprojects.com/knowledge/ir/nec.php
 111  *        http://wiki.altium.com/display/ADOH/NEC+Infrared+Transmission+Protocol
 112  */
 113 struct img_ir_decoder img_ir_nec = {
 114         .type = RC_BIT_NEC | RC_BIT_NECX | RC_BIT_NEC32,
 115         .control = {
 116                 .decoden = 1,
 117                 .code_type = IMG_IR_CODETYPE_PULSEDIST,
 118         },
 119         /* main timings */
 120         .unit = 562500, /* 562.5 us */
 121         .timings = {
 122                 /* leader symbol */
 123                 .ldr = {
 124                         .pulse = { 16   /* 9ms */ },
 125                         .space = { 8    /* 4.5ms */ },
 126                 },
 127                 /* 0 symbol */
 128                 .s00 = {
 129                         .pulse = { 1    /* 562.5 us */ },
 130                         .space = { 1    /* 562.5 us */ },
 131                 },
 132                 /* 1 symbol */
 133                 .s01 = {
 134                         .pulse = { 1    /* 562.5 us */ },
 135                         .space = { 3    /* 1687.5 us */ },
 136                 },
 137                 /* free time */
 138                 .ft = {
 139                         .minlen = 32,
 140                         .maxlen = 32,
 141                         .ft_min = 10,   /* 5.625 ms */
 142                 },
 143         },
 144         /* repeat codes */
 145         .repeat = 108,                  /* 108 ms */
 146         .rtimings = {
 147                 /* leader symbol */
 148                 .ldr = {
 149                         .space = { 4    /* 2.25 ms */ },
 150                 },
 151                 /* free time */
 152                 .ft = {
 153                         .minlen = 0,    /* repeat code has no data */
 154                         .maxlen = 0,
 155                 },
 156         },
 157         /* scancode logic */
 158         .scancode = img_ir_nec_scancode,
 159         .filter = img_ir_nec_filter,
 160 };