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 #include <linux/log2.h>
  15
  16 /* Convert NEC data to a scancode */
  17 static int img_ir_nec_scancode(int len, u64 raw, u64 enabled_protocols,
  18                                struct img_ir_scancode_req *request)
  19 {
  20         unsigned int addr, addr_inv, data, data_inv;
  21         /* a repeat code has no data */
  22         if (!len)
  23                 return IMG_IR_REPEATCODE;
  24         if (len != 32)
  25                 return -EINVAL;
  26         /* raw encoding: ddDDaaAA */
  27         addr     = (raw >>  0) & 0xff;
  28         addr_inv = (raw >>  8) & 0xff;
  29         data     = (raw >> 16) & 0xff;
  30         data_inv = (raw >> 24) & 0xff;
  31         if ((data_inv ^ data) != 0xff) {
  32                 /* 32-bit NEC (used by Apple and TiVo remotes) */
  33                 /* scan encoding: as transmitted, MSBit = first received bit */
  34                 request->scancode = bitrev8(addr)     << 24 |
  35                                 bitrev8(addr_inv) << 16 |
  36                                 bitrev8(data)     <<  8 |
  37                                 bitrev8(data_inv);
  38                 request->protocol = RC_PROTO_NEC32;
  39         } else if ((addr_inv ^ addr) != 0xff) {
  40                 /* Extended NEC */
  41                 /* scan encoding: AAaaDD */
  42                 request->scancode = addr     << 16 |
  43                                 addr_inv <<  8 |
  44                                 data;
  45                 request->protocol = RC_PROTO_NECX;
  46         } else {
  47                 /* Normal NEC */
  48                 /* scan encoding: AADD */
  49                 request->scancode = addr << 8 |
  50                                 data;
  51                 request->protocol = RC_PROTO_NEC;
  52         }
  53         return IMG_IR_SCANCODE;
  54 }
  55
  56 /* Convert NEC scancode to NEC data filter */
  57 static int img_ir_nec_filter(const struct rc_scancode_filter *in,
  58                              struct img_ir_filter *out, u64 protocols)
  59 {
  60         unsigned int addr, addr_inv, data, data_inv;
  61         unsigned int addr_m, addr_inv_m, data_m, data_inv_m;
  62
  63         data       = in->data & 0xff;
  64         data_m     = in->mask & 0xff;
  65
  66         protocols &= RC_PROTO_BIT_NEC | RC_PROTO_BIT_NECX | RC_PROTO_BIT_NEC32;
  67
  68         /*
  69          * If only one bit is set, we were requested to do an exact
  70          * protocol. This should be the case for wakeup filters; for
  71          * normal filters, guess the protocol from the scancode.
  72          */
  73         if (!is_power_of_2(protocols)) {
  74                 if ((in->data | in->mask) & 0xff000000)
  75                         protocols = RC_PROTO_BIT_NEC32;
  76                 else if ((in->data | in->mask) & 0x00ff0000)
  77                         protocols = RC_PROTO_BIT_NECX;
  78                 else
  79                         protocols = RC_PROTO_BIT_NEC;
  80         }
  81
  82         if (protocols == RC_PROTO_BIT_NEC32) {
  83                 /* 32-bit NEC (used by Apple and TiVo remotes) */
  84                 /* scan encoding: as transmitted, MSBit = first received bit */
  85                 addr       = bitrev8(in->data >> 24);
  86                 addr_m     = bitrev8(in->mask >> 24);
  87                 addr_inv   = bitrev8(in->data >> 16);
  88                 addr_inv_m = bitrev8(in->mask >> 16);
  89                 data       = bitrev8(in->data >>  8);
  90                 data_m     = bitrev8(in->mask >>  8);
  91                 data_inv   = bitrev8(in->data >>  0);
  92                 data_inv_m = bitrev8(in->mask >>  0);
  93         } else if (protocols == RC_PROTO_BIT_NECX) {
  94                 /* Extended NEC */
  95                 /* scan encoding AAaaDD */
  96                 addr       = (in->data >> 16) & 0xff;
  97                 addr_m     = (in->mask >> 16) & 0xff;
  98                 addr_inv   = (in->data >>  8) & 0xff;
  99                 addr_inv_m = (in->mask >>  8) & 0xff;
 100                 data_inv   = data ^ 0xff;
 101                 data_inv_m = data_m;
 102         } else {
 103                 /* Normal NEC */
 104                 /* scan encoding: AADD */
 105                 addr       = (in->data >>  8) & 0xff;
 106                 addr_m     = (in->mask >>  8) & 0xff;
 107                 addr_inv   = addr ^ 0xff;
 108                 addr_inv_m = addr_m;
 109                 data_inv   = data ^ 0xff;
 110                 data_inv_m = data_m;
 111         }
 112
 113         /* raw encoding: ddDDaaAA */
 114         out->data = data_inv << 24 |
 115                     data     << 16 |
 116                     addr_inv <<  8 |
 117                     addr;
 118         out->mask = data_inv_m << 24 |
 119                     data_m     << 16 |
 120                     addr_inv_m <<  8 |
 121                     addr_m;
 122         return 0;
 123 }
 124
 125 /*
 126  * NEC decoder
 127  * See also http://www.sbprojects.com/knowledge/ir/nec.php
 128  *        http://wiki.altium.com/display/ADOH/NEC+Infrared+Transmission+Protocol
 129  */
 130 struct img_ir_decoder img_ir_nec = {
 131         .type = RC_PROTO_BIT_NEC | RC_PROTO_BIT_NECX | RC_PROTO_BIT_NEC32,
 132         .control = {
 133                 .decoden = 1,
 134                 .code_type = IMG_IR_CODETYPE_PULSEDIST,
 135         },
 136         /* main timings */
 137         .unit = 562500, /* 562.5 us */
 138         .timings = {
 139                 /* leader symbol */
 140                 .ldr = {
 141                         .pulse = { 16   /* 9ms */ },
 142                         .space = { 8    /* 4.5ms */ },
 143                 },
 144                 /* 0 symbol */
 145                 .s00 = {
 146                         .pulse = { 1    /* 562.5 us */ },
 147                         .space = { 1    /* 562.5 us */ },
 148                 },
 149                 /* 1 symbol */
 150                 .s01 = {
 151                         .pulse = { 1    /* 562.5 us */ },
 152                         .space = { 3    /* 1687.5 us */ },
 153                 },
 154                 /* free time */
 155                 .ft = {
 156                         .minlen = 32,
 157                         .maxlen = 32,
 158                         .ft_min = 10,   /* 5.625 ms */
 159                 },
 160         },
 161         /* repeat codes */
 162         .repeat = 108,                  /* 108 ms */
 163         .rtimings = {
 164                 /* leader symbol */
 165                 .ldr = {
 166                         .space = { 4    /* 2.25 ms */ },
 167                 },
 168                 /* free time */
 169                 .ft = {
 170                         .minlen = 0,    /* repeat code has no data */
 171                         .maxlen = 0,
 172                 },
 173         },
 174         /* scancode logic */
 175         .scancode = img_ir_nec_scancode,
 176         .filter = img_ir_nec_filter,
 177 };