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