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

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * ImgTec IR Decoder setup for NEC protocol.
   4  *
   5  * Copyright 2010-2014 Imagination Technologies Ltd.
   6  */
   7
   8 #include "img-ir-hw.h"
   9 #include <linux/bitrev.h>
  10 #include <linux/log2.h>
  11
  12 /* Convert NEC data to a scancode */
  13 static int img_ir_nec_scancode(int len, u64 raw, u64 enabled_protocols,
  14                                struct img_ir_scancode_req *request)
  15 {
  16         unsigned int addr, addr_inv, data, data_inv;
  17         /* a repeat code has no data */
  18         if (!len)
  19                 return IMG_IR_REPEATCODE;
  20         if (len != 32)
  21                 return -EINVAL;
  22         /* raw encoding: ddDDaaAA */
  23         addr     = (raw >>  0) & 0xff;
  24         addr_inv = (raw >>  8) & 0xff;
  25         data     = (raw >> 16) & 0xff;
  26         data_inv = (raw >> 24) & 0xff;
  27         if ((data_inv ^ data) != 0xff) {
  28                 /* 32-bit NEC (used by Apple and TiVo remotes) */
  29                 /* scan encoding: as transmitted, MSBit = first received bit */
  30                 request->scancode = bitrev8(addr)     << 24 |
  31                                 bitrev8(addr_inv) << 16 |
  32                                 bitrev8(data)     <<  8 |
  33                                 bitrev8(data_inv);
  34                 request->protocol = RC_PROTO_NEC32;
  35         } else if ((addr_inv ^ addr) != 0xff) {
  36                 /* Extended NEC */
  37                 /* scan encoding: AAaaDD */
  38                 request->scancode = addr     << 16 |
  39                                 addr_inv <<  8 |
  40                                 data;
  41                 request->protocol = RC_PROTO_NECX;
  42         } else {
  43                 /* Normal NEC */
  44                 /* scan encoding: AADD */
  45                 request->scancode = addr << 8 |
  46                                 data;
  47                 request->protocol = RC_PROTO_NEC;
  48         }
  49         return IMG_IR_SCANCODE;
  50 }
  51
  52 /* Convert NEC scancode to NEC data filter */
  53 static int img_ir_nec_filter(const struct rc_scancode_filter *in,
  54                              struct img_ir_filter *out, u64 protocols)
  55 {
  56         unsigned int addr, addr_inv, data, data_inv;
  57         unsigned int addr_m, addr_inv_m, data_m, data_inv_m;
  58
  59         data       = in->data & 0xff;
  60         data_m     = in->mask & 0xff;
  61
  62         protocols &= RC_PROTO_BIT_NEC | RC_PROTO_BIT_NECX | RC_PROTO_BIT_NEC32;
  63
  64         /*
  65          * If only one bit is set, we were requested to do an exact
  66          * protocol. This should be the case for wakeup filters; for
  67          * normal filters, guess the protocol from the scancode.
  68          */
  69         if (!is_power_of_2(protocols)) {
  70                 if ((in->data | in->mask) & 0xff000000)
  71                         protocols = RC_PROTO_BIT_NEC32;
  72                 else if ((in->data | in->mask) & 0x00ff0000)
  73                         protocols = RC_PROTO_BIT_NECX;
  74                 else
  75                         protocols = RC_PROTO_BIT_NEC;
  76         }
  77
  78         if (protocols == RC_PROTO_BIT_NEC32) {
  79                 /* 32-bit NEC (used by Apple and TiVo remotes) */
  80                 /* scan encoding: as transmitted, MSBit = first received bit */
  81                 addr       = bitrev8(in->data >> 24);
  82                 addr_m     = bitrev8(in->mask >> 24);
  83                 addr_inv   = bitrev8(in->data >> 16);
  84                 addr_inv_m = bitrev8(in->mask >> 16);
  85                 data       = bitrev8(in->data >>  8);
  86                 data_m     = bitrev8(in->mask >>  8);
  87                 data_inv   = bitrev8(in->data >>  0);
  88                 data_inv_m = bitrev8(in->mask >>  0);
  89         } else if (protocols == RC_PROTO_BIT_NECX) {
  90                 /* Extended NEC */
  91                 /* scan encoding AAaaDD */
  92                 addr       = (in->data >> 16) & 0xff;
  93                 addr_m     = (in->mask >> 16) & 0xff;
  94                 addr_inv   = (in->data >>  8) & 0xff;
  95                 addr_inv_m = (in->mask >>  8) & 0xff;
  96                 data_inv   = data ^ 0xff;
  97                 data_inv_m = data_m;
  98         } else {
  99                 /* Normal NEC */
 100                 /* scan encoding: AADD */
 101                 addr       = (in->data >>  8) & 0xff;
 102                 addr_m     = (in->mask >>  8) & 0xff;
 103                 addr_inv   = addr ^ 0xff;
 104                 addr_inv_m = addr_m;
 105                 data_inv   = data ^ 0xff;
 106                 data_inv_m = data_m;
 107         }
 108
 109         /* raw encoding: ddDDaaAA */
 110         out->data = data_inv << 24 |
 111                     data     << 16 |
 112                     addr_inv <<  8 |
 113                     addr;
 114         out->mask = data_inv_m << 24 |
 115                     data_m     << 16 |
 116                     addr_inv_m <<  8 |
 117                     addr_m;
 118         return 0;
 119 }
 120
 121 /*
 122  * NEC decoder
 123  * See also http://www.sbprojects.com/knowledge/ir/nec.php
 124  *        http://wiki.altium.com/display/ADOH/NEC+Infrared+Transmission+Protocol
 125  */
 126 struct img_ir_decoder img_ir_nec = {
 127         .type = RC_PROTO_BIT_NEC | RC_PROTO_BIT_NECX | RC_PROTO_BIT_NEC32,
 128         .control = {
 129                 .decoden = 1,
 130                 .code_type = IMG_IR_CODETYPE_PULSEDIST,
 131         },
 132         /* main timings */
 133         .unit = 562500, /* 562.5 us */
 134         .timings = {
 135                 /* leader symbol */
 136                 .ldr = {
 137                         .pulse = { 16   /* 9ms */ },
 138                         .space = { 8    /* 4.5ms */ },
 139                 },
 140                 /* 0 symbol */
 141                 .s00 = {
 142                         .pulse = { 1    /* 562.5 us */ },
 143                         .space = { 1    /* 562.5 us */ },
 144                 },
 145                 /* 1 symbol */
 146                 .s01 = {
 147                         .pulse = { 1    /* 562.5 us */ },
 148                         .space = { 3    /* 1687.5 us */ },
 149                 },
 150                 /* free time */
 151                 .ft = {
 152                         .minlen = 32,
 153                         .maxlen = 32,
 154                         .ft_min = 10,   /* 5.625 ms */
 155                 },
 156         },
 157         /* repeat codes */
 158         .repeat = 108,                  /* 108 ms */
 159         .rtimings = {
 160                 /* leader symbol */
 161                 .ldr = {
 162                         .space = { 4    /* 2.25 ms */ },
 163                 },
 164                 /* free time */
 165                 .ft = {
 166                         .minlen = 0,    /* repeat code has no data */
 167                         .maxlen = 0,
 168                 },
 169         },
 170         /* scancode logic */
 171         .scancode = img_ir_nec_scancode,
 172         .filter = img_ir_nec_filter,
 173 };