img-ir-nec.c
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/*
* ImgTec IR Decoder setup for NEC protocol.
*
* Copyright 2010-2014 Imagination Technologies Ltd.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by the
* Free Software Foundation; either version 2 of the License, or (at your
* option) any later version.
*/
#include "img-ir-hw.h"
#include <linux/bitrev.h>
/* Convert NEC data to a scancode */
static int img_ir_nec_scancode(int len, u64 raw, u64 enabled_protocols,
struct img_ir_scancode_req *request)
{
unsigned int addr, addr_inv, data, data_inv;
/* a repeat code has no data */
if (!len)
return IMG_IR_REPEATCODE;
if (len != 32)
return -EINVAL;
/* raw encoding: ddDDaaAA */
addr = (raw >> 0) & 0xff;
addr_inv = (raw >> 8) & 0xff;
data = (raw >> 16) & 0xff;
data_inv = (raw >> 24) & 0xff;
if ((data_inv ^ data) != 0xff) {
/* 32-bit NEC (used by Apple and TiVo remotes) */
/* scan encoding: as transmitted, MSBit = first received bit */
request->scancode = bitrev8(addr) << 24 |
bitrev8(addr_inv) << 16 |
bitrev8(data) << 8 |
bitrev8(data_inv);
} else if ((addr_inv ^ addr) != 0xff) {
/* Extended NEC */
/* scan encoding: AAaaDD */
request->scancode = addr << 16 |
addr_inv << 8 |
data;
} else {
/* Normal NEC */
/* scan encoding: AADD */
request->scancode = addr << 8 |
data;
}
request->protocol = RC_TYPE_NEC;
return IMG_IR_SCANCODE;
}
/* Convert NEC scancode to NEC data filter */
static int img_ir_nec_filter(const struct rc_scancode_filter *in,
struct img_ir_filter *out, u64 protocols)
{
unsigned int addr, addr_inv, data, data_inv;
unsigned int addr_m, addr_inv_m, data_m, data_inv_m;
data = in->data & 0xff;
data_m = in->mask & 0xff;
if ((in->data | in->mask) & 0xff000000) {
/* 32-bit NEC (used by Apple and TiVo remotes) */
/* scan encoding: as transmitted, MSBit = first received bit */
addr = bitrev8(in->data >> 24);
addr_m = bitrev8(in->mask >> 24);
addr_inv = bitrev8(in->data >> 16);
addr_inv_m = bitrev8(in->mask >> 16);
data = bitrev8(in->data >> 8);
data_m = bitrev8(in->mask >> 8);
data_inv = bitrev8(in->data >> 0);
data_inv_m = bitrev8(in->mask >> 0);
} else if ((in->data | in->mask) & 0x00ff0000) {
/* Extended NEC */
/* scan encoding AAaaDD */
addr = (in->data >> 16) & 0xff;
addr_m = (in->mask >> 16) & 0xff;
addr_inv = (in->data >> 8) & 0xff;
addr_inv_m = (in->mask >> 8) & 0xff;
data_inv = data ^ 0xff;
data_inv_m = data_m;
} else {
/* Normal NEC */
/* scan encoding: AADD */
addr = (in->data >> 8) & 0xff;
addr_m = (in->mask >> 8) & 0xff;
addr_inv = addr ^ 0xff;
addr_inv_m = addr_m;
data_inv = data ^ 0xff;
data_inv_m = data_m;
}
/* raw encoding: ddDDaaAA */
out->data = data_inv << 24 |
data << 16 |
addr_inv << 8 |
addr;
out->mask = data_inv_m << 24 |
data_m << 16 |
addr_inv_m << 8 |
addr_m;
return 0;
}
/*
* NEC decoder
* See also http://www.sbprojects.com/knowledge/ir/nec.php
* http://wiki.altium.com/display/ADOH/NEC+Infrared+Transmission+Protocol
*/
struct img_ir_decoder img_ir_nec = {
.type = RC_BIT_NEC,
.control = {
.decoden = 1,
.code_type = IMG_IR_CODETYPE_PULSEDIST,
},
/* main timings */
.unit = 562500, /* 562.5 us */
.timings = {
/* leader symbol */
.ldr = {
.pulse = { 16 /* 9ms */ },
.space = { 8 /* 4.5ms */ },
},
/* 0 symbol */
.s00 = {
.pulse = { 1 /* 562.5 us */ },
.space = { 1 /* 562.5 us */ },
},
/* 1 symbol */
.s01 = {
.pulse = { 1 /* 562.5 us */ },
.space = { 3 /* 1687.5 us */ },
},
/* free time */
.ft = {
.minlen = 32,
.maxlen = 32,
.ft_min = 10, /* 5.625 ms */
},
},
/* repeat codes */
.repeat = 108, /* 108 ms */
.rtimings = {
/* leader symbol */
.ldr = {
.space = { 4 /* 2.25 ms */ },
},
/* free time */
.ft = {
.minlen = 0, /* repeat code has no data */
.maxlen = 0,
},
},
/* scancode logic */
.scancode = img_ir_nec_scancode,
.filter = img_ir_nec_filter,
};