img-ir-rc6.c
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/*
* ImgTec IR Decoder setup for Philips RC-6 protocol.
*
* Copyright 2012-2014 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"
/* Convert RC6 data to a scancode */
static int img_ir_rc6_scancode(int len, u64 raw, u64 enabled_protocols,
struct img_ir_scancode_req *request)
{
unsigned int addr, cmd, mode, trl1, trl2;
/*
* Due to a side effect of the decoder handling the double length
* Trailer bit, the header information is a bit scrambled, and the
* raw data is shifted incorrectly.
* This workaround effectively recovers the header bits.
*
* The Header field should look like this:
*
* StartBit ModeBit2 ModeBit1 ModeBit0 TrailerBit
*
* But what we get is:
*
* ModeBit2 ModeBit1 ModeBit0 TrailerBit1 TrailerBit2
*
* The start bit is not important to recover the scancode.
*/
raw >>= 27;
trl1 = (raw >> 17) & 0x01;
trl2 = (raw >> 16) & 0x01;
mode = (raw >> 18) & 0x07;
addr = (raw >> 8) & 0xff;
cmd = raw & 0xff;
/*
* Due to the above explained irregularity the trailer bits cannot
* have the same value.
*/
if (trl1 == trl2)
return -EINVAL;
/* Only mode 0 supported for now */
if (mode)
return -EINVAL;
request->protocol = RC_TYPE_RC6_0;
request->scancode = addr << 8 | cmd;
request->toggle = trl2;
return IMG_IR_SCANCODE;
}
/* Convert RC6 scancode to RC6 data filter */
static int img_ir_rc6_filter(const struct rc_scancode_filter *in,
struct img_ir_filter *out, u64 protocols)
{
/* Not supported by the hw. */
return -EINVAL;
}
/*
* RC-6 decoder
* see http://www.sbprojects.com/knowledge/ir/rc6.php
*/
struct img_ir_decoder img_ir_rc6 = {
.type = RC_BIT_RC6_0,
.control = {
.bitorien = 1,
.code_type = IMG_IR_CODETYPE_BIPHASE,
.decoden = 1,
.decodinpol = 1,
},
/* main timings */
.tolerance = 20,
/*
* Due to a quirk in the img-ir decoder, default header values do
* not work, the values described below were extracted from
* successful RTL test cases.
*/
.timings = {
/* leader symbol */
.ldr = {
.pulse = { 650 },
.space = { 660 },
},
/* 0 symbol */
.s00 = {
.pulse = { 370 },
.space = { 370 },
},
/* 01 symbol */
.s01 = {
.pulse = { 370 },
.space = { 370 },
},
/* free time */
.ft = {
.minlen = 21,
.maxlen = 21,
.ft_min = 2666, /* 2.666 ms */
},
},
/* scancode logic */
.scancode = img_ir_rc6_scancode,
.filter = img_ir_rc6_filter,
};