118 lines
		
	
	
		
			2.6 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			118 lines
		
	
	
		
			2.6 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
/*
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 * ImgTec IR Decoder setup for Philips RC-6 protocol.
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 *
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 * Copyright 2012-2014 Imagination Technologies Ltd.
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 *
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 * This program is free software; you can redistribute it and/or modify
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 * it under the terms of the GNU General Public License as published by the
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 * Free Software Foundation; either version 2 of the License, or (at your
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 * option) any later version.
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 */
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#include "img-ir-hw.h"
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/* Convert RC6 data to a scancode */
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static int img_ir_rc6_scancode(int len, u64 raw, u64 enabled_protocols,
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				struct img_ir_scancode_req *request)
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{
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	unsigned int addr, cmd, mode, trl1, trl2;
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	/*
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	 * Due to a side effect of the decoder handling the double length
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	 * Trailer bit, the header information is a bit scrambled, and the
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	 * raw data is shifted incorrectly.
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	 * This workaround effectively recovers the header bits.
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	 *
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	 * The Header field should look like this:
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	 *
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	 * StartBit ModeBit2 ModeBit1 ModeBit0 TrailerBit
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	 *
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	 * But what we get is:
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	 *
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	 * ModeBit2 ModeBit1 ModeBit0 TrailerBit1 TrailerBit2
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	 *
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	 * The start bit is not important to recover the scancode.
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	 */
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	raw	>>= 27;
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	trl1	= (raw >>  17)	& 0x01;
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	trl2	= (raw >>  16)	& 0x01;
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	mode	= (raw >>  18)	& 0x07;
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	addr	= (raw >>   8)	& 0xff;
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	cmd	=  raw		& 0xff;
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	/*
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	 * Due to the above explained irregularity the trailer bits cannot
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	 * have the same value.
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	 */
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	if (trl1 == trl2)
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		return -EINVAL;
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	/* Only mode 0 supported for now */
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	if (mode)
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		return -EINVAL;
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	request->protocol = RC_PROTO_RC6_0;
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	request->scancode = addr << 8 | cmd;
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	request->toggle	  = trl2;
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	return IMG_IR_SCANCODE;
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}
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/* Convert RC6 scancode to RC6 data filter */
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static int img_ir_rc6_filter(const struct rc_scancode_filter *in,
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				 struct img_ir_filter *out, u64 protocols)
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{
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	/* Not supported by the hw. */
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	return -EINVAL;
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}
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/*
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 * RC-6 decoder
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 * see http://www.sbprojects.com/knowledge/ir/rc6.php
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 */
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struct img_ir_decoder img_ir_rc6 = {
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	.type		= RC_PROTO_BIT_RC6_0,
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	.control	= {
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		.bitorien	= 1,
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		.code_type	= IMG_IR_CODETYPE_BIPHASE,
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		.decoden	= 1,
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		.decodinpol	= 1,
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	},
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	/* main timings */
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	.tolerance	= 20,
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	/*
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	 * Due to a quirk in the img-ir decoder, default header values do
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	 * not work, the values described below were extracted from
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	 * successful RTL test cases.
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	 */
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	.timings	= {
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		/* leader symbol */
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		.ldr = {
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			.pulse	= { 650 },
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			.space	= { 660 },
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		},
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		/* 0 symbol */
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		.s00 = {
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			.pulse	= { 370 },
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			.space	= { 370 },
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		},
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		/* 01 symbol */
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		.s01 = {
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			.pulse	= { 370 },
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			.space	= { 370 },
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		},
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		/* free time */
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		.ft  = {
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			.minlen = 21,
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			.maxlen = 21,
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			.ft_min = 2666,	/* 2.666 ms */
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		},
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	},
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	/* scancode logic */
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	.scancode	= img_ir_rc6_scancode,
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	.filter		= img_ir_rc6_filter,
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};
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