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kernel/linux-rt-4.4.41/drivers/media/rc/img-ir/img-ir-rc6.c 2.62 KB
5113f6f70   김현기   kernel add
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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,
  };