1/*
2 * ImgTec IR Decoder setup for Philips RC-6 protocol.
3 *
4 * Copyright 2012-2014 Imagination Technologies Ltd.
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by the
8 * Free Software Foundation; either version 2 of the License, or (at your
9 * option) any later version.
10 */
11
12#include "img-ir-hw.h"
13
14/* Convert RC6 data to a scancode */
15static int img_ir_rc6_scancode(int len, u64 raw, u64 enabled_protocols,
16				struct img_ir_scancode_req *request)
17{
18	unsigned int addr, cmd, mode, trl1, trl2;
19
20	/*
21	 * Due to a side effect of the decoder handling the double length
22	 * Trailer bit, the header information is a bit scrambled, and the
23	 * raw data is shifted incorrectly.
24	 * This workaround effectively recovers the header bits.
25	 *
26	 * The Header field should look like this:
27	 *
28	 * StartBit ModeBit2 ModeBit1 ModeBit0 TrailerBit
29	 *
30	 * But what we get is:
31	 *
32	 * ModeBit2 ModeBit1 ModeBit0 TrailerBit1 TrailerBit2
33	 *
34	 * The start bit is not important to recover the scancode.
35	 */
36
37	raw	>>= 27;
38
39	trl1	= (raw >>  17)	& 0x01;
40	trl2	= (raw >>  16)	& 0x01;
41
42	mode	= (raw >>  18)	& 0x07;
43	addr	= (raw >>   8)	& 0xff;
44	cmd	=  raw		& 0xff;
45
46	/*
47	 * Due to the above explained irregularity the trailer bits cannot
48	 * have the same value.
49	 */
50	if (trl1 == trl2)
51		return -EINVAL;
52
53	/* Only mode 0 supported for now */
54	if (mode)
55		return -EINVAL;
56
57	request->protocol = RC_TYPE_RC6_0;
58	request->scancode = addr << 8 | cmd;
59	request->toggle	  = trl2;
60	return IMG_IR_SCANCODE;
61}
62
63/* Convert RC6 scancode to RC6 data filter */
64static int img_ir_rc6_filter(const struct rc_scancode_filter *in,
65				 struct img_ir_filter *out, u64 protocols)
66{
67	/* Not supported by the hw. */
68	return -EINVAL;
69}
70
71/*
72 * RC-6 decoder
73 * see http://www.sbprojects.com/knowledge/ir/rc6.php
74 */
75struct img_ir_decoder img_ir_rc6 = {
76	.type		= RC_BIT_RC6_0,
77	.control	= {
78		.bitorien	= 1,
79		.code_type	= IMG_IR_CODETYPE_BIPHASE,
80		.decoden	= 1,
81		.decodinpol	= 1,
82	},
83	/* main timings */
84	.tolerance	= 20,
85	/*
86	 * Due to a quirk in the img-ir decoder, default header values do
87	 * not work, the values described below were extracted from
88	 * successful RTL test cases.
89	 */
90	.timings	= {
91		/* leader symbol */
92		.ldr = {
93			.pulse	= { 650 },
94			.space	= { 660 },
95		},
96		/* 0 symbol */
97		.s00 = {
98			.pulse	= { 370 },
99			.space	= { 370 },
100		},
101		/* 01 symbol */
102		.s01 = {
103			.pulse	= { 370 },
104			.space	= { 370 },
105		},
106		/* free time */
107		.ft  = {
108			.minlen = 21,
109			.maxlen = 21,
110			.ft_min = 2666,	/* 2.666 ms */
111		},
112	},
113
114	/* scancode logic */
115	.scancode	= img_ir_rc6_scancode,
116	.filter		= img_ir_rc6_filter,
117};
118