xref: /linux/drivers/media/rc/img-ir/img-ir-rc5.c (revision ca55b2fef3a9373fcfc30f82fd26bc7fccbda732)
1 /*
2  * ImgTec IR Decoder setup for Philips RC-5 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 RC5 data to a scancode */
15 static int img_ir_rc5_scancode(int len, u64 raw, u64 enabled_protocols,
16 				struct img_ir_scancode_req *request)
17 {
18 	unsigned int addr, cmd, tgl, start;
19 
20 	/* Quirk in the decoder shifts everything by 2 to the left. */
21 	raw   >>= 2;
22 
23 	start	=  (raw >> 13)	& 0x01;
24 	tgl	=  (raw >> 11)	& 0x01;
25 	addr	=  (raw >>  6)	& 0x1f;
26 	cmd	=   raw		& 0x3f;
27 	/*
28 	 * 12th bit is used to extend the command in extended RC5 and has
29 	 * no effect on standard RC5.
30 	 */
31 	cmd	+= ((raw >> 12) & 0x01) ? 0 : 0x40;
32 
33 	if (!start)
34 		return -EINVAL;
35 
36 	request->protocol = RC_TYPE_RC5;
37 	request->scancode = addr << 8 | cmd;
38 	request->toggle   = tgl;
39 	return IMG_IR_SCANCODE;
40 }
41 
42 /* Convert RC5 scancode to RC5 data filter */
43 static int img_ir_rc5_filter(const struct rc_scancode_filter *in,
44 				 struct img_ir_filter *out, u64 protocols)
45 {
46 	/* Not supported by the hw. */
47 	return -EINVAL;
48 }
49 
50 /*
51  * RC-5 decoder
52  * see http://www.sbprojects.com/knowledge/ir/rc5.php
53  */
54 struct img_ir_decoder img_ir_rc5 = {
55 	.type      = RC_BIT_RC5,
56 	.control   = {
57 		.bitoriend2	= 1,
58 		.code_type	= IMG_IR_CODETYPE_BIPHASE,
59 		.decodend2	= 1,
60 	},
61 	/* main timings */
62 	.tolerance	= 16,
63 	.unit		= 888888, /* 1/36k*32=888.888microseconds */
64 	.timings	= {
65 		/* 10 symbol */
66 		.s10 = {
67 			.pulse	= { 1 },
68 			.space	= { 1 },
69 		},
70 
71 		/* 11 symbol */
72 		.s11 = {
73 			.pulse	= { 1 },
74 			.space	= { 1 },
75 		},
76 
77 		/* free time */
78 		.ft  = {
79 			.minlen = 14,
80 			.maxlen = 14,
81 			.ft_min = 5,
82 		},
83 	},
84 
85 	/* scancode logic */
86 	.scancode	= img_ir_rc5_scancode,
87 	.filter		= img_ir_rc5_filter,
88 };
89