1 /*
2  * ImgTec IR Decoder setup for NEC protocol.
3  *
4  * Copyright 2010-2014 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 #include <linux/bitrev.h>
14 
15 /* Convert NEC data to a scancode */
16 static int img_ir_nec_scancode(int len, u64 raw, u64 enabled_protocols,
17 			       struct img_ir_scancode_req *request)
18 {
19 	unsigned int addr, addr_inv, data, data_inv;
20 	/* a repeat code has no data */
21 	if (!len)
22 		return IMG_IR_REPEATCODE;
23 	if (len != 32)
24 		return -EINVAL;
25 	/* raw encoding: ddDDaaAA */
26 	addr     = (raw >>  0) & 0xff;
27 	addr_inv = (raw >>  8) & 0xff;
28 	data     = (raw >> 16) & 0xff;
29 	data_inv = (raw >> 24) & 0xff;
30 	if ((data_inv ^ data) != 0xff) {
31 		/* 32-bit NEC (used by Apple and TiVo remotes) */
32 		/* scan encoding: as transmitted, MSBit = first received bit */
33 		request->scancode = bitrev8(addr)     << 24 |
34 				bitrev8(addr_inv) << 16 |
35 				bitrev8(data)     <<  8 |
36 				bitrev8(data_inv);
37 		request->protocol = RC_TYPE_NEC32;
38 	} else if ((addr_inv ^ addr) != 0xff) {
39 		/* Extended NEC */
40 		/* scan encoding: AAaaDD */
41 		request->scancode = addr     << 16 |
42 				addr_inv <<  8 |
43 				data;
44 		request->protocol = RC_TYPE_NECX;
45 	} else {
46 		/* Normal NEC */
47 		/* scan encoding: AADD */
48 		request->scancode = addr << 8 |
49 				data;
50 		request->protocol = RC_TYPE_NEC;
51 	}
52 	return IMG_IR_SCANCODE;
53 }
54 
55 /* Convert NEC scancode to NEC data filter */
56 static int img_ir_nec_filter(const struct rc_scancode_filter *in,
57 			     struct img_ir_filter *out, u64 protocols)
58 {
59 	unsigned int addr, addr_inv, data, data_inv;
60 	unsigned int addr_m, addr_inv_m, data_m, data_inv_m;
61 
62 	data       = in->data & 0xff;
63 	data_m     = in->mask & 0xff;
64 
65 	if ((in->data | in->mask) & 0xff000000) {
66 		/* 32-bit NEC (used by Apple and TiVo remotes) */
67 		/* scan encoding: as transmitted, MSBit = first received bit */
68 		addr       = bitrev8(in->data >> 24);
69 		addr_m     = bitrev8(in->mask >> 24);
70 		addr_inv   = bitrev8(in->data >> 16);
71 		addr_inv_m = bitrev8(in->mask >> 16);
72 		data       = bitrev8(in->data >>  8);
73 		data_m     = bitrev8(in->mask >>  8);
74 		data_inv   = bitrev8(in->data >>  0);
75 		data_inv_m = bitrev8(in->mask >>  0);
76 	} else if ((in->data | in->mask) & 0x00ff0000) {
77 		/* Extended NEC */
78 		/* scan encoding AAaaDD */
79 		addr       = (in->data >> 16) & 0xff;
80 		addr_m     = (in->mask >> 16) & 0xff;
81 		addr_inv   = (in->data >>  8) & 0xff;
82 		addr_inv_m = (in->mask >>  8) & 0xff;
83 		data_inv   = data ^ 0xff;
84 		data_inv_m = data_m;
85 	} else {
86 		/* Normal NEC */
87 		/* scan encoding: AADD */
88 		addr       = (in->data >>  8) & 0xff;
89 		addr_m     = (in->mask >>  8) & 0xff;
90 		addr_inv   = addr ^ 0xff;
91 		addr_inv_m = addr_m;
92 		data_inv   = data ^ 0xff;
93 		data_inv_m = data_m;
94 	}
95 
96 	/* raw encoding: ddDDaaAA */
97 	out->data = data_inv << 24 |
98 		    data     << 16 |
99 		    addr_inv <<  8 |
100 		    addr;
101 	out->mask = data_inv_m << 24 |
102 		    data_m     << 16 |
103 		    addr_inv_m <<  8 |
104 		    addr_m;
105 	return 0;
106 }
107 
108 /*
109  * NEC decoder
110  * See also http://www.sbprojects.com/knowledge/ir/nec.php
111  *        http://wiki.altium.com/display/ADOH/NEC+Infrared+Transmission+Protocol
112  */
113 struct img_ir_decoder img_ir_nec = {
114 	.type = RC_BIT_NEC | RC_BIT_NECX | RC_BIT_NEC32,
115 	.control = {
116 		.decoden = 1,
117 		.code_type = IMG_IR_CODETYPE_PULSEDIST,
118 	},
119 	/* main timings */
120 	.unit = 562500, /* 562.5 us */
121 	.timings = {
122 		/* leader symbol */
123 		.ldr = {
124 			.pulse = { 16	/* 9ms */ },
125 			.space = { 8	/* 4.5ms */ },
126 		},
127 		/* 0 symbol */
128 		.s00 = {
129 			.pulse = { 1	/* 562.5 us */ },
130 			.space = { 1	/* 562.5 us */ },
131 		},
132 		/* 1 symbol */
133 		.s01 = {
134 			.pulse = { 1	/* 562.5 us */ },
135 			.space = { 3	/* 1687.5 us */ },
136 		},
137 		/* free time */
138 		.ft = {
139 			.minlen = 32,
140 			.maxlen = 32,
141 			.ft_min = 10,	/* 5.625 ms */
142 		},
143 	},
144 	/* repeat codes */
145 	.repeat = 108,			/* 108 ms */
146 	.rtimings = {
147 		/* leader symbol */
148 		.ldr = {
149 			.space = { 4	/* 2.25 ms */ },
150 		},
151 		/* free time */
152 		.ft = {
153 			.minlen = 0,	/* repeat code has no data */
154 			.maxlen = 0,
155 		},
156 	},
157 	/* scancode logic */
158 	.scancode = img_ir_nec_scancode,
159 	.filter = img_ir_nec_filter,
160 };
161