1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * ImgTec IR Decoder setup for NEC protocol.
4 *
5 * Copyright 2010-2014 Imagination Technologies Ltd.
6 */
7
8 #include "img-ir-hw.h"
9 #include <linux/bitrev.h>
10 #include <linux/log2.h>
11
12 /* Convert NEC data to a scancode */
13 static int img_ir_nec_scancode(int len, u64 raw, u64 enabled_protocols,
14 struct img_ir_scancode_req *request)
15 {
16 unsigned int addr, addr_inv, data, data_inv;
17 /* a repeat code has no data */
18 if (!len)
19 return IMG_IR_REPEATCODE;
20 if (len != 32)
21 return -EINVAL;
22 /* raw encoding: ddDDaaAA */
23 addr = (raw >> 0) & 0xff;
24 addr_inv = (raw >> 8) & 0xff;
25 data = (raw >> 16) & 0xff;
26 data_inv = (raw >> 24) & 0xff;
27 if ((data_inv ^ data) != 0xff) {
28 /* 32-bit NEC (used by Apple and TiVo remotes) */
29 /* scan encoding: as transmitted, MSBit = first received bit */
30 request->scancode = bitrev8(addr) << 24 |
31 bitrev8(addr_inv) << 16 |
32 bitrev8(data) << 8 |
33 bitrev8(data_inv);
34 request->protocol = RC_PROTO_NEC32;
35 } else if ((addr_inv ^ addr) != 0xff) {
36 /* Extended NEC */
37 /* scan encoding: AAaaDD */
38 request->scancode = addr << 16 |
39 addr_inv << 8 |
40 data;
41 request->protocol = RC_PROTO_NECX;
42 } else {
43 /* Normal NEC */
44 /* scan encoding: AADD */
45 request->scancode = addr << 8 |
46 data;
47 request->protocol = RC_PROTO_NEC;
48 }
49 return IMG_IR_SCANCODE;
50 }
51
52 /* Convert NEC scancode to NEC data filter */
53 static int img_ir_nec_filter(const struct rc_scancode_filter *in,
54 struct img_ir_filter *out, u64 protocols)
55 {
56 unsigned int addr, addr_inv, data, data_inv;
57 unsigned int addr_m, addr_inv_m, data_m, data_inv_m;
58
59 data = in->data & 0xff;
60 data_m = in->mask & 0xff;
61
62 protocols &= RC_PROTO_BIT_NEC | RC_PROTO_BIT_NECX | RC_PROTO_BIT_NEC32;
63
64 /*
65 * If only one bit is set, we were requested to do an exact
66 * protocol. This should be the case for wakeup filters; for
67 * normal filters, guess the protocol from the scancode.
68 */
69 if (!is_power_of_2(protocols)) {
70 if ((in->data | in->mask) & 0xff000000)
71 protocols = RC_PROTO_BIT_NEC32;
72 else if ((in->data | in->mask) & 0x00ff0000)
73 protocols = RC_PROTO_BIT_NECX;
74 else
75 protocols = RC_PROTO_BIT_NEC;
76 }
77
78 if (protocols == RC_PROTO_BIT_NEC32) {
79 /* 32-bit NEC (used by Apple and TiVo remotes) */
80 /* scan encoding: as transmitted, MSBit = first received bit */
81 addr = bitrev8(in->data >> 24);
82 addr_m = bitrev8(in->mask >> 24);
83 addr_inv = bitrev8(in->data >> 16);
84 addr_inv_m = bitrev8(in->mask >> 16);
85 data = bitrev8(in->data >> 8);
86 data_m = bitrev8(in->mask >> 8);
87 data_inv = bitrev8(in->data >> 0);
88 data_inv_m = bitrev8(in->mask >> 0);
89 } else if (protocols == RC_PROTO_BIT_NECX) {
90 /* Extended NEC */
91 /* scan encoding AAaaDD */
92 addr = (in->data >> 16) & 0xff;
93 addr_m = (in->mask >> 16) & 0xff;
94 addr_inv = (in->data >> 8) & 0xff;
95 addr_inv_m = (in->mask >> 8) & 0xff;
96 data_inv = data ^ 0xff;
97 data_inv_m = data_m;
98 } else {
99 /* Normal NEC */
100 /* scan encoding: AADD */
101 addr = (in->data >> 8) & 0xff;
102 addr_m = (in->mask >> 8) & 0xff;
103 addr_inv = addr ^ 0xff;
104 addr_inv_m = addr_m;
105 data_inv = data ^ 0xff;
106 data_inv_m = data_m;
107 }
108
109 /* raw encoding: ddDDaaAA */
110 out->data = data_inv << 24 |
111 data << 16 |
112 addr_inv << 8 |
113 addr;
114 out->mask = data_inv_m << 24 |
115 data_m << 16 |
116 addr_inv_m << 8 |
117 addr_m;
118 return 0;
119 }
120
121 /*
122 * NEC decoder
123 * See also http://www.sbprojects.com/knowledge/ir/nec.php
124 * http://wiki.altium.com/display/ADOH/NEC+Infrared+Transmission+Protocol
125 */
126 struct img_ir_decoder img_ir_nec = {
127 .type = RC_PROTO_BIT_NEC | RC_PROTO_BIT_NECX | RC_PROTO_BIT_NEC32,
128 .control = {
129 .decoden = 1,
130 .code_type = IMG_IR_CODETYPE_PULSEDIST,
131 },
132 /* main timings */
133 .unit = 562500, /* 562.5 us */
134 .timings = {
135 /* leader symbol */
136 .ldr = {
137 .pulse = { 16 /* 9ms */ },
138 .space = { 8 /* 4.5ms */ },
139 },
140 /* 0 symbol */
141 .s00 = {
142 .pulse = { 1 /* 562.5 us */ },
143 .space = { 1 /* 562.5 us */ },
144 },
145 /* 1 symbol */
146 .s01 = {
147 .pulse = { 1 /* 562.5 us */ },
148 .space = { 3 /* 1687.5 us */ },
149 },
150 /* free time */
151 .ft = {
152 .minlen = 32,
153 .maxlen = 32,
154 .ft_min = 10, /* 5.625 ms */
155 },
156 },
157 /* repeat codes */
158 .repeat = 108, /* 108 ms */
159 .rtimings = {
160 /* leader symbol */
161 .ldr = {
162 .space = { 4 /* 2.25 ms */ },
163 },
164 /* free time */
165 .ft = {
166 .minlen = 0, /* repeat code has no data */
167 .maxlen = 0,
168 },
169 },
170 /* scancode logic */
171 .scancode = img_ir_nec_scancode,
172 .filter = img_ir_nec_filter,
173 };