Commit | Line | Data |
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995187be | 1 | /* ir-nec-decoder.c - handle NEC IR Pulse/Space protocol |
a3572c34 | 2 | * |
37e59f87 | 3 | * Copyright (C) 2010 by Mauro Carvalho Chehab |
a3572c34 MCC |
4 | * |
5 | * This program is free software; you can redistribute it and/or modify | |
6 | * it under the terms of the GNU General Public License as published by | |
7 | * the Free Software Foundation version 2 of the License. | |
8 | * | |
9 | * This program is distributed in the hope that it will be useful, | |
10 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
11 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
12 | * GNU General Public License for more details. | |
13 | */ | |
14 | ||
724e2495 | 15 | #include <linux/bitrev.h> |
7a707b89 | 16 | #include <linux/module.h> |
f62de675 | 17 | #include "rc-core-priv.h" |
a3572c34 | 18 | |
67780d6a | 19 | #define NEC_NBITS 32 |
724e2495 | 20 | #define NEC_UNIT 562500 /* ns */ |
e40b1127 DH |
21 | #define NEC_HEADER_PULSE (16 * NEC_UNIT) |
22 | #define NECX_HEADER_PULSE (8 * NEC_UNIT) /* Less common NEC variant */ | |
23 | #define NEC_HEADER_SPACE (8 * NEC_UNIT) | |
e31f4127 | 24 | #define NEC_REPEAT_SPACE (4 * NEC_UNIT) |
e40b1127 DH |
25 | #define NEC_BIT_PULSE (1 * NEC_UNIT) |
26 | #define NEC_BIT_0_SPACE (1 * NEC_UNIT) | |
27 | #define NEC_BIT_1_SPACE (3 * NEC_UNIT) | |
28 | #define NEC_TRAILER_PULSE (1 * NEC_UNIT) | |
29 | #define NEC_TRAILER_SPACE (10 * NEC_UNIT) /* even longer in reality */ | |
86ff071c | 30 | #define NECX_REPEAT_BITS 1 |
9f154782 | 31 | |
2f16f631 MCC |
32 | enum nec_state { |
33 | STATE_INACTIVE, | |
2f16f631 | 34 | STATE_HEADER_SPACE, |
724e2495 DH |
35 | STATE_BIT_PULSE, |
36 | STATE_BIT_SPACE, | |
37 | STATE_TRAILER_PULSE, | |
2f16f631 MCC |
38 | STATE_TRAILER_SPACE, |
39 | }; | |
40 | ||
2f16f631 | 41 | /** |
587835a4 | 42 | * ir_nec_decode() - Decode one NEC pulse or space |
d8b4b582 | 43 | * @dev: the struct rc_dev descriptor of the device |
e40b1127 | 44 | * @duration: the struct ir_raw_event descriptor of the pulse/space |
2f16f631 MCC |
45 | * |
46 | * This function returns -EINVAL if the pulse violates the state machine | |
9f154782 | 47 | */ |
d8b4b582 | 48 | static int ir_nec_decode(struct rc_dev *dev, struct ir_raw_event ev) |
9f154782 | 49 | { |
d8b4b582 | 50 | struct nec_dec *data = &dev->raw->nec; |
724e2495 DH |
51 | u32 scancode; |
52 | u8 address, not_address, command, not_command; | |
4be22b6a | 53 | bool send_32bits = false; |
9f154782 | 54 | |
4651918a ML |
55 | if (!is_timing_event(ev)) { |
56 | if (ev.reset) | |
57 | data->state = STATE_INACTIVE; | |
724e2495 DH |
58 | return 0; |
59 | } | |
a3572c34 | 60 | |
e40b1127 DH |
61 | IR_dprintk(2, "NEC decode started at state %d (%uus %s)\n", |
62 | data->state, TO_US(ev.duration), TO_STR(ev.pulse)); | |
9f154782 | 63 | |
2f16f631 | 64 | switch (data->state) { |
a3572c34 | 65 | |
724e2495 | 66 | case STATE_INACTIVE: |
e40b1127 DH |
67 | if (!ev.pulse) |
68 | break; | |
69 | ||
743135e7 | 70 | if (eq_margin(ev.duration, NEC_HEADER_PULSE, NEC_UNIT * 2)) { |
86ff071c ML |
71 | data->is_nec_x = false; |
72 | data->necx_repeat = false; | |
73 | } else if (eq_margin(ev.duration, NECX_HEADER_PULSE, NEC_UNIT / 2)) | |
74 | data->is_nec_x = true; | |
75 | else | |
e40b1127 DH |
76 | break; |
77 | ||
78 | data->count = 0; | |
79 | data->state = STATE_HEADER_SPACE; | |
2f16f631 | 80 | return 0; |
724e2495 | 81 | |
2f16f631 | 82 | case STATE_HEADER_SPACE: |
e40b1127 DH |
83 | if (ev.pulse) |
84 | break; | |
85 | ||
743135e7 | 86 | if (eq_margin(ev.duration, NEC_HEADER_SPACE, NEC_UNIT)) { |
724e2495 | 87 | data->state = STATE_BIT_PULSE; |
9f154782 | 88 | return 0; |
e40b1127 | 89 | } else if (eq_margin(ev.duration, NEC_REPEAT_SPACE, NEC_UNIT / 2)) { |
21d33014 MB |
90 | if (!dev->keypressed) { |
91 | IR_dprintk(1, "Discarding last key repeat: event after key up\n"); | |
92 | } else { | |
93 | rc_repeat(dev); | |
94 | IR_dprintk(1, "Repeat last key\n"); | |
95 | data->state = STATE_TRAILER_PULSE; | |
96 | } | |
2f16f631 MCC |
97 | return 0; |
98 | } | |
e40b1127 | 99 | |
724e2495 DH |
100 | break; |
101 | ||
102 | case STATE_BIT_PULSE: | |
e40b1127 DH |
103 | if (!ev.pulse) |
104 | break; | |
105 | ||
106 | if (!eq_margin(ev.duration, NEC_BIT_PULSE, NEC_UNIT / 2)) | |
107 | break; | |
108 | ||
109 | data->state = STATE_BIT_SPACE; | |
110 | return 0; | |
724e2495 DH |
111 | |
112 | case STATE_BIT_SPACE: | |
e40b1127 | 113 | if (ev.pulse) |
724e2495 DH |
114 | break; |
115 | ||
86ff071c ML |
116 | if (data->necx_repeat && data->count == NECX_REPEAT_BITS && |
117 | geq_margin(ev.duration, | |
118 | NEC_TRAILER_SPACE, NEC_UNIT / 2)) { | |
119 | IR_dprintk(1, "Repeat last key\n"); | |
ca86674b | 120 | rc_repeat(dev); |
86ff071c ML |
121 | data->state = STATE_INACTIVE; |
122 | return 0; | |
123 | ||
124 | } else if (data->count > NECX_REPEAT_BITS) | |
125 | data->necx_repeat = false; | |
126 | ||
c216369e | 127 | data->bits <<= 1; |
e40b1127 | 128 | if (eq_margin(ev.duration, NEC_BIT_1_SPACE, NEC_UNIT / 2)) |
c216369e | 129 | data->bits |= 1; |
e40b1127 DH |
130 | else if (!eq_margin(ev.duration, NEC_BIT_0_SPACE, NEC_UNIT / 2)) |
131 | break; | |
724e2495 DH |
132 | data->count++; |
133 | ||
e40b1127 DH |
134 | if (data->count == NEC_NBITS) |
135 | data->state = STATE_TRAILER_PULSE; | |
136 | else | |
724e2495 | 137 | data->state = STATE_BIT_PULSE; |
e40b1127 DH |
138 | |
139 | return 0; | |
140 | ||
141 | case STATE_TRAILER_PULSE: | |
142 | if (!ev.pulse) | |
143 | break; | |
144 | ||
145 | if (!eq_margin(ev.duration, NEC_TRAILER_PULSE, NEC_UNIT / 2)) | |
146 | break; | |
147 | ||
148 | data->state = STATE_TRAILER_SPACE; | |
149 | return 0; | |
150 | ||
151 | case STATE_TRAILER_SPACE: | |
152 | if (ev.pulse) | |
153 | break; | |
154 | ||
155 | if (!geq_margin(ev.duration, NEC_TRAILER_SPACE, NEC_UNIT / 2)) | |
156 | break; | |
724e2495 | 157 | |
c216369e DH |
158 | address = bitrev8((data->bits >> 24) & 0xff); |
159 | not_address = bitrev8((data->bits >> 16) & 0xff); | |
160 | command = bitrev8((data->bits >> 8) & 0xff); | |
161 | not_command = bitrev8((data->bits >> 0) & 0xff); | |
724e2495 DH |
162 | |
163 | if ((command ^ not_command) != 0xff) { | |
164 | IR_dprintk(1, "NEC checksum error: received 0x%08x\n", | |
c216369e | 165 | data->bits); |
4be22b6a | 166 | send_32bits = true; |
2f16f631 | 167 | } |
a3572c34 | 168 | |
4be22b6a JW |
169 | if (send_32bits) { |
170 | /* NEC transport, but modified protocol, used by at | |
171 | * least Apple and TiVo remotes */ | |
42f5e630 | 172 | scancode = data->bits; |
4be22b6a JW |
173 | IR_dprintk(1, "NEC (modified) scancode 0x%08x\n", scancode); |
174 | } else if ((address ^ not_address) != 0xff) { | |
724e2495 DH |
175 | /* Extended NEC */ |
176 | scancode = address << 16 | | |
177 | not_address << 8 | | |
178 | command; | |
179 | IR_dprintk(1, "NEC (Ext) scancode 0x%06x\n", scancode); | |
180 | } else { | |
e40b1127 | 181 | /* Normal NEC */ |
724e2495 DH |
182 | scancode = address << 8 | command; |
183 | IR_dprintk(1, "NEC scancode 0x%04x\n", scancode); | |
a3572c34 | 184 | } |
724e2495 | 185 | |
86ff071c ML |
186 | if (data->is_nec_x) |
187 | data->necx_repeat = true; | |
188 | ||
120703f9 | 189 | rc_keydown(dev, RC_TYPE_NEC, scancode, 0); |
e40b1127 | 190 | data->state = STATE_INACTIVE; |
2f16f631 | 191 | return 0; |
724e2495 | 192 | } |
a3572c34 | 193 | |
39cac375 MCC |
194 | IR_dprintk(1, "NEC decode failed at count %d state %d (%uus %s)\n", |
195 | data->count, data->state, TO_US(ev.duration), TO_STR(ev.pulse)); | |
2f16f631 | 196 | data->state = STATE_INACTIVE; |
a3572c34 MCC |
197 | return -EINVAL; |
198 | } | |
ada39630 | 199 | |
995187be | 200 | static struct ir_raw_handler nec_handler = { |
c003ab1b | 201 | .protocols = RC_BIT_NEC, |
20d5f116 | 202 | .decode = ir_nec_decode, |
995187be MCC |
203 | }; |
204 | ||
205 | static int __init ir_nec_decode_init(void) | |
206 | { | |
207 | ir_raw_handler_register(&nec_handler); | |
208 | ||
209 | printk(KERN_INFO "IR NEC protocol handler initialized\n"); | |
210 | return 0; | |
211 | } | |
212 | ||
213 | static void __exit ir_nec_decode_exit(void) | |
214 | { | |
215 | ir_raw_handler_unregister(&nec_handler); | |
216 | } | |
217 | ||
218 | module_init(ir_nec_decode_init); | |
219 | module_exit(ir_nec_decode_exit); | |
220 | ||
221 | MODULE_LICENSE("GPL"); | |
37e59f87 | 222 | MODULE_AUTHOR("Mauro Carvalho Chehab"); |
995187be MCC |
223 | MODULE_AUTHOR("Red Hat Inc. (http://www.redhat.com)"); |
224 | MODULE_DESCRIPTION("NEC IR protocol decoder"); |