Commit | Line | Data |
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995187be | 1 | /* ir-nec-decoder.c - handle NEC IR Pulse/Space protocol |
a3572c34 MCC |
2 | * |
3 | * Copyright (C) 2010 by Mauro Carvalho Chehab <mchehab@redhat.com> | |
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> |
f62de675 | 16 | #include "rc-core-priv.h" |
a3572c34 | 17 | |
67780d6a | 18 | #define NEC_NBITS 32 |
724e2495 | 19 | #define NEC_UNIT 562500 /* ns */ |
e40b1127 DH |
20 | #define NEC_HEADER_PULSE (16 * NEC_UNIT) |
21 | #define NECX_HEADER_PULSE (8 * NEC_UNIT) /* Less common NEC variant */ | |
22 | #define NEC_HEADER_SPACE (8 * NEC_UNIT) | |
e31f4127 | 23 | #define NEC_REPEAT_SPACE (4 * NEC_UNIT) |
e40b1127 DH |
24 | #define NEC_BIT_PULSE (1 * NEC_UNIT) |
25 | #define NEC_BIT_0_SPACE (1 * NEC_UNIT) | |
26 | #define NEC_BIT_1_SPACE (3 * NEC_UNIT) | |
27 | #define NEC_TRAILER_PULSE (1 * NEC_UNIT) | |
28 | #define NEC_TRAILER_SPACE (10 * NEC_UNIT) /* even longer in reality */ | |
86ff071c | 29 | #define NECX_REPEAT_BITS 1 |
9f154782 | 30 | |
2f16f631 MCC |
31 | enum nec_state { |
32 | STATE_INACTIVE, | |
2f16f631 | 33 | STATE_HEADER_SPACE, |
724e2495 DH |
34 | STATE_BIT_PULSE, |
35 | STATE_BIT_SPACE, | |
36 | STATE_TRAILER_PULSE, | |
2f16f631 MCC |
37 | STATE_TRAILER_SPACE, |
38 | }; | |
39 | ||
2f16f631 | 40 | /** |
587835a4 | 41 | * ir_nec_decode() - Decode one NEC pulse or space |
d8b4b582 | 42 | * @dev: the struct rc_dev descriptor of the device |
e40b1127 | 43 | * @duration: the struct ir_raw_event descriptor of the pulse/space |
2f16f631 MCC |
44 | * |
45 | * This function returns -EINVAL if the pulse violates the state machine | |
9f154782 | 46 | */ |
d8b4b582 | 47 | static int ir_nec_decode(struct rc_dev *dev, struct ir_raw_event ev) |
9f154782 | 48 | { |
d8b4b582 | 49 | struct nec_dec *data = &dev->raw->nec; |
724e2495 DH |
50 | u32 scancode; |
51 | u8 address, not_address, command, not_command; | |
4be22b6a | 52 | bool send_32bits = false; |
9f154782 | 53 | |
52b66144 | 54 | if (!(dev->raw->enabled_protocols & RC_TYPE_NEC)) |
7f20d32d MCC |
55 | return 0; |
56 | ||
4651918a ML |
57 | if (!is_timing_event(ev)) { |
58 | if (ev.reset) | |
59 | data->state = STATE_INACTIVE; | |
724e2495 DH |
60 | return 0; |
61 | } | |
a3572c34 | 62 | |
e40b1127 DH |
63 | IR_dprintk(2, "NEC decode started at state %d (%uus %s)\n", |
64 | data->state, TO_US(ev.duration), TO_STR(ev.pulse)); | |
9f154782 | 65 | |
2f16f631 | 66 | switch (data->state) { |
a3572c34 | 67 | |
724e2495 | 68 | case STATE_INACTIVE: |
e40b1127 DH |
69 | if (!ev.pulse) |
70 | break; | |
71 | ||
86ff071c ML |
72 | if (eq_margin(ev.duration, NEC_HEADER_PULSE, NEC_UNIT / 2)) { |
73 | data->is_nec_x = false; | |
74 | data->necx_repeat = false; | |
75 | } else if (eq_margin(ev.duration, NECX_HEADER_PULSE, NEC_UNIT / 2)) | |
76 | data->is_nec_x = true; | |
77 | else | |
e40b1127 DH |
78 | break; |
79 | ||
80 | data->count = 0; | |
81 | data->state = STATE_HEADER_SPACE; | |
2f16f631 | 82 | return 0; |
724e2495 | 83 | |
2f16f631 | 84 | case STATE_HEADER_SPACE: |
e40b1127 DH |
85 | if (ev.pulse) |
86 | break; | |
87 | ||
88 | if (eq_margin(ev.duration, NEC_HEADER_SPACE, NEC_UNIT / 2)) { | |
724e2495 | 89 | data->state = STATE_BIT_PULSE; |
9f154782 | 90 | return 0; |
e40b1127 | 91 | } else if (eq_margin(ev.duration, NEC_REPEAT_SPACE, NEC_UNIT / 2)) { |
21d33014 MB |
92 | if (!dev->keypressed) { |
93 | IR_dprintk(1, "Discarding last key repeat: event after key up\n"); | |
94 | } else { | |
95 | rc_repeat(dev); | |
96 | IR_dprintk(1, "Repeat last key\n"); | |
97 | data->state = STATE_TRAILER_PULSE; | |
98 | } | |
2f16f631 MCC |
99 | return 0; |
100 | } | |
e40b1127 | 101 | |
724e2495 DH |
102 | break; |
103 | ||
104 | case STATE_BIT_PULSE: | |
e40b1127 DH |
105 | if (!ev.pulse) |
106 | break; | |
107 | ||
108 | if (!eq_margin(ev.duration, NEC_BIT_PULSE, NEC_UNIT / 2)) | |
109 | break; | |
110 | ||
111 | data->state = STATE_BIT_SPACE; | |
112 | return 0; | |
724e2495 DH |
113 | |
114 | case STATE_BIT_SPACE: | |
e40b1127 | 115 | if (ev.pulse) |
724e2495 DH |
116 | break; |
117 | ||
86ff071c ML |
118 | if (data->necx_repeat && data->count == NECX_REPEAT_BITS && |
119 | geq_margin(ev.duration, | |
120 | NEC_TRAILER_SPACE, NEC_UNIT / 2)) { | |
121 | IR_dprintk(1, "Repeat last key\n"); | |
ca86674b | 122 | rc_repeat(dev); |
86ff071c ML |
123 | data->state = STATE_INACTIVE; |
124 | return 0; | |
125 | ||
126 | } else if (data->count > NECX_REPEAT_BITS) | |
127 | data->necx_repeat = false; | |
128 | ||
c216369e | 129 | data->bits <<= 1; |
e40b1127 | 130 | if (eq_margin(ev.duration, NEC_BIT_1_SPACE, NEC_UNIT / 2)) |
c216369e | 131 | data->bits |= 1; |
e40b1127 DH |
132 | else if (!eq_margin(ev.duration, NEC_BIT_0_SPACE, NEC_UNIT / 2)) |
133 | break; | |
724e2495 DH |
134 | data->count++; |
135 | ||
e40b1127 DH |
136 | if (data->count == NEC_NBITS) |
137 | data->state = STATE_TRAILER_PULSE; | |
138 | else | |
724e2495 | 139 | data->state = STATE_BIT_PULSE; |
e40b1127 DH |
140 | |
141 | return 0; | |
142 | ||
143 | case STATE_TRAILER_PULSE: | |
144 | if (!ev.pulse) | |
145 | break; | |
146 | ||
147 | if (!eq_margin(ev.duration, NEC_TRAILER_PULSE, NEC_UNIT / 2)) | |
148 | break; | |
149 | ||
150 | data->state = STATE_TRAILER_SPACE; | |
151 | return 0; | |
152 | ||
153 | case STATE_TRAILER_SPACE: | |
154 | if (ev.pulse) | |
155 | break; | |
156 | ||
157 | if (!geq_margin(ev.duration, NEC_TRAILER_SPACE, NEC_UNIT / 2)) | |
158 | break; | |
724e2495 | 159 | |
c216369e DH |
160 | address = bitrev8((data->bits >> 24) & 0xff); |
161 | not_address = bitrev8((data->bits >> 16) & 0xff); | |
162 | command = bitrev8((data->bits >> 8) & 0xff); | |
163 | not_command = bitrev8((data->bits >> 0) & 0xff); | |
724e2495 DH |
164 | |
165 | if ((command ^ not_command) != 0xff) { | |
166 | IR_dprintk(1, "NEC checksum error: received 0x%08x\n", | |
c216369e | 167 | data->bits); |
4be22b6a | 168 | send_32bits = true; |
2f16f631 | 169 | } |
a3572c34 | 170 | |
4be22b6a JW |
171 | if (send_32bits) { |
172 | /* NEC transport, but modified protocol, used by at | |
173 | * least Apple and TiVo remotes */ | |
174 | scancode = data->bits; | |
175 | IR_dprintk(1, "NEC (modified) scancode 0x%08x\n", scancode); | |
176 | } else if ((address ^ not_address) != 0xff) { | |
724e2495 DH |
177 | /* Extended NEC */ |
178 | scancode = address << 16 | | |
179 | not_address << 8 | | |
180 | command; | |
181 | IR_dprintk(1, "NEC (Ext) scancode 0x%06x\n", scancode); | |
182 | } else { | |
e40b1127 | 183 | /* Normal NEC */ |
724e2495 DH |
184 | scancode = address << 8 | command; |
185 | IR_dprintk(1, "NEC scancode 0x%04x\n", scancode); | |
a3572c34 | 186 | } |
724e2495 | 187 | |
86ff071c ML |
188 | if (data->is_nec_x) |
189 | data->necx_repeat = true; | |
190 | ||
ca86674b | 191 | rc_keydown(dev, scancode, 0); |
e40b1127 | 192 | data->state = STATE_INACTIVE; |
2f16f631 | 193 | return 0; |
724e2495 | 194 | } |
a3572c34 | 195 | |
e40b1127 DH |
196 | IR_dprintk(1, "NEC decode failed at state %d (%uus %s)\n", |
197 | data->state, TO_US(ev.duration), TO_STR(ev.pulse)); | |
2f16f631 | 198 | data->state = STATE_INACTIVE; |
a3572c34 MCC |
199 | return -EINVAL; |
200 | } | |
ada39630 | 201 | |
995187be | 202 | static struct ir_raw_handler nec_handler = { |
52b66144 | 203 | .protocols = RC_TYPE_NEC, |
20d5f116 | 204 | .decode = ir_nec_decode, |
995187be MCC |
205 | }; |
206 | ||
207 | static int __init ir_nec_decode_init(void) | |
208 | { | |
209 | ir_raw_handler_register(&nec_handler); | |
210 | ||
211 | printk(KERN_INFO "IR NEC protocol handler initialized\n"); | |
212 | return 0; | |
213 | } | |
214 | ||
215 | static void __exit ir_nec_decode_exit(void) | |
216 | { | |
217 | ir_raw_handler_unregister(&nec_handler); | |
218 | } | |
219 | ||
220 | module_init(ir_nec_decode_init); | |
221 | module_exit(ir_nec_decode_exit); | |
222 | ||
223 | MODULE_LICENSE("GPL"); | |
224 | MODULE_AUTHOR("Mauro Carvalho Chehab <mchehab@redhat.com>"); | |
225 | MODULE_AUTHOR("Red Hat Inc. (http://www.redhat.com)"); | |
226 | MODULE_DESCRIPTION("NEC IR protocol decoder"); |