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> |
3f113e36 | 16 | #include "ir-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 |
9f154782 | 42 | * @input_dev: the struct input_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 | */ |
e40b1127 | 47 | static int ir_nec_decode(struct input_dev *input_dev, struct ir_raw_event ev) |
9f154782 | 48 | { |
2f16f631 | 49 | struct ir_input_dev *ir_dev = input_get_drvdata(input_dev); |
c216369e | 50 | struct nec_dec *data = &ir_dev->raw->nec; |
724e2495 DH |
51 | u32 scancode; |
52 | u8 address, not_address, command, not_command; | |
9f154782 | 53 | |
667c9ebe | 54 | if (!(ir_dev->raw->enabled_protocols & IR_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)) { |
2f16f631 MCC |
92 | ir_repeat(input_dev); |
93 | IR_dprintk(1, "Repeat last key\n"); | |
724e2495 | 94 | data->state = STATE_TRAILER_PULSE; |
2f16f631 MCC |
95 | return 0; |
96 | } | |
e40b1127 | 97 | |
724e2495 DH |
98 | break; |
99 | ||
100 | case STATE_BIT_PULSE: | |
e40b1127 DH |
101 | if (!ev.pulse) |
102 | break; | |
103 | ||
104 | if (!eq_margin(ev.duration, NEC_BIT_PULSE, NEC_UNIT / 2)) | |
105 | break; | |
106 | ||
107 | data->state = STATE_BIT_SPACE; | |
108 | return 0; | |
724e2495 DH |
109 | |
110 | case STATE_BIT_SPACE: | |
e40b1127 | 111 | if (ev.pulse) |
724e2495 DH |
112 | break; |
113 | ||
86ff071c ML |
114 | if (data->necx_repeat && data->count == NECX_REPEAT_BITS && |
115 | geq_margin(ev.duration, | |
116 | NEC_TRAILER_SPACE, NEC_UNIT / 2)) { | |
117 | IR_dprintk(1, "Repeat last key\n"); | |
118 | ir_repeat(input_dev); | |
119 | data->state = STATE_INACTIVE; | |
120 | return 0; | |
121 | ||
122 | } else if (data->count > NECX_REPEAT_BITS) | |
123 | data->necx_repeat = false; | |
124 | ||
c216369e | 125 | data->bits <<= 1; |
e40b1127 | 126 | if (eq_margin(ev.duration, NEC_BIT_1_SPACE, NEC_UNIT / 2)) |
c216369e | 127 | data->bits |= 1; |
e40b1127 DH |
128 | else if (!eq_margin(ev.duration, NEC_BIT_0_SPACE, NEC_UNIT / 2)) |
129 | break; | |
724e2495 DH |
130 | data->count++; |
131 | ||
e40b1127 DH |
132 | if (data->count == NEC_NBITS) |
133 | data->state = STATE_TRAILER_PULSE; | |
134 | else | |
724e2495 | 135 | data->state = STATE_BIT_PULSE; |
e40b1127 DH |
136 | |
137 | return 0; | |
138 | ||
139 | case STATE_TRAILER_PULSE: | |
140 | if (!ev.pulse) | |
141 | break; | |
142 | ||
143 | if (!eq_margin(ev.duration, NEC_TRAILER_PULSE, NEC_UNIT / 2)) | |
144 | break; | |
145 | ||
146 | data->state = STATE_TRAILER_SPACE; | |
147 | return 0; | |
148 | ||
149 | case STATE_TRAILER_SPACE: | |
150 | if (ev.pulse) | |
151 | break; | |
152 | ||
153 | if (!geq_margin(ev.duration, NEC_TRAILER_SPACE, NEC_UNIT / 2)) | |
154 | break; | |
724e2495 | 155 | |
c216369e DH |
156 | address = bitrev8((data->bits >> 24) & 0xff); |
157 | not_address = bitrev8((data->bits >> 16) & 0xff); | |
158 | command = bitrev8((data->bits >> 8) & 0xff); | |
159 | not_command = bitrev8((data->bits >> 0) & 0xff); | |
724e2495 DH |
160 | |
161 | if ((command ^ not_command) != 0xff) { | |
162 | IR_dprintk(1, "NEC checksum error: received 0x%08x\n", | |
c216369e | 163 | data->bits); |
724e2495 | 164 | break; |
2f16f631 | 165 | } |
a3572c34 | 166 | |
724e2495 DH |
167 | if ((address ^ not_address) != 0xff) { |
168 | /* Extended NEC */ | |
169 | scancode = address << 16 | | |
170 | not_address << 8 | | |
171 | command; | |
172 | IR_dprintk(1, "NEC (Ext) scancode 0x%06x\n", scancode); | |
173 | } else { | |
e40b1127 | 174 | /* Normal NEC */ |
724e2495 DH |
175 | scancode = address << 8 | command; |
176 | IR_dprintk(1, "NEC scancode 0x%04x\n", scancode); | |
a3572c34 | 177 | } |
724e2495 | 178 | |
86ff071c ML |
179 | if (data->is_nec_x) |
180 | data->necx_repeat = true; | |
181 | ||
724e2495 | 182 | ir_keydown(input_dev, scancode, 0); |
e40b1127 | 183 | data->state = STATE_INACTIVE; |
2f16f631 | 184 | return 0; |
724e2495 | 185 | } |
a3572c34 | 186 | |
e40b1127 DH |
187 | IR_dprintk(1, "NEC decode failed at state %d (%uus %s)\n", |
188 | data->state, TO_US(ev.duration), TO_STR(ev.pulse)); | |
2f16f631 | 189 | data->state = STATE_INACTIVE; |
a3572c34 MCC |
190 | return -EINVAL; |
191 | } | |
ada39630 | 192 | |
995187be | 193 | static struct ir_raw_handler nec_handler = { |
667c9ebe | 194 | .protocols = IR_TYPE_NEC, |
20d5f116 | 195 | .decode = ir_nec_decode, |
995187be MCC |
196 | }; |
197 | ||
198 | static int __init ir_nec_decode_init(void) | |
199 | { | |
200 | ir_raw_handler_register(&nec_handler); | |
201 | ||
202 | printk(KERN_INFO "IR NEC protocol handler initialized\n"); | |
203 | return 0; | |
204 | } | |
205 | ||
206 | static void __exit ir_nec_decode_exit(void) | |
207 | { | |
208 | ir_raw_handler_unregister(&nec_handler); | |
209 | } | |
210 | ||
211 | module_init(ir_nec_decode_init); | |
212 | module_exit(ir_nec_decode_exit); | |
213 | ||
214 | MODULE_LICENSE("GPL"); | |
215 | MODULE_AUTHOR("Mauro Carvalho Chehab <mchehab@redhat.com>"); | |
216 | MODULE_AUTHOR("Red Hat Inc. (http://www.redhat.com)"); | |
217 | MODULE_DESCRIPTION("NEC IR protocol decoder"); |