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733419b5 | 1 | /* ir-rc5-decoder.c - handle RC5(x) IR Pulse/Space protocol |
db1423a6 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 | ||
15 | /* | |
733419b5 DH |
16 | * This code handles 14 bits RC5 protocols and 20 bits RC5x protocols. |
17 | * There are other variants that use a different number of bits. | |
18 | * This is currently unsupported. | |
19 | * It considers a carrier of 36 kHz, with a total of 14/20 bits, where | |
9b09df51 | 20 | * the first two bits are start bits, and a third one is a filing bit |
db1423a6 MCC |
21 | */ |
22 | ||
3f113e36 | 23 | #include "ir-core-priv.h" |
db1423a6 | 24 | |
9b09df51 | 25 | #define RC5_NBITS 14 |
733419b5 DH |
26 | #define RC5X_NBITS 20 |
27 | #define CHECK_RC5X_NBITS 8 | |
724e2495 | 28 | #define RC5_UNIT 888888 /* ns */ |
e40b1127 DH |
29 | #define RC5_BIT_START (1 * RC5_UNIT) |
30 | #define RC5_BIT_END (1 * RC5_UNIT) | |
31 | #define RC5X_SPACE (4 * RC5_UNIT) | |
db1423a6 MCC |
32 | |
33 | /* Used to register rc5_decoder clients */ | |
34 | static LIST_HEAD(decoder_list); | |
6eb9435b | 35 | static DEFINE_SPINLOCK(decoder_lock); |
db1423a6 MCC |
36 | |
37 | enum rc5_state { | |
38 | STATE_INACTIVE, | |
724e2495 DH |
39 | STATE_BIT_START, |
40 | STATE_BIT_END, | |
733419b5 | 41 | STATE_CHECK_RC5X, |
724e2495 | 42 | STATE_FINISHED, |
db1423a6 MCC |
43 | }; |
44 | ||
45 | struct decoder_data { | |
46 | struct list_head list; | |
47 | struct ir_input_dev *ir_dev; | |
db1423a6 MCC |
48 | |
49 | /* State machine control */ | |
50 | enum rc5_state state; | |
724e2495 | 51 | u32 rc5_bits; |
e40b1127 | 52 | struct ir_raw_event prev_ev; |
724e2495 | 53 | unsigned count; |
733419b5 | 54 | unsigned wanted_bits; |
db1423a6 MCC |
55 | }; |
56 | ||
57 | ||
58 | /** | |
59 | * get_decoder_data() - gets decoder data | |
60 | * @input_dev: input device | |
61 | * | |
62 | * Returns the struct decoder_data that corresponds to a device | |
63 | */ | |
64 | ||
65 | static struct decoder_data *get_decoder_data(struct ir_input_dev *ir_dev) | |
66 | { | |
67 | struct decoder_data *data = NULL; | |
68 | ||
69 | spin_lock(&decoder_lock); | |
70 | list_for_each_entry(data, &decoder_list, list) { | |
71 | if (data->ir_dev == ir_dev) | |
72 | break; | |
73 | } | |
74 | spin_unlock(&decoder_lock); | |
75 | return data; | |
76 | } | |
77 | ||
db1423a6 | 78 | /** |
724e2495 | 79 | * ir_rc5_decode() - Decode one RC-5 pulse or space |
db1423a6 | 80 | * @input_dev: the struct input_dev descriptor of the device |
e40b1127 | 81 | * @ev: the struct ir_raw_event descriptor of the pulse/space |
db1423a6 MCC |
82 | * |
83 | * This function returns -EINVAL if the pulse violates the state machine | |
84 | */ | |
e40b1127 | 85 | static int ir_rc5_decode(struct input_dev *input_dev, struct ir_raw_event ev) |
db1423a6 MCC |
86 | { |
87 | struct decoder_data *data; | |
88 | struct ir_input_dev *ir_dev = input_get_drvdata(input_dev); | |
733419b5 | 89 | u8 toggle; |
724e2495 | 90 | u32 scancode; |
db1423a6 MCC |
91 | |
92 | data = get_decoder_data(ir_dev); | |
93 | if (!data) | |
94 | return -EINVAL; | |
95 | ||
667c9ebe DH |
96 | if (!(ir_dev->raw->enabled_protocols & IR_TYPE_RC5)) |
97 | return 0; | |
7f20d32d | 98 | |
e40b1127 | 99 | if (IS_RESET(ev)) { |
db1423a6 | 100 | data->state = STATE_INACTIVE; |
db1423a6 | 101 | return 0; |
724e2495 | 102 | } |
db1423a6 | 103 | |
e40b1127 | 104 | if (!geq_margin(ev.duration, RC5_UNIT, RC5_UNIT / 2)) |
724e2495 | 105 | goto out; |
db1423a6 | 106 | |
724e2495 | 107 | again: |
e40b1127 DH |
108 | IR_dprintk(2, "RC5(x) decode started at state %i (%uus %s)\n", |
109 | data->state, TO_US(ev.duration), TO_STR(ev.pulse)); | |
db1423a6 | 110 | |
e40b1127 | 111 | if (!geq_margin(ev.duration, RC5_UNIT, RC5_UNIT / 2)) |
724e2495 | 112 | return 0; |
db1423a6 | 113 | |
724e2495 | 114 | switch (data->state) { |
db1423a6 | 115 | |
724e2495 | 116 | case STATE_INACTIVE: |
e40b1127 DH |
117 | if (!ev.pulse) |
118 | break; | |
119 | ||
120 | data->state = STATE_BIT_START; | |
121 | data->count = 1; | |
122 | /* We just need enough bits to get to STATE_CHECK_RC5X */ | |
123 | data->wanted_bits = RC5X_NBITS; | |
124 | decrease_duration(&ev, RC5_BIT_START); | |
125 | goto again; | |
724e2495 DH |
126 | |
127 | case STATE_BIT_START: | |
e40b1127 DH |
128 | if (!eq_margin(ev.duration, RC5_BIT_START, RC5_UNIT / 2)) |
129 | break; | |
130 | ||
131 | data->rc5_bits <<= 1; | |
132 | if (!ev.pulse) | |
133 | data->rc5_bits |= 1; | |
134 | data->count++; | |
135 | data->prev_ev = ev; | |
136 | data->state = STATE_BIT_END; | |
137 | return 0; | |
9b09df51 | 138 | |
724e2495 | 139 | case STATE_BIT_END: |
e40b1127 DH |
140 | if (!is_transition(&ev, &data->prev_ev)) |
141 | break; | |
142 | ||
143 | if (data->count == data->wanted_bits) | |
144 | data->state = STATE_FINISHED; | |
145 | else if (data->count == CHECK_RC5X_NBITS) | |
146 | data->state = STATE_CHECK_RC5X; | |
147 | else | |
148 | data->state = STATE_BIT_START; | |
149 | ||
150 | decrease_duration(&ev, RC5_BIT_END); | |
151 | goto again; | |
724e2495 | 152 | |
733419b5 | 153 | case STATE_CHECK_RC5X: |
e40b1127 | 154 | if (!ev.pulse && geq_margin(ev.duration, RC5X_SPACE, RC5_UNIT / 2)) { |
733419b5 DH |
155 | /* RC5X */ |
156 | data->wanted_bits = RC5X_NBITS; | |
e40b1127 | 157 | decrease_duration(&ev, RC5X_SPACE); |
733419b5 DH |
158 | } else { |
159 | /* RC5 */ | |
160 | data->wanted_bits = RC5_NBITS; | |
161 | } | |
162 | data->state = STATE_BIT_START; | |
163 | goto again; | |
164 | ||
724e2495 | 165 | case STATE_FINISHED: |
e40b1127 DH |
166 | if (ev.pulse) |
167 | break; | |
168 | ||
733419b5 DH |
169 | if (data->wanted_bits == RC5X_NBITS) { |
170 | /* RC5X */ | |
171 | u8 xdata, command, system; | |
172 | xdata = (data->rc5_bits & 0x0003F) >> 0; | |
173 | command = (data->rc5_bits & 0x00FC0) >> 6; | |
174 | system = (data->rc5_bits & 0x1F000) >> 12; | |
175 | toggle = (data->rc5_bits & 0x20000) ? 1 : 0; | |
176 | command += (data->rc5_bits & 0x01000) ? 0 : 0x40; | |
177 | scancode = system << 16 | command << 8 | xdata; | |
178 | ||
179 | IR_dprintk(1, "RC5X scancode 0x%06x (toggle: %u)\n", | |
180 | scancode, toggle); | |
181 | ||
182 | } else { | |
183 | /* RC5 */ | |
184 | u8 command, system; | |
185 | command = (data->rc5_bits & 0x0003F) >> 0; | |
186 | system = (data->rc5_bits & 0x007C0) >> 6; | |
187 | toggle = (data->rc5_bits & 0x00800) ? 1 : 0; | |
188 | command += (data->rc5_bits & 0x01000) ? 0 : 0x40; | |
189 | scancode = system << 8 | command; | |
190 | ||
191 | IR_dprintk(1, "RC5 scancode 0x%04x (toggle: %u)\n", | |
192 | scancode, toggle); | |
193 | } | |
194 | ||
724e2495 | 195 | ir_keydown(input_dev, scancode, toggle); |
db1423a6 MCC |
196 | data->state = STATE_INACTIVE; |
197 | return 0; | |
198 | } | |
199 | ||
724e2495 | 200 | out: |
e40b1127 DH |
201 | IR_dprintk(1, "RC5(x) decode failed at state %i (%uus %s)\n", |
202 | data->state, TO_US(ev.duration), TO_STR(ev.pulse)); | |
db1423a6 MCC |
203 | data->state = STATE_INACTIVE; |
204 | return -EINVAL; | |
205 | } | |
206 | ||
db1423a6 MCC |
207 | static int ir_rc5_register(struct input_dev *input_dev) |
208 | { | |
209 | struct ir_input_dev *ir_dev = input_get_drvdata(input_dev); | |
210 | struct decoder_data *data; | |
db1423a6 MCC |
211 | |
212 | data = kzalloc(sizeof(*data), GFP_KERNEL); | |
667c9ebe | 213 | if (!data) |
db1423a6 | 214 | return -ENOMEM; |
db1423a6 MCC |
215 | |
216 | data->ir_dev = ir_dev; | |
db1423a6 MCC |
217 | |
218 | spin_lock(&decoder_lock); | |
219 | list_add_tail(&data->list, &decoder_list); | |
220 | spin_unlock(&decoder_lock); | |
221 | ||
222 | return 0; | |
223 | } | |
224 | ||
225 | static int ir_rc5_unregister(struct input_dev *input_dev) | |
226 | { | |
227 | struct ir_input_dev *ir_dev = input_get_drvdata(input_dev); | |
228 | static struct decoder_data *data; | |
229 | ||
230 | data = get_decoder_data(ir_dev); | |
231 | if (!data) | |
232 | return 0; | |
233 | ||
db1423a6 MCC |
234 | spin_lock(&decoder_lock); |
235 | list_del(&data->list); | |
236 | spin_unlock(&decoder_lock); | |
237 | ||
238 | return 0; | |
239 | } | |
240 | ||
241 | static struct ir_raw_handler rc5_handler = { | |
667c9ebe | 242 | .protocols = IR_TYPE_RC5, |
db1423a6 MCC |
243 | .decode = ir_rc5_decode, |
244 | .raw_register = ir_rc5_register, | |
245 | .raw_unregister = ir_rc5_unregister, | |
246 | }; | |
247 | ||
248 | static int __init ir_rc5_decode_init(void) | |
249 | { | |
250 | ir_raw_handler_register(&rc5_handler); | |
251 | ||
733419b5 | 252 | printk(KERN_INFO "IR RC5(x) protocol handler initialized\n"); |
db1423a6 MCC |
253 | return 0; |
254 | } | |
255 | ||
256 | static void __exit ir_rc5_decode_exit(void) | |
257 | { | |
258 | ir_raw_handler_unregister(&rc5_handler); | |
259 | } | |
260 | ||
261 | module_init(ir_rc5_decode_init); | |
262 | module_exit(ir_rc5_decode_exit); | |
263 | ||
264 | MODULE_LICENSE("GPL"); | |
265 | MODULE_AUTHOR("Mauro Carvalho Chehab <mchehab@redhat.com>"); | |
266 | MODULE_AUTHOR("Red Hat Inc. (http://www.redhat.com)"); | |
733419b5 | 267 | MODULE_DESCRIPTION("RC5(x) IR protocol decoder"); |