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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 | ||
f62de675 | 23 | #include "rc-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 | 32 | |
db1423a6 MCC |
33 | enum rc5_state { |
34 | STATE_INACTIVE, | |
724e2495 DH |
35 | STATE_BIT_START, |
36 | STATE_BIT_END, | |
733419b5 | 37 | STATE_CHECK_RC5X, |
724e2495 | 38 | STATE_FINISHED, |
db1423a6 MCC |
39 | }; |
40 | ||
db1423a6 | 41 | /** |
724e2495 | 42 | * ir_rc5_decode() - Decode one RC-5 pulse or space |
d8b4b582 | 43 | * @dev: the struct rc_dev descriptor of the device |
e40b1127 | 44 | * @ev: the struct ir_raw_event descriptor of the pulse/space |
db1423a6 MCC |
45 | * |
46 | * This function returns -EINVAL if the pulse violates the state machine | |
47 | */ | |
d8b4b582 | 48 | static int ir_rc5_decode(struct rc_dev *dev, struct ir_raw_event ev) |
db1423a6 | 49 | { |
d8b4b582 | 50 | struct rc5_dec *data = &dev->raw->rc5; |
733419b5 | 51 | u8 toggle; |
724e2495 | 52 | u32 scancode; |
db1423a6 | 53 | |
52b66144 | 54 | if (!(dev->raw->enabled_protocols & RC_TYPE_RC5)) |
667c9ebe | 55 | return 0; |
7f20d32d | 56 | |
4651918a ML |
57 | if (!is_timing_event(ev)) { |
58 | if (ev.reset) | |
59 | data->state = STATE_INACTIVE; | |
db1423a6 | 60 | return 0; |
724e2495 | 61 | } |
db1423a6 | 62 | |
e40b1127 | 63 | if (!geq_margin(ev.duration, RC5_UNIT, RC5_UNIT / 2)) |
724e2495 | 64 | goto out; |
db1423a6 | 65 | |
724e2495 | 66 | again: |
e40b1127 DH |
67 | IR_dprintk(2, "RC5(x) decode started at state %i (%uus %s)\n", |
68 | data->state, TO_US(ev.duration), TO_STR(ev.pulse)); | |
db1423a6 | 69 | |
e40b1127 | 70 | if (!geq_margin(ev.duration, RC5_UNIT, RC5_UNIT / 2)) |
724e2495 | 71 | return 0; |
db1423a6 | 72 | |
724e2495 | 73 | switch (data->state) { |
db1423a6 | 74 | |
724e2495 | 75 | case STATE_INACTIVE: |
e40b1127 DH |
76 | if (!ev.pulse) |
77 | break; | |
78 | ||
79 | data->state = STATE_BIT_START; | |
80 | data->count = 1; | |
81 | /* We just need enough bits to get to STATE_CHECK_RC5X */ | |
82 | data->wanted_bits = RC5X_NBITS; | |
83 | decrease_duration(&ev, RC5_BIT_START); | |
84 | goto again; | |
724e2495 DH |
85 | |
86 | case STATE_BIT_START: | |
e40b1127 DH |
87 | if (!eq_margin(ev.duration, RC5_BIT_START, RC5_UNIT / 2)) |
88 | break; | |
89 | ||
c216369e | 90 | data->bits <<= 1; |
e40b1127 | 91 | if (!ev.pulse) |
c216369e | 92 | data->bits |= 1; |
e40b1127 | 93 | data->count++; |
e40b1127 DH |
94 | data->state = STATE_BIT_END; |
95 | return 0; | |
9b09df51 | 96 | |
724e2495 | 97 | case STATE_BIT_END: |
d8b4b582 | 98 | if (!is_transition(&ev, &dev->raw->prev_ev)) |
e40b1127 DH |
99 | break; |
100 | ||
101 | if (data->count == data->wanted_bits) | |
102 | data->state = STATE_FINISHED; | |
103 | else if (data->count == CHECK_RC5X_NBITS) | |
104 | data->state = STATE_CHECK_RC5X; | |
105 | else | |
106 | data->state = STATE_BIT_START; | |
107 | ||
108 | decrease_duration(&ev, RC5_BIT_END); | |
109 | goto again; | |
724e2495 | 110 | |
733419b5 | 111 | case STATE_CHECK_RC5X: |
e40b1127 | 112 | if (!ev.pulse && geq_margin(ev.duration, RC5X_SPACE, RC5_UNIT / 2)) { |
733419b5 DH |
113 | /* RC5X */ |
114 | data->wanted_bits = RC5X_NBITS; | |
e40b1127 | 115 | decrease_duration(&ev, RC5X_SPACE); |
733419b5 DH |
116 | } else { |
117 | /* RC5 */ | |
118 | data->wanted_bits = RC5_NBITS; | |
119 | } | |
120 | data->state = STATE_BIT_START; | |
121 | goto again; | |
122 | ||
724e2495 | 123 | case STATE_FINISHED: |
e40b1127 DH |
124 | if (ev.pulse) |
125 | break; | |
126 | ||
733419b5 DH |
127 | if (data->wanted_bits == RC5X_NBITS) { |
128 | /* RC5X */ | |
129 | u8 xdata, command, system; | |
c216369e DH |
130 | xdata = (data->bits & 0x0003F) >> 0; |
131 | command = (data->bits & 0x00FC0) >> 6; | |
132 | system = (data->bits & 0x1F000) >> 12; | |
133 | toggle = (data->bits & 0x20000) ? 1 : 0; | |
134 | command += (data->bits & 0x01000) ? 0 : 0x40; | |
733419b5 DH |
135 | scancode = system << 16 | command << 8 | xdata; |
136 | ||
137 | IR_dprintk(1, "RC5X scancode 0x%06x (toggle: %u)\n", | |
138 | scancode, toggle); | |
139 | ||
140 | } else { | |
141 | /* RC5 */ | |
142 | u8 command, system; | |
c216369e DH |
143 | command = (data->bits & 0x0003F) >> 0; |
144 | system = (data->bits & 0x007C0) >> 6; | |
145 | toggle = (data->bits & 0x00800) ? 1 : 0; | |
146 | command += (data->bits & 0x01000) ? 0 : 0x40; | |
733419b5 DH |
147 | scancode = system << 8 | command; |
148 | ||
149 | IR_dprintk(1, "RC5 scancode 0x%04x (toggle: %u)\n", | |
150 | scancode, toggle); | |
151 | } | |
152 | ||
ca86674b | 153 | rc_keydown(dev, scancode, toggle); |
db1423a6 MCC |
154 | data->state = STATE_INACTIVE; |
155 | return 0; | |
156 | } | |
157 | ||
724e2495 | 158 | out: |
e40b1127 DH |
159 | IR_dprintk(1, "RC5(x) decode failed at state %i (%uus %s)\n", |
160 | data->state, TO_US(ev.duration), TO_STR(ev.pulse)); | |
db1423a6 MCC |
161 | data->state = STATE_INACTIVE; |
162 | return -EINVAL; | |
163 | } | |
164 | ||
db1423a6 | 165 | static struct ir_raw_handler rc5_handler = { |
52b66144 | 166 | .protocols = RC_TYPE_RC5, |
db1423a6 | 167 | .decode = ir_rc5_decode, |
db1423a6 MCC |
168 | }; |
169 | ||
170 | static int __init ir_rc5_decode_init(void) | |
171 | { | |
172 | ir_raw_handler_register(&rc5_handler); | |
173 | ||
733419b5 | 174 | printk(KERN_INFO "IR RC5(x) protocol handler initialized\n"); |
db1423a6 MCC |
175 | return 0; |
176 | } | |
177 | ||
178 | static void __exit ir_rc5_decode_exit(void) | |
179 | { | |
180 | ir_raw_handler_unregister(&rc5_handler); | |
181 | } | |
182 | ||
183 | module_init(ir_rc5_decode_init); | |
184 | module_exit(ir_rc5_decode_exit); | |
185 | ||
186 | MODULE_LICENSE("GPL"); | |
187 | MODULE_AUTHOR("Mauro Carvalho Chehab <mchehab@redhat.com>"); | |
188 | MODULE_AUTHOR("Red Hat Inc. (http://www.redhat.com)"); | |
733419b5 | 189 | MODULE_DESCRIPTION("RC5(x) IR protocol decoder"); |