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733419b5 | 1 | /* ir-rc5-decoder.c - handle RC5(x) IR Pulse/Space protocol |
db1423a6 | 2 | * |
37e59f87 | 3 | * Copyright (C) 2010 by Mauro Carvalho Chehab |
db1423a6 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 | ||
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" |
7a707b89 | 24 | #include <linux/module.h> |
db1423a6 | 25 | |
9b09df51 | 26 | #define RC5_NBITS 14 |
733419b5 DH |
27 | #define RC5X_NBITS 20 |
28 | #define CHECK_RC5X_NBITS 8 | |
724e2495 | 29 | #define RC5_UNIT 888888 /* ns */ |
e40b1127 DH |
30 | #define RC5_BIT_START (1 * RC5_UNIT) |
31 | #define RC5_BIT_END (1 * RC5_UNIT) | |
32 | #define RC5X_SPACE (4 * RC5_UNIT) | |
db1423a6 | 33 | |
db1423a6 MCC |
34 | enum rc5_state { |
35 | STATE_INACTIVE, | |
724e2495 DH |
36 | STATE_BIT_START, |
37 | STATE_BIT_END, | |
733419b5 | 38 | STATE_CHECK_RC5X, |
724e2495 | 39 | STATE_FINISHED, |
db1423a6 MCC |
40 | }; |
41 | ||
db1423a6 | 42 | /** |
724e2495 | 43 | * ir_rc5_decode() - Decode one RC-5 pulse or space |
d8b4b582 | 44 | * @dev: the struct rc_dev descriptor of the device |
e40b1127 | 45 | * @ev: the struct ir_raw_event descriptor of the pulse/space |
db1423a6 MCC |
46 | * |
47 | * This function returns -EINVAL if the pulse violates the state machine | |
48 | */ | |
d8b4b582 | 49 | static int ir_rc5_decode(struct rc_dev *dev, struct ir_raw_event ev) |
db1423a6 | 50 | { |
d8b4b582 | 51 | struct rc5_dec *data = &dev->raw->rc5; |
733419b5 | 52 | u8 toggle; |
724e2495 | 53 | u32 scancode; |
120703f9 | 54 | enum rc_type protocol; |
db1423a6 | 55 | |
c5540fbb | 56 | if (!(dev->enabled_protocols & (RC_BIT_RC5 | RC_BIT_RC5X))) |
c003ab1b | 57 | return 0; |
7f20d32d | 58 | |
4651918a ML |
59 | if (!is_timing_event(ev)) { |
60 | if (ev.reset) | |
61 | data->state = STATE_INACTIVE; | |
db1423a6 | 62 | return 0; |
724e2495 | 63 | } |
db1423a6 | 64 | |
e40b1127 | 65 | if (!geq_margin(ev.duration, RC5_UNIT, RC5_UNIT / 2)) |
724e2495 | 66 | goto out; |
db1423a6 | 67 | |
724e2495 | 68 | again: |
e40b1127 DH |
69 | IR_dprintk(2, "RC5(x) decode started at state %i (%uus %s)\n", |
70 | data->state, TO_US(ev.duration), TO_STR(ev.pulse)); | |
db1423a6 | 71 | |
e40b1127 | 72 | if (!geq_margin(ev.duration, RC5_UNIT, RC5_UNIT / 2)) |
724e2495 | 73 | return 0; |
db1423a6 | 74 | |
724e2495 | 75 | switch (data->state) { |
db1423a6 | 76 | |
724e2495 | 77 | case STATE_INACTIVE: |
e40b1127 DH |
78 | if (!ev.pulse) |
79 | break; | |
80 | ||
81 | data->state = STATE_BIT_START; | |
82 | data->count = 1; | |
83 | /* We just need enough bits to get to STATE_CHECK_RC5X */ | |
84 | data->wanted_bits = RC5X_NBITS; | |
85 | decrease_duration(&ev, RC5_BIT_START); | |
86 | goto again; | |
724e2495 DH |
87 | |
88 | case STATE_BIT_START: | |
e40b1127 DH |
89 | if (!eq_margin(ev.duration, RC5_BIT_START, RC5_UNIT / 2)) |
90 | break; | |
91 | ||
c216369e | 92 | data->bits <<= 1; |
e40b1127 | 93 | if (!ev.pulse) |
c216369e | 94 | data->bits |= 1; |
e40b1127 | 95 | data->count++; |
e40b1127 DH |
96 | data->state = STATE_BIT_END; |
97 | return 0; | |
9b09df51 | 98 | |
724e2495 | 99 | case STATE_BIT_END: |
d8b4b582 | 100 | if (!is_transition(&ev, &dev->raw->prev_ev)) |
e40b1127 DH |
101 | break; |
102 | ||
103 | if (data->count == data->wanted_bits) | |
104 | data->state = STATE_FINISHED; | |
105 | else if (data->count == CHECK_RC5X_NBITS) | |
106 | data->state = STATE_CHECK_RC5X; | |
107 | else | |
108 | data->state = STATE_BIT_START; | |
109 | ||
110 | decrease_duration(&ev, RC5_BIT_END); | |
111 | goto again; | |
724e2495 | 112 | |
733419b5 | 113 | case STATE_CHECK_RC5X: |
e40b1127 | 114 | if (!ev.pulse && geq_margin(ev.duration, RC5X_SPACE, RC5_UNIT / 2)) { |
733419b5 DH |
115 | /* RC5X */ |
116 | data->wanted_bits = RC5X_NBITS; | |
e40b1127 | 117 | decrease_duration(&ev, RC5X_SPACE); |
733419b5 DH |
118 | } else { |
119 | /* RC5 */ | |
120 | data->wanted_bits = RC5_NBITS; | |
121 | } | |
122 | data->state = STATE_BIT_START; | |
123 | goto again; | |
124 | ||
724e2495 | 125 | case STATE_FINISHED: |
e40b1127 DH |
126 | if (ev.pulse) |
127 | break; | |
128 | ||
733419b5 DH |
129 | if (data->wanted_bits == RC5X_NBITS) { |
130 | /* RC5X */ | |
131 | u8 xdata, command, system; | |
c5540fbb | 132 | if (!(dev->enabled_protocols & RC_BIT_RC5X)) { |
c003ab1b DH |
133 | data->state = STATE_INACTIVE; |
134 | return 0; | |
135 | } | |
c216369e DH |
136 | xdata = (data->bits & 0x0003F) >> 0; |
137 | command = (data->bits & 0x00FC0) >> 6; | |
138 | system = (data->bits & 0x1F000) >> 12; | |
139 | toggle = (data->bits & 0x20000) ? 1 : 0; | |
140 | command += (data->bits & 0x01000) ? 0 : 0x40; | |
733419b5 | 141 | scancode = system << 16 | command << 8 | xdata; |
120703f9 | 142 | protocol = RC_TYPE_RC5X; |
733419b5 DH |
143 | |
144 | IR_dprintk(1, "RC5X scancode 0x%06x (toggle: %u)\n", | |
145 | scancode, toggle); | |
146 | ||
147 | } else { | |
148 | /* RC5 */ | |
149 | u8 command, system; | |
c5540fbb | 150 | if (!(dev->enabled_protocols & RC_BIT_RC5)) { |
c003ab1b DH |
151 | data->state = STATE_INACTIVE; |
152 | return 0; | |
153 | } | |
c216369e DH |
154 | command = (data->bits & 0x0003F) >> 0; |
155 | system = (data->bits & 0x007C0) >> 6; | |
156 | toggle = (data->bits & 0x00800) ? 1 : 0; | |
157 | command += (data->bits & 0x01000) ? 0 : 0x40; | |
733419b5 | 158 | scancode = system << 8 | command; |
120703f9 | 159 | protocol = RC_TYPE_RC5; |
733419b5 DH |
160 | |
161 | IR_dprintk(1, "RC5 scancode 0x%04x (toggle: %u)\n", | |
162 | scancode, toggle); | |
163 | } | |
164 | ||
120703f9 | 165 | rc_keydown(dev, protocol, scancode, toggle); |
db1423a6 MCC |
166 | data->state = STATE_INACTIVE; |
167 | return 0; | |
168 | } | |
169 | ||
724e2495 | 170 | out: |
e40b1127 DH |
171 | IR_dprintk(1, "RC5(x) decode failed at state %i (%uus %s)\n", |
172 | data->state, TO_US(ev.duration), TO_STR(ev.pulse)); | |
db1423a6 MCC |
173 | data->state = STATE_INACTIVE; |
174 | return -EINVAL; | |
175 | } | |
176 | ||
db1423a6 | 177 | static struct ir_raw_handler rc5_handler = { |
c003ab1b | 178 | .protocols = RC_BIT_RC5 | RC_BIT_RC5X, |
db1423a6 | 179 | .decode = ir_rc5_decode, |
db1423a6 MCC |
180 | }; |
181 | ||
182 | static int __init ir_rc5_decode_init(void) | |
183 | { | |
184 | ir_raw_handler_register(&rc5_handler); | |
185 | ||
733419b5 | 186 | printk(KERN_INFO "IR RC5(x) protocol handler initialized\n"); |
db1423a6 MCC |
187 | return 0; |
188 | } | |
189 | ||
190 | static void __exit ir_rc5_decode_exit(void) | |
191 | { | |
192 | ir_raw_handler_unregister(&rc5_handler); | |
193 | } | |
194 | ||
195 | module_init(ir_rc5_decode_init); | |
196 | module_exit(ir_rc5_decode_exit); | |
197 | ||
198 | MODULE_LICENSE("GPL"); | |
37e59f87 | 199 | MODULE_AUTHOR("Mauro Carvalho Chehab"); |
db1423a6 | 200 | MODULE_AUTHOR("Red Hat Inc. (http://www.redhat.com)"); |
733419b5 | 201 | MODULE_DESCRIPTION("RC5(x) IR protocol decoder"); |