Commit | Line | Data |
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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" |
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; |
db1423a6 | 54 | |
52b66144 | 55 | if (!(dev->raw->enabled_protocols & RC_TYPE_RC5)) |
667c9ebe | 56 | return 0; |
7f20d32d | 57 | |
4651918a ML |
58 | if (!is_timing_event(ev)) { |
59 | if (ev.reset) | |
60 | data->state = STATE_INACTIVE; | |
db1423a6 | 61 | return 0; |
724e2495 | 62 | } |
db1423a6 | 63 | |
e40b1127 | 64 | if (!geq_margin(ev.duration, RC5_UNIT, RC5_UNIT / 2)) |
724e2495 | 65 | goto out; |
db1423a6 | 66 | |
724e2495 | 67 | again: |
e40b1127 DH |
68 | IR_dprintk(2, "RC5(x) decode started at state %i (%uus %s)\n", |
69 | data->state, TO_US(ev.duration), TO_STR(ev.pulse)); | |
db1423a6 | 70 | |
e40b1127 | 71 | if (!geq_margin(ev.duration, RC5_UNIT, RC5_UNIT / 2)) |
724e2495 | 72 | return 0; |
db1423a6 | 73 | |
724e2495 | 74 | switch (data->state) { |
db1423a6 | 75 | |
724e2495 | 76 | case STATE_INACTIVE: |
e40b1127 DH |
77 | if (!ev.pulse) |
78 | break; | |
79 | ||
80 | data->state = STATE_BIT_START; | |
81 | data->count = 1; | |
82 | /* We just need enough bits to get to STATE_CHECK_RC5X */ | |
83 | data->wanted_bits = RC5X_NBITS; | |
84 | decrease_duration(&ev, RC5_BIT_START); | |
85 | goto again; | |
724e2495 DH |
86 | |
87 | case STATE_BIT_START: | |
e40b1127 DH |
88 | if (!eq_margin(ev.duration, RC5_BIT_START, RC5_UNIT / 2)) |
89 | break; | |
90 | ||
c216369e | 91 | data->bits <<= 1; |
e40b1127 | 92 | if (!ev.pulse) |
c216369e | 93 | data->bits |= 1; |
e40b1127 | 94 | data->count++; |
e40b1127 DH |
95 | data->state = STATE_BIT_END; |
96 | return 0; | |
9b09df51 | 97 | |
724e2495 | 98 | case STATE_BIT_END: |
d8b4b582 | 99 | if (!is_transition(&ev, &dev->raw->prev_ev)) |
e40b1127 DH |
100 | break; |
101 | ||
102 | if (data->count == data->wanted_bits) | |
103 | data->state = STATE_FINISHED; | |
104 | else if (data->count == CHECK_RC5X_NBITS) | |
105 | data->state = STATE_CHECK_RC5X; | |
106 | else | |
107 | data->state = STATE_BIT_START; | |
108 | ||
109 | decrease_duration(&ev, RC5_BIT_END); | |
110 | goto again; | |
724e2495 | 111 | |
733419b5 | 112 | case STATE_CHECK_RC5X: |
e40b1127 | 113 | if (!ev.pulse && geq_margin(ev.duration, RC5X_SPACE, RC5_UNIT / 2)) { |
733419b5 DH |
114 | /* RC5X */ |
115 | data->wanted_bits = RC5X_NBITS; | |
e40b1127 | 116 | decrease_duration(&ev, RC5X_SPACE); |
733419b5 DH |
117 | } else { |
118 | /* RC5 */ | |
119 | data->wanted_bits = RC5_NBITS; | |
120 | } | |
121 | data->state = STATE_BIT_START; | |
122 | goto again; | |
123 | ||
724e2495 | 124 | case STATE_FINISHED: |
e40b1127 DH |
125 | if (ev.pulse) |
126 | break; | |
127 | ||
733419b5 DH |
128 | if (data->wanted_bits == RC5X_NBITS) { |
129 | /* RC5X */ | |
130 | u8 xdata, command, system; | |
c216369e DH |
131 | xdata = (data->bits & 0x0003F) >> 0; |
132 | command = (data->bits & 0x00FC0) >> 6; | |
133 | system = (data->bits & 0x1F000) >> 12; | |
134 | toggle = (data->bits & 0x20000) ? 1 : 0; | |
135 | command += (data->bits & 0x01000) ? 0 : 0x40; | |
733419b5 DH |
136 | scancode = system << 16 | command << 8 | xdata; |
137 | ||
138 | IR_dprintk(1, "RC5X scancode 0x%06x (toggle: %u)\n", | |
139 | scancode, toggle); | |
140 | ||
141 | } else { | |
142 | /* RC5 */ | |
143 | u8 command, system; | |
c216369e DH |
144 | command = (data->bits & 0x0003F) >> 0; |
145 | system = (data->bits & 0x007C0) >> 6; | |
146 | toggle = (data->bits & 0x00800) ? 1 : 0; | |
147 | command += (data->bits & 0x01000) ? 0 : 0x40; | |
733419b5 DH |
148 | scancode = system << 8 | command; |
149 | ||
150 | IR_dprintk(1, "RC5 scancode 0x%04x (toggle: %u)\n", | |
151 | scancode, toggle); | |
152 | } | |
153 | ||
ca86674b | 154 | rc_keydown(dev, scancode, toggle); |
db1423a6 MCC |
155 | data->state = STATE_INACTIVE; |
156 | return 0; | |
157 | } | |
158 | ||
724e2495 | 159 | out: |
e40b1127 DH |
160 | IR_dprintk(1, "RC5(x) decode failed at state %i (%uus %s)\n", |
161 | data->state, TO_US(ev.duration), TO_STR(ev.pulse)); | |
db1423a6 MCC |
162 | data->state = STATE_INACTIVE; |
163 | return -EINVAL; | |
164 | } | |
165 | ||
db1423a6 | 166 | static struct ir_raw_handler rc5_handler = { |
52b66144 | 167 | .protocols = RC_TYPE_RC5, |
db1423a6 | 168 | .decode = ir_rc5_decode, |
db1423a6 MCC |
169 | }; |
170 | ||
171 | static int __init ir_rc5_decode_init(void) | |
172 | { | |
173 | ir_raw_handler_register(&rc5_handler); | |
174 | ||
733419b5 | 175 | printk(KERN_INFO "IR RC5(x) protocol handler initialized\n"); |
db1423a6 MCC |
176 | return 0; |
177 | } | |
178 | ||
179 | static void __exit ir_rc5_decode_exit(void) | |
180 | { | |
181 | ir_raw_handler_unregister(&rc5_handler); | |
182 | } | |
183 | ||
184 | module_init(ir_rc5_decode_init); | |
185 | module_exit(ir_rc5_decode_exit); | |
186 | ||
187 | MODULE_LICENSE("GPL"); | |
188 | MODULE_AUTHOR("Mauro Carvalho Chehab <mchehab@redhat.com>"); | |
189 | MODULE_AUTHOR("Red Hat Inc. (http://www.redhat.com)"); | |
733419b5 | 190 | MODULE_DESCRIPTION("RC5(x) IR protocol decoder"); |