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e87b540b | 1 | /* ir-rc5-decoder.c - decoder for RC5(x) and StreamZap protocols |
db1423a6 | 2 | * |
37e59f87 | 3 | * Copyright (C) 2010 by Mauro Carvalho Chehab |
e87b540b | 4 | * Copyright (C) 2010 by Jarod Wilson <jarod@redhat.com> |
db1423a6 MCC |
5 | * |
6 | * This program is free software; you can redistribute it and/or modify | |
7 | * it under the terms of the GNU General Public License as published by | |
8 | * the Free Software Foundation version 2 of the License. | |
9 | * | |
10 | * This program is distributed in the hope that it will be useful, | |
11 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
12 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
13 | * GNU General Public License for more details. | |
14 | */ | |
15 | ||
16 | /* | |
e87b540b DH |
17 | * This decoder handles the 14 bit RC5 protocol, 15 bit "StreamZap" protocol |
18 | * and 20 bit RC5x protocol. | |
db1423a6 MCC |
19 | */ |
20 | ||
f62de675 | 21 | #include "rc-core-priv.h" |
7a707b89 | 22 | #include <linux/module.h> |
db1423a6 | 23 | |
9b09df51 | 24 | #define RC5_NBITS 14 |
e87b540b | 25 | #define RC5_SZ_NBITS 15 |
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) | |
bbdb34c9 | 32 | #define RC5_TRAILER (6 * RC5_UNIT) /* In reality, approx 100 */ |
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 | |
4651918a ML |
56 | if (!is_timing_event(ev)) { |
57 | if (ev.reset) | |
58 | data->state = STATE_INACTIVE; | |
db1423a6 | 59 | return 0; |
724e2495 | 60 | } |
db1423a6 | 61 | |
e40b1127 | 62 | if (!geq_margin(ev.duration, RC5_UNIT, RC5_UNIT / 2)) |
724e2495 | 63 | goto out; |
db1423a6 | 64 | |
724e2495 | 65 | again: |
e87b540b | 66 | IR_dprintk(2, "RC5(x/sz) decode started at state %i (%uus %s)\n", |
e40b1127 | 67 | data->state, TO_US(ev.duration), TO_STR(ev.pulse)); |
db1423a6 | 68 | |
e40b1127 | 69 | if (!geq_margin(ev.duration, RC5_UNIT, RC5_UNIT / 2)) |
724e2495 | 70 | return 0; |
db1423a6 | 71 | |
724e2495 | 72 | switch (data->state) { |
db1423a6 | 73 | |
724e2495 | 74 | case STATE_INACTIVE: |
e40b1127 DH |
75 | if (!ev.pulse) |
76 | break; | |
77 | ||
78 | data->state = STATE_BIT_START; | |
79 | data->count = 1; | |
e40b1127 DH |
80 | decrease_duration(&ev, RC5_BIT_START); |
81 | goto again; | |
724e2495 DH |
82 | |
83 | case STATE_BIT_START: | |
e87b540b DH |
84 | if (!ev.pulse && geq_margin(ev.duration, RC5_TRAILER, RC5_UNIT / 2)) { |
85 | data->state = STATE_FINISHED; | |
86 | goto again; | |
87 | } | |
88 | ||
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 | ||
e87b540b | 103 | if (data->count == CHECK_RC5X_NBITS) |
e40b1127 DH |
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)) { |
e87b540b | 113 | data->is_rc5x = true; |
e40b1127 | 114 | decrease_duration(&ev, RC5X_SPACE); |
e87b540b DH |
115 | } else |
116 | data->is_rc5x = false; | |
733419b5 DH |
117 | data->state = STATE_BIT_START; |
118 | goto again; | |
119 | ||
724e2495 | 120 | case STATE_FINISHED: |
e40b1127 DH |
121 | if (ev.pulse) |
122 | break; | |
123 | ||
e87b540b | 124 | if (data->is_rc5x && data->count == RC5X_NBITS) { |
733419b5 DH |
125 | /* RC5X */ |
126 | u8 xdata, command, system; | |
0fcd3f0a | 127 | if (!(dev->enabled_protocols & RC_BIT_RC5X_20)) { |
c003ab1b DH |
128 | data->state = STATE_INACTIVE; |
129 | return 0; | |
130 | } | |
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; | |
fd844d90 | 135 | command += (data->bits & 0x40000) ? 0 : 0x40; |
733419b5 | 136 | scancode = system << 16 | command << 8 | xdata; |
0fcd3f0a | 137 | protocol = RC_TYPE_RC5X_20; |
733419b5 | 138 | |
e87b540b | 139 | } else if (!data->is_rc5x && data->count == RC5_NBITS) { |
733419b5 DH |
140 | /* RC5 */ |
141 | u8 command, system; | |
c5540fbb | 142 | if (!(dev->enabled_protocols & RC_BIT_RC5)) { |
c003ab1b DH |
143 | data->state = STATE_INACTIVE; |
144 | return 0; | |
145 | } | |
c216369e DH |
146 | command = (data->bits & 0x0003F) >> 0; |
147 | system = (data->bits & 0x007C0) >> 6; | |
148 | toggle = (data->bits & 0x00800) ? 1 : 0; | |
149 | command += (data->bits & 0x01000) ? 0 : 0x40; | |
733419b5 | 150 | scancode = system << 8 | command; |
120703f9 | 151 | protocol = RC_TYPE_RC5; |
733419b5 | 152 | |
e87b540b DH |
153 | } else if (!data->is_rc5x && data->count == RC5_SZ_NBITS) { |
154 | /* RC5 StreamZap */ | |
155 | u8 command, system; | |
156 | if (!(dev->enabled_protocols & RC_BIT_RC5_SZ)) { | |
157 | data->state = STATE_INACTIVE; | |
158 | return 0; | |
159 | } | |
160 | command = (data->bits & 0x0003F) >> 0; | |
161 | system = (data->bits & 0x02FC0) >> 6; | |
162 | toggle = (data->bits & 0x01000) ? 1 : 0; | |
163 | scancode = system << 6 | command; | |
164 | protocol = RC_TYPE_RC5_SZ; | |
165 | ||
166 | } else | |
167 | break; | |
168 | ||
169 | IR_dprintk(1, "RC5(x/sz) scancode 0x%06x (p: %u, t: %u)\n", | |
170 | scancode, protocol, toggle); | |
733419b5 | 171 | |
120703f9 | 172 | rc_keydown(dev, protocol, scancode, toggle); |
db1423a6 MCC |
173 | data->state = STATE_INACTIVE; |
174 | return 0; | |
175 | } | |
176 | ||
724e2495 | 177 | out: |
32570579 MCC |
178 | IR_dprintk(1, "RC5(x/sz) decode failed at state %i count %d (%uus %s)\n", |
179 | data->state, data->count, TO_US(ev.duration), TO_STR(ev.pulse)); | |
db1423a6 MCC |
180 | data->state = STATE_INACTIVE; |
181 | return -EINVAL; | |
182 | } | |
183 | ||
db1423a6 | 184 | static struct ir_raw_handler rc5_handler = { |
0fcd3f0a | 185 | .protocols = RC_BIT_RC5 | RC_BIT_RC5X_20 | RC_BIT_RC5_SZ, |
db1423a6 | 186 | .decode = ir_rc5_decode, |
db1423a6 MCC |
187 | }; |
188 | ||
189 | static int __init ir_rc5_decode_init(void) | |
190 | { | |
191 | ir_raw_handler_register(&rc5_handler); | |
192 | ||
e87b540b | 193 | printk(KERN_INFO "IR RC5(x/sz) protocol handler initialized\n"); |
db1423a6 MCC |
194 | return 0; |
195 | } | |
196 | ||
197 | static void __exit ir_rc5_decode_exit(void) | |
198 | { | |
199 | ir_raw_handler_unregister(&rc5_handler); | |
200 | } | |
201 | ||
202 | module_init(ir_rc5_decode_init); | |
203 | module_exit(ir_rc5_decode_exit); | |
204 | ||
205 | MODULE_LICENSE("GPL"); | |
e87b540b | 206 | MODULE_AUTHOR("Mauro Carvalho Chehab and Jarod Wilson"); |
db1423a6 | 207 | MODULE_AUTHOR("Red Hat Inc. (http://www.redhat.com)"); |
e87b540b | 208 | MODULE_DESCRIPTION("RC5(x/sz) IR protocol decoder"); |