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7a569f52 JW |
1 | /* ir-rc5-sz-decoder.c - handle RC5 Streamzap IR Pulse/Space protocol |
2 | * | |
37e59f87 | 3 | * Copyright (C) 2010 by Mauro Carvalho Chehab |
7a569f52 JW |
4 | * Copyright (C) 2010 by Jarod Wilson <jarod@redhat.com> |
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 | /* | |
17 | * This code handles the 15 bit RC5-ish protocol used by the Streamzap | |
18 | * PC Remote. | |
19 | * It considers a carrier of 36 kHz, with a total of 15 bits, where | |
20 | * the first two bits are start bits, and a third one is a filing bit | |
21 | */ | |
22 | ||
f62de675 | 23 | #include "rc-core-priv.h" |
7a707b89 | 24 | #include <linux/module.h> |
7a569f52 JW |
25 | |
26 | #define RC5_SZ_NBITS 15 | |
27 | #define RC5_UNIT 888888 /* ns */ | |
28 | #define RC5_BIT_START (1 * RC5_UNIT) | |
29 | #define RC5_BIT_END (1 * RC5_UNIT) | |
30 | ||
31 | enum rc5_sz_state { | |
32 | STATE_INACTIVE, | |
33 | STATE_BIT_START, | |
34 | STATE_BIT_END, | |
35 | STATE_FINISHED, | |
36 | }; | |
37 | ||
38 | /** | |
39 | * ir_rc5_sz_decode() - Decode one RC-5 Streamzap pulse or space | |
d8b4b582 | 40 | * @dev: the struct rc_dev descriptor of the device |
7a569f52 JW |
41 | * @ev: the struct ir_raw_event descriptor of the pulse/space |
42 | * | |
43 | * This function returns -EINVAL if the pulse violates the state machine | |
44 | */ | |
d8b4b582 | 45 | static int ir_rc5_sz_decode(struct rc_dev *dev, struct ir_raw_event ev) |
7a569f52 | 46 | { |
d8b4b582 | 47 | struct rc5_sz_dec *data = &dev->raw->rc5_sz; |
7a569f52 JW |
48 | u8 toggle, command, system; |
49 | u32 scancode; | |
50 | ||
9719afae | 51 | if (!(dev->enabled_protocols & RC_BIT_RC5_SZ)) |
c003ab1b | 52 | return 0; |
7a569f52 | 53 | |
4651918a ML |
54 | if (!is_timing_event(ev)) { |
55 | if (ev.reset) | |
56 | data->state = STATE_INACTIVE; | |
7a569f52 JW |
57 | return 0; |
58 | } | |
59 | ||
60 | if (!geq_margin(ev.duration, RC5_UNIT, RC5_UNIT / 2)) | |
61 | goto out; | |
62 | ||
63 | again: | |
64 | IR_dprintk(2, "RC5-sz decode started at state %i (%uus %s)\n", | |
65 | data->state, TO_US(ev.duration), TO_STR(ev.pulse)); | |
66 | ||
67 | if (!geq_margin(ev.duration, RC5_UNIT, RC5_UNIT / 2)) | |
68 | return 0; | |
69 | ||
70 | switch (data->state) { | |
71 | ||
72 | case STATE_INACTIVE: | |
73 | if (!ev.pulse) | |
74 | break; | |
75 | ||
76 | data->state = STATE_BIT_START; | |
77 | data->count = 1; | |
78 | data->wanted_bits = RC5_SZ_NBITS; | |
79 | decrease_duration(&ev, RC5_BIT_START); | |
80 | goto again; | |
81 | ||
82 | case STATE_BIT_START: | |
83 | if (!eq_margin(ev.duration, RC5_BIT_START, RC5_UNIT / 2)) | |
84 | break; | |
85 | ||
86 | data->bits <<= 1; | |
87 | if (!ev.pulse) | |
88 | data->bits |= 1; | |
89 | data->count++; | |
90 | data->state = STATE_BIT_END; | |
91 | return 0; | |
92 | ||
93 | case STATE_BIT_END: | |
d8b4b582 | 94 | if (!is_transition(&ev, &dev->raw->prev_ev)) |
7a569f52 JW |
95 | break; |
96 | ||
97 | if (data->count == data->wanted_bits) | |
98 | data->state = STATE_FINISHED; | |
99 | else | |
100 | data->state = STATE_BIT_START; | |
101 | ||
102 | decrease_duration(&ev, RC5_BIT_END); | |
103 | goto again; | |
104 | ||
105 | case STATE_FINISHED: | |
106 | if (ev.pulse) | |
107 | break; | |
108 | ||
109 | /* RC5-sz */ | |
110 | command = (data->bits & 0x0003F) >> 0; | |
111 | system = (data->bits & 0x02FC0) >> 6; | |
112 | toggle = (data->bits & 0x01000) ? 1 : 0; | |
113 | scancode = system << 6 | command; | |
114 | ||
115 | IR_dprintk(1, "RC5-sz scancode 0x%04x (toggle: %u)\n", | |
116 | scancode, toggle); | |
117 | ||
ca86674b | 118 | rc_keydown(dev, scancode, toggle); |
7a569f52 JW |
119 | data->state = STATE_INACTIVE; |
120 | return 0; | |
121 | } | |
122 | ||
123 | out: | |
124 | IR_dprintk(1, "RC5-sz decode failed at state %i (%uus %s)\n", | |
125 | data->state, TO_US(ev.duration), TO_STR(ev.pulse)); | |
126 | data->state = STATE_INACTIVE; | |
127 | return -EINVAL; | |
128 | } | |
129 | ||
130 | static struct ir_raw_handler rc5_sz_handler = { | |
c003ab1b | 131 | .protocols = RC_BIT_RC5_SZ, |
7a569f52 JW |
132 | .decode = ir_rc5_sz_decode, |
133 | }; | |
134 | ||
135 | static int __init ir_rc5_sz_decode_init(void) | |
136 | { | |
137 | ir_raw_handler_register(&rc5_sz_handler); | |
138 | ||
139 | printk(KERN_INFO "IR RC5 (streamzap) protocol handler initialized\n"); | |
140 | return 0; | |
141 | } | |
142 | ||
143 | static void __exit ir_rc5_sz_decode_exit(void) | |
144 | { | |
145 | ir_raw_handler_unregister(&rc5_sz_handler); | |
146 | } | |
147 | ||
148 | module_init(ir_rc5_sz_decode_init); | |
149 | module_exit(ir_rc5_sz_decode_exit); | |
150 | ||
151 | MODULE_LICENSE("GPL"); | |
152 | MODULE_AUTHOR("Jarod Wilson <jarod@redhat.com>"); | |
153 | MODULE_AUTHOR("Red Hat Inc. (http://www.redhat.com)"); | |
154 | MODULE_DESCRIPTION("RC5 (streamzap) IR protocol decoder"); |