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1 | /* ir-xmp-decoder.c - handle XMP IR Pulse/Space protocol |
2 | * | |
3 | * Copyright (C) 2014 by Marcel Mol | |
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 | * - Based on info from http://www.hifi-remote.com | |
15 | * - Ignore Toggle=9 frames | |
16 | * - Ignore XMP-1 XMP-2 difference, always store 16 bit OBC | |
17 | */ | |
18 | ||
19 | #include <linux/bitrev.h> | |
20 | #include <linux/module.h> | |
21 | #include "rc-core-priv.h" | |
22 | ||
23 | #define XMP_UNIT 136000 /* ns */ | |
24 | #define XMP_LEADER 210000 /* ns */ | |
25 | #define XMP_NIBBLE_PREFIX 760000 /* ns */ | |
26 | #define XMP_HALFFRAME_SPACE 13800000 /* ns */ | |
27 | #define XMP_TRAILER_SPACE 20000000 /* should be 80ms but not all dureation supliers can go that high */ | |
28 | ||
29 | enum xmp_state { | |
30 | STATE_INACTIVE, | |
31 | STATE_LEADER_PULSE, | |
32 | STATE_NIBBLE_SPACE, | |
33 | }; | |
34 | ||
35 | /** | |
36 | * ir_xmp_decode() - Decode one XMP pulse or space | |
37 | * @dev: the struct rc_dev descriptor of the device | |
38 | * @duration: the struct ir_raw_event descriptor of the pulse/space | |
39 | * | |
40 | * This function returns -EINVAL if the pulse violates the state machine | |
41 | */ | |
42 | static int ir_xmp_decode(struct rc_dev *dev, struct ir_raw_event ev) | |
43 | { | |
44 | struct xmp_dec *data = &dev->raw->xmp; | |
45 | ||
1dee9b59 MM |
46 | if (!is_timing_event(ev)) { |
47 | if (ev.reset) | |
48 | data->state = STATE_INACTIVE; | |
49 | return 0; | |
50 | } | |
51 | ||
52 | IR_dprintk(2, "XMP decode started at state %d %d (%uus %s)\n", | |
53 | data->state, data->count, TO_US(ev.duration), TO_STR(ev.pulse)); | |
54 | ||
55 | switch (data->state) { | |
56 | ||
57 | case STATE_INACTIVE: | |
58 | if (!ev.pulse) | |
59 | break; | |
60 | ||
61 | if (eq_margin(ev.duration, XMP_LEADER, XMP_UNIT / 2)) { | |
62 | data->count = 0; | |
63 | data->state = STATE_NIBBLE_SPACE; | |
64 | } | |
65 | ||
66 | return 0; | |
67 | ||
68 | case STATE_LEADER_PULSE: | |
69 | if (!ev.pulse) | |
70 | break; | |
71 | ||
72 | if (eq_margin(ev.duration, XMP_LEADER, XMP_UNIT / 2)) | |
73 | data->state = STATE_NIBBLE_SPACE; | |
74 | ||
75 | return 0; | |
76 | ||
77 | case STATE_NIBBLE_SPACE: | |
78 | if (ev.pulse) | |
79 | break; | |
80 | ||
81 | if (geq_margin(ev.duration, XMP_TRAILER_SPACE, XMP_NIBBLE_PREFIX)) { | |
82 | int divider, i; | |
83 | u8 addr, subaddr, subaddr2, toggle, oem, obc1, obc2, sum1, sum2; | |
84 | u32 *n; | |
85 | u32 scancode; | |
86 | ||
87 | if (data->count != 16) { | |
88 | IR_dprintk(2, "received TRAILER period at index %d: %u\n", | |
89 | data->count, ev.duration); | |
90 | data->state = STATE_INACTIVE; | |
91 | return -EINVAL; | |
92 | } | |
93 | ||
94 | n = data->durations; | |
95 | /* | |
96 | * the 4th nibble should be 15 so base the divider on this | |
97 | * to transform durations into nibbles. Substract 2000 from | |
98 | * the divider to compensate for fluctuations in the signal | |
99 | */ | |
100 | divider = (n[3] - XMP_NIBBLE_PREFIX) / 15 - 2000; | |
101 | if (divider < 50) { | |
102 | IR_dprintk(2, "divider to small %d.\n", divider); | |
103 | data->state = STATE_INACTIVE; | |
104 | return -EINVAL; | |
105 | } | |
106 | ||
107 | /* convert to nibbles and do some sanity checks */ | |
108 | for (i = 0; i < 16; i++) | |
109 | n[i] = (n[i] - XMP_NIBBLE_PREFIX) / divider; | |
110 | sum1 = (15 + n[0] + n[1] + n[2] + n[3] + | |
111 | n[4] + n[5] + n[6] + n[7]) % 16; | |
112 | sum2 = (15 + n[8] + n[9] + n[10] + n[11] + | |
113 | n[12] + n[13] + n[14] + n[15]) % 16; | |
114 | ||
115 | if (sum1 != 15 || sum2 != 15) { | |
116 | IR_dprintk(2, "checksum errors sum1=0x%X sum2=0x%X\n", | |
117 | sum1, sum2); | |
118 | data->state = STATE_INACTIVE; | |
119 | return -EINVAL; | |
120 | } | |
121 | ||
122 | subaddr = n[0] << 4 | n[2]; | |
123 | subaddr2 = n[8] << 4 | n[11]; | |
124 | oem = n[4] << 4 | n[5]; | |
125 | addr = n[6] << 4 | n[7]; | |
126 | toggle = n[10]; | |
127 | obc1 = n[12] << 4 | n[13]; | |
128 | obc2 = n[14] << 4 | n[15]; | |
129 | if (subaddr != subaddr2) { | |
130 | IR_dprintk(2, "subaddress nibbles mismatch 0x%02X != 0x%02X\n", | |
131 | subaddr, subaddr2); | |
132 | data->state = STATE_INACTIVE; | |
133 | return -EINVAL; | |
134 | } | |
135 | if (oem != 0x44) | |
136 | IR_dprintk(1, "Warning: OEM nibbles 0x%02X. Expected 0x44\n", | |
137 | oem); | |
138 | ||
139 | scancode = addr << 24 | subaddr << 16 | | |
140 | obc1 << 8 | obc2; | |
141 | IR_dprintk(1, "XMP scancode 0x%06x\n", scancode); | |
142 | ||
143 | if (toggle == 0) { | |
144 | rc_keydown(dev, RC_TYPE_XMP, scancode, 0); | |
145 | } else { | |
146 | rc_repeat(dev); | |
147 | IR_dprintk(1, "Repeat last key\n"); | |
148 | } | |
149 | data->state = STATE_INACTIVE; | |
150 | ||
151 | return 0; | |
152 | ||
153 | } else if (geq_margin(ev.duration, XMP_HALFFRAME_SPACE, XMP_NIBBLE_PREFIX)) { | |
154 | /* Expect 8 or 16 nibble pulses. 16 in case of 'final' frame */ | |
155 | if (data->count == 16) { | |
156 | IR_dprintk(2, "received half frame pulse at index %d. Probably a final frame key-up event: %u\n", | |
157 | data->count, ev.duration); | |
158 | /* | |
159 | * TODO: for now go back to half frame position | |
160 | * so trailer can be found and key press | |
161 | * can be handled. | |
162 | */ | |
163 | data->count = 8; | |
164 | } | |
165 | ||
166 | else if (data->count != 8) | |
167 | IR_dprintk(2, "received half frame pulse at index %d: %u\n", | |
168 | data->count, ev.duration); | |
169 | data->state = STATE_LEADER_PULSE; | |
170 | ||
171 | return 0; | |
172 | ||
173 | } else if (geq_margin(ev.duration, XMP_NIBBLE_PREFIX, XMP_UNIT)) { | |
174 | /* store nibble raw data, decode after trailer */ | |
175 | if (data->count == 16) { | |
176 | IR_dprintk(2, "to many pulses (%d) ignoring: %u\n", | |
177 | data->count, ev.duration); | |
178 | data->state = STATE_INACTIVE; | |
179 | return -EINVAL; | |
180 | } | |
181 | data->durations[data->count] = ev.duration; | |
182 | data->count++; | |
183 | data->state = STATE_LEADER_PULSE; | |
184 | ||
185 | return 0; | |
186 | ||
187 | } | |
188 | ||
189 | break; | |
190 | } | |
191 | ||
192 | IR_dprintk(1, "XMP decode failed at count %d state %d (%uus %s)\n", | |
193 | data->count, data->state, TO_US(ev.duration), TO_STR(ev.pulse)); | |
194 | data->state = STATE_INACTIVE; | |
195 | return -EINVAL; | |
196 | } | |
197 | ||
198 | static struct ir_raw_handler xmp_handler = { | |
199 | .protocols = RC_BIT_XMP, | |
200 | .decode = ir_xmp_decode, | |
201 | }; | |
202 | ||
203 | static int __init ir_xmp_decode_init(void) | |
204 | { | |
205 | ir_raw_handler_register(&xmp_handler); | |
206 | ||
207 | printk(KERN_INFO "IR XMP protocol handler initialized\n"); | |
208 | return 0; | |
209 | } | |
210 | ||
211 | static void __exit ir_xmp_decode_exit(void) | |
212 | { | |
213 | ir_raw_handler_unregister(&xmp_handler); | |
214 | } | |
215 | ||
216 | module_init(ir_xmp_decode_init); | |
217 | module_exit(ir_xmp_decode_exit); | |
218 | ||
219 | MODULE_LICENSE("GPL"); | |
220 | MODULE_AUTHOR("Marcel Mol <marcel@mesa.nl>"); | |
221 | MODULE_AUTHOR("MESA Consulting (http://www.mesa.nl)"); | |
222 | MODULE_DESCRIPTION("XMP IR protocol decoder"); |