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Marcel J.E. Mol1dee9b52014-07-26 17:28:26 -03001/* 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
29enum 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 */
42static int ir_xmp_decode(struct rc_dev *dev, struct ir_raw_event ev)
43{
44 struct xmp_dec *data = &dev->raw->xmp;
45
46 if (!(dev->enabled_protocols & RC_BIT_XMP))
47 return 0;
48
49 if (!is_timing_event(ev)) {
50 if (ev.reset)
51 data->state = STATE_INACTIVE;
52 return 0;
53 }
54
55 IR_dprintk(2, "XMP decode started at state %d %d (%uus %s)\n",
56 data->state, data->count, TO_US(ev.duration), TO_STR(ev.pulse));
57
58 switch (data->state) {
59
60 case STATE_INACTIVE:
61 if (!ev.pulse)
62 break;
63
64 if (eq_margin(ev.duration, XMP_LEADER, XMP_UNIT / 2)) {
65 data->count = 0;
66 data->state = STATE_NIBBLE_SPACE;
67 }
68
69 return 0;
70
71 case STATE_LEADER_PULSE:
72 if (!ev.pulse)
73 break;
74
75 if (eq_margin(ev.duration, XMP_LEADER, XMP_UNIT / 2))
76 data->state = STATE_NIBBLE_SPACE;
77
78 return 0;
79
80 case STATE_NIBBLE_SPACE:
81 if (ev.pulse)
82 break;
83
84 if (geq_margin(ev.duration, XMP_TRAILER_SPACE, XMP_NIBBLE_PREFIX)) {
85 int divider, i;
86 u8 addr, subaddr, subaddr2, toggle, oem, obc1, obc2, sum1, sum2;
87 u32 *n;
88 u32 scancode;
89
90 if (data->count != 16) {
91 IR_dprintk(2, "received TRAILER period at index %d: %u\n",
92 data->count, ev.duration);
93 data->state = STATE_INACTIVE;
94 return -EINVAL;
95 }
96
97 n = data->durations;
98 /*
99 * the 4th nibble should be 15 so base the divider on this
100 * to transform durations into nibbles. Substract 2000 from
101 * the divider to compensate for fluctuations in the signal
102 */
103 divider = (n[3] - XMP_NIBBLE_PREFIX) / 15 - 2000;
104 if (divider < 50) {
105 IR_dprintk(2, "divider to small %d.\n", divider);
106 data->state = STATE_INACTIVE;
107 return -EINVAL;
108 }
109
110 /* convert to nibbles and do some sanity checks */
111 for (i = 0; i < 16; i++)
112 n[i] = (n[i] - XMP_NIBBLE_PREFIX) / divider;
113 sum1 = (15 + n[0] + n[1] + n[2] + n[3] +
114 n[4] + n[5] + n[6] + n[7]) % 16;
115 sum2 = (15 + n[8] + n[9] + n[10] + n[11] +
116 n[12] + n[13] + n[14] + n[15]) % 16;
117
118 if (sum1 != 15 || sum2 != 15) {
119 IR_dprintk(2, "checksum errors sum1=0x%X sum2=0x%X\n",
120 sum1, sum2);
121 data->state = STATE_INACTIVE;
122 return -EINVAL;
123 }
124
125 subaddr = n[0] << 4 | n[2];
126 subaddr2 = n[8] << 4 | n[11];
127 oem = n[4] << 4 | n[5];
128 addr = n[6] << 4 | n[7];
129 toggle = n[10];
130 obc1 = n[12] << 4 | n[13];
131 obc2 = n[14] << 4 | n[15];
132 if (subaddr != subaddr2) {
133 IR_dprintk(2, "subaddress nibbles mismatch 0x%02X != 0x%02X\n",
134 subaddr, subaddr2);
135 data->state = STATE_INACTIVE;
136 return -EINVAL;
137 }
138 if (oem != 0x44)
139 IR_dprintk(1, "Warning: OEM nibbles 0x%02X. Expected 0x44\n",
140 oem);
141
142 scancode = addr << 24 | subaddr << 16 |
143 obc1 << 8 | obc2;
144 IR_dprintk(1, "XMP scancode 0x%06x\n", scancode);
145
146 if (toggle == 0) {
147 rc_keydown(dev, RC_TYPE_XMP, scancode, 0);
148 } else {
149 rc_repeat(dev);
150 IR_dprintk(1, "Repeat last key\n");
151 }
152 data->state = STATE_INACTIVE;
153
154 return 0;
155
156 } else if (geq_margin(ev.duration, XMP_HALFFRAME_SPACE, XMP_NIBBLE_PREFIX)) {
157 /* Expect 8 or 16 nibble pulses. 16 in case of 'final' frame */
158 if (data->count == 16) {
159 IR_dprintk(2, "received half frame pulse at index %d. Probably a final frame key-up event: %u\n",
160 data->count, ev.duration);
161 /*
162 * TODO: for now go back to half frame position
163 * so trailer can be found and key press
164 * can be handled.
165 */
166 data->count = 8;
167 }
168
169 else if (data->count != 8)
170 IR_dprintk(2, "received half frame pulse at index %d: %u\n",
171 data->count, ev.duration);
172 data->state = STATE_LEADER_PULSE;
173
174 return 0;
175
176 } else if (geq_margin(ev.duration, XMP_NIBBLE_PREFIX, XMP_UNIT)) {
177 /* store nibble raw data, decode after trailer */
178 if (data->count == 16) {
179 IR_dprintk(2, "to many pulses (%d) ignoring: %u\n",
180 data->count, ev.duration);
181 data->state = STATE_INACTIVE;
182 return -EINVAL;
183 }
184 data->durations[data->count] = ev.duration;
185 data->count++;
186 data->state = STATE_LEADER_PULSE;
187
188 return 0;
189
190 }
191
192 break;
193 }
194
195 IR_dprintk(1, "XMP decode failed at count %d state %d (%uus %s)\n",
196 data->count, data->state, TO_US(ev.duration), TO_STR(ev.pulse));
197 data->state = STATE_INACTIVE;
198 return -EINVAL;
199}
200
201static struct ir_raw_handler xmp_handler = {
202 .protocols = RC_BIT_XMP,
203 .decode = ir_xmp_decode,
204};
205
206static int __init ir_xmp_decode_init(void)
207{
208 ir_raw_handler_register(&xmp_handler);
209
210 printk(KERN_INFO "IR XMP protocol handler initialized\n");
211 return 0;
212}
213
214static void __exit ir_xmp_decode_exit(void)
215{
216 ir_raw_handler_unregister(&xmp_handler);
217}
218
219module_init(ir_xmp_decode_init);
220module_exit(ir_xmp_decode_exit);
221
222MODULE_LICENSE("GPL");
223MODULE_AUTHOR("Marcel Mol <marcel@mesa.nl>");
224MODULE_AUTHOR("MESA Consulting (http://www.mesa.nl)");
225MODULE_DESCRIPTION("XMP IR protocol decoder");