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 * @ev: 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 46 if (!is_timing_event(ev)) { 47 if (ev.reset) 48 data->state = STATE_INACTIVE; 49 return 0; 50 } 51 52 dev_dbg(&dev->dev, "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 dev_dbg(&dev->dev, "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. Subtract 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 dev_dbg(&dev->dev, "divider to small %d.\n", 103 divider); 104 data->state = STATE_INACTIVE; 105 return -EINVAL; 106 } 107 108 /* convert to nibbles and do some sanity checks */ 109 for (i = 0; i < 16; i++) 110 n[i] = (n[i] - XMP_NIBBLE_PREFIX) / divider; 111 sum1 = (15 + n[0] + n[1] + n[2] + n[3] + 112 n[4] + n[5] + n[6] + n[7]) % 16; 113 sum2 = (15 + n[8] + n[9] + n[10] + n[11] + 114 n[12] + n[13] + n[14] + n[15]) % 16; 115 116 if (sum1 != 15 || sum2 != 15) { 117 dev_dbg(&dev->dev, "checksum errors sum1=0x%X sum2=0x%X\n", 118 sum1, sum2); 119 data->state = STATE_INACTIVE; 120 return -EINVAL; 121 } 122 123 subaddr = n[0] << 4 | n[2]; 124 subaddr2 = n[8] << 4 | n[11]; 125 oem = n[4] << 4 | n[5]; 126 addr = n[6] << 4 | n[7]; 127 toggle = n[10]; 128 obc1 = n[12] << 4 | n[13]; 129 obc2 = n[14] << 4 | n[15]; 130 if (subaddr != subaddr2) { 131 dev_dbg(&dev->dev, "subaddress nibbles mismatch 0x%02X != 0x%02X\n", 132 subaddr, subaddr2); 133 data->state = STATE_INACTIVE; 134 return -EINVAL; 135 } 136 if (oem != 0x44) 137 dev_dbg(&dev->dev, "Warning: OEM nibbles 0x%02X. Expected 0x44\n", 138 oem); 139 140 scancode = addr << 24 | subaddr << 16 | 141 obc1 << 8 | obc2; 142 dev_dbg(&dev->dev, "XMP scancode 0x%06x\n", scancode); 143 144 if (toggle == 0) { 145 rc_keydown(dev, RC_PROTO_XMP, scancode, 0); 146 } else { 147 rc_repeat(dev); 148 dev_dbg(&dev->dev, "Repeat last key\n"); 149 } 150 data->state = STATE_INACTIVE; 151 152 return 0; 153 154 } else if (geq_margin(ev.duration, XMP_HALFFRAME_SPACE, XMP_NIBBLE_PREFIX)) { 155 /* Expect 8 or 16 nibble pulses. 16 in case of 'final' frame */ 156 if (data->count == 16) { 157 dev_dbg(&dev->dev, "received half frame pulse at index %d. Probably a final frame key-up event: %u\n", 158 data->count, ev.duration); 159 /* 160 * TODO: for now go back to half frame position 161 * so trailer can be found and key press 162 * can be handled. 163 */ 164 data->count = 8; 165 } 166 167 else if (data->count != 8) 168 dev_dbg(&dev->dev, "received half frame pulse at index %d: %u\n", 169 data->count, ev.duration); 170 data->state = STATE_LEADER_PULSE; 171 172 return 0; 173 174 } else if (geq_margin(ev.duration, XMP_NIBBLE_PREFIX, XMP_UNIT)) { 175 /* store nibble raw data, decode after trailer */ 176 if (data->count == 16) { 177 dev_dbg(&dev->dev, "to many pulses (%d) ignoring: %u\n", 178 data->count, ev.duration); 179 data->state = STATE_INACTIVE; 180 return -EINVAL; 181 } 182 data->durations[data->count] = ev.duration; 183 data->count++; 184 data->state = STATE_LEADER_PULSE; 185 186 return 0; 187 188 } 189 190 break; 191 } 192 193 dev_dbg(&dev->dev, "XMP decode failed at count %d state %d (%uus %s)\n", 194 data->count, data->state, TO_US(ev.duration), TO_STR(ev.pulse)); 195 data->state = STATE_INACTIVE; 196 return -EINVAL; 197 } 198 199 static struct ir_raw_handler xmp_handler = { 200 .protocols = RC_PROTO_BIT_XMP, 201 .decode = ir_xmp_decode, 202 .min_timeout = XMP_TRAILER_SPACE, 203 }; 204 205 static int __init ir_xmp_decode_init(void) 206 { 207 ir_raw_handler_register(&xmp_handler); 208 209 printk(KERN_INFO "IR XMP protocol handler initialized\n"); 210 return 0; 211 } 212 213 static void __exit ir_xmp_decode_exit(void) 214 { 215 ir_raw_handler_unregister(&xmp_handler); 216 } 217 218 module_init(ir_xmp_decode_init); 219 module_exit(ir_xmp_decode_exit); 220 221 MODULE_LICENSE("GPL"); 222 MODULE_AUTHOR("Marcel Mol <marcel@mesa.nl>"); 223 MODULE_AUTHOR("MESA Consulting (http://www.mesa.nl)"); 224 MODULE_DESCRIPTION("XMP IR protocol decoder"); 225