Marcel J.E. Mol | 1dee9b5 | 2014-07-26 17:28:26 -0300 | [diff] [blame] | 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 | |
| 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 | |
| 201 | static struct ir_raw_handler xmp_handler = { |
| 202 | .protocols = RC_BIT_XMP, |
| 203 | .decode = ir_xmp_decode, |
| 204 | }; |
| 205 | |
| 206 | static 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 | |
| 214 | static void __exit ir_xmp_decode_exit(void) |
| 215 | { |
| 216 | ir_raw_handler_unregister(&xmp_handler); |
| 217 | } |
| 218 | |
| 219 | module_init(ir_xmp_decode_init); |
| 220 | module_exit(ir_xmp_decode_exit); |
| 221 | |
| 222 | MODULE_LICENSE("GPL"); |
| 223 | MODULE_AUTHOR("Marcel Mol <marcel@mesa.nl>"); |
| 224 | MODULE_AUTHOR("MESA Consulting (http://www.mesa.nl)"); |
| 225 | MODULE_DESCRIPTION("XMP IR protocol decoder"); |