root/drivers/media/rc/ir-mce_kbd-decoder.c

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DEFINITIONS

This source file includes following definitions.
  1. mce_kbd_rx_timeout
  2. ir_mce_kbd_process_keyboard_data
  3. ir_mce_kbd_process_mouse_data
  4. ir_mce_kbd_decode
  5. ir_mce_kbd_register
  6. ir_mce_kbd_unregister
  7. ir_mce_kbd_encode
  8. ir_mce_kbd_decode_init
  9. ir_mce_kbd_decode_exit

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /* ir-mce_kbd-decoder.c - A decoder for the RC6-ish keyboard/mouse IR protocol
   3  * used by the Microsoft Remote Keyboard for Windows Media Center Edition,
   4  * referred to by Microsoft's Windows Media Center remote specification docs
   5  * as "an internal protocol called MCIR-2".
   6  *
   7  * Copyright (C) 2011 by Jarod Wilson <jarod@redhat.com>
   8  */
   9 #include <linux/module.h>
  10 
  11 #include "rc-core-priv.h"
  12 
  13 /*
  14  * This decoder currently supports:
  15  * - MCIR-2 29-bit IR signals used for mouse movement and buttons
  16  * - MCIR-2 32-bit IR signals used for standard keyboard keys
  17  *
  18  * The media keys on the keyboard send RC-6 signals that are indistinguishable
  19  * from the keys of the same name on the stock MCE remote, and will be handled
  20  * by the standard RC-6 decoder, and be made available to the system via the
  21  * input device for the remote, rather than the keyboard/mouse one.
  22  */
  23 
  24 #define MCIR2_UNIT              333333  /* ns */
  25 #define MCIR2_HEADER_NBITS      5
  26 #define MCIR2_MOUSE_NBITS       29
  27 #define MCIR2_KEYBOARD_NBITS    32
  28 #define MCIR2_PREFIX_PULSE      (8 * MCIR2_UNIT)
  29 #define MCIR2_PREFIX_SPACE      (1 * MCIR2_UNIT)
  30 #define MCIR2_MAX_LEN           (3 * MCIR2_UNIT)
  31 #define MCIR2_BIT_START         (1 * MCIR2_UNIT)
  32 #define MCIR2_BIT_END           (1 * MCIR2_UNIT)
  33 #define MCIR2_BIT_0             (1 * MCIR2_UNIT)
  34 #define MCIR2_BIT_SET           (2 * MCIR2_UNIT)
  35 #define MCIR2_MODE_MASK         0xf     /* for the header bits */
  36 #define MCIR2_KEYBOARD_HEADER   0x4
  37 #define MCIR2_MOUSE_HEADER      0x1
  38 #define MCIR2_MASK_KEYS_START   0xe0
  39 
  40 enum mce_kbd_mode {
  41         MCIR2_MODE_KEYBOARD,
  42         MCIR2_MODE_MOUSE,
  43         MCIR2_MODE_UNKNOWN,
  44 };
  45 
  46 enum mce_kbd_state {
  47         STATE_INACTIVE,
  48         STATE_HEADER_BIT_START,
  49         STATE_HEADER_BIT_END,
  50         STATE_BODY_BIT_START,
  51         STATE_BODY_BIT_END,
  52         STATE_FINISHED,
  53 };
  54 
  55 static unsigned char kbd_keycodes[256] = {
  56         KEY_RESERVED,   KEY_RESERVED,   KEY_RESERVED,   KEY_RESERVED,   KEY_A,
  57         KEY_B,          KEY_C,          KEY_D,          KEY_E,          KEY_F,
  58         KEY_G,          KEY_H,          KEY_I,          KEY_J,          KEY_K,
  59         KEY_L,          KEY_M,          KEY_N,          KEY_O,          KEY_P,
  60         KEY_Q,          KEY_R,          KEY_S,          KEY_T,          KEY_U,
  61         KEY_V,          KEY_W,          KEY_X,          KEY_Y,          KEY_Z,
  62         KEY_1,          KEY_2,          KEY_3,          KEY_4,          KEY_5,
  63         KEY_6,          KEY_7,          KEY_8,          KEY_9,          KEY_0,
  64         KEY_ENTER,      KEY_ESC,        KEY_BACKSPACE,  KEY_TAB,        KEY_SPACE,
  65         KEY_MINUS,      KEY_EQUAL,      KEY_LEFTBRACE,  KEY_RIGHTBRACE, KEY_BACKSLASH,
  66         KEY_BACKSLASH,  KEY_SEMICOLON,  KEY_APOSTROPHE, KEY_GRAVE,      KEY_COMMA,
  67         KEY_DOT,        KEY_SLASH,      KEY_CAPSLOCK,   KEY_F1,         KEY_F2,
  68         KEY_F3,         KEY_F4,         KEY_F5,         KEY_F6,         KEY_F7,
  69         KEY_F8,         KEY_F9,         KEY_F10,        KEY_F11,        KEY_F12,
  70         KEY_SYSRQ,      KEY_SCROLLLOCK, KEY_PAUSE,      KEY_INSERT,     KEY_HOME,
  71         KEY_PAGEUP,     KEY_DELETE,     KEY_END,        KEY_PAGEDOWN,   KEY_RIGHT,
  72         KEY_LEFT,       KEY_DOWN,       KEY_UP,         KEY_NUMLOCK,    KEY_KPSLASH,
  73         KEY_KPASTERISK, KEY_KPMINUS,    KEY_KPPLUS,     KEY_KPENTER,    KEY_KP1,
  74         KEY_KP2,        KEY_KP3,        KEY_KP4,        KEY_KP5,        KEY_KP6,
  75         KEY_KP7,        KEY_KP8,        KEY_KP9,        KEY_KP0,        KEY_KPDOT,
  76         KEY_102ND,      KEY_COMPOSE,    KEY_POWER,      KEY_KPEQUAL,    KEY_F13,
  77         KEY_F14,        KEY_F15,        KEY_F16,        KEY_F17,        KEY_F18,
  78         KEY_F19,        KEY_F20,        KEY_F21,        KEY_F22,        KEY_F23,
  79         KEY_F24,        KEY_OPEN,       KEY_HELP,       KEY_PROPS,      KEY_FRONT,
  80         KEY_STOP,       KEY_AGAIN,      KEY_UNDO,       KEY_CUT,        KEY_COPY,
  81         KEY_PASTE,      KEY_FIND,       KEY_MUTE,       KEY_VOLUMEUP,   KEY_VOLUMEDOWN,
  82         KEY_RESERVED,   KEY_RESERVED,   KEY_RESERVED,   KEY_KPCOMMA,    KEY_RESERVED,
  83         KEY_RO,         KEY_KATAKANAHIRAGANA, KEY_YEN,  KEY_HENKAN,     KEY_MUHENKAN,
  84         KEY_KPJPCOMMA,  KEY_RESERVED,   KEY_RESERVED,   KEY_RESERVED,   KEY_HANGUEL,
  85         KEY_HANJA,      KEY_KATAKANA,   KEY_HIRAGANA,   KEY_ZENKAKUHANKAKU, KEY_RESERVED,
  86         KEY_RESERVED,   KEY_RESERVED,   KEY_RESERVED,   KEY_RESERVED,   KEY_RESERVED,
  87         KEY_RESERVED,   KEY_RESERVED,   KEY_RESERVED,   KEY_RESERVED,   KEY_RESERVED,
  88         KEY_RESERVED,   KEY_RESERVED,   KEY_RESERVED,   KEY_RESERVED,   KEY_RESERVED,
  89         KEY_RESERVED,   KEY_RESERVED,   KEY_RESERVED,   KEY_RESERVED,   KEY_RESERVED,
  90         KEY_RESERVED,   KEY_RESERVED,   KEY_RESERVED,   KEY_RESERVED,   KEY_RESERVED,
  91         KEY_RESERVED,   KEY_RESERVED,   KEY_RESERVED,   KEY_RESERVED,   KEY_RESERVED,
  92         KEY_RESERVED,   KEY_RESERVED,   KEY_RESERVED,   KEY_RESERVED,   KEY_RESERVED,
  93         KEY_RESERVED,   KEY_RESERVED,   KEY_RESERVED,   KEY_RESERVED,   KEY_RESERVED,
  94         KEY_RESERVED,   KEY_RESERVED,   KEY_RESERVED,   KEY_RESERVED,   KEY_RESERVED,
  95         KEY_RESERVED,   KEY_RESERVED,   KEY_RESERVED,   KEY_RESERVED,   KEY_RESERVED,
  96         KEY_RESERVED,   KEY_RESERVED,   KEY_RESERVED,   KEY_RESERVED,   KEY_RESERVED,
  97         KEY_RESERVED,   KEY_RESERVED,   KEY_RESERVED,   KEY_RESERVED,   KEY_RESERVED,
  98         KEY_RESERVED,   KEY_RESERVED,   KEY_RESERVED,   KEY_RESERVED,   KEY_RESERVED,
  99         KEY_RESERVED,   KEY_RESERVED,   KEY_RESERVED,   KEY_RESERVED,   KEY_RESERVED,
 100         KEY_RESERVED,   KEY_RESERVED,   KEY_RESERVED,   KEY_RESERVED,   KEY_LEFTCTRL,
 101         KEY_LEFTSHIFT,  KEY_LEFTALT,    KEY_LEFTMETA,   KEY_RIGHTCTRL,  KEY_RIGHTSHIFT,
 102         KEY_RIGHTALT,   KEY_RIGHTMETA,  KEY_PLAYPAUSE,  KEY_STOPCD,     KEY_PREVIOUSSONG,
 103         KEY_NEXTSONG,   KEY_EJECTCD,    KEY_VOLUMEUP,   KEY_VOLUMEDOWN, KEY_MUTE,
 104         KEY_WWW,        KEY_BACK,       KEY_FORWARD,    KEY_STOP,       KEY_FIND,
 105         KEY_SCROLLUP,   KEY_SCROLLDOWN, KEY_EDIT,       KEY_SLEEP,      KEY_COFFEE,
 106         KEY_REFRESH,    KEY_CALC,       KEY_RESERVED,   KEY_RESERVED,   KEY_RESERVED,
 107         KEY_RESERVED
 108 };
 109 
 110 static void mce_kbd_rx_timeout(struct timer_list *t)
 111 {
 112         struct ir_raw_event_ctrl *raw = from_timer(raw, t, mce_kbd.rx_timeout);
 113         unsigned char maskcode;
 114         unsigned long flags;
 115         int i;
 116 
 117         dev_dbg(&raw->dev->dev, "timer callback clearing all keys\n");
 118 
 119         spin_lock_irqsave(&raw->mce_kbd.keylock, flags);
 120 
 121         if (time_is_before_eq_jiffies(raw->mce_kbd.rx_timeout.expires)) {
 122                 for (i = 0; i < 7; i++) {
 123                         maskcode = kbd_keycodes[MCIR2_MASK_KEYS_START + i];
 124                         input_report_key(raw->dev->input_dev, maskcode, 0);
 125                 }
 126 
 127                 for (i = 0; i < MCIR2_MASK_KEYS_START; i++)
 128                         input_report_key(raw->dev->input_dev, kbd_keycodes[i],
 129                                          0);
 130 
 131                 input_sync(raw->dev->input_dev);
 132         }
 133         spin_unlock_irqrestore(&raw->mce_kbd.keylock, flags);
 134 }
 135 
 136 static enum mce_kbd_mode mce_kbd_mode(struct mce_kbd_dec *data)
 137 {
 138         switch (data->header & MCIR2_MODE_MASK) {
 139         case MCIR2_KEYBOARD_HEADER:
 140                 return MCIR2_MODE_KEYBOARD;
 141         case MCIR2_MOUSE_HEADER:
 142                 return MCIR2_MODE_MOUSE;
 143         default:
 144                 return MCIR2_MODE_UNKNOWN;
 145         }
 146 }
 147 
 148 static void ir_mce_kbd_process_keyboard_data(struct rc_dev *dev, u32 scancode)
 149 {
 150         u8 keydata1  = (scancode >> 8) & 0xff;
 151         u8 keydata2  = (scancode >> 16) & 0xff;
 152         u8 shiftmask = scancode & 0xff;
 153         unsigned char maskcode;
 154         int i, keystate;
 155 
 156         dev_dbg(&dev->dev, "keyboard: keydata2 = 0x%02x, keydata1 = 0x%02x, shiftmask = 0x%02x\n",
 157                 keydata2, keydata1, shiftmask);
 158 
 159         for (i = 0; i < 7; i++) {
 160                 maskcode = kbd_keycodes[MCIR2_MASK_KEYS_START + i];
 161                 if (shiftmask & (1 << i))
 162                         keystate = 1;
 163                 else
 164                         keystate = 0;
 165                 input_report_key(dev->input_dev, maskcode, keystate);
 166         }
 167 
 168         if (keydata1)
 169                 input_report_key(dev->input_dev, kbd_keycodes[keydata1], 1);
 170         if (keydata2)
 171                 input_report_key(dev->input_dev, kbd_keycodes[keydata2], 1);
 172 
 173         if (!keydata1 && !keydata2) {
 174                 for (i = 0; i < MCIR2_MASK_KEYS_START; i++)
 175                         input_report_key(dev->input_dev, kbd_keycodes[i], 0);
 176         }
 177 }
 178 
 179 static void ir_mce_kbd_process_mouse_data(struct rc_dev *dev, u32 scancode)
 180 {
 181         /* raw mouse coordinates */
 182         u8 xdata = (scancode >> 7) & 0x7f;
 183         u8 ydata = (scancode >> 14) & 0x7f;
 184         int x, y;
 185         /* mouse buttons */
 186         bool right = scancode & 0x40;
 187         bool left  = scancode & 0x20;
 188 
 189         if (xdata & 0x40)
 190                 x = -((~xdata & 0x7f) + 1);
 191         else
 192                 x = xdata;
 193 
 194         if (ydata & 0x40)
 195                 y = -((~ydata & 0x7f) + 1);
 196         else
 197                 y = ydata;
 198 
 199         dev_dbg(&dev->dev, "mouse: x = %d, y = %d, btns = %s%s\n",
 200                 x, y, left ? "L" : "", right ? "R" : "");
 201 
 202         input_report_rel(dev->input_dev, REL_X, x);
 203         input_report_rel(dev->input_dev, REL_Y, y);
 204 
 205         input_report_key(dev->input_dev, BTN_LEFT, left);
 206         input_report_key(dev->input_dev, BTN_RIGHT, right);
 207 }
 208 
 209 /**
 210  * ir_mce_kbd_decode() - Decode one mce_kbd pulse or space
 211  * @dev:        the struct rc_dev descriptor of the device
 212  * @ev:         the struct ir_raw_event descriptor of the pulse/space
 213  *
 214  * This function returns -EINVAL if the pulse violates the state machine
 215  */
 216 static int ir_mce_kbd_decode(struct rc_dev *dev, struct ir_raw_event ev)
 217 {
 218         struct mce_kbd_dec *data = &dev->raw->mce_kbd;
 219         u32 scancode;
 220         unsigned long delay;
 221         struct lirc_scancode lsc = {};
 222 
 223         if (!is_timing_event(ev)) {
 224                 if (ev.reset)
 225                         data->state = STATE_INACTIVE;
 226                 return 0;
 227         }
 228 
 229         if (!geq_margin(ev.duration, MCIR2_UNIT, MCIR2_UNIT / 2))
 230                 goto out;
 231 
 232 again:
 233         dev_dbg(&dev->dev, "started at state %i (%uus %s)\n",
 234                 data->state, TO_US(ev.duration), TO_STR(ev.pulse));
 235 
 236         if (!geq_margin(ev.duration, MCIR2_UNIT, MCIR2_UNIT / 2))
 237                 return 0;
 238 
 239         switch (data->state) {
 240 
 241         case STATE_INACTIVE:
 242                 if (!ev.pulse)
 243                         break;
 244 
 245                 /* Note: larger margin on first pulse since each MCIR2_UNIT
 246                    is quite short and some hardware takes some time to
 247                    adjust to the signal */
 248                 if (!eq_margin(ev.duration, MCIR2_PREFIX_PULSE, MCIR2_UNIT))
 249                         break;
 250 
 251                 data->state = STATE_HEADER_BIT_START;
 252                 data->count = 0;
 253                 data->header = 0;
 254                 return 0;
 255 
 256         case STATE_HEADER_BIT_START:
 257                 if (geq_margin(ev.duration, MCIR2_MAX_LEN, MCIR2_UNIT / 2))
 258                         break;
 259 
 260                 data->header <<= 1;
 261                 if (ev.pulse)
 262                         data->header |= 1;
 263                 data->count++;
 264                 data->state = STATE_HEADER_BIT_END;
 265                 return 0;
 266 
 267         case STATE_HEADER_BIT_END:
 268                 decrease_duration(&ev, MCIR2_BIT_END);
 269 
 270                 if (data->count != MCIR2_HEADER_NBITS) {
 271                         data->state = STATE_HEADER_BIT_START;
 272                         goto again;
 273                 }
 274 
 275                 switch (mce_kbd_mode(data)) {
 276                 case MCIR2_MODE_KEYBOARD:
 277                         data->wanted_bits = MCIR2_KEYBOARD_NBITS;
 278                         break;
 279                 case MCIR2_MODE_MOUSE:
 280                         data->wanted_bits = MCIR2_MOUSE_NBITS;
 281                         break;
 282                 default:
 283                         dev_dbg(&dev->dev, "not keyboard or mouse data\n");
 284                         goto out;
 285                 }
 286 
 287                 data->count = 0;
 288                 data->body = 0;
 289                 data->state = STATE_BODY_BIT_START;
 290                 goto again;
 291 
 292         case STATE_BODY_BIT_START:
 293                 if (geq_margin(ev.duration, MCIR2_MAX_LEN, MCIR2_UNIT / 2))
 294                         break;
 295 
 296                 data->body <<= 1;
 297                 if (ev.pulse)
 298                         data->body |= 1;
 299                 data->count++;
 300                 data->state = STATE_BODY_BIT_END;
 301                 return 0;
 302 
 303         case STATE_BODY_BIT_END:
 304                 if (data->count == data->wanted_bits)
 305                         data->state = STATE_FINISHED;
 306                 else
 307                         data->state = STATE_BODY_BIT_START;
 308 
 309                 decrease_duration(&ev, MCIR2_BIT_END);
 310                 goto again;
 311 
 312         case STATE_FINISHED:
 313                 if (ev.pulse)
 314                         break;
 315 
 316                 switch (data->wanted_bits) {
 317                 case MCIR2_KEYBOARD_NBITS:
 318                         scancode = data->body & 0xffffff;
 319                         dev_dbg(&dev->dev, "keyboard data 0x%08x\n",
 320                                 data->body);
 321                         spin_lock(&data->keylock);
 322                         if (scancode) {
 323                                 delay = nsecs_to_jiffies(dev->timeout) +
 324                                         msecs_to_jiffies(100);
 325                                 mod_timer(&data->rx_timeout, jiffies + delay);
 326                         } else {
 327                                 del_timer(&data->rx_timeout);
 328                         }
 329                         /* Pass data to keyboard buffer parser */
 330                         ir_mce_kbd_process_keyboard_data(dev, scancode);
 331                         spin_unlock(&data->keylock);
 332                         lsc.rc_proto = RC_PROTO_MCIR2_KBD;
 333                         break;
 334                 case MCIR2_MOUSE_NBITS:
 335                         scancode = data->body & 0x1fffff;
 336                         dev_dbg(&dev->dev, "mouse data 0x%06x\n", scancode);
 337                         /* Pass data to mouse buffer parser */
 338                         ir_mce_kbd_process_mouse_data(dev, scancode);
 339                         lsc.rc_proto = RC_PROTO_MCIR2_MSE;
 340                         break;
 341                 default:
 342                         dev_dbg(&dev->dev, "not keyboard or mouse data\n");
 343                         goto out;
 344                 }
 345 
 346                 lsc.scancode = scancode;
 347                 ir_lirc_scancode_event(dev, &lsc);
 348                 data->state = STATE_INACTIVE;
 349                 input_event(dev->input_dev, EV_MSC, MSC_SCAN, scancode);
 350                 input_sync(dev->input_dev);
 351                 return 0;
 352         }
 353 
 354 out:
 355         dev_dbg(&dev->dev, "failed at state %i (%uus %s)\n",
 356                 data->state, TO_US(ev.duration), TO_STR(ev.pulse));
 357         data->state = STATE_INACTIVE;
 358         return -EINVAL;
 359 }
 360 
 361 static int ir_mce_kbd_register(struct rc_dev *dev)
 362 {
 363         struct mce_kbd_dec *mce_kbd = &dev->raw->mce_kbd;
 364 
 365         timer_setup(&mce_kbd->rx_timeout, mce_kbd_rx_timeout, 0);
 366         spin_lock_init(&mce_kbd->keylock);
 367 
 368         return 0;
 369 }
 370 
 371 static int ir_mce_kbd_unregister(struct rc_dev *dev)
 372 {
 373         struct mce_kbd_dec *mce_kbd = &dev->raw->mce_kbd;
 374 
 375         del_timer_sync(&mce_kbd->rx_timeout);
 376 
 377         return 0;
 378 }
 379 
 380 static const struct ir_raw_timings_manchester ir_mce_kbd_timings = {
 381         .leader_pulse   = MCIR2_PREFIX_PULSE,
 382         .invert         = 1,
 383         .clock          = MCIR2_UNIT,
 384         .trailer_space  = MCIR2_UNIT * 10,
 385 };
 386 
 387 /**
 388  * ir_mce_kbd_encode() - Encode a scancode as a stream of raw events
 389  *
 390  * @protocol:   protocol to encode
 391  * @scancode:   scancode to encode
 392  * @events:     array of raw ir events to write into
 393  * @max:        maximum size of @events
 394  *
 395  * Returns:     The number of events written.
 396  *              -ENOBUFS if there isn't enough space in the array to fit the
 397  *              encoding. In this case all @max events will have been written.
 398  */
 399 static int ir_mce_kbd_encode(enum rc_proto protocol, u32 scancode,
 400                              struct ir_raw_event *events, unsigned int max)
 401 {
 402         struct ir_raw_event *e = events;
 403         int len, ret;
 404         u64 raw;
 405 
 406         if (protocol == RC_PROTO_MCIR2_KBD) {
 407                 raw = scancode |
 408                       ((u64)MCIR2_KEYBOARD_HEADER << MCIR2_KEYBOARD_NBITS);
 409                 len = MCIR2_KEYBOARD_NBITS + MCIR2_HEADER_NBITS;
 410         } else {
 411                 raw = scancode |
 412                       ((u64)MCIR2_MOUSE_HEADER << MCIR2_MOUSE_NBITS);
 413                 len = MCIR2_MOUSE_NBITS + MCIR2_HEADER_NBITS;
 414         }
 415 
 416         ret = ir_raw_gen_manchester(&e, max, &ir_mce_kbd_timings, len, raw);
 417         if (ret < 0)
 418                 return ret;
 419 
 420         return e - events;
 421 }
 422 
 423 static struct ir_raw_handler mce_kbd_handler = {
 424         .protocols      = RC_PROTO_BIT_MCIR2_KBD | RC_PROTO_BIT_MCIR2_MSE,
 425         .decode         = ir_mce_kbd_decode,
 426         .encode         = ir_mce_kbd_encode,
 427         .raw_register   = ir_mce_kbd_register,
 428         .raw_unregister = ir_mce_kbd_unregister,
 429         .carrier        = 36000,
 430         .min_timeout    = MCIR2_MAX_LEN + MCIR2_UNIT / 2,
 431 };
 432 
 433 static int __init ir_mce_kbd_decode_init(void)
 434 {
 435         ir_raw_handler_register(&mce_kbd_handler);
 436 
 437         printk(KERN_INFO "IR MCE Keyboard/mouse protocol handler initialized\n");
 438         return 0;
 439 }
 440 
 441 static void __exit ir_mce_kbd_decode_exit(void)
 442 {
 443         ir_raw_handler_unregister(&mce_kbd_handler);
 444 }
 445 
 446 module_init(ir_mce_kbd_decode_init);
 447 module_exit(ir_mce_kbd_decode_exit);
 448 
 449 MODULE_LICENSE("GPL");
 450 MODULE_AUTHOR("Jarod Wilson <jarod@redhat.com>");
 451 MODULE_DESCRIPTION("MCE Keyboard/mouse IR protocol decoder");

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