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ir-functions.c

/*
 *
 * some common structs and functions to handle infrared remotes via
 * input layer ...
 *
 * (c) 2003 Gerd Knorr <kraxel@bytesex.org> [SuSE Labs]
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

#include <linux/module.h>
#include <linux/string.h>
#include <linux/jiffies.h>
#include <media/ir-common.h>

/* -------------------------------------------------------------------------- */

MODULE_AUTHOR("Gerd Knorr <kraxel@bytesex.org> [SuSE Labs]");
MODULE_LICENSE("GPL");

static int repeat = 1;
module_param(repeat, int, 0444);
MODULE_PARM_DESC(repeat,"auto-repeat for IR keys (default: on)");

static int debug = 0;    /* debug level (0,1,2) */
module_param(debug, int, 0644);

#define dprintk(level, fmt, arg...) if (debug >= level) \
      printk(KERN_DEBUG fmt , ## arg)

/* -------------------------------------------------------------------------- */

static void ir_input_key_event(struct input_dev *dev, struct ir_input_state *ir)
{
      if (KEY_RESERVED == ir->keycode) {
            printk(KERN_INFO "%s: unknown key: key=0x%02x raw=0x%02x down=%d\n",
                   dev->name,ir->ir_key,ir->ir_raw,ir->keypressed);
            return;
      }
      dprintk(1,"%s: key event code=%d down=%d\n",
            dev->name,ir->keycode,ir->keypressed);
      input_report_key(dev,ir->keycode,ir->keypressed);
      input_sync(dev);
}

/* -------------------------------------------------------------------------- */

void ir_input_init(struct input_dev *dev, struct ir_input_state *ir,
               int ir_type, IR_KEYTAB_TYPE *ir_codes)
{
      int i;

      ir->ir_type = ir_type;
      if (ir_codes)
            memcpy(ir->ir_codes, ir_codes, sizeof(ir->ir_codes));


      dev->keycode     = ir->ir_codes;
      dev->keycodesize = sizeof(IR_KEYTAB_TYPE);
      dev->keycodemax  = IR_KEYTAB_SIZE;
      for (i = 0; i < IR_KEYTAB_SIZE; i++)
            set_bit(ir->ir_codes[i], dev->keybit);
      clear_bit(0, dev->keybit);

      set_bit(EV_KEY, dev->evbit);
      if (repeat)
            set_bit(EV_REP, dev->evbit);
}

void ir_input_nokey(struct input_dev *dev, struct ir_input_state *ir)
{
      if (ir->keypressed) {
            ir->keypressed = 0;
            ir_input_key_event(dev,ir);
      }
}

void ir_input_keydown(struct input_dev *dev, struct ir_input_state *ir,
                  u32 ir_key, u32 ir_raw)
{
      u32 keycode = IR_KEYCODE(ir->ir_codes, ir_key);

      if (ir->keypressed && ir->keycode != keycode) {
            ir->keypressed = 0;
            ir_input_key_event(dev,ir);
      }
      if (!ir->keypressed) {
            ir->ir_key  = ir_key;
            ir->ir_raw  = ir_raw;
            ir->keycode = keycode;
            ir->keypressed = 1;
            ir_input_key_event(dev,ir);
      }
}

/* -------------------------------------------------------------------------- */
/* extract mask bits out of data and pack them into the result */
u32 ir_extract_bits(u32 data, u32 mask)
{
      u32 vbit = 1, value = 0;

      do {
          if (mask&1) {
            if (data&1)
                  value |= vbit;
            vbit<<=1;
          }
          data>>=1;
      } while (mask>>=1);

      return value;
}

static int inline getbit(u32 *samples, int bit)
{
      return (samples[bit/32] & (1 << (31-(bit%32)))) ? 1 : 0;
}

/* sump raw samples for visual debugging ;) */
int ir_dump_samples(u32 *samples, int count)
{
      int i, bit, start;

      printk(KERN_DEBUG "ir samples: ");
      start = 0;
      for (i = 0; i < count * 32; i++) {
            bit = getbit(samples,i);
            if (bit)
                  start = 1;
            if (0 == start)
                  continue;
            printk("%s", bit ? "#" : "_");
      }
      printk("\n");
      return 0;
}

/* decode raw samples, pulse distance coding used by NEC remotes */
int ir_decode_pulsedistance(u32 *samples, int count, int low, int high)
{
      int i,last,bit,len;
      u32 curBit;
      u32 value;

      /* find start burst */
      for (i = len = 0; i < count * 32; i++) {
            bit = getbit(samples,i);
            if (bit) {
                  len++;
            } else {
                  if (len >= 29)
                        break;
                  len = 0;
            }
      }

      /* start burst to short */
      if (len < 29)
            return 0xffffffff;

      /* find start silence */
      for (len = 0; i < count * 32; i++) {
            bit = getbit(samples,i);
            if (bit) {
                  break;
            } else {
                  len++;
            }
      }

      /* silence to short */
      if (len < 7)
            return 0xffffffff;

      /* go decoding */
      len   = 0;
      last = 1;
      value = 0; curBit = 1;
      for (; i < count * 32; i++) {
            bit  = getbit(samples,i);
            if (last) {
                  if(bit) {
                        continue;
                  } else {
                        len = 1;
                  }
            } else {
                  if (bit) {
                        if (len > (low + high) /2)
                              value |= curBit;
                        curBit <<= 1;
                        if (curBit == 1)
                              break;
                  } else {
                        len++;
                  }
            }
            last = bit;
      }

      return value;
}

/* decode raw samples, biphase coding, used by rc5 for example */
int ir_decode_biphase(u32 *samples, int count, int low, int high)
{
      int i,last,bit,len,flips;
      u32 value;

      /* find start bit (1) */
      for (i = 0; i < 32; i++) {
            bit = getbit(samples,i);
            if (bit)
                  break;
      }

      /* go decoding */
      len   = 0;
      flips = 0;
      value = 1;
      for (; i < count * 32; i++) {
            if (len > high)
                  break;
            if (flips > 1)
                  break;
            last = bit;
            bit  = getbit(samples,i);
            if (last == bit) {
                  len++;
                  continue;
            }
            if (len < low) {
                  len++;
                  flips++;
                  continue;
            }
            value <<= 1;
            value |= bit;
            flips = 0;
            len   = 1;
      }
      return value;
}

/* RC5 decoding stuff, moved from bttv-input.c to share it with
 * saa7134 */

/* decode raw bit pattern to RC5 code */
u32 ir_rc5_decode(unsigned int code)
{
      unsigned int org_code = code;
      unsigned int pair;
      unsigned int rc5 = 0;
      int i;

      for (i = 0; i < 14; ++i) {
            pair = code & 0x3;
            code >>= 2;

            rc5 <<= 1;
            switch (pair) {
            case 0:
            case 2:
                  break;
            case 1:
                  rc5 |= 1;
                  break;
            case 3:
                  dprintk(1, "ir-common: ir_rc5_decode(%x) bad code\n", org_code);
                  return 0;
            }
      }
      dprintk(1, "ir-common: code=%x, rc5=%x, start=%x, toggle=%x, address=%x, "
            "instr=%x\n", rc5, org_code, RC5_START(rc5),
            RC5_TOGGLE(rc5), RC5_ADDR(rc5), RC5_INSTR(rc5));
      return rc5;
}

void ir_rc5_timer_end(unsigned long data)
{
      struct card_ir *ir = (struct card_ir *)data;
      struct timeval tv;
      unsigned long current_jiffies, timeout;
      u32 gap;
      u32 rc5 = 0;

      /* get time */
      current_jiffies = jiffies;
      do_gettimeofday(&tv);

      /* avoid overflow with gap >1s */
      if (tv.tv_sec - ir->base_time.tv_sec > 1) {
            gap = 200000;
      } else {
            gap = 1000000 * (tv.tv_sec - ir->base_time.tv_sec) +
                tv.tv_usec - ir->base_time.tv_usec;
      }

      /* signal we're ready to start a new code */
      ir->active = 0;

      /* Allow some timer jitter (RC5 is ~24ms anyway so this is ok) */
      if (gap < 28000) {
            dprintk(1, "ir-common: spurious timer_end\n");
            return;
      }

      if (ir->last_bit < 20) {
            /* ignore spurious codes (caused by light/other remotes) */
            dprintk(1, "ir-common: short code: %x\n", ir->code);
      } else {
            ir->code = (ir->code << ir->shift_by) | 1;
            rc5 = ir_rc5_decode(ir->code);

            /* two start bits? */
            if (RC5_START(rc5) != ir->start) {
                  dprintk(1, "ir-common: rc5 start bits invalid: %u\n", RC5_START(rc5));

                  /* right address? */
            } else if (RC5_ADDR(rc5) == ir->addr) {
                  u32 toggle = RC5_TOGGLE(rc5);
                  u32 instr = RC5_INSTR(rc5);

                  /* Good code, decide if repeat/repress */
                  if (toggle != RC5_TOGGLE(ir->last_rc5) ||
                      instr != RC5_INSTR(ir->last_rc5)) {
                        dprintk(1, "ir-common: instruction %x, toggle %x\n", instr,
                              toggle);
                        ir_input_nokey(ir->dev, &ir->ir);
                        ir_input_keydown(ir->dev, &ir->ir, instr,
                                     instr);
                  }

                  /* Set/reset key-up timer */
                  timeout = current_jiffies +
                          msecs_to_jiffies(ir->rc5_key_timeout);
                  mod_timer(&ir->timer_keyup, timeout);

                  /* Save code for repeat test */
                  ir->last_rc5 = rc5;
            }
      }
}

void ir_rc5_timer_keyup(unsigned long data)
{
      struct card_ir *ir = (struct card_ir *)data;

      dprintk(1, "ir-common: key released\n");
      ir_input_nokey(ir->dev, &ir->ir);
}

EXPORT_SYMBOL_GPL(ir_input_init);
EXPORT_SYMBOL_GPL(ir_input_nokey);
EXPORT_SYMBOL_GPL(ir_input_keydown);

EXPORT_SYMBOL_GPL(ir_extract_bits);
EXPORT_SYMBOL_GPL(ir_dump_samples);
EXPORT_SYMBOL_GPL(ir_decode_biphase);
EXPORT_SYMBOL_GPL(ir_decode_pulsedistance);

EXPORT_SYMBOL_GPL(ir_rc5_decode);
EXPORT_SYMBOL_GPL(ir_rc5_timer_end);
EXPORT_SYMBOL_GPL(ir_rc5_timer_keyup);

/*
 * Local variables:
 * c-basic-offset: 8
 * End:
 */

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