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timer.c

/*
 *  Copyright (c) by Lee Revell <rlrevell@joe-job.com>
 *                   Clemens Ladisch <clemens@ladisch.de>
 *  Routines for control of EMU10K1 chips
 *
 *  BUGS:
 *    --
 *
 *  TODO:
 *    --
 *
 *   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 <sound/driver.h>
#include <linux/time.h>
#include <sound/core.h>
#include <sound/emu10k1.h>

static int snd_emu10k1_timer_start(struct snd_timer *timer)
{
      struct snd_emu10k1 *emu;
      unsigned long flags;
      unsigned int delay;

      emu = snd_timer_chip(timer);
      delay = timer->sticks - 1;
      if (delay < 5 ) /* minimum time is 5 ticks */
            delay = 5;
      spin_lock_irqsave(&emu->reg_lock, flags);
      snd_emu10k1_intr_enable(emu, INTE_INTERVALTIMERENB);
      outw(delay & TIMER_RATE_MASK, emu->port + TIMER);
      spin_unlock_irqrestore(&emu->reg_lock, flags);
      return 0;
}

static int snd_emu10k1_timer_stop(struct snd_timer *timer)
{
      struct snd_emu10k1 *emu;
      unsigned long flags;

      emu = snd_timer_chip(timer);
      spin_lock_irqsave(&emu->reg_lock, flags);
      snd_emu10k1_intr_disable(emu, INTE_INTERVALTIMERENB);
      spin_unlock_irqrestore(&emu->reg_lock, flags);
      return 0;
}

static int snd_emu10k1_timer_precise_resolution(struct snd_timer *timer,
                                     unsigned long *num, unsigned long *den)
{
      *num = 1;
      *den = 48000;
      return 0;
}

static struct snd_timer_hardware snd_emu10k1_timer_hw = {
      .flags = SNDRV_TIMER_HW_AUTO,
      .resolution = 20833, /* 1 sample @ 48KHZ = 20.833...us */
      .ticks = 1024,
      .start = snd_emu10k1_timer_start,
      .stop = snd_emu10k1_timer_stop,
      .precise_resolution = snd_emu10k1_timer_precise_resolution,
};

int __devinit snd_emu10k1_timer(struct snd_emu10k1 *emu, int device)
{
      struct snd_timer *timer = NULL;
      struct snd_timer_id tid;
      int err;

      tid.dev_class = SNDRV_TIMER_CLASS_CARD;
      tid.dev_sclass = SNDRV_TIMER_SCLASS_NONE;
      tid.card = emu->card->number;
      tid.device = device;
      tid.subdevice = 0;
      if ((err = snd_timer_new(emu->card, "EMU10K1", &tid, &timer)) >= 0) {
            strcpy(timer->name, "EMU10K1 timer");
            timer->private_data = emu;
            timer->hw = snd_emu10k1_timer_hw;
      }
      emu->timer = timer;
      return err;
}

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