timer.c

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/*
 *  Copyright (c) by Lee Revell <[email protected]>
 *                   Clemens Ladisch <[email protected]>
 *  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 <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;
}