// SPDX-License-Identifier: GPL-2.0-or-later
/*
 *  Copyright (c) by Lee Revell <rlrevell@joe-job.com>
 *                   Clemens Ladisch <clemens@ladisch.de>
 *                   Oswald Buddenhagen <oswald.buddenhagen@gmx.de>
 *
 *  Routines for control of EMU10K1 chips
 */

#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 int delay;

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

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

        emu = snd_timer_chip(timer);
        snd_emu10k1_intr_disable(emu, INTE_INTERVALTIMERENB);
        return 0;
}

static unsigned long snd_emu10k1_timer_c_resolution(struct snd_timer *timer)
{
        struct snd_emu10k1 *emu = snd_timer_chip(timer);

        if (emu->card_capabilities->emu_model &&
            emu->emu1010.word_clock == 44100)
                return 22676;  // 1 sample @ 44.1 kHz = 22.675736...us
        else
                return 20833;  // 1 sample @ 48 kHz = 20.833...us
}

static int snd_emu10k1_timer_precise_resolution(struct snd_timer *timer,
                                               unsigned long *num, unsigned long *den)
{
        struct snd_emu10k1 *emu = snd_timer_chip(timer);

        *num = 1;
        if (emu->card_capabilities->emu_model)
                *den = emu->emu1010.word_clock;
        else
                *den = 48000;
        return 0;
}

static const struct snd_timer_hardware snd_emu10k1_timer_hw = {
        .flags = SNDRV_TIMER_HW_AUTO,
        .ticks = 1024,
        .start = snd_emu10k1_timer_start,
        .stop = snd_emu10k1_timer_stop,
        .c_resolution = snd_emu10k1_timer_c_resolution,
        .precise_resolution = snd_emu10k1_timer_precise_resolution,
};

int 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;
        err = snd_timer_new(emu->card, "EMU10K1", &tid, &timer);
        if (err >= 0) {
                strscpy(timer->name, "EMU10K1 timer");
                timer->private_data = emu;
                timer->hw = snd_emu10k1_timer_hw;
        }
        emu->timer = timer;
        return err;
}