root/sound/drivers/opl4/opl4_mixer.c
// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * OPL4 mixer functions
 * Copyright (c) 2003 by Clemens Ladisch <clemens@ladisch.de>
 */

#include "opl4_local.h"
#include <sound/control.h>

static int snd_opl4_ctl_info(struct snd_kcontrol *kcontrol, struct snd_ctl_elem_info *uinfo)
{
        uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
        uinfo->count = 2;
        uinfo->value.integer.min = 0;
        uinfo->value.integer.max = 7;
        return 0;
}

static int snd_opl4_ctl_get(struct snd_kcontrol *kcontrol, struct snd_ctl_elem_value *ucontrol)
{
        struct snd_opl4 *opl4 = snd_kcontrol_chip(kcontrol);
        u8 reg = kcontrol->private_value;
        u8 value;

        guard(spinlock_irqsave)(&opl4->reg_lock);
        value = snd_opl4_read(opl4, reg);
        ucontrol->value.integer.value[0] = 7 - (value & 7);
        ucontrol->value.integer.value[1] = 7 - ((value >> 3) & 7);
        return 0;
}

static int snd_opl4_ctl_put(struct snd_kcontrol *kcontrol, struct snd_ctl_elem_value *ucontrol)
{
        struct snd_opl4 *opl4 = snd_kcontrol_chip(kcontrol);
        u8 reg = kcontrol->private_value;
        u8 value, old_value;

        value = (7 - (ucontrol->value.integer.value[0] & 7)) |
                ((7 - (ucontrol->value.integer.value[1] & 7)) << 3);
        guard(spinlock_irqsave)(&opl4->reg_lock);
        old_value = snd_opl4_read(opl4, reg);
        snd_opl4_write(opl4, reg, value);
        return value != old_value;
}

static const struct snd_kcontrol_new snd_opl4_controls[] = {
        {
                .iface = SNDRV_CTL_ELEM_IFACE_MIXER,
                .name = "FM Playback Volume",
                .info = snd_opl4_ctl_info,
                .get = snd_opl4_ctl_get,
                .put = snd_opl4_ctl_put,
                .private_value = OPL4_REG_MIX_CONTROL_FM
        },
        {
                .iface = SNDRV_CTL_ELEM_IFACE_MIXER,
                .name = "Wavetable Playback Volume",
                .info = snd_opl4_ctl_info,
                .get = snd_opl4_ctl_get,
                .put = snd_opl4_ctl_put,
                .private_value = OPL4_REG_MIX_CONTROL_PCM
        }
};

int snd_opl4_create_mixer(struct snd_opl4 *opl4)
{
        struct snd_card *card = opl4->card;
        int i, err;

        strcat(card->mixername, ",OPL4");

        for (i = 0; i < 2; ++i) {
                err = snd_ctl_add(card, snd_ctl_new1(&snd_opl4_controls[i], opl4));
                if (err < 0)
                        return err;
        }
        return 0;
}