linux/sound/drivers/opl4/opl4_mixer.c
Takashi Iwai 2eccd40803 ALSA: drivers: Constify snd_kcontrol_new items
Most of snd_kcontrol_new definitions are read-only and passed as-is.
Let's declare them as const for further optimization.
Constify snd_kcontrol_new items

There should be no functional changes by this patch.

Link: https://lore.kernel.org/r/20200103081714.9560-34-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>
2020-01-03 09:24:23 +01:00

83 lines
2.2 KiB
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);
unsigned long flags;
u8 reg = kcontrol->private_value;
u8 value;
spin_lock_irqsave(&opl4->reg_lock, flags);
value = snd_opl4_read(opl4, reg);
spin_unlock_irqrestore(&opl4->reg_lock, flags);
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);
unsigned long flags;
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);
spin_lock_irqsave(&opl4->reg_lock, flags);
old_value = snd_opl4_read(opl4, reg);
snd_opl4_write(opl4, reg, value);
spin_unlock_irqrestore(&opl4->reg_lock, flags);
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;
}