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/* mixer_hw.c
** Copyright (c) 2019, The Linux Foundation.
**
** Redistribution and use in source and binary forms, with or without
** modification, are permitted provided that the following conditions are
** met:
** * Redistributions of source code must retain the above copyright
** notice, this list of conditions and the following disclaimer.
** * Redistributions in binary form must reproduce the above
** copyright notice, this list of conditions and the following
** disclaimer in the documentation and/or other materials provided
** with the distribution.
** * Neither the name of The Linux Foundation nor the names of its
** contributors may be used to endorse or promote products derived
** from this software without specific prior written permission.
**
** THIS SOFTWARE IS PROVIDED "AS IS" AND ANY EXPRESS OR IMPLIED
** WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
** MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT
** ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS
** BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
** CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
** SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
** BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
** WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
** OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN
** IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
**/
#include <stdio.h>
#include <stdlib.h>
#include <stdarg.h>
#include <stdint.h>
#include <stdbool.h>
#include <string.h>
#include <unistd.h>
#include <fcntl.h>
#include <errno.h>
#include <ctype.h>
#include <poll.h>
#include <sys/ioctl.h>
#include <linux/ioctl.h>
#include <sound/asound.h>
#include "mixer_io.h"
/** Store the hardware (kernel interface) mixer data */
struct mixer_hw_data {
/* Card number for the mixer */
unsigned int card;
/* File descriptor of the mixer device node */
int fd;
};
static void mixer_hw_close(void *data)
{
struct mixer_hw_data *hw_data = data;
if (!hw_data)
return;
if (hw_data->fd >= 0)
close(hw_data->fd);
hw_data->fd = -1;
free(hw_data);
hw_data = NULL;
}
static int mixer_hw_ioctl(void *data, unsigned int cmd, ...)
{
struct mixer_hw_data *hw_data = data;
va_list ap;
void *arg;
va_start(ap, cmd);
arg = va_arg(ap, void *);
va_end(ap);
return ioctl(hw_data->fd, cmd, arg);
}
static ssize_t mixer_hw_read_event(void *data, struct snd_ctl_event *ev,
size_t size)
{
struct mixer_hw_data *hw_data = data;
return read(hw_data->fd, ev, size);
}
static const struct mixer_ops mixer_hw_ops = {
.close = mixer_hw_close,
.ioctl = mixer_hw_ioctl,
.read_event = mixer_hw_read_event,
};
int mixer_hw_open(unsigned int card, void **data,
const struct mixer_ops **ops)
{
struct mixer_hw_data *hw_data;
int fd;
char fn[256];
snprintf(fn, sizeof(fn), "/dev/snd/controlC%u", card);
fd = open(fn, O_RDWR);
if (fd < 0)
return fd;
hw_data = calloc(1, sizeof(*hw_data));
if (!hw_data)
return -1;
hw_data->card = card;
hw_data->fd = fd;
*data = hw_data;
*ops = &mixer_hw_ops;
return fd;
}
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