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Diffstat (limited to 'src/mixer_hw.c')
-rw-r--r-- | src/mixer_hw.c | 112 |
1 files changed, 112 insertions, 0 deletions
diff --git a/src/mixer_hw.c b/src/mixer_hw.c new file mode 100644 index 0000000..2e86dfa --- /dev/null +++ b/src/mixer_hw.c @@ -0,0 +1,112 @@ +/* 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 const struct mixer_ops mixer_hw_ops = { + .close = mixer_hw_close, + .ioctl = mixer_hw_ioctl, +}; + +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; +} |