sample_alsa_soc_driver

This is a sample code for Linux ALSA SoC sound card device driver.

How to Use

Get the Linux kernel source and extract to /usr/src/linux.

• ex) apt-get install linux-source
• ex) wget https://cdn.kernel.org/pub/linux/kernel/v4.x/linux-x.y.z.tar.xz

Build the Linux kernel.

This device driver depends on ALSA SoC audio kernel libraries. Please set CONFIG_SND_SOC=m (or y) to enable the libraries.

# cd /usr/src/linux
# make menuconfig
# make

Location of CONFIG_SND_SOC as follows.

-> Device Drivers
  -> Sound card support (CONFIG_SOUND)
    -> Advanced Linux Sound Architecture (CONFIG_SND)
      -> ALSA for SoC audio support (CONFIG_SND_SOC)

Build this sample.

$ cd sample_alsa_soc_driver
$ make
make ARCH=x86_64 CROSS_COMPILE= -C /usr/src/linux M=/home/user/sample_alsa_soc_driver LDDINC=/home/user/sample_alsa_soc_driver modules
make[1]: Entering directory '/usr/src/linux'
  CC [M]  /home/katsuhiro/share/projects/c/sample_alsa_soc_driver/snd-sample-device.o
  CC [M]  /home/katsuhiro/share/projects/c/sample_alsa_soc_driver/snd-sample-utils.o
  ...
  CC      /home/katsuhiro/share/projects/c/sample_alsa_soc_driver/snd-sample-drv.mod.o
  LD [M]  /home/katsuhiro/share/projects/c/sample_alsa_soc_driver/snd-sample-drv.ko
make[1]: Leaving directory '/usr/src/linux'

Do insmod and rmmod.

Run modprobe if you set CONFIG_SND_SOC=m before running insmod.

# modprobe snd-soc-core

# insmod snd-sample-core.ko
# insmod snd-sample-i2s.ko
# insmod snd-sample-i2s-spdif.ko
# insmod snd-sample-device.ko
snd-sample-i2s snd-sample-i2s.0: Probed.
util_func.
snd-sample-i2s snd-sample-i2s.0: created.
platform spdif-dit.0: created.
snd-sample-i2s-spdif snd-sample-i2s-spdif.0: Probed.
snd-sample-i2s snd-sample-i2s.0: DAI probe.
snd-sample-i2s snd-sample-i2s.0: New.
snd-sample-i2s-spdif snd-sample-i2s-spdif.0: snd-soc-dummy-dai <-> snd-sample-i2s-dai0 mapping ok
snd-sample-i2s-spdif snd-sample-i2s-spdif.0: created.
loaded.

# rmmod snd-sample-device
snd-sample-i2s-spdif snd-sample-i2s-spdif.0: Removed.
snd-sample-i2s snd-sample-i2s.0: DAI remove.
snd-sample-i2s snd-sample-i2s.0: Free.
snd-sample-i2s snd-sample-i2s.0: Removed.
unloaded.

# rmmod snd-sample-i2s
# rmmod snd-sample-i2s-spdif
# rmmod snd-sample-core