To use the HiFiBerry DAC, you need a specific Linux kernel. The kernels from the standard distributions will not work, because the I2S module is not part of the standard kernel yet. There are two ways to get the kernel.

• The easy way: Update the kernel using rpi-update to the latest version.
• The hard, but flexible way: compile it by yourself. Following the guide below it should not be too hard to compile the kernel by yourself and transfer it to your Raspberry Pi.

Compile the Linux kernel including PCM5102A support

Note that this guide is based on the special Linux 3.8 kernel. Since 3.10.23, HiFiBerry DAC support is already included in the standard Raspberry Pi kernel sources. You can use the sources, that come with your distribution instead of using the sources from Git as shown below.

The original guide to the compilation of the Linux kernel with I2S support was written on the Noise is good blog. I will only summarize the important steps here. This guide uses an Ubuntu Linux distribution. It is only needed to cross-compile the kernel.

1. Backup the SD card of the Raspberry Pi. We will replace the kernel of the operating system. If anything goes wrong, the Raspberry Pi will not boot anymore. Therefore it is a good idea, to have a backup. I usually dump the whole SD card on my Mac using dd.
2. Get the necessary tools and the ARM crosscompiler
   sudo apt-get update
sudo apt-get install git gcc-arm-linux-gnueabi make ncurses-dev
cd tools
git clone git://github.com/raspberrypi/tools.git
# we don't use the compiler from the tools package, but from the ubuntu package
CCPREFIX=/usr/bin/arm-linux-gnueabi-
3. Download the Linux kernel code with enabled I2S support from Github
   cd
mkdir linux
cd linux
git init
git fetch git://github.com/koalo/linux.git rpi-3.8.y-asocdev:refs/remotes/origin/rpi-3.8.y-asocdev
git checkout rpi-3.8.y-asocdev
   For the newer 3.10 kernel use the following commands:
   git fetch git://github.com/koalo/linux.git rpi-3.10.y:refs/remotes/origin/rpi-3.10.y
git checkout rpi-3.10.y

4. Clean up everything
cd ~/linux
make mrproper

5. Get the Kernel configuration from your Raspberry Pi
   1. Log on to your Raspberry Pi
   2. sudo zcat /proc/config.gz > .config
   3. Copy the .config file to the ~/linux directory on your computer
6. Enable the DMA module and the SOC codec driver
   1. ARCH=arm CROSS_COMPILE=${CCPREFIX} make oldconfig
ARCH=arm CROSS_COMPILE=${CCPREFIX} make menuconfig
   2. Device drivers –> Sound card support –> Advanced Linux Sound Architecture –> Alsa for SOC audio support –> Enable PCM5102 driver (or “build all ASoC CODEC drivers”)
   3. Device drivers –> DMA engine support –> BCM2708 DMA Engine support
7. Compile the kernel and the modules
   ARCH=arm CROSS_COMPILE=${CCPREFIX} make -j6
mkdir ~/modules
MODULES_TEMP=~/modules/
ARCH=arm CROSS_COMPILE=${CCPREFIX} INSTALL_MOD_PATH=${MODULES_TEMP} make modules_install
8. Collect all parts and transfer them to the Raspberry Pi
# package the kernel
cd ~/tools/mkimage
./imagetool-uncompressed.py ${KERNEL_SRC}/arch/arm/boot/zImage
# Copy the files
scp kernel.img pi@ip-of-your-raspberry-pi:
cd ~/modules
tar cvfz ../modules.tar.gz ./*
scp ../modules.tar.gz pi@ip-of-your-raspberry-pi:
9. Extract the data on your Raspberry Pi
cd /
rm -rf lib/modules lib/firmware
tar xvfz ~pi/modules.tar.gz
cp ~pi/kernel.img /boot
sync
reboot

If everything is correct, the Raspberry Pi should boot as usual.

Configure modules to load

Use the following /etc/modules.conf configuration:

$ more /etc/modules
# /etc/modules: kernel modules to load at boot time.
#
# This file contains the names of kernel modules that should be loaded
# at boot time, one per line. Lines beginning with "#" are ignored.
# Parameters can be specified after the module name.
#loop
#snd-bcm2835
snd_soc_bcm2708
snd_soc_bcm2708_i2s
bcm2708_dmaengine
snd_soc_pcm5102a
snd_soc_rpi_pcm5102a

This disables the onboard sound card and enables the HiFiBerry Mini DAC.

Also check the /etc/modprobe.d directory for all *blacklist.conf files. Have a look at all of them if one of the modules configured in /etc/modules.conf is blacklisted. Often the i2c-bcm2708 module is blacklisted. Delete those lines.

Reboot again.

Check if the Linux kernel recognizes the sound card

$ aplay -l
**** List of PLAYBACK Hardware Devices ****
card 0: sndrpipcm5102a [snd_rpi_pcm5102a], device 0: PCM5102A HiFi pcm5102a-hifi-0 []
Subdevices: 1/1
Subdevice #0: subdevice #0

That’s it, you can now use HifiBerry Mini like any other sound card.