Cirrus Logic Audio Card working on the Raspberry Pi 2

I tried the patched kernel with Ubuntu MATE Beta 15.04 and it worked.

But with the new stable release of Ubuntu the kernel breaks all network connections and input devices even bluetooth keyboard

Hello,

thank you for the provided image. The audio works fine.

However, I am trying to compile the kernel with cirrus driver and RT patch without success. I assume it already fails with the cirrus part.

I followed the cirrus instructions from here: https://github.com/CirrusLogic/rpi-linux/wiki/Building-the-code

and added the RT patch from https://www.kernel.org/pub/linux/kernel/projects/rt/3.18/older/patch-3.18.9-rt5.patch.gz

How did you build your image, Ragnar?

Martin

Hello,

thank you for the provided image. The audio works fine.

However, I am trying to compile the kernel with cirrus driver and RT patch without success. I assume it already fails with the cirrus part.

I followed the cirrus instructions from here: https://github.com/CirrusLogic/rpi-linux/wiki/Building-the-code

and added the RT patch from https://www.kernel.org/pub/linux/kernel/projects/rt/3.18/older/patch-3.18.9-rt5.patch.gz

How did you build your image, Ragnar?

Martin

Without success? Do you get any error message? Btw compiling takes several hours so maybe just wait longer? What was your last stap you did  following the guide?

Sorry, I should have been more specific. The kernel compiled fine but there was no audio. The provided image worked though.

aplay -l
aplay: device_list:252: no soundcards found...

I used the flash image as basis, compiled the kernel with cirrus and just copied the kernel and .dts file (even though it already existed of course). The reason was to see if my own compilation worked, so I could blame the rt patch if did not later on.

I went through the entire cross compilation guide using Xubuntu on a virtual machine and using scp to copy the file onto the pi2.

I wouldn't compile the kernel on another computer. Compiling on the pi is slower but easier You can simple let the kernel compile at night and the next morning it's ready. Also that way you can use other OS's like Ubuntu MATE

I'd very much recommend cross-compiling on a fast computer. On my notebook compiling a RPi kernel takes minutes. Cross-compiling a kernel for the RPi is very well documented and is relatively easy, not much more difficult then compiling on the RPi itself. Just my 2¢

I have only built the Cirrus 3.18 kernel once by cross-compiling. My cross-compiling environment is a Virtual-Boxed Lubuntu 14.04LTS, 64-bit machine on a fairly slow Windows XP host. Nowadays I use a build cluster comprising four RPi2B running distcc. The RPi cluster builds a kernel from scratch about four times faster than the old laptop.

Anyway, I have dredged up the bash history files from the one cross-compilation I did. That was for an RPi2B kernel. I followed the build instructions from Cirrus' Wiki pretty much to the letter.

NOTE: This is cobbled together from several different history files and partly from memory. I might have missed things...

Set up the build environment.

mkdir bin
cd ~/bin
mkdir raspberrypi
cd raspberrypi
git clone --depth 1 https://github.com/raspberrypi/tools
cd ~
mkdir code
cd code
git clone --depth 1 https://github.com/CirrusLogic/rpi-linux.git
export CCPREFIX=~/bin/raspberrypi/tools/arm-bcm2708/gcc-linaro-arm-linux-gnueabihf-raspbian-x64/bin/arm-linux-gnueabihf-

Build the kernel.

cd rpi-linux
make ARCH=arm bcm2709_defconfig
make ARCH=arm menuconfig # I add a couple of drivers I need.
ARCH=arm CROSS_COMPILE=${CCPREFIX} make -j4
ARCH=arm CROSS_COMPILE=${CCPREFIX} make -j4 modules

Put the kernel modules into a correct directory structure, but in a temporary directory.

mkdir -p ../modules_tmp
export INSTALL_MOD_PATH=../modules_tmp/
ARCH=arm CROSS_COMPILE=${CCPREFIX} make modules_install

Copy the kernel modules to the target machine. I use rsync, but scp -r works as well.

cd ../modules_tmp
rsync -av . target_machine:/
cd ../rpi-linux

Put the "This kernel is Device Tree enabled" signature on the kernel file and copy it to the target machine. Without the DT signature, the overlay file and hence the drivers will not load.

pushd arch/arm/boot/
mv zImage zImage.org
~/bin/raspberrypi/tools/mkimage/mkknlimg zImage.org zImage
scp zImage target_machine:/boot/kernel7.img
rm zImage.org
popd

Copy the overlay file to the target machine. NOTE: It's the .dtb file, not the .dts.

scp arch/arm/boot/dts/rpi-cirrus-wm5102-overlay.dtb target_machine:/boot/overlays/

Optionally, build a deb package. It will contain the kernel and modules, but not the overlay file.

ARCH=arm CROSS_COMPILE=${CCPREFIX} KBUILD_DEBARCH=armhf make deb-pkg

I hope you find something useful in the above.

As to how I built the image file itself:

I started out with a bog standard Raspbian image from the Foundation that I renamed to 2015-02-16-raspbian-wheezyW_CL.img.

I loopback mounted the partitions of the image file and then just copied and edited files manually.

First, I create mount points for the two partitions of the image.

mkdir -p /mnt/newboot /mnt/newroot

Then, I use fdisk to find out where the image file's partitions start.

root@quadripi# fdisk -l 2015-02-16-raspbian-wheezyW_CL.img

Disk 2015-02-16-raspbian-wheezyW_CL.img: 3276 MB, 3276800000 bytes
255 heads, 63 sectors/track, 398 cylinders, total 6400000 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x0009bf4f

                             Device Boot      Start         End      Blocks   Id  System
2015-02-16-raspbian-wheezyW_CL.img1            8192      122879       57344    c  W95 FAT32 (LBA)
2015-02-16-raspbian-wheezyW_CL.img2          122880     6399999     3138560   83  Linux

And finally, I mount the image's partitions to /mnt/newboot and /mnt/newroot respectively.

root@quadripi# mount -o loop,offset=$((8192 * 512)) 2015-02-16-raspbian-wheezyW_CL.img /mnt/newboot
root@quadripi# mount -o loop,offset=$((122880 * 512)) 2015-02-16-raspbian-wheezyW_CL.img /mnt/newroot

Then, it's just a matter of copying files to and editing files in the right places.

When done, unmount /mnt/newboot and /mnt/newroot and you have an image file ready to be flashed to an SD card.

Simple, really

--

Ragnar

I did cross-compile it on a fast Ubuntu computer, compiling is not the issue. It has to miss some configuration. I agree with Jeremy on this one.

Edit:

ragnar.jensen, thank you very much for the detailed instructions. I did follow it (hopefully to the letter) as well. But I will check your post step by step again, I might have missed something.

If everything works out, I should end up with your working image.

ragnar.jensen, looks like I missed this one

ARCH=arm CROSS_COMPILE=${CCPREFIX} make -j4 modules 

and I might missed reexecuting

./Playback_to_Lineout.sh

Are these settings stored permanently?

What do you mean by

Put the "This kernel is Device Tree enabled" signature on the kernel file and copy it to the target machine.

?

I used your image "2015-02-16-raspbian-wheezyW_CL.img" as base, installed sox, executed Playback_to_Lineout.sh and audio was working with .wav und .flac fine.

But after following the steps and copying my own compiled kernel I get this:

pi@raspberrypi ~ $ play testfile.wav 
play WARN alsa: can't encode 0-bit Unknown or not applicable
play FAIL sox: Sorry, there is no default audio device configured
pi@raspberrypi ~ $ aplay -l
**** List of PLAYBACK Hardware Devices ****
card 0: sndrpiwsp [snd_rpi_wsp], device 0: WM5102 AiFi wm5102-aif1-0 []
  Subdevices: 1/1
  Subdevice #0: subdevice #0

Thank you very much for your help!

The Cirrus Logic drivers are loaded by means of the Device Tree mechanism, controlled by the overlay file /boot/overlays/rpi-cirrus-wm5102-overlay.dtb.

You have to mark the kernel as Device Tree capable, otherwise the DT mechanism will be turned off. If it's not marked, it won't even try to load the overlay file and as a consequence the drivers aren't loaded either.

That's what these commands do:

mv zImage zImage.org 
~/bin/raspberrypi/tools/mkimage/mkknlimg zImage.org zImage

zImage is the compressed kernel image. Rename it to zImage.org and then run the command mkknlimg on it to create a new zImage with a Device-Tree-Capable stamp on it.

There's another command - knlinfo - to check if a kernel file has a DT stamp on it.

E.g.

$  ~/bin/raspberrypi/tools/mkimage/knlinfo zImage  # This kernel image is DT capable.
Kernel trailer found at 3946712/0x3c38d8:
  KVer: "Linux version 3.18.9-v7cludlmmapfllirq (ragnar@quadripi) (gcc version 4.8.3 (Raspbian 4.8.3-13) ) #5 SMP PREEMPT Fri May 1 18:06:15 CEST 2015"
  DTOK: true

$ ~/bin/raspberrypi/tools/mkimage/knlinfo zImage.org # This kernel image does not have the DT stamp.
* no trailer

Are these settings stored permanently?

Yes. The script /etc/init.d/alsa-utils saves all ALSA settings at shutdown and restores them at boot.

--

Ragnar

Thank you for the explanation.

Since I followed your guide and checked the image with knlinfo, the kernel should be DT capable.

Thus I should end up with an exact copy of your kernel. How come the audio card is not working? Even though aplay -l looks the fine.

I think it might be a problem with sox.

Try these

export AUDIODEV=hw:0,0

export AUDIODRIVER=alsa

before running sox.

Can you play the file with aplay?

--

Ragnar