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sonocotta / tas5805m-for-raspbian-paspberry-pi-zero

device tree and kernel module for running TI TAS5805M DAC on Raspberry Pi
GNU General Public License v3.0
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TAS5805M DAC running Raspbian on Raspberry Pi (Zero, Zero W, Zero 2W)

This repository contains the device tree and source for the tas5805m kernel module for Raspberry Pi Zero running under Raspbian. I prepared this repo to do it quickly

We're about to build kernel modules, so we need to install a few dependencies first (all commands going forward are running on the target host, ie Raspberry Pi) 

$ sudo apt update && sudo apt install git raspberrypi-kernel-headers build-essential -y

Let's get code from GitHub 

$ git clone https://github.com/sonocotta/tas5805m-for-raspbian-paspberry-pi-zero && cd tas5805m-for-raspbian-paspberry-pi-zero

Device tree

We need to add user overlays to enable I2S (disabled by default) and enable a sound card on that port

$ sudo ./compile-overlay.sh

this will compile the overlay file, put the compiled file under /boot/overlays

Next add to /boot/config.txt

# Enable DAC
dtoverlay=tas5805m,i2creg=0x2d

You may also comment out built-in audio and HDMI if you're running headless

#dtparam=audio=on
#dtoverlay=vc4-kms-v3d

You need to reboot for changes to take effect, but this will not work just yet. The problem is we are referencing the tas5805m kernel module there, and this one is not included in Raspbian. Therefore we will build it on the same board using current kernel sources that we just installed

Kernel module

Now you are ready to build. The first command produces tas5805m.ko file among others. Second will copy it to the appropriate kernel modules folder.

$ make all
$ sudo make install

Now we are ready to reboot and check if we have a sound card listed

$ aplay -l
**** List of PLAYBACK Hardware Devices ****
card 0: LouderRaspberry [Louder-Raspberry], device 0: bcm2835-i2s-tas5805m-amplifier tas5805m-amplifier-0 [bcm2835-i2s-tas5805m-amplifier tas5805m-amplifier-0]
  Subdevices: 1/1
  Subdevice #0: subdevice #0

Check if new module is correctly loaded

$ lsmod | grep tas5805m
tas5805m                6269  1
regmap_i2c              5027  1 tas5805m
snd_soc_core          240140  4 snd_soc_simple_card_utils,snd_soc_bcm2835_i2s,tas5805m,snd_soc_simple_card

Now quick test if audio is functional

speaker-test -t sine -f 500 -c 2

And finally, I can hear a beeping sound in both speakers. Hooray!

References