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Enable I2C, I2s, SPI in boot-config file? - Printable Version

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+--- Thread: Enable I2C, I2s, SPI in boot-config file? (/showthread.php?tid=5409)

Enable I2C, I2s, SPI in boot-config file? - HelgeMK - 12-01-2017

Hi, 

I wonder if someone can help me with this one: in the past I used a Raspberry Pi to run via the GPIOs a stepper motor. That required updating of the /boot/config.txt file (on the RPi) as follows:

Enable i2c, i2s and spi (only if not already enabled)

$ echo "dtparam=i2c_arm=on" >> /boot/config.txt

$ echo "dtparam=i2s=on" >> /boot/config.txt

$ echo "dtparam=spi=on" >> /boot/config.txt

$ echo "dtoverlay=pps-gpio,gpiopin=24" >> /boot/config.txt

I have not found in the boot directory of the Rock64 anything similar, and do not know whether required.

In this Forum I came across this thread on 

https://forum.pine64.org/showthread.php?tid=5331 which refers to a package RPi.GPIO-PineA64 package to configure the GPIOs. Is this something I should do to enable I2C, I2s and SPI?

Would really appreciate your help.

Thanks in advance, 

Helge

RE: Enable I2C, I2s, SPI in boot-config file? - Kappuchino - 07-15-2018

Helge, I have a similar problem. Have you figured out what you were hoping to achieve?

RE: Enable I2C, I2s, SPI in boot-config file? - KnReLe - 07-16-2018

It seems that the way things are, the devices are not enablet right away. However, they can be enabled via "dts overlays", essentially additional changes to the internal "device tree" structure.

See https://github.com/ayufan-rock64/linux-build/blob/master/recipes/additional-devices.md#use-additional-devices

There is an example there of enabling a network interface. I found that I could enable the i2c-0 bus (the one on pins P3 and P5) by the following command, run as root:

enable_dtoverlay i2c0 i2c@ff150000 okay

where the names such as "i2c@ff150000" are found in the device-tree-source file on the github repository:

https://github.com/ayufan-rock64/linux-kernel/blob/release-4.4/arch/arm64/boot/dts/rockchip/rk3328.dtsi

Now, note that a number of GPIOs are already in use for various other purposes (the SPI for exampe is used for an on-board memory chip) and might not be readily available.

To have this happen on startup, put it into /etc/rc.local

RE: Enable I2C, I2s, SPI in boot-config file? - pas059 - 08-14-2018

Hi,

starting with the info given in the post KnReLe, i write a little app in C++ that uses i2c0 bus. This works but requires the app to be executed as root. As i'm not a linux expert, i were looking for a solution and find the following so that this i2c bus could be used all the time outside root:

  1. create a user group (for instance i2cuser) and add rock64 (my user account) to the group 
       $sudo addgroup i2cuser   $sudo usermod -a -G i2cuser rock64
  2. create a script /usr/local/sbin/i2c0add.sh :
    Code:
    #!/bin/bash
    #script to add i2c-0 to the devices
    echo Create /dev/i2c-0
    enable_dtoverlay i2c0 i2c@ff150000 okay
    #change owner:group of /dev/i2c-0
    chown root:i2cuser /dev/i2c-0


  3. create a systemd service file /etc/systemd/system/i2c0add.service :
    Code:
    [Unit]
    Description=Service to create i2c0 device
    After=sockets.target

    [Service]
    Type=oneshot
    RemainAfterExit=no
    ExecStart=/usr/local/sbin/i2c0add.sh

    [Install]
    WantedBy=multi-user.target


  4. enable the execution of the service at startup:
      $sudo systemctl enable /etc/systemd/system/i2c0add.service
I hope that i did not forget something. I not sure that this is the best solution but this works.
In addition, linux version is 18.04 LTS (Bionic Beaver)
I am also looking for a solution for using the gpio lines as non root, but until now without success. 
If someone has a solution....



Regards