News:

Attention: For security reasons,please choose a user name *different* from your login name.
Also make sure to choose a secure password and change it regularly.

Main Menu

set PS I2C Clock

Started by Bo850, December 12, 2024, 05:31:26 PM

Previous topic - Next topic

Bo850

Hello,

We are working with a TEC0850 and want to reduce the clock frequency on the first I2C bus from 400kHz (real 300kHz) to 100kHz. But we cannot do this by setting the clock-frequency in the DeviceTree "system-user.dtsi". Where or how can we reduce the clock?

root@petalinux:~# dmesg | grep i2c
[1.678223] i2c /dev entries driver
[ 1.678461] cdns-i2c ff020000.i2c: 400 kHz mmio ff020000 irq 32
[ 1.678847] cdns-i2c ff030000.i2c: 400 kHz mmio ff030000 irq 33
[1.680091] i2c i2c-0: Added multiplexed i2c bus 2
[1.680256] i2c i2c-0: Added multiplexed i2c bus 3

system-user.dtsi snippet

i2c0 {
    #address-cells = <1>;
    #size-cells = <0>;
    // Instantiate IIC multiplexer driver
    i2cmux: i2cmux@70 {
        compatible = "nxp,pca9548";
        #address-cells = <1>;
        #size-cells = <0>;
        reg = <0x70>;
        clock-frequency = <10000>;
        bb@0 { // /dev/i2c-2 TE0xyz
            #address-cells = <1>;
            #size-cells = <0>;
            reg = <0>;
            clock-frequency = <10000>;