Linux/PROCESSOR-SDK-AM437X: kernel 3.12 brightness issue

vimal kumar56

Tool/software: Linux

I am working on ti-sdk-linux-7.00.... having Linux version 3.12.20+. I am able to change the values of /sys/class/backlight/backlight.11/brightness from 0 to 8, But the brightness always remains at maximum. The values are changing but brightness is not changing at all.

In recent ti-sdk releases and linux version 4.10* is working fine. Any help how to make it work in 3.12 kernel.

over 8 years ago

0 Margarita Gashova over 8 years ago

TI__Guru* 80190 points

Hello,

I would recommend you to use the latest software release.
You could check these wikis:
processors.wiki.ti.com/.../AM335x_PWM_Driver's_Guide
processors.wiki.ti.com/.../Linux_Core_PWM_User's_Guide

Hope this helps.

BR
Margarita

0 vimal kumar56 over 8 years ago in reply to Margarita Gashova

Intellectual 560 points

Hi sir I end up reading these references and drivers probe. I found that I might have passing wrong parameters while enabling the "ehrpwm1_tblclk " in am43xx-clocks.dtsi file.

in 3.14 kernel and above the node is like

ehrpwm1_tbclk: ehrpwm1_tbclk {
#clock-cells = <0>;
compatible = "ti,gate-clock";
clocks = <&l4ls_gclk>;
ti,bit-shift = <1>;
reg = <0x0664>;
};

But in 3.12 kernel the node is like:

ehrpwm1_tbclk: ehrpwm1_tbclk@44df0664 {
#clock-cells = <0>;
compatible = "ti,gate-clock";
clocks = <&l4ls_gclk>;
ti,bit-shift = <1>;
reg = <0x44df0664 0x4>;
};

If you see the way "reg parameter" passed in both is different, how I put this 0x44df from seeing in another nodes being used in 3.12 kernel.

Can you suggest me where can I find the correct reg address for ehrpw1_tblclk.

Thank you.

Processors

Processors forum

Linux/PROCESSOR-SDK-AM437X: kernel 3.12 brightness issue