PWM frequency for LCD brightness in linux-3.10-at91

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merliness
Posts: 20
Joined: Mon Feb 06, 2012 2:57 pm

PWM frequency for LCD brightness in linux-3.10-at91

Mon May 29, 2017 3:33 pm

Hello,
I use the ARM AT91SAM9G35 with the linux-3.10-at91 and I would like to change the basic frequency of the LCD brightness. In this version of Linux, I think that , the backlight driver is not managed via the device tree. How do I change the base PWM
frequency and level of the backlight ?
In advance, thank you for your answer.
Best Regards,
blue_z
Location: USA
Posts: 1560
Joined: Thu Apr 19, 2007 10:15 pm

Re: PWM frequency for LCD brightness in linux-3.10-at91

Tue May 30, 2017 8:21 pm

merliness wrote:... I would like to change the basic frequency of the LCD brightness.
Since brightness does not have a frequency, what are you actually trying to accomplish?
merliness wrote:In this version of Linux, I think that , the backlight driver is not managed via the device tree.
"Managed" is the wrong word; the Device Tree is for configuration.
The backlight is also not a descrete device, but composed of bits and pieces scattered about the board.
merliness wrote:How do I change the base PWM frequency
You would have to hack the driver.
merliness wrote:... and level of the backlight ?
Use the sysfs interface.

Regards

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