i.MX ProcessorsのトピックModify LED brightness level

Modify LED brightness level

pehenazam — Thu, 24 Aug 2017 09:34:54 GMT

I'd to modify minimum/maximum brightness for the LED driver (PCA9632 driver). in linux I have the interface for to set brightness level between 0 and 10 using interface `/sys/class/backlight/backlight_keypad/`

I can modify `/sys/class/backlight/backlight_keypad/brightness` but I cannot modify it out of 0-10. I like to have it 0-256 so I can have lower brightness. Based on the driver datasheet and driver source in Individual brightness control mode, each LED output has its own 8-bit resolution (256 steps) so it should be possible to set 0-256. But where should I change it so I would have all 0-256 levels, in the driver source code or linux kernel or somewhere else?

Thanks

Re: Modify LED brightness level

igorpadykov — Thu, 24 Aug 2017 10:09:59 GMT

Hi Pehen

one can check what actual values are written by driver/application, as brightness change

may be very small for 1 bit and it intentionally uses less levels. For debugging one can use

AN4553 Using Open Source Debugging Tools for Linux on i.MX Processors
http://www.nxp.com/assets/documents/data/en/application-notes/AN4553.pdf

Best regards
igor
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