LED backlight driver

Dushara Jayasinghe dushara at successful.com.au
Wed Nov 23 20:09:42 EST 2016

Hi all,

Just a generic question re backlight drivers in the 4.4 kernel.

I'm working on an embedded system where the hardware configuration is 
specified in the device tree. On the LCD panel side, there's a simple 
panel driver which has an optional reference to a backlight driver.

I noticed that there are bunch of drivers that interfaces to various 
hardware controllers (e.g. bl-pwm, lm3533 etc). It makes sense to me 
that there could be a backlight driver that references an led_cdev 
driver (again via the device tree mechanism). However no such driver 
exists and I wonder if there is a technical reason for this. As far as I 
can see, the API seems to map quite nicely...

Just to add a bit more context, the board I'm working on has an LCD 
panel with the backlight driven by an LT3593 LED controller. The kernel 
has an old LED driver for this particular controller 
(drivers/led/leds-lt3593) - which I've modified to add DT support. 
Rather than writing an additional controller specific backlight driver, 
I thought it makes more sense to provide a more generic solution.


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