Pavel and Jacek On 11/17/2017 10:30 AM, Jingoo Han wrote: > On Friday, November 17, 2017 6:21 AM, Pavel Machek wrote: >> >> Hi! >> >>>>> If that does not yet exist... you want to create glue layer to be >> able >>>>> to use LED as a display backlight. (It may already exist, no idea). >>>>> >>>>> ... >>>>> >>>>> Actually or maybe a LED trigger. Just set LED's trigger to "this is >>>>> display backlight". >>>> >>>> There is one already: >>>> >>>> drivers/leds/trigger/ledtrig-backlight.c >>>> >>>> It adds a LED class device to the fb_notifier_list >>>> (drivers/video/fbdev/core/fb_notify.c) >>>> >>>> using fb_register_client(). The same is used in >>>> backlight_device_register (drivers/video/backlight/backlight.c). >>>> >>>> Actually why do you want to have this driver in the LED subsystem, >>>> if it is advertised as "designed for LCD display backlighting"? >>> >>> Well this is also advertised as a driver for Smart phone and tablet >> devices. And having worked with the Android lighting >>> solutions this is the preferred subsystem for Android. The Android OS >> manages the led brightness based on ALS values and in >>> turn calls into the driver to control the brightness register through >> the vendor provided lighting HAL. >>> >> >> Well.. if it can control other LEDs than just backlight, I believe it >> can stay in the LED subsystem. > > I also agree with your opinion. I will make the necessary changes for v4. Just a heads up I won't be posting v4 until after the US holiday so you don't think I abandoned everything. Dan > > Best regards, > Jingoo Han > >> >>> I am going to look at the backlight source to figure out how to get the >> same functionality using the backlight subsystem. >>> Otherwise I will plug in this driver to the backlight subsystem through >> the notifier. >>> >> >> The backlight trigger should be ok. >> >> Best regards, >> > Pavel >> -- >> (english) http://www.livejournal.com/~pavelmachek >> (cesky, pictures) >> http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html > -- ------------------ Dan Murphy -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
