Re: [PATCH] platform/chrome: Add Wilco EC keyboard backlight LEDs support

From: Pavel Machek
Date: Fri Mar 08 2019 - 17:13:24 EST


Hi!

> > This patch is meant to be applied on top of the for-next
> > branch of the platform/chrome repository, as it uses some of
> > the code staged there.
> >
> > The EC is in charge of controlling the keyboard backlight on
> > the Wilco platform. We expose a standard LED class device at
> > /sys/class/leds/wilco::kbd_backlight. This driver is modeled
> > after the standard Chrome OS keyboard backlight driver at
> > drivers/platform/chrome/cros_kbd_led_backlight.c
> >
> > Some Wilco devices do not support a keyboard backlight. This
> > is checked in probe(), and in this case the sysfs entry will
> > not appear, and everything will behave normally.
>
> It would be even better if we did not register platform device if EC
> does not support backlight.
>
> > + data->led.brightness_set = keyboard_led_set_brightness;
> > + data->led.brightness_get = keyboard_led_get_brightness;
>
> wilco_ec_mailbox() may sleep, so you need to assign it to
> led.brightness_set_blocking.

Hmm. Seeing get method there... can the EC change the brightness
without command from kernel?
Pavel
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

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