Re: [PATCH v12 1/2] leds: core: Introduce LED pattern trigger

From: Bjorn Andersson
Date: Mon Sep 24 2018 - 19:54:59 EST


On Mon 10 Sep 19:47 PDT 2018, Baolin Wang wrote:
[..]
> diff --git a/Documentation/ABI/testing/sysfs-class-led-trigger-pattern b/Documentation/ABI/testing/sysfs-class-led-trigger-pattern
[..]
> +What: /sys/class/leds/<led>/hw_pattern
> +Date: September 2018
> +KernelVersion: 4.20
> +Description:
> + Specify a hardware pattern for the LED, for LED hardware that
> + supports autonomously controlling brightness over time, according
> + to some preprogrammed hardware patterns.
> +
> + Since different LED hardware can have different semantics of
> + hardware patterns, each driver is expected to provide its own
> + description for the hardware patterns in their ABI documentation
> + file.
> +
> +What: /sys/class/leds/<led>/repeat
> +Date: September 2018
> +KernelVersion: 4.20
> +Description:
> + Specify a pattern repeat number. -1 means repeat indefinitely,
> + other negative numbers and number 0 are invalid.
> +
> + This file will always return the originally written repeat
> + number.

This captures the infinite case much better, thanks!

Given that 0 is described as invalid, does this imply that setting a new
pattern the repeat will be disabled? And hence if my hardware supports
only infinite or no-repeat setting a new pattern is the way to disable
further repeats (rather than just setting repeat = 0)?


Regardless, I believe the semantics of these two files will work fine
for my Qualcomm LPG driver.

Regards,
Bjorn