Re: [PATCH v2 2/2] leds/powernv: Add driver for PowerNV platform

On 03/25/2015 10:51 AM, Benjamin Herrenschmidt wrote:

On Fri, 2015-03-20 at 16:34 +0530, Vasant Hegde wrote:

quoted

From: Anshuman Khandual <redacted>

This patch implements LED driver for PowerNV platform using the existing
generic LED class framework. It registers classdev structures for all
individual LEDs detected on the system through LED specific device tree
nodes. Device tree nodes specify what all kind of LEDs present on the
same location code. It registers LED classdev structure for each of them.

The platform level implementation of LED get and set state has been
achieved through OPAL calls. These calls are made available for the
driver by exporting from architecture specific codes.

As per the LED class framework, the 'brightness_set' function should not
sleep. Hence these functions have been implemented through global work
queue tasks which might sleep on OPAL async call completion.

All the system LEDs can be found in the same regular path /sys/class/leds/.
There are two different kind of LEDs present for the same location code,
one being the identify indicator and other one being the fault indicator.
We don't use LED colors. Hence our LEDs have names in this format.

        <location_code>:<ATTENTION|IDENTIFY|FAULT>

Any positive brightness value would turn on the LED and a zero value
would turn off the LED. The driver will return LED_FULL (255) for any
turned on LED and LED_OFF for any turned off LED.

Bryan, Richard,

  Did you get a chance to review this patchset?

-Vasant

Any comment from the LEDs folks ? I am not too familiar with the LED
subsystem so I would appreciate at least a cursory review of the high
level design :-)