From mboxrd@z Thu Jan 1 00:00:00 1970 From: Felix Brack Subject: Re: [PATCH] leds: pca9532: Extend pca9532 device tree support Date: Wed, 8 Feb 2017 17:12:09 +0100 Message-ID: References: Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org To: Jacek Anaszewski , riku.voipio@iki.fi, rpurdie@rpsys.net, pavel@ucw.cz, linux-leds@vger.kernel.org, linux-kernel@vger.kernel.org Cc: f.brack@eets.ch List-Id: linux-leds@vger.kernel.org Hello Jacek, On 07.02.2017 21:45, Jacek Anaszewski wrote: > Hi Felix, > > Thanks for the patch. > > On 02/07/2017 07:11 PM, Felix Brack wrote: >> This patch extends the device tree support for the pca9532 allowing LEDs to blink, dim or even being unchanged, i.e. not being turned off during driver initialization. > > Isn't it possible to apply desired settings with existing LED subsystem > brightness file, and delay_on/off files exposed by timer trigger? > > Best regards, > Jacek Anaszewski > This might be a misunderstanding. My patch is not meant to replace anything for driving the LEDs once the kernel is fully loaded. The LED subsystem offers quite a lot of possibilities to do this. My patch mainly deals with the 'default' state of the LEDs immediately when the driver gets loaded. Here is an example: I have a system with a LED named 'RUN' which is turned on steady by U-Boot (indicating "system booting"). When the PCA9532 driver loads this LED gets turned off due to initialization. However I would like it remain lit until later a script will make that 'RUN' LED blink (indicating "system running"). This script will of course use the existing LED subsystem to do so. To keep the 'RUN' LED lit I need the DT property 'default-state' being set to 'PCA9532_KEEP'. regards, Felix