From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752131AbdBIJVF (ORCPT ); Thu, 9 Feb 2017 04:21:05 -0500 Received: from mail.ltec.ch ([95.143.48.181]:43999 "EHLO mail.ltec.ch" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752042AbdBIJUq (ORCPT ); Thu, 9 Feb 2017 04:20:46 -0500 Subject: Re: [PATCH] leds: pca9532: Extend pca9532 device tree support 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 References: <725c338e-af4c-1332-6c27-462c2dc1b97f@gmail.com> From: Felix Brack Message-ID: <3bfc9206-18c7-470b-ca53-d7bdb9a34f0a@ltec.ch> Date: Thu, 9 Feb 2017 09:41:19 +0100 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:45.0) Gecko/20100101 Thunderbird/45.7.1 MIME-Version: 1.0 In-Reply-To: <725c338e-af4c-1332-6c27-462c2dc1b97f@gmail.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello Jacek, On 08.02.2017 20:42, Jacek Anaszewski wrote: > Hi Felix, > > On 02/08/2017 05:12 PM, Felix Brack wrote: >> 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'. > > It looks like all you need is default-state property. For the example with keeping the 'RUN' led turned on, yes. However I would have to configure PSC and PWM registers to make the 'RUN' LED blink, for example. > I'd rather avoid exposing prescaler and pwm registers in DT. I don't see that exposing PSC and PWM registers to the DT would do any harm. Is there something I'm missing here? > One could pass parameters to the driver but I think that is worse, as nowadays we have DT. regards Felix