From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933295AbcI1QMP (ORCPT ); Wed, 28 Sep 2016 12:12:15 -0400 Received: from muru.com ([72.249.23.125]:43264 "EHLO muru.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932579AbcI1QMH (ORCPT ); Wed, 28 Sep 2016 12:12:07 -0400 Date: Wed, 28 Sep 2016 09:12:03 -0700 From: Tony Lindgren To: "H. Nikolaus Schaller" Cc: =?utf-8?Q?Beno=C3=AEt?= Cousson , Rob Herring , Mark Rutland , Russell King , linux-omap@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, letux-kernel@openphoenux.org Subject: Re: [PATCH 2/3] DT: EVM: add LEDs Message-ID: <20160928161202.sv2xtcotypex2aop@atomide.com> References: <20160927194904.4im7ukktg5afjmki@atomide.com> <21B97601-328A-41DC-84EE-AA15A6977E98@goldelico.com> <20160928033703.erwozguik4rie3cn@atomide.com> <6004B143-F64B-4DA9-A054-3F2AB3FC2346@goldelico.com> <20160928151234.c3x36lhnvk4potdy@atomide.com> <22676D6D-0669-41BC-B45D-FCC07E8C14CB@goldelico.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <22676D6D-0669-41BC-B45D-FCC07E8C14CB@goldelico.com> User-Agent: Mutt/1.6.2-neo (2016-07-23) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * H. Nikolaus Schaller [160928 08:29]: > > > Am 28.09.2016 um 17:12 schrieb Tony Lindgren : > > > > * H. Nikolaus Schaller [160927 23:50]: > >> Hi, > >> > >>> Am 28.09.2016 um 05:37 schrieb Tony Lindgren : > >>> > >>> * H. Nikolaus Schaller [160927 13:11]: > >>>>> Am 27.09.2016 um 21:49 schrieb Tony Lindgren : > >>>>> How about this for defaults: > >>>>> > >>>>> - heartbeat for led3 > >>>>> - cpu0 for led4 > >>>>> - cpu1 for led5 > >>>> > >>>> Good idea. Will try. > >>>> > >>>> What I don't exactly know is if these gpios based on an I2C-expander > >>>> can handle cpu activity triggers or if they are locked up if this i2c > >>>> processing triggers another cpu activity... > >>> > >>> Oh right, if the GPIOs are on the i2c bus > >> > >> yes, they are all gpio9 which is the tca6424 on i2c5. > >> > >>> it's probably not a good > >>> idea :) Or at least will be inaccurate if the bus can sleep. > >> > >> I have tested a little by writing to /sys/class/leds/.../trigger. > >> > >> If I make one LED trigger by "cpu0" it is always on and if I make > >> a second one triggered by "cpu1" the heartbeat becomes irregular. > >> > >> So indeed this does not work. > > > > So should we just leave the default trigger unpopulated then? > > It is a matter of taste and something not easy to decide... > > And everything can be changed from user-space by some script > running during the boot process to a more meaningful setting. > > So the initial setting doesn't matter really much. > > Having some of the LEDs as heartbeat gives an (additional) > feedback that the kernel has booted. > > We could even take led1, led3 and led5 as heartbeat and the other > two as default-on. Would give a nice pattern showing that the LEDs > are not broken... > > So let me know how you would like to have it and I add it to a PATCH v2. Up to you for the blinking, I'm fine with the original version too unless you feel like changing it. Regards, Tony