From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alexandre Belloni Subject: Re: leds-pwm: issue in __led_pwm_set() Date: Thu, 26 Sep 2013 09:13:55 +0200 Message-ID: <5243DEB3.5020405@free-electrons.com> References: <524340CD.4060403@free-electrons.com> <52437FA4.8090501@ti.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Return-path: Received: from top.free-electrons.com ([176.31.233.9]:42053 "EHLO mail.free-electrons.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1752294Ab3IZHN6 (ORCPT ); Thu, 26 Sep 2013 03:13:58 -0400 In-Reply-To: <52437FA4.8090501@ti.com> Sender: linux-leds-owner@vger.kernel.org List-Id: linux-leds@vger.kernel.org To: Milo Kim Cc: linux-leds@vger.kernel.org, Thierry Reding On 26/09/2013 02:28, Milo Kim wrote: > Looping Thierry who maintains the PWM subsystem. > > I'm thinking your PWM driver is > https://lkml.org/lkml/2013/9/24/776. > Is it correct? > That is the one yes. > However, I can't find any pin control for the PWM output. > Just clock control and internal register access, PWM_EN and PWM_DIS. > Is the pin controlled via the registers? > Pin control is taken care of by the pinctrl-at91 driver, shouldn't that be enough ? > Best regards, > Milo > > On 09/26/2013 05:00 AM, Alexandre Belloni wrote: >> Hi, >> >> I'm using leds-pwm on an atmel sama5d31 based board. I have one >> question/issue. In __led_pwm_set(), if the duty cycle is 0, >> pwm_disable() is called. This won't work fine on that platform. What >> happens is that pwm_config() correctly sets the duty cycle to 0 which is >> behaving correctly with that controller (and in my case, putting the >> line low). But the call to pwm_disable() is making the pwm controller >> release the line and then it is set to high. >> >> I've tried various configurations, like configuring a pull-down on the >> pin but I still observe the same behavior. For now, I have a workaround >> in atmel-pwm (I activate the output overdrive when duty cycle is 0). But >> I believe, we should find another way to do that. >> >> Any input is appreciated. >> >> Regards, >> > > -- > To unsubscribe from this list: send the line "unsubscribe linux-leds" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html -- Alexandre Belloni, Free Electrons Embedded Linux, Kernel and Android engineering http://free-electrons.com