From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752576Ab2H3HKQ (ORCPT ); Thu, 30 Aug 2012 03:10:16 -0400 Received: from mailout2.samsung.com ([203.254.224.25]:28658 "EHLO mailout2.samsung.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751925Ab2H3HKM convert rfc822-to-8bit (ORCPT ); Thu, 30 Aug 2012 03:10:12 -0400 X-AuditID: cbfee61a-b7fc66d0000043b7-0b-503f11d358e3 From: Jingoo Han To: "'Lars-Peter Clausen'" Cc: "'Thierry Reding'" , linux-kernel@vger.kernel.org, "'Sascha Hauer'" , linux-arm-kernel@lists.infradead.org, "'Dmitry Torokhov'" , linux-input@vger.kernel.org, "'Bryan Wu'" , "'Richard Purdie'" , linux-leds@vger.kernel.org, "'Florian Tobias Schandinat'" , linux-fbdev@vger.kernel.org, "=?utf-8?Q?'Beno=C3=AEt_Th=C3=A9baudeau'?=" , "'Jingoo Han'" References: <217877237.2758643.1345731587941.JavaMail.root@advansee.com> <50364FA4.7000401@metafoo.de> In-reply-to: <50364FA4.7000401@metafoo.de> Subject: Re: [PATCH] pwm: Call pwm_enable() before pwm_config() Date: Thu, 30 Aug 2012 16:10:11 +0900 Message-id: <002001cd867e$7e964130$7bc2c390$%han@samsung.com> MIME-version: 1.0 Content-type: text/plain; charset=utf-8 Content-transfer-encoding: 8BIT X-Mailer: Microsoft Office Outlook 12.0 Thread-index: Ac2BR2Mq93YkOxlERIyQgCbVgluCwgFNkDtw Content-language: ko X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFrrJLMWRmVeSWpSXmKPExsVy+t9jAd3LgvYBBq+eSFuc6PvAanHz0zdW i8u75rBZbH2zjtGBxePzJrkAxigum5TUnMyy1CJ9uwSujIefAwoWcFf0NJ9ha2B8wdHFyMkh IWAi8bnvFDuELSZx4d56ti5GLg4hgUWMEjumbWOBcH4xSpz8dp4VpIpNQE3iy5fDYB0iAloS U7+9ZQUpYhZYzSJx+v9rsISQQIbE698H2UBsTqCirZ33WUBsYQF7iRsr5zCC2CwCqhKTzvaC xXkFbCWu7ZvHDmELSvyYfA8ozgE0VF1iypRckDCzgLbEk3cXWEHCEkDhR391QUwRASOJ4yeF ISpEJPa9eMc4gVFoFpI5sxDmzEIyZxaSjgWMLKsYRVMLkguKk9JzDfWKE3OLS/PS9ZLzczcx ggP8mdQOxpUNFocYBTgYlXh4OTLtAoRYE8uKK3MPMUpwMCuJ8LLz2wcI8aYkVlalFuXHF5Xm pBYfYpTmYFES53U6B1QtkJ5YkpqdmlqQWgSTZeLglGpg7K0scns2PYm1dWVB8kOlj43rFmSV 63x6MiPQ4XlgXNMluad2qgard19k5dy8pyt24VbPjAWflet4xBxevuNQX5YpEyf2+Np0+5op 8emVmeKynAdXxylM3z41d9uvecwVh0JyzOY6h31ZkH37eKht1yzZve39Vj7LmKcfn3j58OM0 rZQZ+yXblViKMxINtZiLihMBSqkvQ2wCAAA= Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Friday, August 24, 2012 12:44 AM, Lars-Peter Clausen wrote: > > On 08/23/2012 04:19 PM, Benoît Thébaudeau wrote: > > Some PWM drivers enable the clock of the PWM peripheral in pwm_enable(). Hence, > > for these drivers, a call to pwm_config() does not have any effect before > > pwm_enable() has been called. > > > > This patch fixes the PWM users to make sure that they call pwm_enable() before > > pwm_config(). > > > > This fixes the first setting of brightness through sysfs that had no effect with > > leds-pwm and the i.MX PWM driver. > > But isn't this a bug in the PWM peripheral driver? With this change the PWM > will start with the old settings first. While this is not so much of a problem > for a backlight (although it might cause a short flickering) it might cause > problems for other applications, like using the PWM pin as a timing generator. > In my opinion it's better to fix the PWM peripheral drivers which have this > problem instead of trying to work around it in every user of the PWM API. Hi Lars-Peter Clausen, I think so. It would be better to fix the PWM peripheral drivers. Best regards, Jingoo Han > > - Lars > -- > To unsubscribe from this list: send the line "unsubscribe linux-fbdev" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html