From mboxrd@z Thu Jan 1 00:00:00 1970 From: Vladimir Zapolskiy Subject: Re: [PATCH 1/2] backlight: pwm: don't call legacy pwm request for device defined in dt Date: Mon, 1 Dec 2014 16:47:38 +0200 Message-ID: <547C7F8A.40707@mentor.com> References: <1413035186-11771-1-git-send-email-vladimir_zapolskiy@mentor.com> <1413035186-11771-2-git-send-email-vladimir_zapolskiy@mentor.com> <20141107134848.GB31950@ulmo> <545CD4DC.4030409@mentor.com> <545CDDF5.70905@mentor.com> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Return-path: Received: from relay1.mentorg.com ([192.94.38.131]:58963 "EHLO relay1.mentorg.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932067AbaLAOro (ORCPT ); Mon, 1 Dec 2014 09:47:44 -0500 In-Reply-To: <545CDDF5.70905@mentor.com> Sender: linux-pwm-owner@vger.kernel.org List-Id: linux-pwm@vger.kernel.org To: Thierry Reding Cc: linux-fbdev@vger.kernel.org, linux-pwm@vger.kernel.org, Jingoo Han , Bryan Wu , Lee Jones Hello Thierry, On 07.11.2014 16:57, Vladimir Zapolskiy wrote: > Thierry, > > On 07.11.2014 16:19, Vladimir Zapolskiy wrote: >> Hi Thierry, >> >> On 07.11.2014 15:48, Thierry Reding wrote: >>> On Sat, Oct 11, 2014 at 04:46:25PM +0300, Vladimir Zapolskiy wrote: >>>> Platform PWM backlight data provided by board's device tree should be >>>> complete enough to successfully request a pwm device using pwm_get() API. >>>> >>>> Based on initial implementation done by Dmitry Eremin-Solenikov. >>>> >>>> Reported-by: Dmitry Eremin-Solenikov >>>> Signed-off-by: Vladimir Zapolskiy >>>> Cc: Thierry Reding >>>> Cc: Jingoo Han >>>> Cc: Bryan Wu >>>> Cc: Lee Jones >>>> --- >>>> drivers/video/backlight/pwm_bl.c | 14 +++++++------- >>>> 1 file changed, 7 insertions(+), 7 deletions(-) >>> >>> I don't really understand what this is supposed to do. The commit >>> message doesn't make a very good job of explaining it either. >>> >>> Can you describe in more detail what problem this fixes and why it >>> should be merged? >> >> thank you for review. >> >> As it is shown by the code this particular change rejects fallback to >> legacy PWM device request (which itself in turn is fixed in the next >> commit) for boards with supplied DTS, "pwm-backlight" compatible node >> and unregistered corresponding PWM device in that node. >> >> I don't know if there is a good enough reason to register PWM backlight >> device connected to some quite arbitrary PWM device, if no PWM device >> information is given in the "pwm-backlight" compatible node, so I think >> it makes sense to change the default policy. >> > > also please note that > Documentation/devicetree/bindings/video/backlight/pwm-backlight.txt > quite fairly describes "pwms" as a required property, but right now this > statement from the documentation is wrong, it is possible to register > pwm-backlight device driver (using notorious pwm_request() legacy API) > connected to some unspecified pwm device. > > I don't think that the current registration policy is correct, that's > why I propose to fix the logic instead of making a documentation update. > have you had a chance to check the rationale of the change? If you accept it, should I make the commit message more verbose? -- With best wishes, Vladimir