From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alex Courbot Date: Thu, 05 Jul 2012 02:36:48 +0000 Subject: Re: [PATCH] pwm-backlight: add regulator and GPIO support Message-Id: <4FF4FDC0.8020405@nvidia.com> List-Id: References: <1340976167-27298-1-git-send-email-acourbot@nvidia.com> <20120704104840.GJ24458@pengutronix.de> <4FF43692.2040805@nvidia.com> <20120704130056.GC30009@pengutronix.de> <4FF45DDF.9000306@nvidia.com> <20120704152451.GA7333@sirena.org.uk> In-Reply-To: <20120704152451.GA7333-GFdadSzt00ze9xe1eoZjHA@public.gmane.org> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Mark Brown Cc: Sascha Hauer , Thierry Reding , "linux-tegra-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , "linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , "linux-fbdev-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" On 07/05/2012 12:24 AM, Mark Brown wrote: > On Thu, Jul 05, 2012 at 12:14:39AM +0900, Alex Courbot wrote: >> On Wed 04 Jul 2012 10:00:56 PM JST, Sascha Hauer wrote: > >>> Also please be aware that using a regulator in the pwm backlight will >>> instantly break all existing users. That's hardly your fault though. > >> Sorry, I don't see why. Could you elaborate on this? > > All existing machines will start failing during probe as they won't be > able to find the regulator - you should ideally make sure everyone in > mainline gets an appropriate regulator set up. Oh, that is a mistake of mine then. Driver probe should continue if no regulator is declared (but should fail if some other error occured). I want to maintain backward compatibility with current users of the driver, so regulator/gpio specification should be optional. Thanks for all the feedback people - I will come back with a new version that addresses the points highlighted and also allows power on/off sequences to be specified in the device tree. Alex.