From mboxrd@z Thu Jan 1 00:00:00 1970 From: marex@denx.de (Marek Vasut) Date: Wed, 20 Mar 2013 15:03:20 +0100 Subject: [PATCH V4 6/9] ARM: mxs: Provide regulator to pwm-backlight In-Reply-To: <20130320082318.GA28775@opensource.wolfsonmicro.com> References: <1363719573-20926-1-git-send-email-achew@nvidia.com> <5148E252.9050900@wwwdotorg.org> <20130320082318.GA28775@opensource.wolfsonmicro.com> Message-ID: <201303201503.20480.marex@denx.de> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Hi Mark, > On Tue, Mar 19, 2013 at 04:10:26PM -0600, Stephen Warren wrote: > > On 03/19/2013 03:27 PM, Marek Vasut wrote: > > > Do we really need a mandatory regulator? Why can't it be optional? > > > > IIRC, the previous advice I've seen is that if a device (driver) uses a > > regulator, it must /require/ a regulator, and if a particular board > > doesn't actually have a SW-controlled regulator, then a fixed- or dummy- > > regulator should be provided to satisfy this requirement. > > > > CC'ing Mark Brown to make sure I really do Recall Correctly. > > Yes, and it should be fixed rather than dummy. The issue is partly that > it's probably important that the device has power so we don't want to > just ignore errors and partly that this is something which applies to > essentially all devices so whatever we do for this case ought to be done > by the core so all devices can benefit and we don't have to duplicate > lots of code in individual drivers. Thanks for clearing this! Best regards, Marek Vasut