From mboxrd@z Thu Jan 1 00:00:00 1970 From: maxime.ripard@free-electrons.com (Maxime Ripard) Date: Fri, 6 Jun 2014 18:05:52 +0200 Subject: [PATCH 3/5] regulator: axp20x: Update the bindings to use a local parent regulator In-Reply-To: <20140605154931.GY2520@sirena.org.uk> References: <1401297069-7423-1-git-send-email-maxime.ripard@free-electrons.com> <1401297069-7423-4-git-send-email-maxime.ripard@free-electrons.com> <20140528185051.GB22488@sirena.org.uk> <20140603131204.GJ27722@lukather> <20140603144319.GD31751@sirena.org.uk> <20140605142729.GG5765@lukather> <20140605154931.GY2520@sirena.org.uk> Message-ID: <20140606160552.GC9791@lukather> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Thu, Jun 05, 2014 at 04:49:31PM +0100, Mark Brown wrote: > On Thu, Jun 05, 2014 at 04:27:29PM +0200, Maxime Ripard wrote: > > > You already list the regulators available and their supply in the > > regulator driver, why do you need to set the regulator parents in the > > mfd driver as well? > > Unless they're being used by the MFD directly there should be no need > for the MFD to know anything about the supplies. Ok. > > My guess is that it's to work around the fact that > > regulator_dev_lookup only looks for the regulator's device of_node (so > > not the PMIC one, but one of its child), which doesn't have the supply > > properties, and then just falls back on the regulator alias > > list. Would it make some sense to add a lookup in the parent device > > of_node (which would be the "main" PMIC node in our case)? > > This sounds like you are passing the MFD child device into the regulator > API when you should be passing the parent device in. We're passing the device coming from the platform_device that is passed in probe, that has been created by mfd_add_device, which is indeed the child device from the MFD device. So we should always use the platform device parent's instead? > > Also, there's also the fact that all the supply properties seems to > > also be mandatory in the DT, even though the regulator itself might > > not be used at all on the board, and the input voltage not wired to > > anything. > > For electrical engineering reasons it's unlikely that the supplies are > actually floating but yes, they are mandatory. This is an issue with > registering one device for the entire regulator subsystem on the PMIC, > it interacts somewhat poorly with deferred probe. However for systems > with full constraints like DT and ACPI ones it should be mostly > sidestepped since the if there is no supply mapped a dummy supply will > be substituted. Yes, they are actually tied to the ground, but it's still something meaningless, that I guess shouldn't be expressed in the DT? -- Maxime Ripard, Free Electrons Embedded Linux, Kernel and Android engineering http://free-electrons.com -------------- next part -------------- A non-text attachment was scrubbed... Name: signature.asc Type: application/pgp-signature Size: 819 bytes Desc: Digital signature URL: