From mboxrd@z Thu Jan 1 00:00:00 1970 From: Maxime Ripard Subject: Re: [PATCH v4] ARM: dts: sun8i: Add dts file for Olimex A33-OLinuXino Date: Thu, 28 Jul 2016 19:53:30 +0200 Message-ID: <20160728175330.GC6682@lukather> References: <1469450243-19138-1-git-send-email-stefan.mavrodiev@gmail.com> <30014119.IrjfP0xFry@linux-cigu> <20160727062146.GA6560@lukather> <1604486.mrBvLz4HRZ@linux-cigu> Reply-To: maxime.ripard-wi1+55ScJUtKEb57/3fJTNBPR1lH4CV8@public.gmane.org Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="9Ek0hoCL9XbhcSqy" Return-path: Sender: linux-sunxi-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org Content-Disposition: inline In-Reply-To: <1604486.mrBvLz4HRZ@linux-cigu> List-Post: , List-Help: , List-Archive: , List-Unsubscribe: , To: stefan.mavrodiev-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org Cc: dt-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org, pawel.moll-5wv7dgnIgG8@public.gmane.org, mark.rutland-5wv7dgnIgG8@public.gmane.org, ijc+devicetree-KcIKpvwj1kUDXYZnReoRVg@public.gmane.org, galak-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org, linux-I+IVW8TIWO2tmTQ+vhA3Yw@public.gmane.org, wens-jdAy2FN1RRM@public.gmane.org, devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-sunxi-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org List-Id: devicetree@vger.kernel.org --9Ek0hoCL9XbhcSqy Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline On Wed, Jul 27, 2016 at 01:02:41PM +0300, stefan.mavrodiev-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org wrote: > On Wednesday, July 27, 2016 8:21:46 AM EEST Maxime Ripard wrote: > > On Wed, Jul 27, 2016 at 08:12:29AM +0300, stefan.mavrodiev-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org wrote: > > > > > +®_dcdc1 { > > > > > + regulator-always-on; > > > > > + regulator-min-microvolt = <3300000>; > > > > > + regulator-max-microvolt = <3300000>; > > > > > + regulator-name = "vcc-dsi"; > > > > > +}; > > > > > > > > What is it used for? Is it really necessary to keep it on at all time? > > > > > > I think so. > > > This is the supply for the MMC. > > > > Then it's poorly named, and you should tie it to the MMC, and remove > > the always-on if it's only used by the mmc. always-on is supposed to > > be for regulators that shouldn't but turned off for the system to stay > > running. Some MMC regulator doesn't fit that description. > > It's named upon the A33 power pin - "VCC-DSI". Usually, it's based on the name of the output in the schematics, precisely because, from one board to another, it might have different usage. > If I remove "always-on" the board still will work, since dcdc1 is tied to > mmc0. > vmmc-supply = <®_dcdc1>; > > We assume this voltage will be always present and there are some pullups that > are tied to it (on i2c0 and i2c1 bus). In this case should I remove "always- > on" from the regulator node? No, you should just tie that regulator to the i2c buses as well. Maxime -- Maxime Ripard, Free Electrons Embedded Linux and Kernel engineering http://free-electrons.com --9Ek0hoCL9XbhcSqy--