From mboxrd@z Thu Jan 1 00:00:00 1970 From: stefan.mavrodiev@gmail.com (stefan.mavrodiev at gmail.com) Date: Wed, 27 Jul 2016 13:02:41 +0300 Subject: [PATCH v4] ARM: dts: sun8i: Add dts file for Olimex A33-OLinuXino In-Reply-To: <20160727062146.GA6560@lukather> References: <1469450243-19138-1-git-send-email-stefan.mavrodiev@gmail.com> <30014119.IrjfP0xFry@linux-cigu> <20160727062146.GA6560@lukather> Message-ID: <1604486.mrBvLz4HRZ@linux-cigu> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org 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 at gmail.com 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". 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? > Maxime Best regards, Stefan Mavrodiev