From mboxrd@z Thu Jan 1 00:00:00 1970 From: Maxime Ripard Subject: Re: [PATCH 1/4] ARM: dts: sunxi: Add regulator-boot-on to usb host port regulator nodes Date: Thu, 25 Jun 2015 13:12:05 +0200 Message-ID: <20150625111205.GC2266@lukather> References: <1434814810-26285-1-git-send-email-hdegoede@redhat.com> <1434814810-26285-2-git-send-email-hdegoede@redhat.com> <5587C720.9040007@redhat.com> <20150623071646.GL2266@lukather> <5589167E.4020905@redhat.com> 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="fblc08uBQ7kpPybH" Return-path: Content-Disposition: inline In-Reply-To: <5589167E.4020905-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org> List-Post: , List-Help: , List-Archive: , List-Unsubscribe: , To: Hans de Goede Cc: Julian Calaby , "Mailing List, Arm" , devicetree , linux-sunxi List-Id: devicetree@vger.kernel.org --fblc08uBQ7kpPybH Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline On Tue, Jun 23, 2015 at 10:19:10AM +0200, Hans de Goede wrote: > Hi, > > On 23-06-15 09:16, Maxime Ripard wrote: > >On Mon, Jun 22, 2015 at 10:28:16AM +0200, Hans de Goede wrote: > >>Hi, > >> > >>On 22-06-15 02:30, Julian Calaby wrote: > >>>Hi Hans, > >>> > >>>On Sun, Jun 21, 2015 at 1:40 AM, Hans de Goede wrote: > >>>>u-boot will have turned on the power to the usb host ports, so mark them > >>>>as regulator-boot-on, this stops the power on the ports from temporarily > >>>>getting turned off during boot, causing issues with e.g. usb powered > >>>>harddisks. > >>> > >>>Stupid question: shouldn't u-boot set this property? > >> > >>We could make u-boot set this property but that will require a lot of code on > >>u-boot's side which is simply not there atm. And traditionally this property > >>is is simply a part of the dts files as shipped with the kernel. > > > >What happens if the property is set but the regulator is not actually > >enabled? > > Then its gets enabled when the regulator loads, so assuming that the usb driver > is enabled in the kernel config 0.5 (built-in) - 3 (module) seconds earlier then > it otherwise would. Ok, perfect then. > This is not a problem since usb-ports are normally always powered anyways That might be true using mainline u-boot, but might not be on other bootloaders, hence why I asked that. Maxime -- Maxime Ripard, Free Electrons Embedded Linux, Kernel and Android engineering http://free-electrons.com --fblc08uBQ7kpPybH--