From mboxrd@z Thu Jan 1 00:00:00 1970 From: hdegoede@redhat.com (Hans de Goede) Date: Thu, 08 May 2014 09:29:16 +0200 Subject: [PATCH 4/7] usb: ehci-platform: add optional reset controller retrieval In-Reply-To: <20140507220049.GC7047@lukather> References: <1399434623-20383-5-git-send-email-maxime.ripard@free-electrons.com> <20140507220049.GC7047@lukather> Message-ID: <536B324C.1040806@redhat.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Hi, On 05/08/2014 12:00 AM, Maxime Ripard wrote: > On Wed, May 07, 2014 at 10:25:55AM -0400, Alan Stern wrote: >> On Tue, 6 May 2014, Maxime Ripard wrote: >> >>> From: Boris BREZILLON >>> >>> On the Allwinner's A31 SoC the reset line connected to the EHCI IP has to >>> be deasserted for the EHCI block to be usable. >>> >>> Add support for an optional reset controller that will be deasserted on >>> power off and asserted on power on. >>> >>> Signed-off-by: Boris BREZILLON >>> Signed-off-by: Maxime Ripard >> >> Is this really a _reset_ line? That is, when you assert the reset >> line, does it actually reset the EHCI controller, or does it merely >> leave the controller in a partially powered-down state? > > It actually resets the whole controller. > >> The difference is important. During suspend, the controller is >> supposed to remember the state of the port connections as well as other >> settings. If it doesn't, the controller and all attached USB devices >> will have to be reinitialized every time the controller resumes, which >> will increase the latency. > > So you're saying that we should move this to the probe then? Yes. Regards, Hans