From mboxrd@z Thu Jan 1 00:00:00 1970 From: Peter Chen Subject: Re: [RFC v2 00/13] usb/mmc/power: Fix USB/LAN when TFTP booting Date: Fri, 6 May 2016 13:44:59 +0800 Message-ID: <20160506054459.GA32359@shlinux2.ap.freescale.net> References: <1462451666-17945-1-git-send-email-k.kozlowski@samsung.com> <20160505224240.GA31429@rob-hp-laptop> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from mail-pa0-f66.google.com ([209.85.220.66]:34142 "EHLO mail-pa0-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751028AbcEFFxU (ORCPT ); Fri, 6 May 2016 01:53:20 -0400 Content-Disposition: inline In-Reply-To: <20160505224240.GA31429@rob-hp-laptop> Sender: linux-pm-owner@vger.kernel.org List-Id: linux-pm@vger.kernel.org To: Rob Herring Cc: Krzysztof Kozlowski , devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-samsung-soc@vger.kernel.org, linux-mmc@vger.kernel.org, linux-pm@vger.kernel.org, linux-usb@vger.kernel.org, Ulf Hansson , Sebastian Reichel , Dmitry Eremin-Solenikov , David Woodhouse , Greg Kroah-Hartman , Mark Brown , hverkuil@xs4all.nl, tjakobi@math.uni-bielefeld.de, Bartlomiej Zolnierkiewicz , m.szyprowski@samsung.com On Thu, May 05, 2016 at 05:42:40PM -0500, Rob Herring wrote: > On Thu, May 05, 2016 at 02:34:13PM +0200, Krzysztof Kozlowski wrote: > > Hi, > > > > This is a different, second try to fix usb3503+lan on Odroid U3 board > > if it was initialized by bootloader (e.g. for TFTP boot). > > > > First version: > > http://www.spinics.net/lists/linux-usb/msg140042.html > > > > > > Problem > > ======= > > When Odroid U3 (usb3503 + smsc95xx + max77686) boots from network (TFTP), > > the usb3503 and LAN smsc95xx do not show up in "lsusb". Hard-reset > > is required, e.g. by suspend to RAM. The actual TFTP boot does > > not have to happen. Just "usb start" from U-Boot is sufficient. > > > > From the schematics, the regulator is a supply only to LAN, however > > without toggling it off/on, the usb3503 hub won appear neither. > > > > > > Solution > > ======== > > This is very similar to the MMC pwrseq behavior so the idea is to: > > 1. Move MMC pwrseq drivers to generic place, > > You can do that, but I'm going to NAK any use of pwrseq bindings outside > of MMC. I think it is the wrong way to do things. The DT should describe > the devices. If they happen to be "simple" then the core can walk the > tree and do any setup. For example, look for "reset-gpios" and toggle > that GPIO. There is no need for a special node. > Oh, I am doing the same thing like this patch set doing. Then, how can we let things be generic like you mention at [1] if without common pwrseq driver/library? The properties like "reset-gpios" under USB child node seems can only be handled by USB driver. > > 2. Extend the pwrseq-simple with regulator toggling, > > 3. Add support to USB hub and port core for pwrseq, > > We discussed this for USB already[1] and is why we defined how to add > USB child devices. The idea is not to add pwrseq to that. > > Rob > > [1] http://www.spinics.net/lists/linux-usb/msg134082.html [1] http://www.spinics.net/lists/linux-usb/msg137312.html -- Best Regards, Peter Chen