From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mathias Nyman Subject: Re: [PATCH 3/6] xhci: probe phy before add usb_hcd Date: Mon, 01 Jun 2015 18:17:04 +0300 Message-ID: <556C7770.70506@intel.com> References: <1432727283-20303-1-git-send-email-chunfeng.yun@mediatek.com> <1432727283-20303-4-git-send-email-chunfeng.yun@mediatek.com> <20150527121843.GA8611@saruman.tx.rr.com> <1433170337.12128.18.camel@mtksdaap41> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1433170337.12128.18.camel@mtksdaap41> Sender: devicetree-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Yingjoe Chen , balbi-l0cyMroinI0@public.gmane.org Cc: chunfeng.yun-NuS5LvNUpcJWk0Htik3J/w@public.gmane.org, Mark Rutland , devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Sascha Hauer , linux-usb-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Rob Herring , linux-mediatek-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, Matthias Brugger , linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, Maxime Ripard , Roger Quadros List-Id: linux-mediatek@lists.infradead.org On 01.06.2015 17:52, Yingjoe Chen wrote: > On Wed, 2015-05-27 at 07:18 -0500, Felipe Balbi wrote: >> On Wed, May 27, 2015 at 07:48:00PM +0800, chunfeng.yun-NuS5LvNUpcJWk0Htik3J/w@public.gmane.org wrote: >>> From: Chunfeng Yun >>> >>> find the phy driver before add primary usb_hcd to avoid acessing >>> xHCI register which may hangup the system when the phy is not loaded >>> yet and the related powers or clocks put in phy driver are not >>> enabled. >> >> it seems like the same clock is needed by PHY and XHCI. This patch looks >> incorrect. > > > Hi, > > I agree that the driver should enable clock it used by itself and not > depends on init order. This should be fixed. > > But in general, I think it make sense to only add hcd after all required > resource are ready. At least it remove unnecessary calls to > usb_add_hcd/usb_remove_hcd. Is it better if the commit message is > changed to something like the below? > > Currently xhci_plat_probe() call usb_add_hcd before trying to init the > phy. However if the phy is not ready at the moment, it have to remove > the hcd and probe again later > > Change the init order so we only add hcd when all required resource are > ready. > Hi Rogers Quadros patchseries that changes how HCDs are created and added for xhci-plat was just sent forward. It first creates both HCDs, then adds them. Doesn't usb_add_hcd() as it's first task take care of the PHYs? I'm hoping to remove that part completely from xhci-plat.c but haven't looked into it properly yet. -Mathias -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html