From mboxrd@z Thu Jan 1 00:00:00 1970 From: Peter Chen Subject: Re: [PATCH v13 06/12] usb: xhci: use bus->sysdev for DMA configuration Date: Wed, 15 Feb 2017 09:35:14 +0800 Message-ID: <20170215013514.GA6579@b29397-desktop> References: <1486776443-2280-1-git-send-email-peter.chen@nxp.com> <1486776443-2280-7-git-send-email-peter.chen@nxp.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org To: Arnd Bergmann Cc: Roger Quadros , Mark Rutland , Peter Chen , Ulf Hansson , Heiko Stuebner , stephen.boyd@linaro.org, frank.li@nxp.com, Linux Kernel Mailing List , gary.bisson@boundarydevices.com, Vivek Gautam , Sriram Dash , festevam@gmail.com, stillcompiling@gmail.com, dbaryshkov@gmail.com, vaibhav.hiremath@linaro.org, Krzysztof Kozlowski , mka@chromium.org, stern@rowland.harvard.edu, devicetree@vger.kernel.org, mail@maciej.szmigiero.name, pawel.moll@arm.com, linux-pm@vger.kernel.org, s.hauer@pengutronix.de, troy.kisky@boundarydevices.com, Rob Herring , Alexander List-Id: devicetree@vger.kernel.org On Tue, Feb 14, 2017 at 01:58:40PM +0100, Arnd Bergmann wrote: > On Tue, Feb 14, 2017 at 1:26 PM, Roger Quadros wrote: > > On 14/02/17 13:44, Arnd Bergmann wrote: > >> On Tue, Feb 14, 2017 at 11:36 AM, Roger Quadros wrote: > > >>> Why are we using sysdev to read DT property? We should be using the > >>> XHCI device (&pdev->dev) here, no? > >> > >> If I remember correctly, this is one of the cases where pdev does not > >> have a device node attached to it because it was created by the driver > >> of the parent device on the fly in case of dwc3. When you have a pure xhci > >> device in DT, the two pointers are the same. > > > > From drivers/usb/dwc3/host.c > > > >> if (dwc->usb3_lpm_capable) { > >> props[0].name = "usb3-lpm-capable"; > >> ret = platform_device_add_properties(xhci, props); > >> if (ret) { > >> dev_err(dwc->dev, "failed to add properties to xHCI\n"); > >> goto err1; > >> } > >> } > > > > So it is setting the usb3-lpm-capable property into the xhci platform device > > and we should be reading the property from there. Why dwc3 needs another "snps,usb3_lpm_capable"? Why not using "usb3-lpm-capable" at firmware directly? Peter > > Hmm, ideally we would only have properties on one of the two, since we > refer to the sysdev for the properties regarding DMA and PHY among other > things, but I guess that's not an option here, since we can't call > platform_device_add_properties() on a dwc_pci device and have to > use the xhci pdev instead. > > Arnd > -- Best Regards, Peter Chen