From mboxrd@z Thu Jan 1 00:00:00 1970 From: balbi@kernel.org (Felipe Balbi) Date: Wed, 15 Feb 2017 13:51:31 +0200 Subject: [PATCH v13 06/12] usb: xhci: use bus->sysdev for DMA configuration In-Reply-To: <2a3d2d65-e531-aaca-d5a1-a71f818cec61@ti.com> References: <1486776443-2280-1-git-send-email-peter.chen@nxp.com> <1486776443-2280-7-git-send-email-peter.chen@nxp.com> <20170215013514.GA6579@b29397-desktop> <20170215085127.GA26227@b29397-desktop> <2a3d2d65-e531-aaca-d5a1-a71f818cec61@ti.com> Message-ID: <87mvdnoenw.fsf@linux.intel.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Hi, Roger Quadros writes: >>>>>>>> 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? >>> >>> dwc3 is not setting "snps,usb3_lpm_capable" but "usb3-lpm-capable" for the >>> xhci platform device. >>> >>> What did you mean by firmware? Did you mean something like BIOS? >>> At least TI platforms don't use any firmware like BIOS. So dwc3 driver >>> needs to create a platform device for xhci on the fly and set the DT properties. >>> >> >> By readying code, the dwc3 calls dwc3_get_properties to set >> dwc->usb3_lpm_capable, and at dwc3/host.c, it sets property >> "usb3-lpm-capable" according to this flag, why not let common >> code xhci-plat.c to get this property from sysdev which is DT >> nodes for dwc3? >> > > Felipe, any comments? Won't work. We have quirk flags which are based on DWC3's revision which is not accessible by xhci-plat. Also, we can't call device_add_property() because it's not really *adding*. It's *setting*, meaning that we would loose all other properties. -- balbi -------------- next part -------------- A non-text attachment was scrubbed... Name: signature.asc Type: application/pgp-signature Size: 832 bytes Desc: not available URL: