From mboxrd@z Thu Jan 1 00:00:00 1970 From: =?iso-8859-1?Q?M=E5ns_Rullg=E5rd?= Subject: Re: [PATCH v3] usb: core: verify devicetree nodes for USB devices Date: Mon, 13 May 2019 11:06:39 +0100 Message-ID: References: <20190509084726.5405-1-m.szyprowski@samsung.com> <7c5579d2-634a-d705-a451-563939957d57@samsung.com> <3544eb61-2bd8-338d-8d62-d95a775528ef@samsung.com> <5d0abe9c-613c-d39b-6746-78e5e5c2bbc5@samsung.com> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: 8BIT Return-path: In-Reply-To: <5d0abe9c-613c-d39b-6746-78e5e5c2bbc5@samsung.com> (Marek Szyprowski's message of "Mon, 13 May 2019 12:03:18 +0200") Sender: linux-kernel-owner@vger.kernel.org To: Marek Szyprowski Cc: Peter Chen , "linux-usb@vger.kernel.org" , "linux-samsung-soc@vger.kernel.org" , "linux-kernel@vger.kernel.org" , Greg Kroah-Hartman , Bartlomiej Zolnierkiewicz , Markus Reichl , Krzysztof Kozlowski List-Id: linux-samsung-soc@vger.kernel.org Marek Szyprowski writes: > Hi Peter, > > On 2019-05-13 11:23, Peter Chen wrote: >>> On 2019-05-13 11:00, Peter Chen wrote: >>>>> On 2019-05-10 05:10, Peter Chen wrote: >>>>>>> Marek Szyprowski writes: >>>>>>>> Commit 69bec7259853 ("USB: core: let USB device know device node") >>>>>>>> added support for attaching devicetree node for USB devices. The >>>>>>>> mentioned commit however identifies the given USB device node only >>>>>>>> by the >>>>> 'reg' >>>>>>>> property in the host controller children nodes. The USB device >>>>>>>> node however also has to have a 'compatible' property as described >>>>>>>> in Documentation/devicetree/bindings/usb/usb-device.txt. Lack for >>>>>>>> the 'compatible' property check might result in assigning a >>>>>>>> devicetree node, which is not intended to be the proper node for the given >>> USB device. >>>>>>>> This is important especially when USB host controller has >>>>>>>> child-nodes for other purposes. For example, Exynos EHCI and OHCI >>>>>>>> drivers already define child-nodes for each physical root hub port >>>>>>>> and assigns respective PHY controller and parameters for them. >>>>>>>> Those binding predates support for USB devicetree nodes. >>>>>>>> >>>>>>>> Checking for the proper compatibility string allows to mitigate >>>>>>>> the conflict between USB device devicetree nodes and the bindings >>>>>>>> for USB controllers with child nodes. It also fixes the >>>>>>>> side-effect of the other commits, like 01fdf179f4b0 ("usb: core: >>>>>>>> skip interfaces disabled in devicetree"), which incorrectly >>>>>>>> disables some devices on Exynos based boards. >>>>>> Hi Marek, >>>>>> >>>>>> The purpose of your patch is do not set of_node for device under USB >>>>>> controller, >>>>> right? >>>>> >>>>> Right. >>>>> >>>> Do you mind doing it at function exynos_ehci_get_phy of ehci-exynos.c? >>> I don't mind fixing it in ehci-exynos, but frankly so far I have no >>> idea how to do it. The problem is that newly created USB devices >>> get of-node pointer pointing to a node which if not intended for >>> them. How this can be fixed in ehci-exynos? >>> >> >> Can't be workaround by setting of_node as NULL for EHCI controller or >> for PHY node at exynos_ehci_get_phy? > > Ah, such workaround? I will check, but this will need to be done with > care, because have a side effect for other subsystems like regulators or > clocks. > > BTW, What's wrong with proper, full verification of USB device nodes? Your approach so far doesn't address the actual problem of a conflict between the generic USB DT bindings and those for the Exynos host controller. If you fix that, the validation issue goes away. -- Måns Rullgård