From mboxrd@z Thu Jan 1 00:00:00 1970 From: =?iso-8859-1?Q?M=E5ns_Rullg=E5rd?= Subject: Re: [PATCH v2] usb: core: verify devicetree nodes for disabled interfaces Date: Wed, 08 May 2019 12:46:33 +0100 Message-ID: References: <106fc58c-1a4f-6605-41d7-b6031c5751a3@samsung.com> <20190508104434.3409-1-m.szyprowski@samsung.com> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: 8BIT Return-path: In-Reply-To: <20190508104434.3409-1-m.szyprowski@samsung.com> (Marek Szyprowski's message of "Wed, 08 May 2019 12:44:34 +0200") Sender: linux-kernel-owner@vger.kernel.org To: Marek Szyprowski Cc: 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: > Commit 01fdf179f4b0 ("usb: core: skip interfaces disabled in devicetree") > add support for disabling given USB device interface by adding nodes to > the USB host controller device. The mentioned commit however identifies > the given USB interface node only by the 'reg' property in the host > controller children nodes and then checks for their the 'status'. The USB > device interface nodes however also has to have a 'compatible' property as > described in Documentation/devicetree/bindings/usb/usb-device.txt. This is > important, because USB host controller might have 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. This conflicts with the proposed > approach and verifying for the presence of the compatible property fixes > this issue without changing the bindings and the way the PHY controllers > are handled by Exynos EHCI/OHCI drivers. > > Reported-by: Markus Reichl > Fixes: 01fdf179f4b0 ("usb: core: skip interfaces disabled in devicetree") > Signed-off-by: Marek Szyprowski > --- > drivers/usb/core/message.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/drivers/usb/core/message.c b/drivers/usb/core/message.c > index e844bb7b5676..6f7d047392bd 100644 > --- a/drivers/usb/core/message.c > +++ b/drivers/usb/core/message.c > @@ -2009,6 +2009,7 @@ int usb_set_configuration(struct usb_device *dev, int configuration) > struct usb_interface *intf = cp->interface[i]; > > if (intf->dev.of_node && > + of_find_property(intf->dev.of_node, "compatible", NULL) && > !of_device_is_available(intf->dev.of_node)) { > dev_info(&dev->dev, "skipping disabled interface %d\n", > intf->cur_altsetting->desc.bInterfaceNumber); > -- I don't think this is the right approach. We don't want to be adding such checks everywhere the of_node is used. A better way might be to not set of_node at all in the absence of a proper "compatible" string. Then there's the problem of how to resolve the incompatibility between the generic USB and Exynos bindings. One possible fix could be to use a child node of the controller node to represent the root hub. Since the driver currently doesn't work at all if a devicetree has nodes for USB devices, there should be no compatibility concerns. -- Måns Rullgård