From mboxrd@z Thu Jan 1 00:00:00 1970 From: Chunfeng Yun Subject: Re: [v2 PATCH] dt-binding: usb: add usb-role-switch property Date: Wed, 8 May 2019 14:26:42 +0800 Message-ID: <1557296802.10179.272.camel@mhfsdcap03> References: <38ff51264e971d5c58940c8435b9d8d274662d50.1557195204.git.chunfeng.yun@mediatek.com> <20190507141305.GA19816@kuha.fi.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20190507141305.GA19816@kuha.fi.intel.com> Sender: linux-kernel-owner@vger.kernel.org To: Heikki Krogerus Cc: Rob Herring , Greg Kroah-Hartman , Mark Rutland , Matthias Brugger , linux-usb@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-mediatek@lists.infradead.org, Biju Das , Yu Chen , Min Guo , Felipe Balbi List-Id: devicetree@vger.kernel.org On Tue, 2019-05-07 at 17:13 +0300, Heikki Krogerus wrote: > On Tue, May 07, 2019 at 10:22:58AM +0800, Chunfeng Yun wrote: > > diff --git a/Documentation/devicetree/bindings/usb/generic.txt b/Documentation/devicetree/bindings/usb/generic.txt > > index 0a74ab8dfdc2..f5a6ad053ecc 100644 > > --- a/Documentation/devicetree/bindings/usb/generic.txt > > +++ b/Documentation/devicetree/bindings/usb/generic.txt > > @@ -30,6 +30,11 @@ Optional properties: > > optional for OTG device. > > - adp-disable: tells OTG controllers we want to disable OTG ADP, ADP is > > optional for OTG device. > > + - usb-role-switch: tells Dual-Role USB controllers we want to handle the role > > + switch between host and device according to the state > > + detected by the USB connector, typically for Type-C, > > + Type-B(micro). > > + see connector/usb-connector.txt. > > That does not look correct to me. Firstly, USB role switches are not > always dual-role USB controllers. Thanks for review, I look through some drivers, you are right, some phys also switch the roles. > Secondly, stating what determines > the role irrelevant IMO. > > Since this is a boolean property, the description for it should simply > explain what does it tell about the capabilities of the device that > has it. The description should not make any assumptions about the > users of the property, and since the property is a "generic" USB > property, I'm not sure it should make any assumptions about the type > of the device that has the property either. Also, I would really like > the description to show the type of the property. Ok I'll add it. > > Why not just say something like this: > > "Boolean property informing that the device is capable of assigning > the USB data role (USB host or USB device) for a given USB connector." will modify it. > > > thanks, >