From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751864AbdCCOhF (ORCPT ); Fri, 3 Mar 2017 09:37:05 -0500 Received: from bh-25.webhostbox.net ([208.91.199.152]:34207 "EHLO bh-25.webhostbox.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751593AbdCCOg7 (ORCPT ); Fri, 3 Mar 2017 09:36:59 -0500 Subject: Re: [PATCH v17 2/3] usb: USB Type-C connector class To: Peter Chen References: <20170221142405.76299-1-heikki.krogerus@linux.intel.com> <20170221142405.76299-3-heikki.krogerus@linux.intel.com> <20170303033529.GA18650@b29397-desktop> <20170303045246.GB18650@b29397-desktop> Cc: Heikki Krogerus , Greg KH , Felipe Balbi , Oliver Neukum , linux-kernel@vger.kernel.org, linux-usb@vger.kernel.org, Roger Quadros , Jun Li From: Guenter Roeck Message-ID: <992c2c82-d266-ca06-8e9a-b755fa358de4@roeck-us.net> Date: Fri, 3 Mar 2017 06:36:50 -0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.5.1 MIME-Version: 1.0 In-Reply-To: <20170303045246.GB18650@b29397-desktop> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit X-Authenticated_sender: linux@roeck-us.net X-OutGoing-Spam-Status: No, score=-1.0 X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - bh-25.webhostbox.net X-AntiAbuse: Original Domain - vger.kernel.org X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12] X-AntiAbuse: Sender Address Domain - roeck-us.net X-Get-Message-Sender-Via: bh-25.webhostbox.net: authenticated_id: linux@roeck-us.net X-Authenticated-Sender: bh-25.webhostbox.net: linux@roeck-us.net X-Source: X-Source-Args: X-Source-Dir: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 03/02/2017 08:52 PM, Peter Chen wrote: > On Thu, Mar 02, 2017 at 08:29:07PM -0800, Guenter Roeck wrote: >> On 03/02/2017 07:35 PM, Peter Chen wrote: >>> On Tue, Feb 21, 2017 at 05:24:04PM +0300, Heikki Krogerus wrote: >>>> +/* --------------------------------------- */ >>>> +/* Driver callbacks to report role updates */ >>>> + >>>> +/** >>>> + * typec_set_data_role - Report data role change >>>> + * @port: The USB Type-C Port where the role was changed >>>> + * @role: The new data role >>>> + * >>>> + * This routine is used by the port drivers to report data role changes. >>>> + */ >>>> +void typec_set_data_role(struct typec_port *port, enum typec_data_role role) >>>> +{ >>>> + if (port->data_role == role) >>>> + return; >>>> + >>>> + port->data_role = role; >>>> + sysfs_notify(&port->dev.kobj, NULL, "data_role"); >>>> + kobject_uevent(&port->dev.kobj, KOBJ_CHANGE); >>>> +} >>>> +EXPORT_SYMBOL_GPL(typec_set_data_role); >>>> + >>> >>> Hi Keikki, >>> >>> Have you tested this interface with real dual-role controller/board? >> >> If it helps, my primary test system is a HP Chromebook 13 G1. >> >>> What interface you use when you receive this event to handle >>> dual-role switch? I am wonder if a common dual-role class is >>> needed, then we can have a common user utility. >> >> I don't really understand "What interface you use when you receive >> this event". Can you explain ? >> > > I mean "How to trigger kernel USB controller driver do role switch?" > I think this should be handled by the lower level driver. I am wide open to other ideas, though. >>> >>> Eg, if "data_role" has changed, the udev can echo "data_role" to >>> /sys/class/usb-dual-role/role >>> >> That sounds like a kernel event delivered to user space via udev or >> sysfs notification and returned back into the kernel through a sysfs >> attribute. Do I understand that correctly ? >> > > Yes. > That doesn't sound like a good idea to me, and I don't see a technical reason to require it. Thanks, Guenter