From: Peter Chen <hzpeterchen@gmail.com>
To: Guenter Roeck <linux@roeck-us.net>
Cc: Heikki Krogerus <heikki.krogerus@linux.intel.com>,
Greg KH <gregkh@linuxfoundation.org>,
Felipe Balbi <felipe.balbi@linux.intel.com>,
Oliver Neukum <oneukum@suse.com>,
linux-kernel@vger.kernel.org, linux-usb@vger.kernel.org,
Roger Quadros <rogerq@ti.com>, Jun Li <jun.li@nxp.com>
Subject: Re: [PATCH v17 2/3] usb: USB Type-C connector class
Date: Mon, 6 Mar 2017 09:24:51 +0800 [thread overview]
Message-ID: <20170306012451.GB23305@b29397-desktop> (raw)
In-Reply-To: <992c2c82-d266-ca06-8e9a-b755fa358de4@roeck-us.net>
On Fri, Mar 03, 2017 at 06:36:50AM -0800, Guenter Roeck wrote:
> 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.
>
Would you show me how it works at your test system if it is not
a private thing?
> >>>
> >>>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.
>
I don't like it either, but current kernel has no ability to handle it
except you use hardware signal like extcon-gpio or controller id as
input pin to SoC handle this event.
--
Best Regards,
Peter Chen
next prev parent reply other threads:[~2017-03-06 1:25 UTC|newest]
Thread overview: 64+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-02-21 14:24 [PATCH v17 0/3] USB Type-C Connector class Heikki Krogerus
2017-02-21 14:24 ` [PATCH v17 1/3] lib/string: add sysfs_match_string helper Heikki Krogerus
2017-02-21 14:24 ` [PATCH v17 2/3] usb: USB Type-C connector class Heikki Krogerus
2017-03-02 15:22 ` Mats Karrman
2017-03-03 3:13 ` Guenter Roeck
2017-03-03 7:29 ` Mats Karrman
2017-03-03 9:48 ` Enric Balletbo Serra
2017-03-03 12:59 ` Heikki Krogerus
2017-03-03 14:49 ` Guenter Roeck
2017-03-03 19:27 ` Mats Karrman
2017-03-06 9:37 ` Oliver Neukum
2017-03-06 13:14 ` Heikki Krogerus
2017-03-07 22:30 ` Mats Karrman
2017-03-08 1:38 ` Guenter Roeck
2017-04-08 23:09 ` USB Type-C Port Manager API concern Mats Karrman
2017-04-09 15:16 ` Guenter Roeck
2017-04-09 21:05 ` Mats Karrman
2017-04-14 2:57 ` Guenter Roeck
2017-04-14 8:30 ` Mats Karrman
2017-03-08 13:58 ` [PATCH v17 2/3] usb: USB Type-C connector class Heikki Krogerus
2017-03-10 22:22 ` Mats Karrman
2017-03-10 23:41 ` Guenter Roeck
2017-04-18 18:52 ` Badhri Jagan Sridharan
2017-04-19 11:23 ` Heikki Krogerus
2017-04-19 14:45 ` Badhri Jagan Sridharan
2017-04-19 15:14 ` Guenter Roeck
2017-04-19 17:22 ` Badhri Jagan Sridharan
2017-04-19 19:29 ` Guenter Roeck
2017-04-20 12:24 ` Heikki Krogerus
2017-04-20 19:46 ` Badhri Jagan Sridharan
2017-04-21 12:12 ` Heikki Krogerus
2017-04-21 13:14 ` Guenter Roeck
2017-04-21 14:27 ` Rajaram R
2017-04-21 16:43 ` Guenter Roeck
2017-04-22 9:23 ` Rajaram R
2017-04-24 17:50 ` Badhri Jagan Sridharan
2017-04-25 8:26 ` Rajaram R
2017-04-25 14:10 ` Guenter Roeck
2017-04-27 6:20 ` Rajaram R
2017-04-27 18:10 ` Guenter Roeck
2017-04-28 10:52 ` Heikki Krogerus
2017-04-20 11:55 ` Heikki Krogerus
2017-03-03 14:41 ` Guenter Roeck
2017-03-03 3:35 ` Peter Chen
2017-03-03 4:29 ` Guenter Roeck
2017-03-03 4:52 ` Peter Chen
2017-03-03 14:36 ` Guenter Roeck
2017-03-06 1:24 ` Peter Chen [this message]
2017-03-03 14:31 ` Heikki Krogerus
2017-03-06 1:15 ` Peter Chen
2017-03-06 13:16 ` Heikki Krogerus
2017-03-07 1:36 ` Peter Chen
2017-03-07 8:57 ` Heikki Krogerus
2017-03-08 1:53 ` Guenter Roeck
2017-03-08 6:50 ` Peter Chen
2017-03-08 14:44 ` Guenter Roeck
2017-03-09 2:00 ` Peter Chen
2017-02-21 14:24 ` [PATCH v17 3/3] usb: typec: add driver for Intel Whiskey Cove PMIC USB Type-C PHY Heikki Krogerus
2017-02-21 15:42 ` [PATCH v17 0/3] USB Type-C Connector class Felipe Balbi
2017-03-21 11:14 ` Heikki Krogerus
2017-03-21 10:23 ` Greg KH
2017-03-21 10:37 ` Heikki Krogerus
2017-03-22 21:15 ` Mats Karrman
2017-03-23 8:16 ` Heikki Krogerus
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