Messages in this thread | | | Subject | Re: [PATCH v17 2/3] usb: USB Type-C connector class | From | Guenter Roeck <> | Date | Fri, 3 Mar 2017 06:36:50 -0800 |
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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
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