Re: [PATCH v10 5/6] usb:cdns3 Add Cadence USB3 DRD Driver
From: Roger Quadros
Date: Mon Aug 12 2019 - 09:05:02 EST
On 12/08/2019 15:46, Felipe Balbi wrote:
> Roger Quadros <rogerq@xxxxxx> writes:
>>> The sysfs file we expose from the class for the role switches is
>>> primarily meant for supporting proprietary protocols that require us
>>> to basically override the connector USB data role. The default role
>>> should always be selected in the drivers.
>> OK. Let's take this example
>> - Port is dual-role port micro AB.
>> - microAB to type-A adapter is connected which pulls ID low. port transitions
>> to "host" role by the controller driver.
>> - proprietary protocol want to switch role to device role so writes "device" to
>> mode switch sysfs. port transitions to "device" role.
>> Now, how does controller driver know to fall back to HW based role switching?
> Use a 'disconnect' or 'suspend' event to go reset it? But that should,
> probably, be done at kernel space, no?
Yes that could be one option.
So after a disconnect, sysfs role should reflect actual hardware role. correct?
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