Re: [PATCH 2/3] usb: roles: look up role switches attached to a graph endpoint

[sashiko-bot@kernel.org]

> usb_role_switch_get() and fwnode_usb_role_switch_get() look for a switch
> on the caller's parent device node or through device_connection.  That does
> not work when one controller exposes a role switch per connector endpoint:
> the switch is registered against the remote graph endpoint and the
> consumer, the connector, has no phandle to it.
> 
> Add usb_role_switch_at_endpoint(), which walks the caller's OF graph
> endpoints and matches a switch registered on the remote endpoint, and try
> it after the existing parent lookup.  A switch that is described by the
> graph but not registered yet comes back as -EPROBE_DEFER, as the rest of
> the role-switch API does, so the caller retries instead of concluding that
> the connector has no role switch at all.  There is no behaviour change for
> existing users: if nothing is registered against an endpoint the lookup
> falls through to the previous paths.
> 
> This is needed by DWC3 designs where two Type-C receptacles share one High
> Speed data bus.
> 
> Signed-off-by: Qianhui Xu <xiaqinghuan@mail.ustc.edu.cn>

Sashiko has reviewed this patch and found no issues.

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Sashiko AI review · https://sashiko.dev/#/patchset/20261106112811.963923-1-xiaqinghuan@mail.ustc.edu.cn?part=2