Re: [PATCH 1/2] dt-bindings: usb: dwc3: Document role-switch-reset-quirk

From: Rob Herring
Date: Tue Oct 26 2021 - 19:25:30 EST


On Sun, Oct 17, 2021 at 02:59:03PM +0200, Sven Peter wrote:
> The dwc3 controller on the Apple M1 must be reset whenever a
> device is unplugged from the root port and triggers a role
> switch notification. Document the quirk to enable this behavior.
>
> Signed-off-by: Sven Peter <sven@xxxxxxxxxxxxx>
> ---
> Documentation/devicetree/bindings/usb/snps,dwc3.yaml | 6 ++++++
> 1 file changed, 6 insertions(+)
>
> diff --git a/Documentation/devicetree/bindings/usb/snps,dwc3.yaml b/Documentation/devicetree/bindings/usb/snps,dwc3.yaml
> index 25ac2c93dc6c..9635e20cab68 100644
> --- a/Documentation/devicetree/bindings/usb/snps,dwc3.yaml
> +++ b/Documentation/devicetree/bindings/usb/snps,dwc3.yaml
> @@ -226,6 +226,12 @@ properties:
> avoid -EPROTO errors with usbhid on some devices (Hikey 970).
> type: boolean
>
> + snps,role-switch-reset-quirk:
> + description:
> + When set, DWC3 will be reset and reinitialized whenever a role switch
> + is performed.
> + type: boolean

This binding is a example of why we don't do a property per quirk. We
end up with a gazillion of them.

Imply this from the SoC specific compatible (I don't recall seeing one
for the M1, so that's a problem).

Rob