Re: [PATCH v2 1/2] dt-bindings: usb: Add the binding example for the Genesys Logic GL3523 hub

[Anand Moon <linux.amoon@gmail.com>]

Hi Krzysztof,

On Thu, 12 Oct 2023 at 13:13, Krzysztof Kozlowski
<krzysztof.kozlowski@linaro.org> wrote:
>
> On 11/10/2023 07:11, Anand Moon wrote:
> > Add the binding example for the USB3.1 Genesys Logic GL3523
> > integrates with USB 3.1 Gen 1 Super Speed and USB 2.0 High-Speed
> > hub.
>
> That's not what the patch does.

Ok I have tried to add an example below the original changes
but the device tree complained of duplicate entries. Hence I
modified these changes.

This change was requested to update the peer-hub example below.
[0] https://lore.kernel.org/all/9fe7d0d2-3582-4b62-be9b-aa9134c18023@linaro.org/

>
> >
> > Signed-off-by: Anand Moon <linux.amoon@gmail.com>
> > ---
> > New patch.
> > ---
> >  .../bindings/usb/genesys,gl850g.yaml          | 28 +++++++++++++++++--
> >  1 file changed, 25 insertions(+), 3 deletions(-)
> >
> > diff --git a/Documentation/devicetree/bindings/usb/genesys,gl850g.yaml b/Documentation/devicetree/bindings/usb/genesys,gl850g.yaml
> > index d0927f6768a4..2f6e0c870e1d 100644
> > --- a/Documentation/devicetree/bindings/usb/genesys,gl850g.yaml
> > +++ b/Documentation/devicetree/bindings/usb/genesys,gl850g.yaml
> > @@ -22,29 +22,51 @@ properties:
> >    reg: true
> >
> >    reset-gpios:
> > +    maxItems: 1
>
> Why?

Following another example, I added this and will drop this.
>
> >      description: GPIO controlling the RESET# pin.
> >
> >    vdd-supply:
> >      description:
> >        the regulator that provides 3.3V core power to the hub.
> >
> > +  peer-hub:
> > +    $ref: /schemas/types.yaml#/definitions/phandle
> > +    description:
> > +      phandle to the peer hub on the controller.
> > +
> >  required:
> >    - compatible
> >    - reg
> > +  - reset-gpios
>
> Why?
see below.
>
> > +  - vdd-supply
> > +  - peer-hub
> >
> >  additionalProperties: false
> >
> >  examples:
> >    - |
> >      #include <dt-bindings/gpio/gpio.h>
> > +
> >      usb {
> >          dr_mode = "host";
> >          #address-cells = <1>;
> >          #size-cells = <0>;
> >
> > -        hub: hub@1 {
> > -            compatible = "usb5e3,608";
> > +        /* 2.0 hub on port 1 */
> > +        hub_2_0: hub@1 {
> > +            compatible = "usb5e3,610";
> >              reg = <1>;
> > -            reset-gpios = <&pio 7 2 GPIO_ACTIVE_LOW>;
> > +            vdd-supply = <&vcc_5v>;
> > +            peer-hub = <&hub_3_0>;
> > +            reset-gpios = <&gpio 20 GPIO_ACTIVE_LOW>;
> > +        };
> > +
> > +        /* 3.1 hub on port 4 */
> > +        hub_3_0: hub@2 {
> > +            compatible = "usb5e3,620";
> > +            reg = <2>;
> > +            vdd-supply = <&vcc_5v>;
> > +            peer-hub = <&hub_2_0>;
> > +            reset-gpios = <&gpio 20 GPIO_ACTIVE_LOW>;
>
> Really, what is happening here?

USB hub GL3523-QFN76 supports two pins CHIP_EN and RST_N pins
so RST_N (GPIOH_4) is used to reset the USB hub,
earlier we were using gpio-hog to reset the hub.

>
> Best regards,
> Krzysztof
>

Thanks
-Anand