linux-kernel - Re: [PATCH v2 1/4] dt-bindings: usb: gpio-sbu-mux: add support for ss-data lanes mux

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Date:   Thu, 4 May 2023 14:47:57 -0500
From:   Rob Herring <robh@...nel.org>
To:     Marco Felsch <m.felsch@...gutronix.de>
Cc:     andreas@...al.se, jun.li@....com,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        Bjorn Andersson <andersson@...nel.org>,
        Heikki Krogerus <heikki.krogerus@...ux.intel.com>,
        Guenter Roeck <linux@...ck-us.net>,
        Shawn Guo <shawnguo@...nel.org>,
        Sascha Hauer <s.hauer@...gutronix.de>,
        Pengutronix Kernel Team <kernel@...gutronix.de>,
        Fabio Estevam <festevam@...il.com>,
        NXP Linux Team <linux-imx@....com>,
        linux-usb@...r.kernel.org, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH v2 1/4] dt-bindings: usb: gpio-sbu-mux: add support for
 ss-data lanes mux

On Thu, May 04, 2023 at 03:46:50PM +0200, Marco Felsch wrote:
> This adds the support for GPIO based USB-C SS data lane muxing.
> 
> Signed-off-by: Marco Felsch <m.felsch@...gutronix.de>
> ---
>  .../devicetree/bindings/usb/gpio-sbu-mux.yaml      | 82 +++++++++++++++++++---
>  1 file changed, 71 insertions(+), 11 deletions(-)
> 
> diff --git a/Documentation/devicetree/bindings/usb/gpio-sbu-mux.yaml b/Documentation/devicetree/bindings/usb/gpio-sbu-mux.yaml
> index bf4b1d016e1f..796f3283ac02 100644
> --- a/Documentation/devicetree/bindings/usb/gpio-sbu-mux.yaml
> +++ b/Documentation/devicetree/bindings/usb/gpio-sbu-mux.yaml
> @@ -4,24 +4,26 @@
>  $id: "http://devicetree.org/schemas/usb/gpio-sbu-mux.yaml#"
>  $schema: "http://devicetree.org/meta-schemas/core.yaml#"
>  
> -title: GPIO-based SBU mux
> +title: GPIO-based SS/SBU mux
>  
>  maintainers:
>    - Bjorn Andersson <andersson@...nel.org>
>  
>  description:
> -  In USB Type-C applications the SBU lines needs to be connected, disconnected
> -  and swapped depending on the altmode and orientation. This binding describes
> -  a family of hardware solutions which switches between these modes using GPIO
> -  signals.
> +  In USB Type-C applications the SS/SBU lines needs to be connected,
> +  disconnected and swapped depending on the altmode and orientation. This
> +  binding describes a family of hardware solutions which switches between these
> +  modes using GPIO signals.

Consider whether the mux-control binding would work for this purpose. 
Then what controls the muxing can be anything.

>  
>  properties:
>    compatible:
> -    items:
> -      - enum:
> -          - onnn,fsusb43l10x
> -          - pericom,pi3usb102
> -      - const: gpio-sbu-mux
> +    oneOf:
> +      - items:
> +          - enum:
> +              - onnn,fsusb43l10x
> +              - pericom,pi3usb102
> +          - const: gpio-sbu-mux
> +      - const: gpio-ss-mux
>  
>    enable-gpios:
>      description: Switch enable GPIO
> @@ -50,10 +52,18 @@ required:
>    - compatible
>    - enable-gpios
>    - select-gpios
> -  - mode-switch
>    - orientation-switch
>    - port
>  
> +if:
> +  properties:
> +    compatible:
> +      contains:
> +        const: gpio-sbu-mux
> +then:
> +  required:
> +    - mode-switch
> +
>  additionalProperties: false
>  
>  examples:
> @@ -107,4 +117,54 @@ examples:
>              };
>          };
>      };
> +
> +  - |
> +    #include <dt-bindings/gpio/gpio.h>
> +
> +    tcpm {
> +        connector {
> +            compatible = "usb-c-connector";
> +
> +            ports {
> +                #address-cells = <1>;
> +                #size-cells = <0>;
> +
> +                port@0 {
> +                    reg = <0>;
> +                    tcpm_hs_out: endpoint {
> +                        remote-endpoint = <&usb_hs_phy_in>;
> +                    };
> +                };
> +
> +                port@1 {
> +                    reg = <1>;
> +                    tcpm_ss_out: endpoint {
> +                        remote-endpoint = <&usb_ss_phy_in>;
> +                    };
> +                };
> +
> +                port@2 {
> +                    reg = <2>;
> +                    tcpm_ss_mux_out: endpoint {
> +                        remote-endpoint = <&ss_mux_in>;
> +                    };
> +                };

port@2 already has a defined use for SBU signals. You can't use it. 
port@1 corresponds to the SS signals.

> +            };
> +        };
> +    };
> +
> +    usb-ss-mux {
> +        compatible = "gpio-ss-mux";
> +
> +        enable-gpios = <&tlmm 101 GPIO_ACTIVE_LOW>;
> +        select-gpios = <&tlmm 164 GPIO_ACTIVE_HIGH>;
> +
> +        orientation-switch;
> +
> +        port {

This is a mux device. It needs an output port and N input ports.

Please present a complete picture of your USB-C related h/w. It's hard 
to review with just 'I have a GPIO controlling the SS muxing'.

Rob