Re: [PATCH v3 1/2] dt-bindings: usb: add documentation for typec switch via GPIO

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Hi,

On 12-03-19 11:45, Heikki Krogerus wrote:
Hi,

On Tue, Mar 12, 2019 at 10:32:00AM +0000, Jun Li wrote:
Hi Hans
-----Original Message-----
From: Hans de Goede <hdegoede@xxxxxxxxxx>
Sent: 2019年3月11日 19:03
To: Jun Li <jun.li@xxxxxxx>; robh+dt@xxxxxxxxxx; heikki.krogerus@xxxxxxxxxxxxxxx
Cc: gregkh@xxxxxxxxxxxxxxxxxxx; andy.shevchenko@xxxxxxxxx;
linux-usb@xxxxxxxxxxxxxxx; devicetree@xxxxxxxxxxxxxxx; dl-linux-imx
<linux-imx@xxxxxxx>
Subject: Re: [PATCH v3 1/2] dt-bindings: usb: add documentation for typec switch
via GPIO

Hi,

On 11-03-19 11:40, Jun Li wrote:
Some typec super speed active channel switch can be controlled via a
GPIO, this binding can be used to specify the switch node by a GPIO
and the remote endpoint of its consumer.

Signed-off-by: Li Jun <jun.li@xxxxxxx>
---
   .../devicetree/bindings/usb/typec-switch-gpio.txt  | 30
++++++++++++++++++++++
   1 file changed, 30 insertions(+)

diff --git
a/Documentation/devicetree/bindings/usb/typec-switch-gpio.txt
b/Documentation/devicetree/bindings/usb/typec-switch-gpio.txt
new file mode 100644
index 0000000..4ef76cf
--- /dev/null
+++ b/Documentation/devicetree/bindings/usb/typec-switch-gpio.txt
@@ -0,0 +1,30 @@
+Typec orientation switch via a GPIO
+-----------------------------------
+
+Required properties:
+- compatible: should be set one of following:
+	- "nxp,ptn36043" for NXP Type-C SuperSpeed active switch.
+
+- gpios: the GPIO used to switch the super speed active channel,
+		GPIO_ACTIVE_HIGH: GPIO state high for cc1;
+		GPIO_ACTIVE_LOW:  GPIO state low for cc1.
+- orientation-switch: must be present.

Shouldn't this have usb-c in the propery name, e.g.:
usb-c-orientation-switch  ?

This is decided by drivers/usb/typec/mux.c:36
/*
  * With OF graph the mux node must have a boolean device property named
  * "orientation-switch".
  */

Yes, but it's still OK to change it. It's not documented anywhere yet.

+
+Required sub-node:
+- port: specify the remote endpoint of typec switch consumer.
+
+Example:
+
+ptn36043 {
+	compatible = "nxp,ptn36043";
+	pinctrl-names = "default";
+	pinctrl-0 = <&pinctrl_ss_sel>;
+	gpios = <&gpio3 15 GPIO_ACTIVE_HIGH>;
+	orientation-switch;
+
+	port {
+		usb3_data_ss: endpoint {
+			remote-endpoint = <&typec_con_ss>;


Isn't this the wrong way around, shouldn't the "usb-c-connector"
compatible port be pointing to the orientation switch, rather then the other way
around?

Hans, in OF graph both endpoints will have a remote-endpoint pointing
to each other..

I am not sure I am getting your point, "usb-c-connector" is the user of typec switch,
yes, it is pointing to the orientation switch provider(i.e, this example node).

Both will work in the end. but to me it feels more natural to group all the
info about the type-c connector together in the "usb-c-connector" compatible port


         ptn36043 {
                 compatible = "nxp,ptn36043";
                 pinctrl-names = "default";
                 pinctrl-0 = <&pinctrl_ss_sel>;
                 gpios = <&gpio3 15 GPIO_ACTIVE_HIGH>;
                 orientation-switch;

                 port {
                         usb3_data_ss: endpoint {
                                 remote-endpoint = <&typec_con_ss>;
                         };
                 };
         };

usb_con: connector {
	compatible = "usb-c-connector";
	...
	ports {
		#address-cells = <1>;
		#size-cells = <0>;

		port@1 {
			reg = <1>;
			typec_con_ss: endpoint {
				remote-endpoint = <&usb3_data_ss>;
			};
		};
	};
};

So like that.

Ah I see, thank you for clarifying that.

Regards,

Hans



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