Re: [PATCH v6 1/6] dt-bindings: usb: add documentation for typec switch simple driver
From: Rob Herring <robh@kernel.org>
Date: 2020-11-30 21:48:24
Also in:
linux-usb
On Mon, Nov 23, 2020 at 10:01:31PM +0800, Li Jun wrote:
quoted hunk ↗ jump to hunk
Some platforms need a simple driver to do some controls according to typec orientation, this can be extended to be a generic driver with compatible with "typec-orientation-switch". Signed-off-by: Li Jun <redacted> --- changes for v6: - Use general mux bindings for typec switch, one typec switch may have 1 or 2 GPIOs for channel selection, if 1 GPIO, only can be used to select cc1 or cc2; if 2 GPIOs, the second GPIO can be used to deselect both channels or keep normal operations. - Add one more connection to usb controller. No changes for v5. changes on v4: - Use compatible instead of bool property for switch matching. - Change switch GPIO to be switch simple. - Change the active channel selection GPIO to be optional. previous discussion: http://patchwork.ozlabs.org/patch/1054342/ .../bindings/usb/typec-switch-simple.yaml | 122 +++++++++++++++++++++ 1 file changed, 122 insertions(+)diff --git a/Documentation/devicetree/bindings/usb/typec-switch-simple.yaml b/Documentation/devicetree/bindings/usb/typec-switch-simple.yaml new file mode 100644 index 0000000..030ade5 --- /dev/null +++ b/Documentation/devicetree/bindings/usb/typec-switch-simple.yaml@@ -0,0 +1,122 @@ +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) +%YAML 1.2 +--- +$id: http://devicetree.org/schemas/usb/typec-switch-simple.yaml# +$schema: http://devicetree.org/meta-schemas/core.yaml# + +title: Typec Orientation Switch Simple Solution Bindings + +maintainers: + - Li Jun <jun.li@nxp.com> + +description: |- + USB SuperSpeed (SS) lanes routing to which side of typec connector is + decided by orientation, this maybe achieved by some simple control like + GPIO toggle. + +properties: + compatible: + const: typec-orientation-switch + + '#mux-control-cells': + const: 0
Who is the mux-control consumer?
+
+ switch-gpios:
+ description: |
+ GPIO specifiers to select the target channel of mux.
+ The first GPIO is for cc1 and cc2 selection, the GPIO flag use
+ GPIO_ACTIVE_HIGH if GPIO physical state high is for cc1; or use
+ GPIO_ACTIVE_LOW if GPIO physical state low is for cc1.
+ The second gpio is to deselect any channles by places all channels
+ in high-impedance state to reduce current consumption, the gpio flag
+ use GPIO_ACTIVE_HIGH if GPIO physical state high is for
+ high-impedance state (so low for normal operations); or Use
+ GPIO_ACTIVE_LOW if GPIO physical state low is for high-impedance
+ state(so high for normal operations).
+ minItems: 1
+ maxItems: 2
+
+ idle-state:
+ description: -|
+ For TYPEC_ORIENTATION_NONE by deselect both channels if supported.
+ const: 2
+
+ # Standard properties described in
+ # Documentation/devicetree/bindings/mux/mux-controller.txt
+
+ port:
+ type: object
+ additionalProperties: false
+ description: -|
+ Connection to the remote endpoint using OF graph bindings that model
+ SS data bus to typec connector.
+
+ properties:
+ '#address-cells':
+ const: 1
+
+ '#size-cells':
+ const: 0
+
+ endpoint@0:
+ type: object
+ description: Endpoint connected to typec connector.
+ additionalProperties: false
+
+ properties:
+ reg:
+ const: 0
+ remote-endpoint: true
+
+ required:
+ - remote-endpoint
+
+ endpoint@1:
+ type: object
+ description: Endpoint connected to usb controller.
+ additionalProperties: false
+
+ properties:
+ reg:
+ const: 1
+ remote-endpoint: true
+
+ required:
+ - remote-endpoint
+
+ required:
+ - endpoint@0
+
+required:
+ - compatible
+ - port
+
+additionalProperties: false
+
+examples:
+ - |
+ #include <dt-bindings/gpio/gpio.h>
+ typec_switch: mux-controller {
+ compatible = "typec-orientation-switch";
+ #mux-control-cells = <0>;
+ pinctrl-names = "default";
+ pinctrl-0 = <&pinctrl_ss_sel>;
+ switch-gpios = <&gpio3 15 GPIO_ACTIVE_HIGH>,
+ <&gpio2 20 GPIO_ACTIVE_HIGH>;
+ idle-state = <2>;
+
+ port {
+ #address-cells = <1>;
+ #size-cells = <0>;
+
+ usb3_orien_sel: endpoint@0 {
+ reg = <0>;
+ remote-endpoint = <&typec_con_ss>;
+ };
+
+ usb3_con_data: endpoint@1 {
+ reg = <1>;
+ remote-endpoint = <&dwc3_0>;
+ };
+ };
This still seems unnecessarily complicated. What I had in mind is just
something like this:
mux: mux-controller {
compatible = "gpio-mux";
#mux-control-cells = <0>;
mux-gpios = <&gpio3 15 GPIO_ACTIVE_HIGH>,
<&gpio2 20 GPIO_ACTIVE_HIGH>;
idle-state = <2>;
};
connector {
compatible = "usb-c-connector";
mux-controls = <&mux>;
...
};
Then you aren't re-implementing the gpio-mux driver.
This should work for *any* mux implementation as long as the mux states
always have the same meanings from the perspective of the connector.
Of course, I have little visibility into the possible h/w
implementations for Type-C and maybe this isn't sufficient. So input
from Type-C experts would be helpful.
Rob