This adds a binding for a GPIO multiplexer driver based on latches
connected to other GPIOs.
Signed-off-by: Sascha Hauer <s.hauer@xxxxxxxxxxxxxx>
Reviewed-by: Rob Herring <robh@xxxxxxxxxx>
---
Notes:
Changes since v3:
- Introduce delays between GPIO toggles as suggested by Serge Semin
Changes since v1:
- Add license to binding file
.../devicetree/bindings/gpio/gpio-latch.yaml | 94 +++++++++++++++++++
1 file changed, 94 insertions(+)
create mode 100644 Documentation/devicetree/bindings/gpio/gpio-latch.yaml
diff --git a/Documentation/devicetree/bindings/gpio/gpio-latch.yaml b/Documentation/devicetree/bindings/gpio/gpio-latch.yaml
new file mode 100644
index 0000000000000..1ed82a2cebdaa
--- /dev/null
+++ b/Documentation/devicetree/bindings/gpio/gpio-latch.yaml
@@ -0,0 +1,94 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/gpio/gpio-latch.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: GPIO latch controller
+
+maintainers:
+ - Sascha Hauer <s.hauer@xxxxxxxxxxxxxx>
+
+description: |
+ This binding describes a GPIO multiplexer based on latches connected to
+ other GPIOs, like this:
+
+ CLK0 ----------------------. ,--------.
+ CLK1 -------------------. `--------|> #0 |
+ | | |
+ OUT0 ----------------+--|-----------|D0 Q0|-----|<
+ OUT1 --------------+-|--|-----------|D1 Q1|-----|<
+ OUT2 ------------+-|-|--|-----------|D2 Q2|-----|<
+ OUT3 ----------+-|-|-|--|-----------|D3 Q3|-----|<
+ OUT4 --------+-|-|-|-|--|-----------|D4 Q4|-----|<
+ OUT5 ------+-|-|-|-|-|--|-----------|D5 Q5|-----|<
+ OUT6 ----+-|-|-|-|-|-|--|-----------|D6 Q6|-----|<
+ OUT7 --+-|-|-|-|-|-|-|--|-----------|D7 Q7|-----|<
+ | | | | | | | | | `--------'
+ | | | | | | | | |
+ | | | | | | | | | ,--------.
+ | | | | | | | | `-----------|> #1 |
+ | | | | | | | | | |
+ | | | | | | | `--------------|D0 Q0|-----|<
+ | | | | | | `----------------|D1 Q1|-----|<
+ | | | | | `------------------|D2 Q2|-----|<
+ | | | | `--------------------|D3 Q3|-----|<
+ | | | `----------------------|D4 Q4|-----|<
+ | | `------------------------|D5 Q5|-----|<
+ | `--------------------------|D6 Q6|-----|<
+ `----------------------------|D7 Q7|-----|<
+ `--------'
+
+ The number of clk-gpios and latched-gpios is not fixed. The actual number
+ of number of latches and the number of inputs per latch is derived from
+ the number of GPIOs given in the corresponding device tree properties.
+
+properties:
+ compatible:
+ const: gpio-latch
+ "#gpio-cells":
+ const: 2
+
+ clk-gpios:
+ description: Array of GPIOs to be used to clock a latch
+
+ latched-gpios:
+ description: Array of GPIOs to be used as inputs per latch
+
+ setup-duration-ns:
+ description: Delay in nanoseconds to wait after the latch inputs have been
+ set up
+
+ clock-duration-ns:
+ description: Delay in nanoseconds to wait between clock output changes
+
+ gpio-controller: true
+
+ gpio-line-names: true
+
+required:
+ - compatible
+ - "#gpio-cells"
+ - gpio-controller
+ - clk-gpios
+ - latched-gpios
+
+additionalProperties: false
+
+examples:
+ - |
+ gpio-latch {
+ #gpio-cells = <2>;
+ pinctrl-names = "default";
+ pinctrl-0 = <&pinctrl_di_do_leds>;
+ compatible = "gpio-latch";
+ gpio-controller;
+ setup-duration-ns = <100>;
+ clock-duration-ns = <100>;
+
+ clk-gpios = <&gpio3 7 0>, <&gpio3 8 0>;
+ latched-gpios = <&gpio3 21 0>, <&gpio3 22 0>,
+ <&gpio3 23 0>, <&gpio3 24 0>,
+ <&gpio3 25 0>, <&gpio3 26 0>,
+ <&gpio3 27 0>, <&gpio3 28 0>;
+ };
--
2.30.2
