[PATCH v6 10/10] dt-bindings: gpio: Add bindings for Cadence I3C gpio expander

[Boris Brezillon <boris.brezillon@bootlin.com>]

Document the Cadence I3C gpio expander bindings.

Signed-off-by: Boris Brezillon <boris.brezillon@bootlin.com>
Reviewed-by: Rob Herring <robh@kernel.org>
---
Changes in v5:
- Add Rob's R-b

Changes in v4:
- Use GPIO_ and IRQ_TYPE_ macros instead of raw numbers
- Fix the unit-address in the example
---
 .../devicetree/bindings/gpio/gpio-cdns-i3c.txt     | 39 ++++++++++++++++++++++
 1 file changed, 39 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/gpio/gpio-cdns-i3c.txt

diff --git a/Documentation/devicetree/bindings/gpio/gpio-cdns-i3c.txt b/Documentation/devicetree/bindings/gpio/gpio-cdns-i3c.txt
new file mode 100644
index 000000000000..d0155a9cea79
--- /dev/null
+++ b/Documentation/devicetree/bindings/gpio/gpio-cdns-i3c.txt
@@ -0,0 +1,39 @@
+* Cadence I3C GPIO expander
+
+The Cadence I3C GPIO expander provides 8 GPIOs controllable over I3C.
+This GPIOs can be configured in output or input mode and if they are in input
+mode they can generate IBIs (In Band Interrupts).
+
+Required properties for GPIO node:
+- reg : 3 cells encoding the I3C static address (none in our case) and the I3C
+	Provisional ID. See Documentation/devicetree/bindings/i3c/i3c.txt for
+	more details.
+	Should be <0x0 0x392 0x0>.
+- gpio-controller : Marks the device node as a gpio controller.
+- #gpio-cells : Should be two. The first cell is the pin number and
+  the second cell is used to specify the gpio polarity (GPIO_ACTIVE_HIGH or
+  GPIO_ACTIVE_LOW)
+- interrupt-controller: Marks the device node as an interrupt controller.
+- #interrupt-cells : Should be 2. The first cell is the GPIO number.
+  The second cell is used to specify trigger type and level flags.
+  The following trigger types are accepted (see
+  <dt-bindings/interrupt-controller/irq.h> for their definition):
+	IRQ_TYPE_EDGE_RISING
+	IRQ_TYPE_EDGE_FALLING
+	IRQ_TYPE_EDGE_BOTH
+	IRQ_TYPE_LEVEL_HIGH
+	IRQ_TYPE_LEVEL_LOW
+
+Example:
+
+	i3c-master@xxx {
+		...
+		i3c_gpio_expander: gpio@0,39200000000 {
+			reg = <0 0x392 0x0>;
+			gpio-controller;
+			#gpio-cells = <2>;
+			interrupt-controller;
+			#interrupt-cells = <2>;
+		};
+		...
+	};
-- 
2.14.1