[PATCH v3 11/11] 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>
---
 .../devicetree/bindings/gpio/gpio-cdns-i3c.txt     | 38 ++++++++++++++++++++++
 1 file changed, 38 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..634b1f268215
--- /dev/null
+++ b/Documentation/devicetree/bindings/gpio/gpio-cdns-i3c.txt
@@ -0,0 +1,38 @@
+* 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:
+      0 = active high
+      1 = 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 bits[3:0] is used to specify trigger type and level flags:
+      1 = low-to-high edge triggered.
+      2 = high-to-low edge triggered.
+      3 = triggered on both edges.
+      4 = active high level-sensitive.
+      8 = active low level-sensitive.
+
+Example:
+
+	i3c-master@xxx {
+		...
+		i3c_gpio_expander: gpio@0,1c9,0 {
+			reg = <0 0x392 0x0>;
+			gpio-controller;
+			#gpio-cells = <2>;
+			interrupt-controller;
+			#interrupt-cells = <2>;
+		};
+		...
+	};
-- 
2.14.1