[PATCH v4 3/3] dt-bindings: gpio: add NPCM sgpio driver bindings

[Jim Liu <jim.t90615@xxxxxxxxx>]

Add dt-bindings document for the Nuvoton NPCM7xx and NPCM8xx sgpio driver

Signed-off-by: Jim Liu <jim.t90615@xxxxxxxxx>
---
Changes for v4:
   - modify in/out property
   - modify bus-frequency property
Changes for v3:
   - modify description
   - modify in/out property name
Changes for v2:
   - modify description
---
 .../bindings/gpio/nuvoton,sgpio.yaml          | 92 +++++++++++++++++++
 1 file changed, 92 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/gpio/nuvoton,sgpio.yaml

diff --git a/Documentation/devicetree/bindings/gpio/nuvoton,sgpio.yaml b/Documentation/devicetree/bindings/gpio/nuvoton,sgpio.yaml
new file mode 100644
index 000000000000..3c01ce61f8d9
--- /dev/null
+++ b/Documentation/devicetree/bindings/gpio/nuvoton,sgpio.yaml
@@ -0,0 +1,92 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/gpio/nuvoton,sgpio.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Nuvoton SGPIO controller
+
+maintainers:
+  - Jim LIU <JJLIU0@xxxxxxxxxxx>
+
+description:
+  This SGPIO controller is for NUVOTON NPCM7xx and NPCM8xx SoC.
+  Nuvoton NPCM7xx SGPIO module is combine serial to parallel IC (HC595)
+  and parallel to serial IC (HC165), and use APB3 clock to control it.
+  This interface has 4 pins  (D_out , D_in, S_CLK, LDSH).
+  NPCM7xx/NPCM8xx have two sgpio module each module can support up
+  to 64 output pins,and up to 64 input pin, the pin is only for gpi or gpo.
+  GPIO pins have sequential, First half is gpo and second half is gpi.
+  GPIO pins can be programmed to support the following options
+  - Support interrupt option for each input port and various interrupt
+    sensitivity option (level-high, level-low, edge-high, edge-low)
+  - ngpios is number of nuvoton,input-ngpios GPIO lines and nuvoton,output-ngpios GPIO lines.
+    nuvoton,input-ngpios GPIO lines is only for gpi.
+    nuvoton,output-ngpios GPIO lines is only for gpo.
+
+properties:
+  compatible:
+    enum:
+      - nuvoton,npcm750-sgpio
+      - nuvoton,npcm845-sgpio
+
+  reg:
+    maxItems: 1
+
+  gpio-controller: true
+
+  '#gpio-cells':
+    const: 2
+
+  interrupts:
+    maxItems: 1
+
+  clocks:
+    maxItems: 1
+
+  nuvoton,input-ngpios:
+    description: The numbers of GPIO's exposed.
+      GPIO lines is only for gpi.
+    minimum: 0
+    maximum: 64
+
+  nuvoton,output-ngpios:
+    description: The numbers of GPIO's exposed.
+      GPIO lines is only for gpo.
+    minimum: 0
+    maximum: 64
+
+  bus-frequency:
+    description: Directly connected to APB bus and 
+      its shift clock is from APB bus clock divided by a programmable value.
+    default: 8000000
+
+required:
+  - compatible
+  - reg
+  - gpio-controller
+  - '#gpio-cells'
+  - interrupts
+  - nuvoton,input-ngpios
+  - nuvoton,output-ngpios
+  - clocks
+  - bus-frequency
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/clock/nuvoton,npcm7xx-clock.h>
+    #include <dt-bindings/interrupt-controller/arm-gic.h>
+    gpio8: gpio@101000 {
+        compatible = "nuvoton,npcm750-sgpio";
+        reg = <0x101000 0x200>;
+        clocks = <&clk NPCM7XX_CLK_APB3>;
+        interrupts = <GIC_SPI 19 IRQ_TYPE_LEVEL_HIGH>;
+        bus-frequency = <8000000>;
+        gpio-controller;
+        #gpio-cells = <2>;
+        nuvoton,input-ngpios = <64>;
+        nuvoton,output-ngpios = <64>;
+        status = "disabled";
+    };
-- 
2.17.1