[PATCH v2 3/3] dt-bindings: gpio: Add Nuvoton NPCM750 serial I/O expansion interface(SGPIO)

[Jim Liu <jim.t90615@gmail.com>]

NPCM750 include two SGPIO modules.
Each module supports up to 64 input and 64 output pins.
the output pin must be serial to parallel device(such as the hc595)
the input in must be parallel to serial device(such as the hc165)

Signed-off-by: Jim Liu <JJLIU0@nuvoton.com>
---
Changes for v2:
   - modify description
---
 .../bindings/gpio/nuvoton,sgpio.yaml          | 79 +++++++++++++++++++
 1 file changed, 79 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..331e3cb28b98
--- /dev/null
+++ b/Documentation/devicetree/bindings/gpio/nuvoton,sgpio.yaml
@@ -0,0 +1,79 @@
+# 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@nuvoton.com>
+
+description:
+  This SGPIO controller is for NUVOTON NPCM7xx and NPCM8xx SoC,
+  NPCM7xx/NPCM8xx have two sgpio module each module can support up
+  to 64 output pins,and up to 64 input pin.
+  Nuvoton NPCM750 SGPIO module is base on serial to parallel IC (HC595)
+  and parallel to serial IC (HC165).
+  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)
+  - Directly connected to APB bus and its shift clock is from APB bus clock
+    divided by a programmable value.
+  - nin_gpios is number of input GPIO lines
+  - nout_gpios is number of output GPIO lines
+  - ngpios is number of nin_gpios GPIO lines and nout_gpios GPIO lines.
+
+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
+
+  nin_gpios: true
+
+  nout_gpios: true
+
+  bus-frequency: true
+
+required:
+  - compatible
+  - reg
+  - gpio-controller
+  - '#gpio-cells'
+  - interrupts
+  - nin_gpios
+  - nout_gpios
+  - clocks
+  - bus-frequency
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/clock/nuvoton,npcm7xx-clock.h>
+    #include <dt-bindings/interrupt-controller/arm-gic.h>
+    sgpio1: sgpio@101000 {
+        compatible = "nuvoton,npcm750-sgpio";
+        reg = <0x101000 0x200>;
+        clocks = <&clk NPCM7XX_CLK_APB3>;
+        interrupts = <GIC_SPI 19 IRQ_TYPE_LEVEL_HIGH>;
+        bus-frequency = <16000000>;
+        gpio-controller;
+        #gpio-cells = <2>;
+        nin_gpios = <64>;
+        nout_gpios = <64>;
+        status = "disabled";
+    };
-- 
2.17.1