dt-bindings: gpio: spacemit: add support for K1 SoC

The GPIO controller of K1 support basic functions as input/output,
all pins can be used as interrupt which route to one IRQ line,
trigger type can be select between rising edge, falling edge, or both.
There are four GPIO banks, each consisting of 32 pins.

Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Rob Herring (Arm) <robh@kernel.org>
Signed-off-by: Yixun Lan <dlan@gentoo.org>
Link: https://lore.kernel.org/r/20250412-03-k1-gpio-v8-1-1c6862d272ec@gentoo.org
Signed-off-by: Bartosz Golaszewski <brgl@bgdev.pl>

Documentation/devicetree/bindings/gpio/spacemit,k1-gpio.yaml

@@ -0,0 +1,96 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/gpio/spacemit,k1-gpio.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: SpacemiT K1 GPIO controller
+
+maintainers:
+  - Yixun Lan <dlan@gentoo.org>
+
+description:
+  The controller's registers are organized as sets of eight 32-bit
+  registers with each set of port controlling 32 pins.  A single
+  interrupt line is shared for all of the pins by the controller.
+
+properties:
+  $nodename:
+    pattern: "^gpio@[0-9a-f]+$"
+
+  compatible:
+    const: spacemit,k1-gpio
+
+  reg:
+    maxItems: 1
+
+  clocks:
+    items:
+      - description: GPIO Core Clock
+      - description: GPIO Bus Clock
+
+  clock-names:
+    items:
+      - const: core
+      - const: bus
+
+  resets:
+    maxItems: 1
+
+  gpio-controller: true
+
+  "#gpio-cells":
+    const: 3
+    description:
+      The first two cells are the GPIO bank index and offset inside the bank,
+      the third cell should specify GPIO flag.
+
+  gpio-ranges: true
+
+  interrupts:
+    maxItems: 1
+
+  interrupt-controller: true
+
+  "#interrupt-cells":
+    const: 3
+    description:
+      The first two cells are the GPIO bank index and offset inside the bank,
+      the third cell should specify interrupt flag. The controller does not
+      support level interrupts, so flags of IRQ_TYPE_LEVEL_HIGH,
+      IRQ_TYPE_LEVEL_LOW should not be used.
+      Refer <dt-bindings/interrupt-controller/irq.h> for valid flags.
+
+required:
+  - compatible
+  - reg
+  - clocks
+  - clock-names
+  - gpio-controller
+  - "#gpio-cells"
+  - interrupts
+  - interrupt-controller
+  - "#interrupt-cells"
+  - gpio-ranges
+
+additionalProperties: false
+
+examples:
+  - |
+    gpio@d4019000 {
+      compatible = "spacemit,k1-gpio";
+      reg = <0xd4019000 0x800>;
+      clocks =<&ccu 9>, <&ccu 61>;
+      clock-names = "core", "bus";
+      gpio-controller;
+      #gpio-cells = <3>;
+      interrupts = <58>;
+      interrupt-controller;
+      interrupt-parent = <&plic>;
+      #interrupt-cells = <3>;
+      gpio-ranges = <&pinctrl 0 0 0 32>,
+                    <&pinctrl 1 0 32 32>,
+                    <&pinctrl 2 0 64 32>,
+                    <&pinctrl 3 0 96 32>;
+    };
+...