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

Add dt-bindings for the pinctrl driver of SpacemiT's K1 SoC.

Reviewed-by: Rob Herring (Arm) <[email protected]>
Signed-off-by: Yixun Lan <[email protected]>
Link: https://lore.kernel.org/[email protected]
Signed-off-by: Linus Walleij <[email protected]>

Author: dlan17

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

@@ -0,0 +1,124 @@
+# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/pinctrl/spacemit,k1-pinctrl.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: SpacemiT K1 SoC Pin Controller
+
+maintainers:
+  - Yixun Lan <[email protected]>
+
+properties:
+  compatible:
+    const: spacemit,k1-pinctrl
+
+  reg:
+    items:
+      - description: pinctrl io memory base
+
+patternProperties:
+  '-cfg$':
+    type: object
+    additionalProperties: false
+
+    description:
+      A pinctrl node should contain at least one subnode representing the
+      pinctrl groups available on the machine.
+
+    patternProperties:
+      '-pins$':
+        type: object
+        additionalProperties: false
+
+        description:
+          Each subnode will list the pins it needs, and how they should
+          be configured, with regard to muxer configuration, bias pull,
+          drive strength, input schmitt trigger, slew rate, power source.
+
+        allOf:
+          - $ref: pincfg-node.yaml#
+          - $ref: pinmux-node.yaml#
+
+        properties:
+          pinmux:
+            description:
+              The list of GPIOs and their mux settings that properties in the
+              node apply to. This should be set using the K1_PADCONF macro to
+              construct the value.
+
+          bias-disable: true
+
+          bias-pull-down: true
+
+          bias-pull-up:
+            description: |
+              typical value for selecting bias pull up or strong pull up.
+              0: normal bias pull up
+              1: strong bias pull up
+            enum: [ 0, 1 ]
+
+          drive-strength:
+            description: |
+              typical current when output high level.
+              1.8V output: 11, 21, 32, 42 (mA)
+              3.3V output: 7, 10, 13, 16, 19, 23, 26, 29 (mA)
+
+          input-schmitt:
+            description: |
+              typical threshold for schmitt trigger.
+              0: buffer mode
+              1: trigger mode
+              2, 3: trigger mode
+            $ref: /schemas/types.yaml#/definitions/uint32
+            enum: [ 0, 1, 2, 3 ]
+
+          power-source:
+            description: external power supplies at 1.8v or 3.3v.
+            enum: [ 1800, 3300 ]
+
+          slew-rate:
+            description: |
+              slew rate for output buffer.
+              0: disable it
+              1: enable it (via bundled value from drive strength)
+              2: slow speed 0
+              3: slow speed 1
+              4: medium speed
+              5: fast speed
+            enum: [ 0, 1, 2, 3, 4, 5 ]
+
+        required:
+          - pinmux
+
+required:
+  - compatible
+  - reg
+
+additionalProperties: false
+
+examples:
+  - |
+    #define K1_PADCONF(pin, func) (((pin) << 16) | (func))
+
+    soc {
+        #address-cells = <2>;
+        #size-cells = <2>;
+
+        pinctrl@d401e000 {
+            compatible = "spacemit,k1-pinctrl";
+            reg = <0x0 0xd401e000 0x0 0x400>;
+
+            uart0_2_cfg: uart0-2-cfg {
+                uart0-2-pins {
+                    pinmux = <K1_PADCONF(68, 2)>,
+                             <K1_PADCONF(69, 2)>;
+
+                    bias-pull-up = <0>;
+                    drive-strength = <32>;
+                };
+            };
+        };
+    };
+
+...