[PATCH v1 1/8] dt-bindings: pinctrl: Add thead,th1520-pinctrl bindings

[Emil Renner Berthing]

Add bindings for the pin controllers on the T-Head TH1520 RISC-V SoC.

Signed-off-by: Emil Renner Berthing <emil.renner.berthing@xxxxxxxxxxxxx>
---
 .../pinctrl/thead,th1520-pinctrl.yaml         | 156 ++++++++++++++++++
 1 file changed, 156 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/pinctrl/thead,th1520-pinctrl.yaml

diff --git a/Documentation/devicetree/bindings/pinctrl/thead,th1520-pinctrl.yaml b/Documentation/devicetree/bindings/pinctrl/thead,th1520-pinctrl.yaml
new file mode 100644
index 000000000000..1b1b446cd498
--- /dev/null
+++ b/Documentation/devicetree/bindings/pinctrl/thead,th1520-pinctrl.yaml
@@ -0,0 +1,156 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/pinctrl/thead,th1520-pinctrl.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: T-Head TH1520 SoC pin controller
+
+maintainers:
+  - Emil Renner Berthing <emil.renner.berthing@xxxxxxxxxxxxx>
+
+description: |
+  Pinmux and pinconf controller in the T-Head TH1520 RISC-V SoC.
+
+  The TH1520 has 3 groups of pads each controlled from different memory ranges.
+  Confusingly the memory ranges are named
+    PADCTRL_AOSYS  -> PAD Group 1
+    PADCTRL1_APSYS -> PAD Group 2
+    PADCTRL0_APSYS -> PAD Group 3
+
+  Each pad can be muxed individually to up to 5 different functions. For most
+  pads only a few of those 5 configurations are valid though, and a few pads in
+  group 1 does not support muxing at all.
+
+  Pinconf is fairly regular except for a few pads in group 1 that either can't
+  be configured or has some special functions. The rest have configurable drive
+  strength, input enable, schmitt trigger, slew rate, pull-up and pull-down in
+  addition to a special strong pull up.
+
+  Certain pads in group 1 can be muxed to AUDIO_PA0 - AUDIO_PA30 functions and
+  are then meant to be used by the audio co-processor. Each such pad can then
+  be further muxed to either audio GPIO or one of 4 functions such as UART, I2C
+  and I2S. If the audio pad is muxed to one of the 4 functions then pinconf is
+  also configured in different registers. All of this is done from a different
+  AUDIO_IOCTRL memory range and is left to the audio co-processor for now.
+
+properties:
+  compatible:
+    enum:
+      - thead,th1520-group1-pinctrl
+      - thead,th1520-group2-pinctrl
+      - thead,th1520-group3-pinctrl
+
+  reg:
+    maxItems: 1
+
+patternProperties:
+  '-[0-9]+$':
+    type: object
+    patternProperties:
+      '-pins$':
+        type: object
+        $ref: /schemas/pinctrl/pincfg-node.yaml
+        description:
+          A pinctrl node should contain at least one subnode describing one
+          or more pads and their associated pinmux and pinconf settings.
+
+        properties:
+          pins:
+            $ref: /schemas/types.yaml#/definitions/string-array
+            description: List of pads that properties in the node apply to.
+
+          function:
+            $ref: /schemas/types.yaml#/definitions/string
+            enum: [ "0", "1", "2", "3", "4", "5" ]
+            description: The mux function to select for the given pins.
+
+          bias-disable: true
+
+          bias-pull-up:
+            type: boolean
+
+          bias-pull-down:
+            type: boolean
+
+          drive-strength:
+            enum: [ 1, 2, 3, 5, 7, 8, 10, 12, 13, 15, 16, 18, 20, 21, 23, 25 ]
+
+          input-enable: true
+
+          input-disable: true
+
+          input-schmitt-enable: true
+
+          input-schmitt-disable: true
+
+          slew-rate:
+            maximum: 1
+
+          thead,strong-pull-up:
+            oneOf:
+              - type: boolean
+              - $ref: /schemas/types.yaml#/definitions/uint32
+                enum: [ 0, 2100 ]
+            description: Enable or disable strong 2.1kOhm pull-up.
+
+        required:
+          - pins
+
+        additionalProperties: false
+
+    additionalProperties: false
+
+required:
+  - compatible
+  - reg
+
+additionalProperties: false
+
+examples:
+  - |
+    padctrl0_apsys: pinctrl@ec007000 {
+        compatible = "thead,th1520-group3-pinctrl";
+        reg = <0xec007000 0x1000>;
+
+        uart0_pins: uart0-0 {
+            tx-pins {
+                pins = "UART0_TXD";
+                function = "0";
+                bias-disable;
+                drive-strength = <3>;
+                input-disable;
+                input-schmitt-disable;
+                slew-rate = <0>;
+            };
+
+            rx-pins {
+                pins = "UART0_RXD";
+                function = "0";
+                bias-disable;
+                drive-strength = <1>;
+                input-enable;
+                input-schmitt-enable;
+                slew-rate = <0>;
+            };
+        };
+    };
+
+    padctrl1_apsys: pinctrl@e7f3c000 {
+        compatible = "thead,th1520-group2-pinctrl";
+        reg = <0xe7f3c000 0x1000>;
+
+        i2c5_pins: i2c5-0 {
+            i2c-pins {
+                pins = "QSPI1_CSN0",    /* I2C5_SCL */
+                       "QSPI1_D0_MOSI"; /* I2C5_SDA */
+                function = "2";
+                bias-disable;
+                drive-strength = <7>;
+                input-enable;
+                input-schmitt-enable;
+                slew-rate = <0>;
+                thead,strong-pull-up;
+            };
+        };
+    };
-- 
2.40.1