dt-bindings: pinctrl: add i.MXRT1050 pinctrl binding doc

Add i.MXRT1050 pinctrl binding doc

Cc: Giulio Benetti <[e-mail]>
Signed-off-by: Jesse Taube <[e-mail]>
Reviewed-by: Rob Herring <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Linus Walleij <[e-mail]>

Documentation/devicetree/bindings/pinctrl/fsl,imxrt1050.yaml

···
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/pinctrl/fsl,imxrt1050.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Freescale IMXRT1050 IOMUX Controller
+
+maintainers:
+  - Giulio Benetti <[e-mail]>
+  - Jesse Taube <[e-mail]>
+
+description:
+  Please refer to fsl,imx-pinctrl.txt and pinctrl-bindings.txt in this directory
+  for common binding part and usage.
+
+properties:
+  compatible:
+    const: fsl,imxrt1050-iomuxc
+
+  reg:
+    maxItems: 1
+
+# Client device subnode's properties
+patternProperties:
+  'grp$':
+    type: object
+    description:
+      Pinctrl node's client devices use subnodes for desired pin configuration.
+      Client device subnodes use below standard properties.
+
+    properties:
+      fsl,pins:
+        description:
+          each entry consists of 6 integers and represents the mux and config
+          setting for one pin. The first 5 integers <mux_reg conf_reg input_reg
+          mux_val input_val> are specified using a PIN_FUNC_ID macro, which can
+          be found in <include/dt-bindings/pinctrl/pins-imxrt1050.h>. The last
+          integer CONFIG is the pad setting value like pull-up on this pin. Please
+          refer to i.MXRT1050 Reference Manual for detailed CONFIG settings.
+        $ref: /schemas/types.yaml#/definitions/uint32-matrix
+        items:
+          items:
+            - description: |
+                "mux_reg" indicates the offset of mux register.
+            - description: |
+                "conf_reg" indicates the offset of pad configuration register.
+            - description: |
+                "input_reg" indicates the offset of select input register.
+            - description: |
+                "mux_val" indicates the mux value to be applied.
+            - description: |
+                "input_val" indicates the select input value to be applied.
+            - description: |
+                "pad_setting" indicates the pad configuration value to be applied.
+
+    required:
+      - fsl,pins
+
+    additionalProperties: false
+
+required:
+  - compatible
+  - reg
+
+additionalProperties: false
+
+examples:
+  - |
+    iomuxc: iomuxc@401f8000 {
+        compatible = "fsl,imxrt1050-iomuxc";
+        reg = <0x401f8000 0x4000>;
+
+        pinctrl_lpuart1: lpuart1grp {
+            fsl,pins =
+              <0x0EC 0x2DC 0x000 0x2 0x0	0xf1>,
+              <0x0F0 0x2E0 0x000 0x2 0x0	0xf1>;
+        };
+    };