dt-bindings: soc: document LiteX SoC Controller bindings

Add documentation for LiteX SoC Controller bindings.
Signed-off-by: NPawel Czarnecki <pczarnecki@internships.antmicro.com>
Signed-off-by: NMateusz Holenko <mholenko@antmicro.com>
Reviewed-by: NRob Herring <robh@kernel.org>
Signed-off-by: NStafford Horne <shorne@gmail.com>

Documentation/devicetree/bindings/soc/litex/litex,soc-controller.yaml

+# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
+# Copyright 2020 Antmicro <www.antmicro.com>
+%YAML 1.2
+---
+$id: "http://devicetree.org/schemas/soc/litex/litex,soc-controller.yaml#"
+$schema: "http://devicetree.org/meta-schemas/core.yaml#"
+
+title: LiteX SoC Controller driver
+
+description: |
+  This is the SoC Controller driver for the LiteX SoC Builder.
+  Its purpose is to verify LiteX CSR (Control&Status Register) access
+  operations and provide functions for other drivers to read/write CSRs
+  and to check if those accessors are ready to be used.
+
+maintainers:
+  - Karol Gugala <kgugala@antmicro.com>
+  - Mateusz Holenko <mholenko@antmicro.com>
+
+properties:
+  compatible:
+    const: litex,soc-controller
+
+  reg:
+    maxItems: 1
+
+required:
+  - compatible
+  - reg
+
+examples:
+  - |
+    soc_ctrl0: soc-controller@f0000000 {
+        compatible = "litex,soc-controller";
+        reg = <0xf0000000 0xc>;
+        status = "okay";
+    };
+
+...

MAINTAINERS

@@ -10172,6 +10172,12 @@ L:	kunit-dev@googlegroups.com
 S:	Maintained
 F:	lib/list-test.c
 
+LITEX PLATFORM
+M:	Karol Gugala <kgugala@antmicro.com>
+M:	Mateusz Holenko <mholenko@antmicro.com>
+S:	Maintained
+F:	Documentation/devicetree/bindings/*/litex,*.yaml
+
 LIVE PATCHING
 M:	Josh Poimboeuf <jpoimboe@redhat.com>
 M:	Jiri Kosina <jikos@kernel.org>