[PATCH 1/3] dt-bindings: add Wiegand controller dt-binding documentation

["Martin Zaťovič" <m.zatovic1@gmail.com>]

A Weigand bus is defined by a Wiegand controller node. This node
can contain one or more device nodes for devices attached to
the controller(it is advised to only connect one device as Wiegand
is a point-to-point bus).

Wiegand controller needs to specify several attributes such as
the pulse length in order to function properly. These attributes
are documented here.

Signed-off-by: Martin Zaťovič <m.zatovic1@gmail.com>
---
 .../bindings/wiegand/wiegand-controller.yaml  | 83 +++++++++++++++++++
 MAINTAINERS                                   |  5 ++
 2 files changed, 88 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/wiegand/wiegand-controller.yaml

diff --git a/Documentation/devicetree/bindings/wiegand/wiegand-controller.yaml b/Documentation/devicetree/bindings/wiegand/wiegand-controller.yaml
new file mode 100644
index 000000000000..645306c65d43
--- /dev/null
+++ b/Documentation/devicetree/bindings/wiegand/wiegand-controller.yaml
@@ -0,0 +1,83 @@
+# SPDX-License-Identifier: GPL-2.0
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/wiegand/wiegand-controller.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Wiegand Controller Generic Binding
+
+maintainers:
+  - Martin Zaťovič <martin.zatovic@tbs-biometrics.com>
+
+description: |
+  Wiegand busses can be described with a node for the Wiegand controller device
+  and a set of child nodes for each SPI slave on the bus.
+
+properties:
+  $nodename:
+    pattern: "^wiegand(@.*|-[0-9a-f])*$"
+
+  compatible:
+    maxItems: 1
+    description: Compatible of the Wiegand controller.
+
+  data-high-gpios:
+    maxItems: 1
+    description: GPIO used as Wiegands data-hi line. This line is initially
+      pulled up to high value. Wiegand write of a bit of value 1 results in
+      this line being pulled down for pulse length duration.
+
+  data-lo-gpios:
+    maxItems: 1
+    description: GPIO used as Wiegands data-lo line. This line is initially
+      pulled up to high value. Wiegand write of a bit of value 0 results in
+      this line being pulled down for pulse length duration.
+
+  pulse-len-us:
+    maxItems: 1
+    description: Length of the low pulse in microseconds.
+
+  interval-len-us:
+    maxItems: 1
+    description: Length of a whole bit (both the pulse and the high phase)
+      in microseconds.
+
+  frame-gap-us:
+    maxItems: 1
+    description: Length of the last bit of a frame (both the pulse and the
+      high phase) in microseconds.
+
+  slave-device:
+    type: object
+
+    properties:
+      compatible:
+        description:
+          Compatible of the Wiegand device.
+
+    required:
+      - compatible
+
+required:
+  - compatible
+  - pulse-len-us
+  - interval-len-us
+  - frame-gap-us
+
+additionalProperties: false
+
+examples:
+  - |
+    wiegand@f00 {
+        compatible = "wiegand-gpio";
+        data-hi-gpios = <&gpio2 7 (GPIO_ACTIVE_HIGH|GPIO_OPEN_DRAIN)>;
+        data-lo-gpios = <&gpio2 6 (GPIO_ACTIVE_HIGH|GPIO_OPEN_DRAIN)>;
+        pulse-len-us = <50>;
+        interval-len-us = <2000>;
+        frame-gap-us = <2000>;
+        status = "okay";
+
+        wiegand-foo-device {
+                compatible = "wiegand-foo";
+        };
+    };
diff --git a/MAINTAINERS b/MAINTAINERS
index 7f86d02cb427..db9624d93af0 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -22428,6 +22428,11 @@ L:	linux-input@vger.kernel.org
 S:	Maintained
 F:	drivers/hid/hid-wiimote*
 
+WIEGAND BUS DRIVER
+M:	Martin Zaťovič <m.zatovic1@gmail.com>
+S:	Maintained
+F:	Documentation/devicetree/bindings/wiegand/wiegand-controller.yaml
+
 WILOCITY WIL6210 WIRELESS DRIVER
 L:	linux-wireless@vger.kernel.org
 S:	Orphan
-- 
2.38.1