[PATCH v4 1/2] dt-bindings: touchscreen: add ad7877 support

[Antoniu Miclaus <antoniu.miclaus@xxxxxxxxxx>]

Add device tree bindings for ad7877.

Signed-off-by: Antoniu Miclaus <antoniu.miclaus@xxxxxxxxxx>
---
changes in v4:
 - add bindings patch first
 - update commit title/body based on review.
 - add units for pen-down-acc-interval property.
 - add default value for adi,acquisition-time-us and adi,vref-delay-us property
 .../input/touchscreen/adi,ad7877.yaml         | 106 ++++++++++++++++++
 1 file changed, 106 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/input/touchscreen/adi,ad7877.yaml

diff --git a/Documentation/devicetree/bindings/input/touchscreen/adi,ad7877.yaml b/Documentation/devicetree/bindings/input/touchscreen/adi,ad7877.yaml
new file mode 100644
index 000000000000..c472f50f7a59
--- /dev/null
+++ b/Documentation/devicetree/bindings/input/touchscreen/adi,ad7877.yaml
@@ -0,0 +1,106 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/input/touchscreen/adi,ad7877.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Analog Devices AD7877 Touch Screen Controller
+
+maintainers:
+  - Antoniu Miclaus <antoniu.miclaus@xxxxxxxxxx>
+
+description: |
+  Analog Devices Touch Screen Controller
+  https://www.analog.com/media/en/technical-documentation/data-sheets/AD7877.pdf
+
+allOf:
+  - $ref: touchscreen.yaml#
+  - $ref: /schemas/spi/spi-peripheral-props.yaml#
+
+properties:
+  compatible:
+    enum:
+      - adi,ad7877
+
+  reg:
+    maxItems: 1
+
+  interrupts:
+    maxItems: 1
+
+  spi-max-frequency:
+    description: AD7877 SPI bus clock frequency.
+    minimum: 10000
+    maximum: 20000000
+
+  adi,stopacq-polarity:
+    description: The polarity of the signal applied to the STOPACQ pin.
+    $ref: /schemas/types.yaml#/definitions/string
+    enum: [low, high]
+
+  adi,first-conv-delay-ns:
+    description: Delay in ns before the first conversion.
+    enum: [500, 128000, 1000000, 8000000]
+
+  adi,pen-down-acc-interval-us:
+    description: Enable the ADC to repeatedly perform conversions.
+    enum: [0, 500, 1000, 8000]
+    default: 0
+
+  adi,acquisition-time-us:
+    description: Select acquisition times in us for the ADC.
+    enum: [2, 4, 8, 16]
+    default: 2
+
+  adi,vref-delay-us:
+    description: Delay required for the SPI transfers depending on the VREF used.
+    default: 100
+
+  touchscreen-average-samples:
+    enum: [1, 4, 8, 16]
+
+  touchscreen-x-plate-ohms:
+    default: 400
+
+  touchscreen-min-x: true
+  touchscreen-min-y: true
+  touchscreen-size-x: true
+  touchscreen-size-y: true
+  touchscreen-max-pressure: true
+
+required:
+  - compatible
+  - reg
+  - interrupts
+  - touchscreen-average-samples
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/interrupt-controller/irq.h>
+    spi {
+      #address-cells = <1>;
+      #size-cells = <0>;
+
+      touchscreen@0 {
+        compatible = "adi,ad7877";
+        reg = <0>;
+        spi-max-frequency = <20000000>;
+        interrupts = <21 IRQ_TYPE_EDGE_FALLING>;
+        interrupt-parent = <&gpio>;
+        adi,vref-delay-us = <100>;
+        adi,stopacq-polarity = "low";
+        adi,first-conv-delay-ns = <500>;
+        adi,pen-down-acc-interval-us = <0>;
+        adi,acquisition-time-us = <2>;
+        touchscreen-average-samples = <16>;
+        touchscreen-x-plate-ohms = <400>;
+        touchscreen-min-x = <0>;
+        touchscreen-min-y = <0>;
+        touchscreen-size-x = <800>;
+        touchscreen-size-y = <480>;
+        touchscreen-max-pressure = <4095>;
+      };
+    };
+...
-- 
2.46.0