Add the Cypress TrueTouch Generation 5 touchscreen device tree bindings
documentation. It can use I2C or SPI bus.
This touchscreen can handle some defined zone that are designed and
sent as button. To be able to customize the keycode sent, the
"linux,code" property in a "button" sub-node can be used.

Signed-off-by: Alistair Francis <redacted>
Reviewed-by: Linus Walleij <redacted>
Reviewed-by: Rob Herring <robh@kernel.org>
---
 .../input/touchscreen/cypress,tt21000.yaml    | 101 ++++++++++++++++++
 1 file changed, 101 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/input/touchscreen/cypress,tt21000.yaml

diff --git a/Documentation/devicetree/bindings/input/touchscreen/cypress,tt21000.yaml b/Documentation/devicetree/bindings/input/touchscreen/cypress,tt21000.yaml
new file mode 100644
index 000000000000..3fc4b7011040
--- /dev/null
+++ b/Documentation/devicetree/bindings/input/touchscreen/cypress,tt21000.yaml

@@ -0,0 +1,101 @@
+# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/input/touchscreen/cypress,tt21000.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Cypress TT2100 touchscreen controller
+
+description: The Cypress TT2100 series (also known as "CYTTSP5" after
+  the marketing name Cypress TrueTouch Standard Product series 5).
+
+maintainers:
+  - Alistair Francis <alistair@alistair23.me>
+
+allOf:
+  - $ref: touchscreen.yaml#
+
+properties:
+  compatible:
+    const: cypress,tt21000
+
+  reg:
+    maxItems: 1
+
+  interrupts:
+    maxItems: 1
+
+  vdd-supply:
+    description: Regulator for voltage.
+
+  reset-gpios:
+    maxItems: 1
+
+  linux,keycodes:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    description: EV_ABS specific event code generated by the axis.