[PATCH v3 1/2] dt-bindings: input: bindings for Adafruit Seesaw Gamepad

From: Anshul Dalal <anshulusr@gmail.com>
To: linux-input@vger.kernel.org, devicetree@vger.kernel.org
Cc: Conor Dooley <conor+dt@kernel.org>,
	Anshul Dalal <anshulusr@gmail.com>,
	Dmitry Torokhov <dmitry.torokhov@gmail.com>,
	Rob Herring <robh+dt@kernel.org>,
	Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
	linux-kernel-mentees@lists.linuxfoundation.org
Subject: [PATCH v3 1/2] dt-bindings: input: bindings for Adafruit Seesaw Gamepad
Date: Mon,  9 Oct 2023 00:27:06 +0530	[thread overview]
Message-ID: <20231008185709.2448423-1-anshulusr@gmail.com> (raw)

A simple driver for a mini gamepad that communicates over i2c, the gamepad
has bidirectional thumb stick input and six buttons.

The gamepad chip utilizes the open framework from Adafruit called 'Seesaw'
to transmit the ADC data for the joystick and digital pin state for the
buttons. I have only implemented the functionality required to receive the
thumb stick and button state.

Product page:
  https://www.adafruit.com/product/5743
Arduino driver:
  https://github.com/adafruit/Adafruit_Seesaw

For testing on a RPi Zero 2W, I utilized the following devicetree overlay:

/dts-v1/;
/plugin/;
/ {
	compatible = "brcm,bcm2835";
	fragment@0 {
		target = <&i2c1>;
		__overlay__ {
			#address-cells = <1>;
			#size-cells = <0>;
			joystick@50 {
				compatible = "adafruit,seesaw-gamepad";
				reg = <0x50>;
			};
		};
	};
};

I used the above overlay as reference for writing this binding. Though the
gamepad also has an interrupt pin that needs to be enabled explicitly (not
currently implemented in driver). The pin triggers a rising edge when a
button is pressed or joystick is moved which can be detected on a GPIO
of the Microcontroller.

I wasn't sure how to represent that functionality in the binding so I have
left it out for now.

Signed-off-by: Anshul Dalal <anshulusr@gmail.com>
---

Changes for v3:
- Updated id field to reflect updated file name from previous version
- Added `reg` property

Changes for v2:
- Renamed file to `adafruit,seesaw-gamepad.yaml`
- Removed quotes for `$id` and `$schema`
- Removed "Bindings for" from the description
- Changed node name to the generic name "joystick"
- Changed compatible to 'adafruit,seesaw-gamepad' instead of 'adafruit,seesaw_gamepad'

 .../input/adafruit,seesaw-gamepad.yaml        | 54 +++++++++++++++++++
 1 file changed, 54 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/input/adafruit,seesaw-gamepad.yaml

diff --git a/Documentation/devicetree/bindings/input/adafruit,seesaw-gamepad.yaml b/Documentation/devicetree/bindings/input/adafruit,seesaw-gamepad.yaml
new file mode 100644
index 000000000000..610c99594439
--- /dev/null
+++ b/Documentation/devicetree/bindings/input/adafruit,seesaw-gamepad.yaml
@@ -0,0 +1,54 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/input/adafruit-seesaw.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Adafruit Mini I2C Gamepad with seesaw
+
+maintainers:
+  - Anshul Dalal <anshulusr@gmail.com>
+
+description: |
+  Adafruit Mini I2C Gamepad
+
+    +-----------------------------+
+    |   ___                       |
+    |  /   \               (X)    |
+    | |  S  |  __   __  (Y)   (A) |
+    |  \___/  |ST| |SE|    (B)    |
+    |                             |
+    +-----------------------------+
+
+  S -> 10-bit percision bidirectional analog joystick
+  ST -> Start
+  SE -> Select
+  X, A, B, Y -> Digital action buttons
+
+  Product page: https://www.adafruit.com/product/5743
+  Arduino Driver: https://github.com/adafruit/Adafruit_Seesaw
+
+properties:
+  compatible:
+    const: adafruit,seesaw-gamepad
+
+  reg:
+    maxItems: 1
+
+required:
+  - compatible
+  - reg
+
+additionalProperties: false
+
+examples:
+  - |
+    i2c {
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        joystick@50 {
+            compatible = "adafruit,seesaw-gamepad";
+            reg = <0x50>;
+        };
+    };
-- 
2.42.0

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