linux-kernel - [PATCHv2 4/4] Input: rotary-encoder

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Date:   Mon,  7 Sep 2020 22:40:45 +0200
From:   Sebastian Reichel <sebastian.reichel@...labora.com>
To:     Dmitry Torokhov <dmitry.torokhov@...il.com>,
        Mylène Josserand 
        <mylene.josserand@...labora.com>, Rob Herring <robh+dt@...nel.org>
Cc:     linux-input@...r.kernel.org, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org, kernel@...labora.com,
        Sebastian Reichel <sebastian.reichel@...labora.com>
Subject: [PATCHv2 4/4] Input: rotary-encoder - Add gpio as push button

From: Mylène Josserand <mylene.josserand@...labora.com>

Add the support of a gpio that can be defined as a push button.
Thanks to that, it is possible to emit a keycode in case of a
"push" event, if the rotary supports that.

The keycode to emit is defined using "linux,code" property
(such as in gpio-keys).

Signed-off-by: Mylène Josserand <mylene.josserand@...labora.com>
[code cleanup to current standards and renamed some properties]
Signed-off-by: Sebastian Reichel <sebastian.reichel@...labora.com>
---
 .../bindings/input/rotary-encoder.yaml        | 21 +++++++++
 drivers/input/misc/rotary_encoder.c           | 43 +++++++++++++++++++
 2 files changed, 64 insertions(+)

diff --git a/Documentation/devicetree/bindings/input/rotary-encoder.yaml b/Documentation/devicetree/bindings/input/rotary-encoder.yaml
index 5b60ea86bd62..682fee104004 100644
--- a/Documentation/devicetree/bindings/input/rotary-encoder.yaml
+++ b/Documentation/devicetree/bindings/input/rotary-encoder.yaml
@@ -74,6 +74,24 @@ properties:
       need to be passed.
     type: boolean
 
+  push-gpios:
+    description: GPIO used as a detection of a push from the rotary-encoder.
+    maxItems: 1
+
+  linux,push-code:
+    description:
+      keycode to emit with the push-gpio of this rotary encoder.
+      If not specified defaults to <28> == KEY_ENTER.
+    $ref: /schemas/types.yaml#/definitions/uint32
+    default: 28
+
+  linux,push-type:
+    description:
+      Specify event type this button/key generates.
+      If not specified defaults to <1> == EV_KEY.
+    $ref: /schemas/types.yaml#definitions/uint32
+    default: 1
+
 required:
   - compatible
   - gpios
@@ -97,4 +115,7 @@ examples:
             linux,axis = <ABS_Y>;
             rotary-encoder,encoding = "binary";
             rotary-encoder,rollover;
+            push-gpios = <&gpio 23 GPIO_ACTIVE_HIGH>;
+            linux,push-code = <KEY_ENTER>;
+            linux,push-type = <EV_KEY>;
     };
diff --git a/drivers/input/misc/rotary_encoder.c b/drivers/input/misc/rotary_encoder.c
index 16ad86fad7cb..484042a5afa0 100644
--- a/drivers/input/misc/rotary_encoder.c
+++ b/drivers/input/misc/rotary_encoder.c
@@ -47,12 +47,33 @@ struct rotary_encoder {
 
 	unsigned int *irq;
 
+	struct gpio_desc *push_gpio;
+	unsigned int push_code;
+	unsigned int push_type;
+
 	bool armed;
 	signed char dir;	/* 1 - clockwise, -1 - CCW */
 
 	unsigned int last_stable;
 };
 
+static irqreturn_t rotary_push_irq(int irq, void *dev_id)
+{
+	struct rotary_encoder *encoder = dev_id;
+	int val;
+
+	mutex_lock(&encoder->access_mutex);
+
+	val = gpiod_get_value_cansleep(encoder->push_gpio);
+
+	input_report_key(encoder->input, encoder->push_code, val);
+	input_sync(encoder->input);
+
+	mutex_unlock(&encoder->access_mutex);
+
+	return IRQ_HANDLED;
+}
+
 static unsigned int rotary_encoder_get_state(struct rotary_encoder *encoder)
 {
 	int i;
@@ -248,6 +269,16 @@ static int rotary_encoder_probe(struct platform_device *pdev)
 		return -EINVAL;
 	}
 
+	encoder->push_gpio = devm_gpiod_get_optional(dev, "push", GPIOD_IN);
+	if (IS_ERR(encoder->push_gpio))
+		return dev_err_probe(dev, PTR_ERR(encoder->push_gpio), "failed to get push-gpio\n");
+
+	encoder->push_code = KEY_ENTER;
+	device_property_read_u32(dev, "linux,push-code", &encoder->push_code);
+
+	encoder->push_type = EV_KEY;
+	device_property_read_u32(dev, "linux,push-type", &encoder->push_type);
+
 	input = devm_input_allocate_device(dev);
 	if (!input)
 		return -ENOMEM;
@@ -304,6 +335,18 @@ static int rotary_encoder_probe(struct platform_device *pdev)
 		}
 	}
 
+	if (encoder->push_gpio) {
+		input_set_capability(encoder->input, encoder->push_type, encoder->push_code);
+		err = devm_request_threaded_irq(dev, gpiod_to_irq(encoder->push_gpio),
+						NULL, rotary_push_irq,
+						IRQF_TRIGGER_RISING |
+						IRQF_TRIGGER_FALLING |
+						IRQF_ONESHOT,
+						DRV_NAME, encoder);
+		if (err)
+			return dev_err_probe(dev, err, "unable to request push IRQ\n");
+	}
+
 	err = input_register_device(input);
 	if (err) {
 		dev_err(dev, "failed to register input device\n");
-- 
2.28.0