[PATCHv2 4/4] Input: rotary-encoder - Add gpio as push button

From: Sebastian Reichel
Date: Mon Sep 07 2020 - 16:41:06 EST


From: Mylène Josserand <mylene.josserand@xxxxxxxxxxxxx>

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@xxxxxxxxxxxxx>
[code cleanup to current standards and renamed some properties]
Signed-off-by: Sebastian Reichel <sebastian.reichel@xxxxxxxxxxxxx>
---
.../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