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Commit 80c99bcd authored by Daniel Mack's avatar Daniel Mack Committed by Dmitry Torokhov
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Input: rotary-encoder - add DT bindings



This adds devicetree bindings to the rotary encoder driver and some
documentation about how to use them. Tested on a PXA3xx platform.

Signed-off-by: default avatarDaniel Mack <zonque@gmail.com>
Signed-off-by: default avatarDmitry Torokhov <dmitry.torokhov@gmail.com>
parent ce919537
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+36 −0
Original line number Diff line number Diff line
Rotary encoder DT bindings

Required properties:
- gpios: a spec for two GPIOs to be used

Optional properties:
- linux,axis: the input subsystem axis to map to this rotary encoder.
  Defaults to 0 (ABS_X / REL_X)
- rotary-encoder,steps: Number of steps in a full turnaround of the
  encoder. Only relevant for absolute axis. Defaults to 24 which is a
  typical value for such devices.
- rotary-encoder,relative-axis: register a relative axis rather than an
  absolute one. Relative axis will only generate +1/-1 events on the input
  device, hence no steps need to be passed.
- rotary-encoder,rollover: Automatic rollove when the rotary value becomes
  greater than the specified steps or smaller than 0. For absolute axis only.
- rotary-encoder,half-period: Makes the driver work on half-period mode.

See Documentation/input/rotary-encoder.txt for more information.

Example:

		rotary@0 {
			compatible = "rotary-encoder";
			gpios = <&gpio 19 1>, <&gpio 20 0>; /* GPIO19 is inverted */
			linux,axis = <0>; /* REL_X */
			rotary-encoder,relative-axis;
		};

		rotary@1 {
			compatible = "rotary-encoder";
			gpios = <&gpio 21 0>, <&gpio 22 0>;
			linux,axis = <1>; /* ABS_Y */
			rotary-encoder,steps = <24>;
			rotary-encoder,rollover;
		};
+80 −16
Original line number Diff line number Diff line
@@ -24,6 +24,8 @@
#include <linux/gpio.h>
#include <linux/rotary_encoder.h>
#include <linux/slab.h>
#include <linux/of_platform.h>
#include <linux/of_gpio.h>

#define DRV_NAME "rotary-encoder"

@@ -140,6 +142,56 @@ static irqreturn_t rotary_encoder_half_period_irq(int irq, void *dev_id)
	return IRQ_HANDLED;
}

#ifdef CONFIG_OF
static struct of_device_id rotary_encoder_of_match[] = {
	{ .compatible = "rotary-encoder", },
	{ },
};
MODULE_DEVICE_TABLE(of, rotary_encoder_of_match);

static struct rotary_encoder_platform_data * __devinit
rotary_encoder_parse_dt(struct device *dev)
{
	const struct of_device_id *of_id =
				of_match_device(rotary_encoder_of_match, dev);
	struct device_node *np = dev->of_node;
	struct rotary_encoder_platform_data *pdata;
	enum of_gpio_flags flags;

	if (!of_id || !np)
		return NULL;

	pdata = kzalloc(sizeof(struct rotary_encoder_platform_data),
			GFP_KERNEL);
	if (!pdata)
		return ERR_PTR(-ENOMEM);

	of_property_read_u32(np, "rotary-encoder,steps", &pdata->steps);
	of_property_read_u32(np, "linux,axis", &pdata->axis);

	pdata->gpio_a = of_get_gpio_flags(np, 0, &flags);
	pdata->inverted_a = flags & OF_GPIO_ACTIVE_LOW;

	pdata->gpio_b = of_get_gpio_flags(np, 1, &flags);
	pdata->inverted_b = flags & OF_GPIO_ACTIVE_LOW;

	pdata->relative_axis = !!of_get_property(np,
					"rotary-encoder,relative-axis", NULL);
	pdata->rollover = !!of_get_property(np,
					"rotary-encoder,rollover", NULL);
	pdata->half_period = !!of_get_property(np,
					"rotary-encoder,half-period", NULL);

	return pdata;
}
#else
static inline struct rotary_encoder_platform_data *
rotary_encoder_parse_dt(struct device *dev)
{
	return NULL;
}
#endif

static int __devinit rotary_encoder_probe(struct platform_device *pdev)
{
	struct device *dev = &pdev->dev;
@@ -150,14 +202,19 @@ static int __devinit rotary_encoder_probe(struct platform_device *pdev)
	int err;

	if (!pdata) {
		dev_err(&pdev->dev, "missing platform data\n");
		return -ENOENT;
		pdata = rotary_encoder_parse_dt(dev);
		if (IS_ERR(pdata))
			return PTR_ERR(pdata);

		if (!pdata) {
			dev_err(dev, "missing platform data\n");
			return -EINVAL;
		}
	}

	encoder = kzalloc(sizeof(struct rotary_encoder), GFP_KERNEL);
	input = input_allocate_device();
	if (!encoder || !input) {
		dev_err(&pdev->dev, "failed to allocate memory for device\n");
		err = -ENOMEM;
		goto exit_free_mem;
	}
@@ -165,10 +222,9 @@ static int __devinit rotary_encoder_probe(struct platform_device *pdev)
	encoder->input = input;
	encoder->pdata = pdata;

	/* create and register the input driver */
	input->name = pdev->name;
	input->id.bustype = BUS_HOST;
	input->dev.parent = &pdev->dev;
	input->dev.parent = dev;

	if (pdata->relative_axis) {
		input->evbit[0] = BIT_MASK(EV_REL);
@@ -179,17 +235,11 @@ static int __devinit rotary_encoder_probe(struct platform_device *pdev)
				     pdata->axis, 0, pdata->steps, 0, 1);
	}

	err = input_register_device(input);
	if (err) {
		dev_err(dev, "failed to register input device\n");
		goto exit_free_mem;
	}

	/* request the GPIOs */
	err = gpio_request_one(pdata->gpio_a, GPIOF_IN, dev_name(dev));
	if (err) {
		dev_err(dev, "unable to request GPIO %d\n", pdata->gpio_a);
		goto exit_unregister_input;
		goto exit_free_mem;
	}

	err = gpio_request_one(pdata->gpio_b, GPIOF_IN, dev_name(dev));
@@ -225,22 +275,30 @@ static int __devinit rotary_encoder_probe(struct platform_device *pdev)
		goto exit_free_irq_a;
	}

	err = input_register_device(input);
	if (err) {
		dev_err(dev, "failed to register input device\n");
		goto exit_free_irq_b;
	}

	platform_set_drvdata(pdev, encoder);

	return 0;

exit_free_irq_b:
	free_irq(encoder->irq_b, encoder);
exit_free_irq_a:
	free_irq(encoder->irq_a, encoder);
exit_free_gpio_b:
	gpio_free(pdata->gpio_b);
exit_free_gpio_a:
	gpio_free(pdata->gpio_a);
exit_unregister_input:
	input_unregister_device(input);
	input = NULL; /* so we don't try to free it */
exit_free_mem:
	input_free_device(input);
	kfree(encoder);
	if (!dev_get_platdata(&pdev->dev))
		kfree(pdata);

	return err;
}

@@ -253,10 +311,15 @@ static int __devexit rotary_encoder_remove(struct platform_device *pdev)
	free_irq(encoder->irq_b, encoder);
	gpio_free(pdata->gpio_a);
	gpio_free(pdata->gpio_b);

	input_unregister_device(encoder->input);
	platform_set_drvdata(pdev, NULL);
	kfree(encoder);

	if (!dev_get_platdata(&pdev->dev))
		kfree(pdata);

	platform_set_drvdata(pdev, NULL);

	return 0;
}

@@ -266,6 +329,7 @@ static struct platform_driver rotary_encoder_driver = {
	.driver		= {
		.name	= DRV_NAME,
		.owner	= THIS_MODULE,
		.of_match_table = of_match_ptr(rotary_encoder_of_match),
	}
};
module_platform_driver(rotary_encoder_driver);