Input: rotary-encoder - add DT bindings

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;

		};

#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"

	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;

	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;

	}

	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);

				     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));

		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;

}

	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;

}

	.driver		= {

		.name	= DRV_NAME,

		.owner	= THIS_MODULE,

		.of_match_table = of_match_ptr(rotary_encoder_of_match),

	}

};

module_platform_driver(rotary_encoder_driver);