[linux.git] / drivers / input / misc / rotary_encoder.c

/*
 * rotary_encoder.c
 *
 * (c) 2009 Daniel Mack <[email protected]>
 *
 * state machine code inspired by code from Tim Ruetz
 *
 * A generic driver for rotary encoders connected to GPIO lines.
 * See file:Documentation/input/rotary_encoder.txt for more information
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/input.h>
#include <linux/device.h>
#include <linux/platform_device.h>
#include <linux/gpio.h>
#include <linux/rotary_encoder.h>

#define DRV_NAME "rotary-encoder"

struct rotary_encoder {
	struct input_dev *input;
	struct rotary_encoder_platform_data *pdata;

	unsigned int axis;
	unsigned int pos;

	unsigned int irq_a;
	unsigned int irq_b;

	bool armed;
	unsigned char dir;	/* 0 - clockwise, 1 - CCW */
};

static irqreturn_t rotary_encoder_irq(int irq, void *dev_id)
{
	struct rotary_encoder *encoder = dev_id;
	struct rotary_encoder_platform_data *pdata = encoder->pdata;
	int a = !!gpio_get_value(pdata->gpio_a);
	int b = !!gpio_get_value(pdata->gpio_b);
	int state;

	a ^= pdata->inverted_a;
	b ^= pdata->inverted_b;
	state = (a << 1) | b;

	switch (state) {

	case 0x0:
		if (!encoder->armed)
			break;

		if (pdata->relative_axis) {
			input_report_rel(encoder->input, pdata->axis,
					 encoder->dir ? -1 : 1);
		} else {
			unsigned int pos = encoder->pos;

			if (encoder->dir) {
				/* turning counter-clockwise */
				if (pdata->rollover)
					pos += pdata->steps;
				if (pos)
					pos--;
			} else {
				/* turning clockwise */
				if (pdata->rollover || pos < pdata->steps)
					pos++;
			}
			if (pdata->rollover)
				pos %= pdata->steps;
			encoder->pos = pos;
			input_report_abs(encoder->input, pdata->axis,
					 encoder->pos);
		}
		input_sync(encoder->input);

		encoder->armed = false;
		break;

	case 0x1:
	case 0x2:
		if (encoder->armed)
			encoder->dir = state - 1;
		break;

	case 0x3:
		encoder->armed = true;
		break;
	}

	return IRQ_HANDLED;
}

static int __devinit rotary_encoder_probe(struct platform_device *pdev)
{
	struct rotary_encoder_platform_data *pdata = pdev->dev.platform_data;
	struct rotary_encoder *encoder;
	struct input_dev *input;
	int err;

	if (!pdata || !pdata->steps) {
		dev_err(&pdev->dev, "invalid platform data\n");
		return -ENOENT;
	}

	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;
	encoder->irq_a = gpio_to_irq(pdata->gpio_a);
	encoder->irq_b = gpio_to_irq(pdata->gpio_b);

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

	if (pdata->relative_axis) {
		input->evbit[0] = BIT_MASK(EV_REL);
		input->relbit[0] = BIT_MASK(pdata->axis);
	} else {
		input->evbit[0] = BIT_MASK(EV_ABS);
		input_set_abs_params(encoder->input,
				     pdata->axis, 0, pdata->steps, 0, 1);
	}

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

	/* request the GPIOs */
	err = gpio_request(pdata->gpio_a, DRV_NAME);
	if (err) {
		dev_err(&pdev->dev, "unable to request GPIO %d\n",
			pdata->gpio_a);
		goto exit_unregister_input;
	}

	err = gpio_request(pdata->gpio_b, DRV_NAME);
	if (err) {
		dev_err(&pdev->dev, "unable to request GPIO %d\n",
			pdata->gpio_b);
		goto exit_free_gpio_a;
	}

	/* request the IRQs */
	err = request_irq(encoder->irq_a, &rotary_encoder_irq,
			  IORESOURCE_IRQ_HIGHEDGE | IORESOURCE_IRQ_LOWEDGE,
			  DRV_NAME, encoder);
	if (err) {
		dev_err(&pdev->dev, "unable to request IRQ %d\n",
			encoder->irq_a);
		goto exit_free_gpio_b;
	}

	err = request_irq(encoder->irq_b, &rotary_encoder_irq,
			  IORESOURCE_IRQ_HIGHEDGE | IORESOURCE_IRQ_LOWEDGE,
			  DRV_NAME, encoder);
	if (err) {
		dev_err(&pdev->dev, "unable to request IRQ %d\n",
			encoder->irq_b);
		goto exit_free_irq_a;
	}

	platform_set_drvdata(pdev, encoder);

	return 0;

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);
	return err;
}

static int __devexit rotary_encoder_remove(struct platform_device *pdev)
{
	struct rotary_encoder *encoder = platform_get_drvdata(pdev);
	struct rotary_encoder_platform_data *pdata = pdev->dev.platform_data;

	free_irq(encoder->irq_a, encoder);
	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);

	return 0;
}

static struct platform_driver rotary_encoder_driver = {
	.probe		= rotary_encoder_probe,
	.remove		= __devexit_p(rotary_encoder_remove),
	.driver		= {
		.name	= DRV_NAME,
		.owner	= THIS_MODULE,
	}
};

static int __init rotary_encoder_init(void)
{
	return platform_driver_register(&rotary_encoder_driver);
}

static void __exit rotary_encoder_exit(void)
{
	platform_driver_unregister(&rotary_encoder_driver);
}

module_init(rotary_encoder_init);
module_exit(rotary_encoder_exit);

MODULE_ALIAS("platform:" DRV_NAME);
MODULE_DESCRIPTION("GPIO rotary encoder driver");
MODULE_AUTHOR("Daniel Mack <[email protected]>");
MODULE_LICENSE("GPL v2");
Commit	Line	Data
73969ff0 DM	1	/*
	2	* rotary_encoder.c
	3	*
	4	* (c) 2009 Daniel Mack <[email protected]>
	5	*
	6	* state machine code inspired by code from Tim Ruetz
	7	*
	8	* A generic driver for rotary encoders connected to GPIO lines.
	9	* See file:Documentation/input/rotary_encoder.txt for more information
	10	*
	11	* This program is free software; you can redistribute it and/or modify
	12	* it under the terms of the GNU General Public License version 2 as
	13	* published by the Free Software Foundation.
	14	*/
	15
	16	#include <linux/kernel.h>
	17	#include <linux/module.h>
	18	#include <linux/init.h>
	19	#include <linux/interrupt.h>
	20	#include <linux/input.h>
	21	#include <linux/device.h>
	22	#include <linux/platform_device.h>
	23	#include <linux/gpio.h>
	24	#include <linux/rotary_encoder.h>
	25
	26	#define DRV_NAME "rotary-encoder"
	27
	28	struct rotary_encoder {
73969ff0 DM	29	struct input_dev *input;
73969ff0 DM	30	struct rotary_encoder_platform_data *pdata;
bd3ce655 HS	31
	32	unsigned int axis;
	33	unsigned int pos;
	34
	35	unsigned int irq_a;
	36	unsigned int irq_b;
	37
	38	bool armed;
	39	unsigned char dir; /* 0 - clockwise, 1 - CCW */
73969ff0 DM	40	};
	41
	42	static irqreturn_t rotary_encoder_irq(int irq, void *dev_id)
	43	{
	44	struct rotary_encoder *encoder = dev_id;
	45	struct rotary_encoder_platform_data *pdata = encoder->pdata;
	46	int a = !!gpio_get_value(pdata->gpio_a);
	47	int b = !!gpio_get_value(pdata->gpio_b);
	48	int state;
	49
	50	a ^= pdata->inverted_a;
	51	b ^= pdata->inverted_b;
	52	state = (a << 1) \| b;
	53
	54	switch (state) {
	55
	56	case 0x0:
	57	if (!encoder->armed)
	58	break;
	59
bd3ce655 HS	60	if (pdata->relative_axis) {
	61	input_report_rel(encoder->input, pdata->axis,
	62	encoder->dir ? -1 : 1);
73969ff0	63	} else {
bd3ce655 HS	64	unsigned int pos = encoder->pos;
	65
	66	if (encoder->dir) {
	67	/* turning counter-clockwise */
	68	if (pdata->rollover)
	69	pos += pdata->steps;
	70	if (pos)
	71	pos--;
	72	} else {
	73	/* turning clockwise */
	74	if (pdata->rollover \|\| pos < pdata->steps)
	75	pos++;
	76	}
	77	if (pdata->rollover)
	78	pos %= pdata->steps;
	79	encoder->pos = pos;
	80	input_report_abs(encoder->input, pdata->axis,
	81	encoder->pos);
73969ff0	82	}
73969ff0 DM	83	input_sync(encoder->input);
73969ff0 DM	84
bd3ce655	85	encoder->armed = false;
73969ff0 DM	86	break;
	87
	88	case 0x1:
	89	case 0x2:
	90	if (encoder->armed)
	91	encoder->dir = state - 1;
	92	break;
	93
	94	case 0x3:
bd3ce655	95	encoder->armed = true;
73969ff0 DM	96	break;
	97	}
	98
	99	return IRQ_HANDLED;
	100	}
	101
	102	static int __devinit rotary_encoder_probe(struct platform_device *pdev)
	103	{
	104	struct rotary_encoder_platform_data *pdata = pdev->dev.platform_data;
	105	struct rotary_encoder *encoder;
	106	struct input_dev *input;
	107	int err;
	108
	109	if (!pdata \|\| !pdata->steps) {
	110	dev_err(&pdev->dev, "invalid platform data\n");
	111	return -ENOENT;
	112	}
	113
	114	encoder = kzalloc(sizeof(struct rotary_encoder), GFP_KERNEL);
	115	input = input_allocate_device();
	116	if (!encoder \|\| !input) {
	117	dev_err(&pdev->dev, "failed to allocate memory for device\n");
	118	err = -ENOMEM;
	119	goto exit_free_mem;
	120	}
	121
	122	encoder->input = input;
	123	encoder->pdata = pdata;
	124	encoder->irq_a = gpio_to_irq(pdata->gpio_a);
	125	encoder->irq_b = gpio_to_irq(pdata->gpio_b);
	126
	127	/* create and register the input driver */
	128	input->name = pdev->name;
	129	input->id.bustype = BUS_HOST;
	130	input->dev.parent = &pdev->dev;
bd3ce655 HS	131
	132	if (pdata->relative_axis) {
	133	input->evbit[0] = BIT_MASK(EV_REL);
	134	input->relbit[0] = BIT_MASK(pdata->axis);
	135	} else {
	136	input->evbit[0] = BIT_MASK(EV_ABS);
	137	input_set_abs_params(encoder->input,
	138	pdata->axis, 0, pdata->steps, 0, 1);
	139	}
73969ff0 DM	140
	141	err = input_register_device(input);
	142	if (err) {
	143	dev_err(&pdev->dev, "failed to register input device\n");
	144	goto exit_free_mem;
	145	}
	146
	147	/* request the GPIOs */
	148	err = gpio_request(pdata->gpio_a, DRV_NAME);
	149	if (err) {
	150	dev_err(&pdev->dev, "unable to request GPIO %d\n",
	151	pdata->gpio_a);
	152	goto exit_unregister_input;
	153	}
	154
	155	err = gpio_request(pdata->gpio_b, DRV_NAME);
	156	if (err) {
	157	dev_err(&pdev->dev, "unable to request GPIO %d\n",
	158	pdata->gpio_b);
	159	goto exit_free_gpio_a;
	160	}
	161
	162	/* request the IRQs */
	163	err = request_irq(encoder->irq_a, &rotary_encoder_irq,
	164	IORESOURCE_IRQ_HIGHEDGE \| IORESOURCE_IRQ_LOWEDGE,
	165	DRV_NAME, encoder);
	166	if (err) {
	167	dev_err(&pdev->dev, "unable to request IRQ %d\n",
	168	encoder->irq_a);
	169	goto exit_free_gpio_b;
	170	}
	171
	172	err = request_irq(encoder->irq_b, &rotary_encoder_irq,
	173	IORESOURCE_IRQ_HIGHEDGE \| IORESOURCE_IRQ_LOWEDGE,
	174	DRV_NAME, encoder);
	175	if (err) {
	176	dev_err(&pdev->dev, "unable to request IRQ %d\n",
	177	encoder->irq_b);
	178	goto exit_free_irq_a;
	179	}
	180
	181	platform_set_drvdata(pdev, encoder);
	182
	183	return 0;
	184
	185	exit_free_irq_a:
	186	free_irq(encoder->irq_a, encoder);
	187	exit_free_gpio_b:
	188	gpio_free(pdata->gpio_b);
	189	exit_free_gpio_a:
	190	gpio_free(pdata->gpio_a);
	191	exit_unregister_input:
	192	input_unregister_device(input);
	193	input = NULL; /* so we don't try to free it */
	194	exit_free_mem:
	195	input_free_device(input);
	196	kfree(encoder);
	197	return err;
	198	}
	199
	200	static int __devexit rotary_encoder_remove(struct platform_device *pdev)
	201	{
	202	struct rotary_encoder *encoder = platform_get_drvdata(pdev);
	203	struct rotary_encoder_platform_data *pdata = pdev->dev.platform_data;
204
205	free_irq(encoder->irq_a, encoder);
206	free_irq(encoder->irq_b, encoder);
207	gpio_free(pdata->gpio_a);
208	gpio_free(pdata->gpio_b);
209	input_unregister_device(encoder->input);
210	platform_set_drvdata(pdev, NULL);
211	kfree(encoder);
212
213	return 0;
214	}
215
216	static struct platform_driver rotary_encoder_driver = {
217	.probe = rotary_encoder_probe,
218	.remove = __devexit_p(rotary_encoder_remove),
219	.driver = {
220	.name = DRV_NAME,
221	.owner = THIS_MODULE,
222	}
223	};
224
225	static int __init rotary_encoder_init(void)
226	{
227	return platform_driver_register(&rotary_encoder_driver);
228	}
229
230	static void __exit rotary_encoder_exit(void)
231	{
232	platform_driver_unregister(&rotary_encoder_driver);
233	}
234
235	module_init(rotary_encoder_init);
236	module_exit(rotary_encoder_exit);
237
238	MODULE_ALIAS("platform:" DRV_NAME);
239	MODULE_DESCRIPTION("GPIO rotary encoder driver");
240	MODULE_AUTHOR("Daniel Mack <[email protected]>");
241	MODULE_LICENSE("GPL v2");
242