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

/*
 * rotary_encoder.c
 *
 * (c) 2009 Daniel Mack <daniel@caiaq.de>
 *
 * 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>
#include <linux/slab.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) {
		dev_err(&pdev->dev, "missing 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_direction_input(pdata->gpio_a);
	if (err) {
		dev_err(&pdev->dev, "unable to set GPIO %d for input\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;
	}

	err = gpio_direction_input(pdata->gpio_b);
	if (err) {
		dev_err(&pdev->dev, "unable to set GPIO %d for input\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 <daniel@caiaq.de>");
MODULE_LICENSE("GPL v2");
Commit	Line	Data
73969ff0 DM	1	/*
	2	* rotary_encoder.c
	3	*
	4	* (c) 2009 Daniel Mack <daniel@caiaq.de>
	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>
5a0e3ad6	25	#include <linux/slab.h>
73969ff0 DM	26
	27	#define DRV_NAME "rotary-encoder"
	28
	29	struct rotary_encoder {
73969ff0 DM	30	struct input_dev *input;
73969ff0 DM	31	struct rotary_encoder_platform_data *pdata;
bd3ce655 HS	32
	33	unsigned int axis;
	34	unsigned int pos;
	35
	36	unsigned int irq_a;
	37	unsigned int irq_b;
	38
	39	bool armed;
	40	unsigned char dir; /* 0 - clockwise, 1 - CCW */
73969ff0 DM	41	};
	42
	43	static irqreturn_t rotary_encoder_irq(int irq, void *dev_id)
	44	{
	45	struct rotary_encoder *encoder = dev_id;
	46	struct rotary_encoder_platform_data *pdata = encoder->pdata;
	47	int a = !!gpio_get_value(pdata->gpio_a);
	48	int b = !!gpio_get_value(pdata->gpio_b);
	49	int state;
	50
	51	a ^= pdata->inverted_a;
	52	b ^= pdata->inverted_b;
	53	state = (a << 1) \| b;
	54
	55	switch (state) {
	56
	57	case 0x0:
	58	if (!encoder->armed)
	59	break;
	60
bd3ce655 HS	61	if (pdata->relative_axis) {
	62	input_report_rel(encoder->input, pdata->axis,
	63	encoder->dir ? -1 : 1);
73969ff0	64	} else {
bd3ce655 HS	65	unsigned int pos = encoder->pos;
	66
	67	if (encoder->dir) {
	68	/* turning counter-clockwise */
	69	if (pdata->rollover)
	70	pos += pdata->steps;
	71	if (pos)
	72	pos--;
	73	} else {
	74	/* turning clockwise */
	75	if (pdata->rollover \|\| pos < pdata->steps)
	76	pos++;
	77	}
	78	if (pdata->rollover)
	79	pos %= pdata->steps;
	80	encoder->pos = pos;
	81	input_report_abs(encoder->input, pdata->axis,
	82	encoder->pos);
73969ff0	83	}
73969ff0 DM	84	input_sync(encoder->input);
73969ff0 DM	85
bd3ce655	86	encoder->armed = false;
73969ff0 DM	87	break;
	88
	89	case 0x1:
	90	case 0x2:
	91	if (encoder->armed)
	92	encoder->dir = state - 1;
	93	break;
	94
	95	case 0x3:
bd3ce655	96	encoder->armed = true;
73969ff0 DM	97	break;
	98	}
	99
	100	return IRQ_HANDLED;
	101	}
	102
	103	static int __devinit rotary_encoder_probe(struct platform_device *pdev)
	104	{
	105	struct rotary_encoder_platform_data *pdata = pdev->dev.platform_data;
	106	struct rotary_encoder *encoder;
	107	struct input_dev *input;
	108	int err;
	109
06ee3d3c HS	110	if (!pdata) {
06ee3d3c HS	111	dev_err(&pdev->dev, "missing platform data\n");
73969ff0 DM	112	return -ENOENT;
	113	}
	114
	115	encoder = kzalloc(sizeof(struct rotary_encoder), GFP_KERNEL);
	116	input = input_allocate_device();
	117	if (!encoder \|\| !input) {
	118	dev_err(&pdev->dev, "failed to allocate memory for device\n");
	119	err = -ENOMEM;
	120	goto exit_free_mem;
	121	}
	122
	123	encoder->input = input;
	124	encoder->pdata = pdata;
	125	encoder->irq_a = gpio_to_irq(pdata->gpio_a);
	126	encoder->irq_b = gpio_to_irq(pdata->gpio_b);
	127
	128	/* create and register the input driver */
	129	input->name = pdev->name;
	130	input->id.bustype = BUS_HOST;
	131	input->dev.parent = &pdev->dev;
bd3ce655 HS	132
	133	if (pdata->relative_axis) {
	134	input->evbit[0] = BIT_MASK(EV_REL);
	135	input->relbit[0] = BIT_MASK(pdata->axis);
	136	} else {
	137	input->evbit[0] = BIT_MASK(EV_ABS);
	138	input_set_abs_params(encoder->input,
	139	pdata->axis, 0, pdata->steps, 0, 1);
	140	}
73969ff0 DM	141
	142	err = input_register_device(input);
	143	if (err) {
	144	dev_err(&pdev->dev, "failed to register input device\n");
	145	goto exit_free_mem;
	146	}
	147
	148	/* request the GPIOs */
	149	err = gpio_request(pdata->gpio_a, DRV_NAME);
	150	if (err) {
	151	dev_err(&pdev->dev, "unable to request GPIO %d\n",
	152	pdata->gpio_a);
	153	goto exit_unregister_input;
	154	}
	155
5deeac99 AC	156	err = gpio_direction_input(pdata->gpio_a);
	157	if (err) {
	158	dev_err(&pdev->dev, "unable to set GPIO %d for input\n",
	159	pdata->gpio_a);
	160	goto exit_unregister_input;
	161	}
	162
73969ff0 DM	163	err = gpio_request(pdata->gpio_b, DRV_NAME);
	164	if (err) {
	165	dev_err(&pdev->dev, "unable to request GPIO %d\n",
	166	pdata->gpio_b);
	167	goto exit_free_gpio_a;
	168	}
	169
5deeac99 AC	170	err = gpio_direction_input(pdata->gpio_b);
	171	if (err) {
	172	dev_err(&pdev->dev, "unable to set GPIO %d for input\n",
	173	pdata->gpio_b);
	174	goto exit_free_gpio_a;
	175	}
	176
73969ff0 DM	177	/* request the IRQs */
	178	err = request_irq(encoder->irq_a, &rotary_encoder_irq,
	179	IORESOURCE_IRQ_HIGHEDGE \| IORESOURCE_IRQ_LOWEDGE,
	180	DRV_NAME, encoder);
	181	if (err) {
	182	dev_err(&pdev->dev, "unable to request IRQ %d\n",
	183	encoder->irq_a);
	184	goto exit_free_gpio_b;
	185	}
	186
	187	err = request_irq(encoder->irq_b, &rotary_encoder_irq,
	188	IORESOURCE_IRQ_HIGHEDGE \| IORESOURCE_IRQ_LOWEDGE,
	189	DRV_NAME, encoder);
	190	if (err) {
	191	dev_err(&pdev->dev, "unable to request IRQ %d\n",
	192	encoder->irq_b);
	193	goto exit_free_irq_a;
	194	}
	195
	196	platform_set_drvdata(pdev, encoder);
	197
	198	return 0;
	199
	200	exit_free_irq_a:
	201	free_irq(encoder->irq_a, encoder);
	202	exit_free_gpio_b:
	203	gpio_free(pdata->gpio_b);
	204	exit_free_gpio_a:
	205	gpio_free(pdata->gpio_a);
	206	exit_unregister_input:
	207	input_unregister_device(input);
	208	input = NULL; /* so we don't try to free it */
	209	exit_free_mem:
	210	input_free_device(input);
	211	kfree(encoder);
	212	return err;
	213	}
	214
	215	static int __devexit rotary_encoder_remove(struct platform_device *pdev)
	216	{
	217	struct rotary_encoder *encoder = platform_get_drvdata(pdev);
	218	struct rotary_encoder_platform_data *pdata = pdev->dev.platform_data;
	219
	220	free_irq(encoder->irq_a, encoder);
	221	free_irq(encoder->irq_b, encoder);
	222	gpio_free(pdata->gpio_a);
	223	gpio_free(pdata->gpio_b);
	224	input_unregister_device(encoder->input);
	225	platform_set_drvdata(pdev, NULL);
	226	kfree(encoder);
	227
	228	return 0;
	229	}
	230
	231	static struct platform_driver rotary_encoder_driver = {
	232	.probe = rotary_encoder_probe,
	233	.remove = __devexit_p(rotary_encoder_remove),
	234	.driver = {
	235	.name = DRV_NAME,
	236	.owner = THIS_MODULE,
	237	}
	238	};
	239
	240	static int __init rotary_encoder_init(void)
241	{
242	return platform_driver_register(&rotary_encoder_driver);
243	}
244
245	static void __exit rotary_encoder_exit(void)
246	{
247	platform_driver_unregister(&rotary_encoder_driver);
248	}
249
250	module_init(rotary_encoder_init);
251	module_exit(rotary_encoder_exit);
252
253	MODULE_ALIAS("platform:" DRV_NAME);
254	MODULE_DESCRIPTION("GPIO rotary encoder driver");
255	MODULE_AUTHOR("Daniel Mack <daniel@caiaq.de>");
256	MODULE_LICENSE("GPL v2");
257