[linux-2.6-block.git] / drivers / input / misc / rotary_encoder.c

/*
 * rotary_encoder.c
 *
 * (c) 2009 Daniel Mack <daniel@caiaq.de>
 * Copyright (C) 2011 Johan Hovold <jhovold@gmail.com>
 *
 * 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>
#include <linux/of_platform.h>
#include <linux/of_gpio.h>

#define DRV_NAME "rotary-encoder"

struct rotary_encoder {
	struct input_dev *input;
	const 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 */

	char last_stable;
};

static int rotary_encoder_get_state(const struct rotary_encoder_platform_data *pdata)
{
	int a = !!gpio_get_value(pdata->gpio_a);
	int b = !!gpio_get_value(pdata->gpio_b);

	a ^= pdata->inverted_a;
	b ^= pdata->inverted_b;

	return ((a << 1) | b);
}

static void rotary_encoder_report_event(struct rotary_encoder *encoder)
{
	const struct rotary_encoder_platform_data *pdata = encoder->pdata;

	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);
}

static irqreturn_t rotary_encoder_irq(int irq, void *dev_id)
{
	struct rotary_encoder *encoder = dev_id;
	int state;

	state = rotary_encoder_get_state(encoder->pdata);

	switch (state) {
	case 0x0:
		if (encoder->armed) {
			rotary_encoder_report_event(encoder);
			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 irqreturn_t rotary_encoder_half_period_irq(int irq, void *dev_id)
{
	struct rotary_encoder *encoder = dev_id;
	int state;

	state = rotary_encoder_get_state(encoder->pdata);

	switch (state) {
	case 0x00:
	case 0x03:
		if (state != encoder->last_stable) {
			rotary_encoder_report_event(encoder);
			encoder->last_stable = state;
		}
		break;

	case 0x01:
	case 0x02:
		encoder->dir = (encoder->last_stable + state) & 0x01;
		break;
	}

	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;
	const struct rotary_encoder_platform_data *pdata = dev_get_platdata(dev);
	struct rotary_encoder *encoder;
	struct input_dev *input;
	irq_handler_t handler;
	int err;

	if (!pdata) {
		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) {
		err = -ENOMEM;
		goto exit_free_mem;
	}

	encoder->input = input;
	encoder->pdata = pdata;

	input->name = pdev->name;
	input->id.bustype = BUS_HOST;
	input->dev.parent = 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);
	}

	/* 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_free_mem;
	}

	err = gpio_request_one(pdata->gpio_b, GPIOF_IN, dev_name(dev));
	if (err) {
		dev_err(dev, "unable to request GPIO %d\n", pdata->gpio_b);
		goto exit_free_gpio_a;
	}

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

	/* request the IRQs */
	if (pdata->half_period) {
		handler = &rotary_encoder_half_period_irq;
		encoder->last_stable = rotary_encoder_get_state(pdata);
	} else {
		handler = &rotary_encoder_irq;
	}

	err = request_irq(encoder->irq_a, handler,
			  IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING,
			  DRV_NAME, encoder);
	if (err) {
		dev_err(dev, "unable to request IRQ %d\n", encoder->irq_a);
		goto exit_free_gpio_b;
	}

	err = request_irq(encoder->irq_b, handler,
			  IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING,
			  DRV_NAME, encoder);
	if (err) {
		dev_err(dev, "unable to request IRQ %d\n", encoder->irq_b);
		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_free_mem:
	input_free_device(input);
	kfree(encoder);
	if (!dev_get_platdata(&pdev->dev))
		kfree(pdata);

	return err;
}

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

	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);
	kfree(encoder);

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

	platform_set_drvdata(pdev, NULL);

	return 0;
}

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

MODULE_ALIAS("platform:" DRV_NAME);
MODULE_DESCRIPTION("GPIO rotary encoder driver");
MODULE_AUTHOR("Daniel Mack <daniel@caiaq.de>, Johan Hovold");
MODULE_LICENSE("GPL v2");
Commit	Line	Data
73969ff0 DM	1	/*
	2	* rotary_encoder.c
	3	*
	4	* (c) 2009 Daniel Mack <daniel@caiaq.de>
e70bdd41	5	* Copyright (C) 2011 Johan Hovold <jhovold@gmail.com>
73969ff0 DM	6	*
	7	* state machine code inspired by code from Tim Ruetz
	8	*
	9	* A generic driver for rotary encoders connected to GPIO lines.
395cf969	10	* See file:Documentation/input/rotary-encoder.txt for more information
73969ff0 DM	11	*
	12	* This program is free software; you can redistribute it and/or modify
	13	* it under the terms of the GNU General Public License version 2 as
	14	* published by the Free Software Foundation.
	15	*/
	16
	17	#include <linux/kernel.h>
	18	#include <linux/module.h>
	19	#include <linux/init.h>
	20	#include <linux/interrupt.h>
	21	#include <linux/input.h>
	22	#include <linux/device.h>
	23	#include <linux/platform_device.h>
	24	#include <linux/gpio.h>
	25	#include <linux/rotary_encoder.h>
5a0e3ad6	26	#include <linux/slab.h>
80c99bcd DM	27	#include <linux/of_platform.h>
80c99bcd DM	28	#include <linux/of_gpio.h>
73969ff0 DM	29
	30	#define DRV_NAME "rotary-encoder"
	31
	32	struct rotary_encoder {
73969ff0	33	struct input_dev *input;
ce919537	34	const struct rotary_encoder_platform_data *pdata;
bd3ce655 HS	35
	36	unsigned int axis;
	37	unsigned int pos;
	38
	39	unsigned int irq_a;
	40	unsigned int irq_b;
	41
	42	bool armed;
	43	unsigned char dir; /* 0 - clockwise, 1 - CCW */
e70bdd41 JH	44
e70bdd41 JH	45	char last_stable;
73969ff0 DM	46	};
73969ff0 DM	47
ce919537	48	static int rotary_encoder_get_state(const struct rotary_encoder_platform_data *pdata)
73969ff0	49	{
73969ff0 DM	50	int a = !!gpio_get_value(pdata->gpio_a);
73969ff0 DM	51	int b = !!gpio_get_value(pdata->gpio_b);
73969ff0 DM	52
	53	a ^= pdata->inverted_a;
	54	b ^= pdata->inverted_b;
73969ff0	55
521a8f5c JH	56	return ((a << 1) \| b);
521a8f5c JH	57	}
73969ff0	58
521a8f5c JH	59	static void rotary_encoder_report_event(struct rotary_encoder *encoder)
521a8f5c JH	60	{
ce919537	61	const struct rotary_encoder_platform_data *pdata = encoder->pdata;
73969ff0	62
521a8f5c JH	63	if (pdata->relative_axis) {
	64	input_report_rel(encoder->input,
	65	pdata->axis, encoder->dir ? -1 : 1);
	66	} else {
	67	unsigned int pos = encoder->pos;
	68
	69	if (encoder->dir) {
	70	/* turning counter-clockwise */
bd3ce655	71	if (pdata->rollover)
521a8f5c JH	72	pos += pdata->steps;
	73	if (pos)
	74	pos--;
	75	} else {
	76	/* turning clockwise */
	77	if (pdata->rollover \|\| pos < pdata->steps)
	78	pos++;
73969ff0	79	}
73969ff0	80
521a8f5c JH	81	if (pdata->rollover)
	82	pos %= pdata->steps;
	83
	84	encoder->pos = pos;
	85	input_report_abs(encoder->input, pdata->axis, encoder->pos);
	86	}
	87
	88	input_sync(encoder->input);
	89	}
	90
	91	static irqreturn_t rotary_encoder_irq(int irq, void *dev_id)
	92	{
	93	struct rotary_encoder *encoder = dev_id;
	94	int state;
	95
	96	state = rotary_encoder_get_state(encoder->pdata);
	97
	98	switch (state) {
	99	case 0x0:
	100	if (encoder->armed) {
	101	rotary_encoder_report_event(encoder);
	102	encoder->armed = false;
	103	}
73969ff0 DM	104	break;
	105
	106	case 0x1:
	107	case 0x2:
	108	if (encoder->armed)
	109	encoder->dir = state - 1;
	110	break;
	111
	112	case 0x3:
bd3ce655	113	encoder->armed = true;
73969ff0 DM	114	break;
	115	}
	116
	117	return IRQ_HANDLED;
	118	}
	119
e70bdd41 JH	120	static irqreturn_t rotary_encoder_half_period_irq(int irq, void *dev_id)
	121	{
	122	struct rotary_encoder *encoder = dev_id;
	123	int state;
	124
	125	state = rotary_encoder_get_state(encoder->pdata);
	126
	127	switch (state) {
	128	case 0x00:
	129	case 0x03:
	130	if (state != encoder->last_stable) {
	131	rotary_encoder_report_event(encoder);
	132	encoder->last_stable = state;
	133	}
	134	break;
	135
	136	case 0x01:
	137	case 0x02:
	138	encoder->dir = (encoder->last_stable + state) & 0x01;
	139	break;
	140	}
	141
	142	return IRQ_HANDLED;
	143	}
	144
80c99bcd DM	145	#ifdef CONFIG_OF
	146	static struct of_device_id rotary_encoder_of_match[] = {
	147	{ .compatible = "rotary-encoder", },
	148	{ },
	149	};
	150	MODULE_DEVICE_TABLE(of, rotary_encoder_of_match);
	151
	152	static struct rotary_encoder_platform_data * __devinit
	153	rotary_encoder_parse_dt(struct device *dev)
	154	{
	155	const struct of_device_id *of_id =
	156	of_match_device(rotary_encoder_of_match, dev);
	157	struct device_node *np = dev->of_node;
	158	struct rotary_encoder_platform_data *pdata;
	159	enum of_gpio_flags flags;
	160
	161	if (!of_id \|\| !np)
	162	return NULL;
	163
	164	pdata = kzalloc(sizeof(struct rotary_encoder_platform_data),
	165	GFP_KERNEL);
	166	if (!pdata)
	167	return ERR_PTR(-ENOMEM);
	168
	169	of_property_read_u32(np, "rotary-encoder,steps", &pdata->steps);
	170	of_property_read_u32(np, "linux,axis", &pdata->axis);
	171
	172	pdata->gpio_a = of_get_gpio_flags(np, 0, &flags);
	173	pdata->inverted_a = flags & OF_GPIO_ACTIVE_LOW;
	174
	175	pdata->gpio_b = of_get_gpio_flags(np, 1, &flags);
	176	pdata->inverted_b = flags & OF_GPIO_ACTIVE_LOW;
	177
	178	pdata->relative_axis = !!of_get_property(np,
	179	"rotary-encoder,relative-axis", NULL);
	180	pdata->rollover = !!of_get_property(np,
	181	"rotary-encoder,rollover", NULL);
	182	pdata->half_period = !!of_get_property(np,
	183	"rotary-encoder,half-period", NULL);
	184
	185	return pdata;
	186	}
	187	#else
	188	static inline struct rotary_encoder_platform_data *
	189	rotary_encoder_parse_dt(struct device *dev)
	190	{
	191	return NULL;
	192	}
	193	#endif
	194
73969ff0 DM	195	static int __devinit rotary_encoder_probe(struct platform_device *pdev)
73969ff0 DM	196	{
ce919537 DT	197	struct device *dev = &pdev->dev;
ce919537 DT	198	const struct rotary_encoder_platform_data *pdata = dev_get_platdata(dev);
73969ff0 DM	199	struct rotary_encoder *encoder;
73969ff0 DM	200	struct input_dev *input;
e70bdd41	201	irq_handler_t handler;
73969ff0 DM	202	int err;
73969ff0 DM	203
06ee3d3c	204	if (!pdata) {
80c99bcd DM	205	pdata = rotary_encoder_parse_dt(dev);
	206	if (IS_ERR(pdata))
	207	return PTR_ERR(pdata);
	208
	209	if (!pdata) {
	210	dev_err(dev, "missing platform data\n");
	211	return -EINVAL;
	212	}
73969ff0 DM	213	}
	214
	215	encoder = kzalloc(sizeof(struct rotary_encoder), GFP_KERNEL);
	216	input = input_allocate_device();
	217	if (!encoder \|\| !input) {
73969ff0 DM	218	err = -ENOMEM;
	219	goto exit_free_mem;
	220	}
	221
	222	encoder->input = input;
	223	encoder->pdata = pdata;
73969ff0	224
73969ff0 DM	225	input->name = pdev->name;
73969ff0 DM	226	input->id.bustype = BUS_HOST;
80c99bcd	227	input->dev.parent = dev;
bd3ce655 HS	228
	229	if (pdata->relative_axis) {
	230	input->evbit[0] = BIT_MASK(EV_REL);
	231	input->relbit[0] = BIT_MASK(pdata->axis);
	232	} else {
	233	input->evbit[0] = BIT_MASK(EV_ABS);
	234	input_set_abs_params(encoder->input,
	235	pdata->axis, 0, pdata->steps, 0, 1);
	236	}
73969ff0	237
73969ff0	238	/* request the GPIOs */
429a34d7	239	err = gpio_request_one(pdata->gpio_a, GPIOF_IN, dev_name(dev));
73969ff0	240	if (err) {
429a34d7	241	dev_err(dev, "unable to request GPIO %d\n", pdata->gpio_a);
80c99bcd	242	goto exit_free_mem;
73969ff0 DM	243	}
73969ff0 DM	244
429a34d7	245	err = gpio_request_one(pdata->gpio_b, GPIOF_IN, dev_name(dev));
5deeac99	246	if (err) {
429a34d7	247	dev_err(dev, "unable to request GPIO %d\n", pdata->gpio_b);
5deeac99 AC	248	goto exit_free_gpio_a;
	249	}
	250
a78769b8 DM	251	encoder->irq_a = gpio_to_irq(pdata->gpio_a);
	252	encoder->irq_b = gpio_to_irq(pdata->gpio_b);
	253
73969ff0	254	/* request the IRQs */
e70bdd41 JH	255	if (pdata->half_period) {
	256	handler = &rotary_encoder_half_period_irq;
	257	encoder->last_stable = rotary_encoder_get_state(pdata);
	258	} else {
	259	handler = &rotary_encoder_irq;
	260	}
	261
	262	err = request_irq(encoder->irq_a, handler,
e0d5f4c3	263	IRQF_TRIGGER_RISING \| IRQF_TRIGGER_FALLING,
73969ff0 DM	264	DRV_NAME, encoder);
73969ff0 DM	265	if (err) {
429a34d7	266	dev_err(dev, "unable to request IRQ %d\n", encoder->irq_a);
73969ff0 DM	267	goto exit_free_gpio_b;
	268	}
	269
e70bdd41	270	err = request_irq(encoder->irq_b, handler,
e0d5f4c3	271	IRQF_TRIGGER_RISING \| IRQF_TRIGGER_FALLING,
73969ff0 DM	272	DRV_NAME, encoder);
73969ff0 DM	273	if (err) {
429a34d7	274	dev_err(dev, "unable to request IRQ %d\n", encoder->irq_b);
73969ff0 DM	275	goto exit_free_irq_a;
	276	}
	277
80c99bcd DM	278	err = input_register_device(input);
	279	if (err) {
	280	dev_err(dev, "failed to register input device\n");
	281	goto exit_free_irq_b;
	282	}
	283
73969ff0 DM	284	platform_set_drvdata(pdev, encoder);
	285
	286	return 0;
	287
80c99bcd DM	288	exit_free_irq_b:
80c99bcd DM	289	free_irq(encoder->irq_b, encoder);
73969ff0 DM	290	exit_free_irq_a:
	291	free_irq(encoder->irq_a, encoder);
	292	exit_free_gpio_b:
	293	gpio_free(pdata->gpio_b);
	294	exit_free_gpio_a:
	295	gpio_free(pdata->gpio_a);
73969ff0 DM	296	exit_free_mem:
	297	input_free_device(input);
	298	kfree(encoder);
80c99bcd DM	299	if (!dev_get_platdata(&pdev->dev))
	300	kfree(pdata);
	301
73969ff0 DM	302	return err;
	303	}
	304
	305	static int __devexit rotary_encoder_remove(struct platform_device *pdev)
	306	{
	307	struct rotary_encoder *encoder = platform_get_drvdata(pdev);
ce919537	308	const struct rotary_encoder_platform_data *pdata = encoder->pdata;
73969ff0 DM	309
	310	free_irq(encoder->irq_a, encoder);
	311	free_irq(encoder->irq_b, encoder);
	312	gpio_free(pdata->gpio_a);
	313	gpio_free(pdata->gpio_b);
80c99bcd	314
73969ff0	315	input_unregister_device(encoder->input);
73969ff0 DM	316	kfree(encoder);
73969ff0 DM	317
80c99bcd DM	318	if (!dev_get_platdata(&pdev->dev))
	319	kfree(pdata);
	320
	321	platform_set_drvdata(pdev, NULL);
	322
73969ff0 DM	323	return 0;
	324	}
	325
	326	static struct platform_driver rotary_encoder_driver = {
	327	.probe = rotary_encoder_probe,
1cb0aa88	328	.remove = rotary_encoder_remove,
73969ff0 DM	329	.driver = {
	330	.name = DRV_NAME,
	331	.owner = THIS_MODULE,
80c99bcd	332	.of_match_table = of_match_ptr(rotary_encoder_of_match),
73969ff0 DM	333	}
73969ff0 DM	334	};
840a746b	335	module_platform_driver(rotary_encoder_driver);
73969ff0 DM	336
	337	MODULE_ALIAS("platform:" DRV_NAME);
	338	MODULE_DESCRIPTION("GPIO rotary encoder driver");
e70bdd41	339	MODULE_AUTHOR("Daniel Mack <daniel@caiaq.de>, Johan Hovold");
73969ff0	340	MODULE_LICENSE("GPL v2");