[GitHub/mt8127/android_kernel_alcatel_ttab.git] / drivers / staging / iio / trigger / iio-trig-gpio.c

/*
 * Industrial I/O - gpio based trigger support
 *
 * Copyright (c) 2008 Jonathan Cameron
 *
 * 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.
 *
 * Currently this is more of a functioning proof of concept that a fully
 * fledged trigger driver.
 *
 * TODO:
 *
 * Add board config elements to allow specification of startup settings.
 * Add configuration settings (irq type etc)
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/interrupt.h>
#include <linux/gpio.h>
#include <linux/slab.h>

#include "../iio.h"
#include "../trigger.h"

LIST_HEAD(iio_gpio_trigger_list);
DEFINE_MUTEX(iio_gpio_trigger_list_lock);

struct iio_gpio_trigger_info {
	struct mutex in_use;
	int gpio;
};
/*
 * Need to reference count these triggers and only enable gpio interrupts
 * as appropriate.
 */

/* So what functionality do we want in here?... */
/* set high / low as interrupt type? */

static irqreturn_t iio_gpio_trigger_poll(int irq, void *private)
{
	iio_trigger_poll(private);
	return IRQ_HANDLED;
}

static DEVICE_ATTR(name, S_IRUGO, iio_trigger_read_name, NULL);

static struct attribute *iio_gpio_trigger_attrs[] = {
	&dev_attr_name.attr,
	NULL,
};

static const struct attribute_group iio_gpio_trigger_attr_group = {
	.attrs = iio_gpio_trigger_attrs,
};

static int iio_gpio_trigger_probe(struct platform_device *dev)
{
	int *pdata = dev->dev.platform_data;
	struct iio_gpio_trigger_info *trig_info;
	struct iio_trigger *trig, *trig2;
	int i, irq, ret = 0;
	if (!pdata) {
		printk(KERN_ERR "No IIO gpio trigger platform data found\n");
		goto error_ret;
	}
	for (i = 0;; i++) {
		if (!gpio_is_valid(pdata[i]))
			break;
		trig = iio_allocate_trigger();
		if (!trig) {
			ret = -ENOMEM;
			goto error_free_completed_registrations;
		}

		trig_info = kzalloc(sizeof(*trig_info), GFP_KERNEL);
		if (!trig_info) {
			ret = -ENOMEM;
			goto error_put_trigger;
		}
		trig->control_attrs = &iio_gpio_trigger_attr_group;
		trig->private_data = trig_info;
		trig_info->gpio = pdata[i];
		trig->owner = THIS_MODULE;
		trig->name = kmalloc(IIO_TRIGGER_NAME_LENGTH, GFP_KERNEL);
		if (!trig->name) {
			ret = -ENOMEM;
			goto error_free_trig_info;
		}
		snprintf((char *)trig->name,
			 IIO_TRIGGER_NAME_LENGTH,
			 "gpiotrig%d",
			 pdata[i]);
		ret = gpio_request(trig_info->gpio, trig->name);
		if (ret)
			goto error_free_name;

		ret = gpio_direction_input(trig_info->gpio);
		if (ret)
			goto error_release_gpio;

		irq = gpio_to_irq(trig_info->gpio);
		if (irq < 0) {
			ret = irq;
			goto error_release_gpio;
		}

		ret = request_irq(irq, iio_gpio_trigger_poll,
				  IRQF_TRIGGER_RISING,
				  trig->name,
				  trig);
		if (ret)
			goto error_release_gpio;

		ret = iio_trigger_register(trig);
		if (ret)
			goto error_release_irq;

		list_add_tail(&trig->alloc_list, &iio_gpio_trigger_list);

	}
	return 0;

/* First clean up the partly allocated trigger */
error_release_irq:
	free_irq(irq, trig);
error_release_gpio:
	gpio_free(trig_info->gpio);
error_free_name:
	kfree(trig->name);
error_free_trig_info:
	kfree(trig_info);
error_put_trigger:
	iio_put_trigger(trig);
error_free_completed_registrations:
	/* The rest should have been added to the iio_gpio_trigger_list */
	list_for_each_entry_safe(trig,
				 trig2,
				 &iio_gpio_trigger_list,
				 alloc_list) {
		trig_info = trig->private_data;
		free_irq(gpio_to_irq(trig_info->gpio), trig);
		gpio_free(trig_info->gpio);
		kfree(trig->name);
		kfree(trig_info);
		iio_trigger_unregister(trig);
	}

error_ret:
	return ret;
}

static int iio_gpio_trigger_remove(struct platform_device *dev)
{
	struct iio_trigger *trig, *trig2;
	struct iio_gpio_trigger_info *trig_info;

	mutex_lock(&iio_gpio_trigger_list_lock);
	list_for_each_entry_safe(trig,
				 trig2,
				 &iio_gpio_trigger_list,
				 alloc_list) {
		trig_info = trig->private_data;
		iio_trigger_unregister(trig);
		free_irq(gpio_to_irq(trig_info->gpio), trig);
		gpio_free(trig_info->gpio);
		kfree(trig->name);
		kfree(trig_info);
		iio_put_trigger(trig);
	}
	mutex_unlock(&iio_gpio_trigger_list_lock);

	return 0;
}

static struct platform_driver iio_gpio_trigger_driver = {
	.probe = iio_gpio_trigger_probe,
	.remove = iio_gpio_trigger_remove,
	.driver = {
		.name = "iio_gpio_trigger",
		.owner = THIS_MODULE,
	},
};

static int __init iio_gpio_trig_init(void)
{
	return platform_driver_register(&iio_gpio_trigger_driver);
}
module_init(iio_gpio_trig_init);

static void __exit iio_gpio_trig_exit(void)
{
	platform_driver_unregister(&iio_gpio_trigger_driver);
}
module_exit(iio_gpio_trig_exit);

MODULE_AUTHOR("Jonathan Cameron <jic23@cam.ac.uk>");
MODULE_DESCRIPTION("Example gpio trigger for the iio subsystem");
MODULE_LICENSE("GPL v2");
Commit	Line	Data
930bae86 JC	1	/*
	2	* Industrial I/O - gpio based trigger support
	3	*
	4	* Copyright (c) 2008 Jonathan Cameron
	5	*
	6	* This program is free software; you can redistribute it and/or modify it
	7	* under the terms of the GNU General Public License version 2 as published by
	8	* the Free Software Foundation.
	9	*
	10	* Currently this is more of a functioning proof of concept that a fully
	11	* fledged trigger driver.
	12	*
	13	* TODO:
	14	*
	15	* Add board config elements to allow specification of startup settings.
	16	* Add configuration settings (irq type etc)
	17	*/
	18
	19	#include <linux/kernel.h>
	20	#include <linux/module.h>
	21	#include <linux/platform_device.h>
	22	#include <linux/interrupt.h>
	23	#include <linux/gpio.h>
5a0e3ad6	24	#include <linux/slab.h>
930bae86 JC	25
	26	#include "../iio.h"
	27	#include "../trigger.h"
	28
	29	LIST_HEAD(iio_gpio_trigger_list);
	30	DEFINE_MUTEX(iio_gpio_trigger_list_lock);
	31
	32	struct iio_gpio_trigger_info {
	33	struct mutex in_use;
	34	int gpio;
	35	};
	36	/*
	37	* Need to reference count these triggers and only enable gpio interrupts
	38	* as appropriate.
	39	*/
	40
	41	/* So what functionality do we want in here?... */
	42	/* set high / low as interrupt type? */
	43
	44	static irqreturn_t iio_gpio_trigger_poll(int irq, void *private)
	45	{
	46	iio_trigger_poll(private);
	47	return IRQ_HANDLED;
	48	}
	49
2fdec576	50	static DEVICE_ATTR(name, S_IRUGO, iio_trigger_read_name, NULL);
930bae86 JC	51
	52	static struct attribute *iio_gpio_trigger_attrs[] = {
	53	&dev_attr_name.attr,
	54	NULL,
	55	};
	56
	57	static const struct attribute_group iio_gpio_trigger_attr_group = {
	58	.attrs = iio_gpio_trigger_attrs,
	59	};
	60
	61	static int iio_gpio_trigger_probe(struct platform_device *dev)
	62	{
	63	int *pdata = dev->dev.platform_data;
	64	struct iio_gpio_trigger_info *trig_info;
	65	struct iio_trigger trig, trig2;
	66	int i, irq, ret = 0;
	67	if (!pdata) {
	68	printk(KERN_ERR "No IIO gpio trigger platform data found\n");
	69	goto error_ret;
	70	}
	71	for (i = 0;; i++) {
	72	if (!gpio_is_valid(pdata[i]))
	73	break;
	74	trig = iio_allocate_trigger();
	75	if (!trig) {
	76	ret = -ENOMEM;
	77	goto error_free_completed_registrations;
	78	}
	79
	80	trig_info = kzalloc(sizeof(*trig_info), GFP_KERNEL);
	81	if (!trig_info) {
	82	ret = -ENOMEM;
	83	goto error_put_trigger;
	84	}
	85	trig->control_attrs = &iio_gpio_trigger_attr_group;
	86	trig->private_data = trig_info;
	87	trig_info->gpio = pdata[i];
	88	trig->owner = THIS_MODULE;
	89	trig->name = kmalloc(IIO_TRIGGER_NAME_LENGTH, GFP_KERNEL);
	90	if (!trig->name) {
	91	ret = -ENOMEM;
	92	goto error_free_trig_info;
	93	}
	94	snprintf((char *)trig->name,
	95	IIO_TRIGGER_NAME_LENGTH,
	96	"gpiotrig%d",
	97	pdata[i]);
	98	ret = gpio_request(trig_info->gpio, trig->name);
	99	if (ret)
	100	goto error_free_name;
	101
	102	ret = gpio_direction_input(trig_info->gpio);
	103	if (ret)
	104	goto error_release_gpio;
	105
	106	irq = gpio_to_irq(trig_info->gpio);
	107	if (irq < 0) {
	108	ret = irq;
	109	goto error_release_gpio;
	110	}
	111
	112	ret = request_irq(irq, iio_gpio_trigger_poll,
	113	IRQF_TRIGGER_RISING,
	114	trig->name,
115	trig);
116	if (ret)
117	goto error_release_gpio;
118
119	ret = iio_trigger_register(trig);
120	if (ret)
121	goto error_release_irq;
122
123	list_add_tail(&trig->alloc_list, &iio_gpio_trigger_list);
124
125	}
126	return 0;
127
128	/* First clean up the partly allocated trigger */
129	error_release_irq:
130	free_irq(irq, trig);
131	error_release_gpio:
132	gpio_free(trig_info->gpio);
133	error_free_name:
134	kfree(trig->name);
135	error_free_trig_info:
136	kfree(trig_info);
137	error_put_trigger:
138	iio_put_trigger(trig);
139	error_free_completed_registrations:
140	/* The rest should have been added to the iio_gpio_trigger_list */
141	list_for_each_entry_safe(trig,
142	trig2,
143	&iio_gpio_trigger_list,
144	alloc_list) {
145	trig_info = trig->private_data;
146	free_irq(gpio_to_irq(trig_info->gpio), trig);
147	gpio_free(trig_info->gpio);
148	kfree(trig->name);
149	kfree(trig_info);
150	iio_trigger_unregister(trig);
151	}
152
153	error_ret:
154	return ret;
155	}
156
157	static int iio_gpio_trigger_remove(struct platform_device *dev)
158	{
159	struct iio_trigger trig, trig2;
160	struct iio_gpio_trigger_info *trig_info;
161
162	mutex_lock(&iio_gpio_trigger_list_lock);
163	list_for_each_entry_safe(trig,
164	trig2,
165	&iio_gpio_trigger_list,
166	alloc_list) {
167	trig_info = trig->private_data;
168	iio_trigger_unregister(trig);
169	free_irq(gpio_to_irq(trig_info->gpio), trig);
170	gpio_free(trig_info->gpio);
171	kfree(trig->name);
172	kfree(trig_info);
173	iio_put_trigger(trig);
174	}
175	mutex_unlock(&iio_gpio_trigger_list_lock);
176
177	return 0;
178	}
179
180	static struct platform_driver iio_gpio_trigger_driver = {
181	.probe = iio_gpio_trigger_probe,
182	.remove = iio_gpio_trigger_remove,
183	.driver = {
184	.name = "iio_gpio_trigger",
185	.owner = THIS_MODULE,
186	},
187	};
188
189	static int __init iio_gpio_trig_init(void)
190	{
191	return platform_driver_register(&iio_gpio_trigger_driver);
192	}
193	module_init(iio_gpio_trig_init);
194
195	static void __exit iio_gpio_trig_exit(void)
196	{
197	platform_driver_unregister(&iio_gpio_trigger_driver);
198	}
199	module_exit(iio_gpio_trig_exit);
200
201	MODULE_AUTHOR("Jonathan Cameron <jic23@cam.ac.uk>");
202	MODULE_DESCRIPTION("Example gpio trigger for the iio subsystem");
203	MODULE_LICENSE("GPL v2");