[linux-2.6-block.git] / drivers / iio / dummy / iio_dummy_evgen.c

/**
 * Copyright (c) 2011 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.
 *
 * Companion module to the iio simple dummy example driver.
 * The purpose of this is to generate 'fake' event interrupts thus
 * allowing that driver's code to be as close as possible to that of
 * a normal driver talking to hardware.  The approach used here
 * is not intended to be general and just happens to work for this
 * particular use case.
 */

#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/mutex.h>
#include <linux/module.h>
#include <linux/sysfs.h>

#include "iio_dummy_evgen.h"
#include <linux/iio/iio.h>
#include <linux/iio/sysfs.h>
#include <linux/irq_work.h>

/* Fiddly bit of faking and irq without hardware */
#define IIO_EVENTGEN_NO 10

/**
 * struct iio_dummy_handle_irq - helper struct to simulate interrupt generation
 * @work: irq_work used to run handlers from hardirq context
 * @irq: fake irq line number to trigger an interrupt
 */
struct iio_dummy_handle_irq {
	struct irq_work work;
	int irq;
};

/**
 * struct iio_dummy_evgen - evgen state
 * @chip: irq chip we are faking
 * @base: base of irq range
 * @enabled: mask of which irqs are enabled
 * @inuse: mask of which irqs are connected
 * @regs: irq regs we are faking
 * @lock: protect the evgen state
 * @handler: helper for a 'hardware-like' interrupt simulation
 */
struct iio_dummy_eventgen {
	struct irq_chip chip;
	int base;
	bool enabled[IIO_EVENTGEN_NO];
	bool inuse[IIO_EVENTGEN_NO];
	struct iio_dummy_regs regs[IIO_EVENTGEN_NO];
	struct mutex lock;
	struct iio_dummy_handle_irq handler;
};

/* We can only ever have one instance of this 'device' */
static struct iio_dummy_eventgen *iio_evgen;
static const char *iio_evgen_name = "iio_dummy_evgen";

static void iio_dummy_event_irqmask(struct irq_data *d)
{
	struct irq_chip *chip = irq_data_get_irq_chip(d);
	struct iio_dummy_eventgen *evgen =
		container_of(chip, struct iio_dummy_eventgen, chip);

	evgen->enabled[d->irq - evgen->base] = false;
}

static void iio_dummy_event_irqunmask(struct irq_data *d)
{
	struct irq_chip *chip = irq_data_get_irq_chip(d);
	struct iio_dummy_eventgen *evgen =
		container_of(chip, struct iio_dummy_eventgen, chip);

	evgen->enabled[d->irq - evgen->base] = true;
}

static void iio_dummy_work_handler(struct irq_work *work)
{
	struct iio_dummy_handle_irq *irq_handler;

	irq_handler = container_of(work, struct iio_dummy_handle_irq, work);
	handle_simple_irq(irq_to_desc(irq_handler->irq));
}

static int iio_dummy_evgen_create(void)
{
	int ret, i;

	iio_evgen = kzalloc(sizeof(*iio_evgen), GFP_KERNEL);
	if (!iio_evgen)
		return -ENOMEM;

	iio_evgen->base = irq_alloc_descs(-1, 0, IIO_EVENTGEN_NO, 0);
	if (iio_evgen->base < 0) {
		ret = iio_evgen->base;
		kfree(iio_evgen);
		return ret;
	}
	iio_evgen->chip.name = iio_evgen_name;
	iio_evgen->chip.irq_mask = &iio_dummy_event_irqmask;
	iio_evgen->chip.irq_unmask = &iio_dummy_event_irqunmask;
	for (i = 0; i < IIO_EVENTGEN_NO; i++) {
		irq_set_chip(iio_evgen->base + i, &iio_evgen->chip);
		irq_set_handler(iio_evgen->base + i, &handle_simple_irq);
		irq_modify_status(iio_evgen->base + i,
				  IRQ_NOREQUEST | IRQ_NOAUTOEN,
				  IRQ_NOPROBE);
	}
	init_irq_work(&iio_evgen->handler.work, iio_dummy_work_handler);
	mutex_init(&iio_evgen->lock);
	return 0;
}

/**
 * iio_dummy_evgen_get_irq() - get an evgen provided irq for a device
 *
 * This function will give a free allocated irq to a client device.
 * That irq can then be caused to 'fire' by using the associated sysfs file.
 */
int iio_dummy_evgen_get_irq(void)
{
	int i, ret = 0;

	if (!iio_evgen)
		return -ENODEV;

	mutex_lock(&iio_evgen->lock);
	for (i = 0; i < IIO_EVENTGEN_NO; i++)
		if (!iio_evgen->inuse[i]) {
			ret = iio_evgen->base + i;
			iio_evgen->inuse[i] = true;
			break;
		}
	mutex_unlock(&iio_evgen->lock);
	if (i == IIO_EVENTGEN_NO)
		return -ENOMEM;
	return ret;
}
EXPORT_SYMBOL_GPL(iio_dummy_evgen_get_irq);

/**
 * iio_dummy_evgen_release_irq() - give the irq back.
 * @irq: irq being returned to the pool
 *
 * Used by client driver instances to give the irqs back when they disconnect
 */
void iio_dummy_evgen_release_irq(int irq)
{
	mutex_lock(&iio_evgen->lock);
	iio_evgen->inuse[irq - iio_evgen->base] = false;
	mutex_unlock(&iio_evgen->lock);
}
EXPORT_SYMBOL_GPL(iio_dummy_evgen_release_irq);

struct iio_dummy_regs *iio_dummy_evgen_get_regs(int irq)
{
	return &iio_evgen->regs[irq - iio_evgen->base];
}
EXPORT_SYMBOL_GPL(iio_dummy_evgen_get_regs);

static void iio_dummy_evgen_free(void)
{
	irq_free_descs(iio_evgen->base, IIO_EVENTGEN_NO);
	kfree(iio_evgen);
}

static void iio_evgen_release(struct device *dev)
{
	iio_dummy_evgen_free();
}

static ssize_t iio_evgen_poke(struct device *dev,
			      struct device_attribute *attr,
			      const char *buf,
			      size_t len)
{
	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
	unsigned long event;
	int ret;

	ret = kstrtoul(buf, 10, &event);
	if (ret)
		return ret;

	iio_evgen->regs[this_attr->address].reg_id   = this_attr->address;
	iio_evgen->regs[this_attr->address].reg_data = event;

	iio_evgen->handler.irq = iio_evgen->base + this_attr->address;
	if (iio_evgen->enabled[this_attr->address])
		irq_work_queue(&iio_evgen->handler.work);

	return len;
}

static IIO_DEVICE_ATTR(poke_ev0, S_IWUSR, NULL, &iio_evgen_poke, 0);
static IIO_DEVICE_ATTR(poke_ev1, S_IWUSR, NULL, &iio_evgen_poke, 1);
static IIO_DEVICE_ATTR(poke_ev2, S_IWUSR, NULL, &iio_evgen_poke, 2);
static IIO_DEVICE_ATTR(poke_ev3, S_IWUSR, NULL, &iio_evgen_poke, 3);
static IIO_DEVICE_ATTR(poke_ev4, S_IWUSR, NULL, &iio_evgen_poke, 4);
static IIO_DEVICE_ATTR(poke_ev5, S_IWUSR, NULL, &iio_evgen_poke, 5);
static IIO_DEVICE_ATTR(poke_ev6, S_IWUSR, NULL, &iio_evgen_poke, 6);
static IIO_DEVICE_ATTR(poke_ev7, S_IWUSR, NULL, &iio_evgen_poke, 7);
static IIO_DEVICE_ATTR(poke_ev8, S_IWUSR, NULL, &iio_evgen_poke, 8);
static IIO_DEVICE_ATTR(poke_ev9, S_IWUSR, NULL, &iio_evgen_poke, 9);

static struct attribute *iio_evgen_attrs[] = {
	&iio_dev_attr_poke_ev0.dev_attr.attr,
	&iio_dev_attr_poke_ev1.dev_attr.attr,
	&iio_dev_attr_poke_ev2.dev_attr.attr,
	&iio_dev_attr_poke_ev3.dev_attr.attr,
	&iio_dev_attr_poke_ev4.dev_attr.attr,
	&iio_dev_attr_poke_ev5.dev_attr.attr,
	&iio_dev_attr_poke_ev6.dev_attr.attr,
	&iio_dev_attr_poke_ev7.dev_attr.attr,
	&iio_dev_attr_poke_ev8.dev_attr.attr,
	&iio_dev_attr_poke_ev9.dev_attr.attr,
	NULL,
};

static const struct attribute_group iio_evgen_group = {
	.attrs = iio_evgen_attrs,
};

static const struct attribute_group *iio_evgen_groups[] = {
	&iio_evgen_group,
	NULL
};

static struct device iio_evgen_dev = {
	.bus = &iio_bus_type,
	.groups = iio_evgen_groups,
	.release = &iio_evgen_release,
};

static __init int iio_dummy_evgen_init(void)
{
	int ret = iio_dummy_evgen_create();

	if (ret < 0)
		return ret;
	device_initialize(&iio_evgen_dev);
	dev_set_name(&iio_evgen_dev, "iio_evgen");
	return device_add(&iio_evgen_dev);
}
module_init(iio_dummy_evgen_init);

static __exit void iio_dummy_evgen_exit(void)
{
	device_unregister(&iio_evgen_dev);
}
module_exit(iio_dummy_evgen_exit);

MODULE_AUTHOR("Jonathan Cameron <jic23@kernel.org>");
MODULE_DESCRIPTION("IIO dummy driver");
MODULE_LICENSE("GPL v2");
Commit	Line	Data
e6477000 JC	1	/**
	2	* Copyright (c) 2011 Jonathan Cameron
	3	*
	4	* This program is free software; you can redistribute it and/or modify it
	5	* under the terms of the GNU General Public License version 2 as published by
	6	* the Free Software Foundation.
	7	*
	8	* Companion module to the iio simple dummy example driver.
	9	* The purpose of this is to generate 'fake' event interrupts thus
	10	* allowing that driver's code to be as close as possible to that of
	11	* a normal driver talking to hardware. The approach used here
	12	* is not intended to be general and just happens to work for this
	13	* particular use case.
	14	*/
	15
	16	#include <linux/kernel.h>
	17	#include <linux/slab.h>
	18	#include <linux/interrupt.h>
	19	#include <linux/irq.h>
	20	#include <linux/mutex.h>
	21	#include <linux/module.h>
	22	#include <linux/sysfs.h>
	23
	24	#include "iio_dummy_evgen.h"
06458e27 JC	25	#include <linux/iio/iio.h>
06458e27 JC	26	#include <linux/iio/sysfs.h>
fd2bb310	27	#include <linux/irq_work.h>
e6477000 JC	28
	29	/* Fiddly bit of faking and irq without hardware */
	30	#define IIO_EVENTGEN_NO 10
fd2bb310 CO	31
	32	/**
	33	* struct iio_dummy_handle_irq - helper struct to simulate interrupt generation
	34	* @work: irq_work used to run handlers from hardirq context
	35	* @irq: fake irq line number to trigger an interrupt
	36	*/
	37	struct iio_dummy_handle_irq {
	38	struct irq_work work;
	39	int irq;
	40	};
	41
e6477000 JC	42	/**
	43	* struct iio_dummy_evgen - evgen state
	44	* @chip: irq chip we are faking
	45	* @base: base of irq range
	46	* @enabled: mask of which irqs are enabled
4abf6f8b	47	* @inuse: mask of which irqs are connected
356ae946	48	* @regs: irq regs we are faking
e6477000	49	* @lock: protect the evgen state
fd2bb310	50	* @handler: helper for a 'hardware-like' interrupt simulation
e6477000 JC	51	*/
	52	struct iio_dummy_eventgen {
	53	struct irq_chip chip;
	54	int base;
	55	bool enabled[IIO_EVENTGEN_NO];
	56	bool inuse[IIO_EVENTGEN_NO];
356ae946	57	struct iio_dummy_regs regs[IIO_EVENTGEN_NO];
e6477000	58	struct mutex lock;
fd2bb310	59	struct iio_dummy_handle_irq handler;
e6477000 JC	60	};
	61
	62	/* We can only ever have one instance of this 'device' */
	63	static struct iio_dummy_eventgen *iio_evgen;
	64	static const char *iio_evgen_name = "iio_dummy_evgen";
	65
	66	static void iio_dummy_event_irqmask(struct irq_data *d)
	67	{
	68	struct irq_chip *chip = irq_data_get_irq_chip(d);
	69	struct iio_dummy_eventgen *evgen =
	70	container_of(chip, struct iio_dummy_eventgen, chip);
	71
	72	evgen->enabled[d->irq - evgen->base] = false;
	73	}
	74
	75	static void iio_dummy_event_irqunmask(struct irq_data *d)
	76	{
	77	struct irq_chip *chip = irq_data_get_irq_chip(d);
	78	struct iio_dummy_eventgen *evgen =
	79	container_of(chip, struct iio_dummy_eventgen, chip);
	80
	81	evgen->enabled[d->irq - evgen->base] = true;
	82	}
	83
fd2bb310 CO	84	static void iio_dummy_work_handler(struct irq_work *work)
	85	{
	86	struct iio_dummy_handle_irq *irq_handler;
	87
	88	irq_handler = container_of(work, struct iio_dummy_handle_irq, work);
d0a76bbf	89	handle_simple_irq(irq_to_desc(irq_handler->irq));
fd2bb310 CO	90	}
fd2bb310 CO	91
e6477000 JC	92	static int iio_dummy_evgen_create(void)
	93	{
	94	int ret, i;
	95
	96	iio_evgen = kzalloc(sizeof(*iio_evgen), GFP_KERNEL);
025c7da9	97	if (!iio_evgen)
e6477000 JC	98	return -ENOMEM;
	99
	100	iio_evgen->base = irq_alloc_descs(-1, 0, IIO_EVENTGEN_NO, 0);
	101	if (iio_evgen->base < 0) {
	102	ret = iio_evgen->base;
	103	kfree(iio_evgen);
	104	return ret;
	105	}
	106	iio_evgen->chip.name = iio_evgen_name;
	107	iio_evgen->chip.irq_mask = &iio_dummy_event_irqmask;
	108	iio_evgen->chip.irq_unmask = &iio_dummy_event_irqunmask;
	109	for (i = 0; i < IIO_EVENTGEN_NO; i++) {
	110	irq_set_chip(iio_evgen->base + i, &iio_evgen->chip);
	111	irq_set_handler(iio_evgen->base + i, &handle_simple_irq);
	112	irq_modify_status(iio_evgen->base + i,
	113	IRQ_NOREQUEST \| IRQ_NOAUTOEN,
	114	IRQ_NOPROBE);
	115	}
fd2bb310	116	init_irq_work(&iio_evgen->handler.work, iio_dummy_work_handler);
e6477000 JC	117	mutex_init(&iio_evgen->lock);
	118	return 0;
	119	}
	120
	121	/**
	122	* iio_dummy_evgen_get_irq() - get an evgen provided irq for a device
	123	*
	124	* This function will give a free allocated irq to a client device.
	125	* That irq can then be caused to 'fire' by using the associated sysfs file.
	126	*/
	127	int iio_dummy_evgen_get_irq(void)
	128	{
	129	int i, ret = 0;
5ae8f440	130
025c7da9	131	if (!iio_evgen)
5ae8f440 SL	132	return -ENODEV;
5ae8f440 SL	133
e6477000 JC	134	mutex_lock(&iio_evgen->lock);
e6477000 JC	135	for (i = 0; i < IIO_EVENTGEN_NO; i++)
6fae58f3	136	if (!iio_evgen->inuse[i]) {
e6477000 JC	137	ret = iio_evgen->base + i;
	138	iio_evgen->inuse[i] = true;
	139	break;
	140	}
	141	mutex_unlock(&iio_evgen->lock);
	142	if (i == IIO_EVENTGEN_NO)
	143	return -ENOMEM;
	144	return ret;
	145	}
	146	EXPORT_SYMBOL_GPL(iio_dummy_evgen_get_irq);
	147
	148	/**
	149	* iio_dummy_evgen_release_irq() - give the irq back.
	150	* @irq: irq being returned to the pool
	151	*
	152	* Used by client driver instances to give the irqs back when they disconnect
	153	*/
62a90da6	154	void iio_dummy_evgen_release_irq(int irq)
e6477000 JC	155	{
	156	mutex_lock(&iio_evgen->lock);
	157	iio_evgen->inuse[irq - iio_evgen->base] = false;
	158	mutex_unlock(&iio_evgen->lock);
e6477000 JC	159	}
	160	EXPORT_SYMBOL_GPL(iio_dummy_evgen_release_irq);
	161
356ae946 DB	162	struct iio_dummy_regs *iio_dummy_evgen_get_regs(int irq)
	163	{
	164	return &iio_evgen->regs[irq - iio_evgen->base];
	165	}
	166	EXPORT_SYMBOL_GPL(iio_dummy_evgen_get_regs);
	167
e6477000 JC	168	static void iio_dummy_evgen_free(void)
	169	{
	170	irq_free_descs(iio_evgen->base, IIO_EVENTGEN_NO);
	171	kfree(iio_evgen);
	172	}
	173
	174	static void iio_evgen_release(struct device *dev)
	175	{
	176	iio_dummy_evgen_free();
	177	}
	178
	179	static ssize_t iio_evgen_poke(struct device *dev,
	180	struct device_attribute *attr,
	181	const char *buf,
	182	size_t len)
	183	{
	184	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
356ae946 DB	185	unsigned long event;
	186	int ret;
	187
	188	ret = kstrtoul(buf, 10, &event);
	189	if (ret)
	190	return ret;
	191
	192	iio_evgen->regs[this_attr->address].reg_id = this_attr->address;
	193	iio_evgen->regs[this_attr->address].reg_data = event;
e6477000	194
fd2bb310	195	iio_evgen->handler.irq = iio_evgen->base + this_attr->address;
e6477000	196	if (iio_evgen->enabled[this_attr->address])
fd2bb310	197	irq_work_queue(&iio_evgen->handler.work);
e6477000 JC	198
	199	return len;
	200	}
	201
	202	static IIO_DEVICE_ATTR(poke_ev0, S_IWUSR, NULL, &iio_evgen_poke, 0);
	203	static IIO_DEVICE_ATTR(poke_ev1, S_IWUSR, NULL, &iio_evgen_poke, 1);
	204	static IIO_DEVICE_ATTR(poke_ev2, S_IWUSR, NULL, &iio_evgen_poke, 2);
	205	static IIO_DEVICE_ATTR(poke_ev3, S_IWUSR, NULL, &iio_evgen_poke, 3);
	206	static IIO_DEVICE_ATTR(poke_ev4, S_IWUSR, NULL, &iio_evgen_poke, 4);
	207	static IIO_DEVICE_ATTR(poke_ev5, S_IWUSR, NULL, &iio_evgen_poke, 5);
	208	static IIO_DEVICE_ATTR(poke_ev6, S_IWUSR, NULL, &iio_evgen_poke, 6);
	209	static IIO_DEVICE_ATTR(poke_ev7, S_IWUSR, NULL, &iio_evgen_poke, 7);
	210	static IIO_DEVICE_ATTR(poke_ev8, S_IWUSR, NULL, &iio_evgen_poke, 8);
	211	static IIO_DEVICE_ATTR(poke_ev9, S_IWUSR, NULL, &iio_evgen_poke, 9);
	212
	213	static struct attribute *iio_evgen_attrs[] = {
	214	&iio_dev_attr_poke_ev0.dev_attr.attr,
	215	&iio_dev_attr_poke_ev1.dev_attr.attr,
	216	&iio_dev_attr_poke_ev2.dev_attr.attr,
	217	&iio_dev_attr_poke_ev3.dev_attr.attr,
	218	&iio_dev_attr_poke_ev4.dev_attr.attr,
	219	&iio_dev_attr_poke_ev5.dev_attr.attr,
	220	&iio_dev_attr_poke_ev6.dev_attr.attr,
	221	&iio_dev_attr_poke_ev7.dev_attr.attr,
	222	&iio_dev_attr_poke_ev8.dev_attr.attr,
	223	&iio_dev_attr_poke_ev9.dev_attr.attr,
	224	NULL,
	225	};
	226
	227	static const struct attribute_group iio_evgen_group = {
	228	.attrs = iio_evgen_attrs,
	229	};
	230
	231	static const struct attribute_group *iio_evgen_groups[] = {
	232	&iio_evgen_group,
	233	NULL
	234	};
	235
	236	static struct device iio_evgen_dev = {
	237	.bus = &iio_bus_type,
	238	.groups = iio_evgen_groups,
	239	.release = &iio_evgen_release,
	240	};
862cb6ce	241
e6477000 JC	242	static __init int iio_dummy_evgen_init(void)
	243	{
	244	int ret = iio_dummy_evgen_create();
4b4c7275	245
e6477000 JC	246	if (ret < 0)
	247	return ret;
	248	device_initialize(&iio_evgen_dev);
	249	dev_set_name(&iio_evgen_dev, "iio_evgen");
	250	return device_add(&iio_evgen_dev);
	251	}
	252	module_init(iio_dummy_evgen_init);
	253
	254	static __exit void iio_dummy_evgen_exit(void)
	255	{
	256	device_unregister(&iio_evgen_dev);
	257	}
	258	module_exit(iio_dummy_evgen_exit);
	259
0f8c9620	260	MODULE_AUTHOR("Jonathan Cameron <jic23@kernel.org>");
e6477000 JC	261	MODULE_DESCRIPTION("IIO dummy driver");
e6477000 JC	262	MODULE_LICENSE("GPL v2");