[mirror_ubuntu-eoan-kernel.git] / drivers / staging / iio / 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>

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

/* 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 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);
	}
	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;

	if (iio_evgen->enabled[this_attr->address])
		handle_nested_irq(iio_evgen->base + this_attr->address);

	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>
e6477000 JC	27
	28	/* Fiddly bit of faking and irq without hardware */
	29	#define IIO_EVENTGEN_NO 10
	30	/**
	31	* struct iio_dummy_evgen - evgen state
	32	* @chip: irq chip we are faking
	33	* @base: base of irq range
	34	* @enabled: mask of which irqs are enabled
4abf6f8b	35	* @inuse: mask of which irqs are connected
356ae946	36	* @regs: irq regs we are faking
e6477000 JC	37	* @lock: protect the evgen state
	38	*/
	39	struct iio_dummy_eventgen {
	40	struct irq_chip chip;
	41	int base;
	42	bool enabled[IIO_EVENTGEN_NO];
	43	bool inuse[IIO_EVENTGEN_NO];
356ae946	44	struct iio_dummy_regs regs[IIO_EVENTGEN_NO];
e6477000 JC	45	struct mutex lock;
	46	};
	47
	48	/* We can only ever have one instance of this 'device' */
	49	static struct iio_dummy_eventgen *iio_evgen;
	50	static const char *iio_evgen_name = "iio_dummy_evgen";
	51
	52	static void iio_dummy_event_irqmask(struct irq_data *d)
	53	{
	54	struct irq_chip *chip = irq_data_get_irq_chip(d);
	55	struct iio_dummy_eventgen *evgen =
	56	container_of(chip, struct iio_dummy_eventgen, chip);
	57
	58	evgen->enabled[d->irq - evgen->base] = false;
	59	}
	60
	61	static void iio_dummy_event_irqunmask(struct irq_data *d)
	62	{
	63	struct irq_chip *chip = irq_data_get_irq_chip(d);
	64	struct iio_dummy_eventgen *evgen =
	65	container_of(chip, struct iio_dummy_eventgen, chip);
	66
	67	evgen->enabled[d->irq - evgen->base] = true;
	68	}
	69
	70	static int iio_dummy_evgen_create(void)
	71	{
	72	int ret, i;
	73
	74	iio_evgen = kzalloc(sizeof(*iio_evgen), GFP_KERNEL);
025c7da9	75	if (!iio_evgen)
e6477000 JC	76	return -ENOMEM;
	77
	78	iio_evgen->base = irq_alloc_descs(-1, 0, IIO_EVENTGEN_NO, 0);
	79	if (iio_evgen->base < 0) {
	80	ret = iio_evgen->base;
	81	kfree(iio_evgen);
	82	return ret;
	83	}
	84	iio_evgen->chip.name = iio_evgen_name;
	85	iio_evgen->chip.irq_mask = &iio_dummy_event_irqmask;
	86	iio_evgen->chip.irq_unmask = &iio_dummy_event_irqunmask;
	87	for (i = 0; i < IIO_EVENTGEN_NO; i++) {
	88	irq_set_chip(iio_evgen->base + i, &iio_evgen->chip);
	89	irq_set_handler(iio_evgen->base + i, &handle_simple_irq);
	90	irq_modify_status(iio_evgen->base + i,
	91	IRQ_NOREQUEST \| IRQ_NOAUTOEN,
	92	IRQ_NOPROBE);
	93	}
	94	mutex_init(&iio_evgen->lock);
	95	return 0;
	96	}
	97
	98	/**
	99	* iio_dummy_evgen_get_irq() - get an evgen provided irq for a device
	100	*
	101	* This function will give a free allocated irq to a client device.
	102	* That irq can then be caused to 'fire' by using the associated sysfs file.
	103	*/
	104	int iio_dummy_evgen_get_irq(void)
	105	{
	106	int i, ret = 0;
5ae8f440	107
025c7da9	108	if (!iio_evgen)
5ae8f440 SL	109	return -ENODEV;
5ae8f440 SL	110
e6477000 JC	111	mutex_lock(&iio_evgen->lock);
e6477000 JC	112	for (i = 0; i < IIO_EVENTGEN_NO; i++)
6fae58f3	113	if (!iio_evgen->inuse[i]) {
e6477000 JC	114	ret = iio_evgen->base + i;
	115	iio_evgen->inuse[i] = true;
	116	break;
	117	}
	118	mutex_unlock(&iio_evgen->lock);
	119	if (i == IIO_EVENTGEN_NO)
	120	return -ENOMEM;
	121	return ret;
	122	}
	123	EXPORT_SYMBOL_GPL(iio_dummy_evgen_get_irq);
	124
	125	/**
	126	* iio_dummy_evgen_release_irq() - give the irq back.
	127	* @irq: irq being returned to the pool
	128	*
	129	* Used by client driver instances to give the irqs back when they disconnect
	130	*/
62a90da6	131	void iio_dummy_evgen_release_irq(int irq)
e6477000 JC	132	{
	133	mutex_lock(&iio_evgen->lock);
	134	iio_evgen->inuse[irq - iio_evgen->base] = false;
	135	mutex_unlock(&iio_evgen->lock);
e6477000 JC	136	}
	137	EXPORT_SYMBOL_GPL(iio_dummy_evgen_release_irq);
	138
356ae946 DB	139	struct iio_dummy_regs *iio_dummy_evgen_get_regs(int irq)
	140	{
	141	return &iio_evgen->regs[irq - iio_evgen->base];
	142	}
	143	EXPORT_SYMBOL_GPL(iio_dummy_evgen_get_regs);
	144
e6477000 JC	145	static void iio_dummy_evgen_free(void)
	146	{
	147	irq_free_descs(iio_evgen->base, IIO_EVENTGEN_NO);
	148	kfree(iio_evgen);
	149	}
	150
	151	static void iio_evgen_release(struct device *dev)
	152	{
	153	iio_dummy_evgen_free();
	154	}
	155
	156	static ssize_t iio_evgen_poke(struct device *dev,
	157	struct device_attribute *attr,
	158	const char *buf,
	159	size_t len)
	160	{
	161	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
356ae946 DB	162	unsigned long event;
	163	int ret;
	164
	165	ret = kstrtoul(buf, 10, &event);
	166	if (ret)
	167	return ret;
	168
	169	iio_evgen->regs[this_attr->address].reg_id = this_attr->address;
	170	iio_evgen->regs[this_attr->address].reg_data = event;
e6477000 JC	171
	172	if (iio_evgen->enabled[this_attr->address])
	173	handle_nested_irq(iio_evgen->base + this_attr->address);
	174
	175	return len;
	176	}
	177
	178	static IIO_DEVICE_ATTR(poke_ev0, S_IWUSR, NULL, &iio_evgen_poke, 0);
	179	static IIO_DEVICE_ATTR(poke_ev1, S_IWUSR, NULL, &iio_evgen_poke, 1);
	180	static IIO_DEVICE_ATTR(poke_ev2, S_IWUSR, NULL, &iio_evgen_poke, 2);
	181	static IIO_DEVICE_ATTR(poke_ev3, S_IWUSR, NULL, &iio_evgen_poke, 3);
	182	static IIO_DEVICE_ATTR(poke_ev4, S_IWUSR, NULL, &iio_evgen_poke, 4);
	183	static IIO_DEVICE_ATTR(poke_ev5, S_IWUSR, NULL, &iio_evgen_poke, 5);
	184	static IIO_DEVICE_ATTR(poke_ev6, S_IWUSR, NULL, &iio_evgen_poke, 6);
	185	static IIO_DEVICE_ATTR(poke_ev7, S_IWUSR, NULL, &iio_evgen_poke, 7);
	186	static IIO_DEVICE_ATTR(poke_ev8, S_IWUSR, NULL, &iio_evgen_poke, 8);
	187	static IIO_DEVICE_ATTR(poke_ev9, S_IWUSR, NULL, &iio_evgen_poke, 9);
	188
	189	static struct attribute *iio_evgen_attrs[] = {
	190	&iio_dev_attr_poke_ev0.dev_attr.attr,
	191	&iio_dev_attr_poke_ev1.dev_attr.attr,
	192	&iio_dev_attr_poke_ev2.dev_attr.attr,
	193	&iio_dev_attr_poke_ev3.dev_attr.attr,
	194	&iio_dev_attr_poke_ev4.dev_attr.attr,
	195	&iio_dev_attr_poke_ev5.dev_attr.attr,
	196	&iio_dev_attr_poke_ev6.dev_attr.attr,
	197	&iio_dev_attr_poke_ev7.dev_attr.attr,
	198	&iio_dev_attr_poke_ev8.dev_attr.attr,
	199	&iio_dev_attr_poke_ev9.dev_attr.attr,
	200	NULL,
	201	};
	202
	203	static const struct attribute_group iio_evgen_group = {
	204	.attrs = iio_evgen_attrs,
	205	};
	206
	207	static const struct attribute_group *iio_evgen_groups[] = {
	208	&iio_evgen_group,
	209	NULL
	210	};
	211
	212	static struct device iio_evgen_dev = {
	213	.bus = &iio_bus_type,
	214	.groups = iio_evgen_groups,
	215	.release = &iio_evgen_release,
	216	};
862cb6ce	217
e6477000 JC	218	static __init int iio_dummy_evgen_init(void)
	219	{
	220	int ret = iio_dummy_evgen_create();
4b4c7275	221
e6477000 JC	222	if (ret < 0)
	223	return ret;
	224	device_initialize(&iio_evgen_dev);
	225	dev_set_name(&iio_evgen_dev, "iio_evgen");
	226	return device_add(&iio_evgen_dev);
	227	}
	228	module_init(iio_dummy_evgen_init);
	229
	230	static __exit void iio_dummy_evgen_exit(void)
	231	{
	232	device_unregister(&iio_evgen_dev);
	233	}
	234	module_exit(iio_dummy_evgen_exit);
	235
0f8c9620	236	MODULE_AUTHOR("Jonathan Cameron <jic23@kernel.org>");
e6477000 JC	237	MODULE_DESCRIPTION("IIO dummy driver");
e6477000 JC	238	MODULE_LICENSE("GPL v2");