2 * Copyright (c) 2011 Jonathan Cameron
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.
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.
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>
24 #include "iio_dummy_evgen.h"
28 /* Fiddly bit of faking and irq without hardware */
29 #define IIO_EVENTGEN_NO 10
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
35 * @inuse: mask of which irqs actually have anyone connected
36 * @lock: protect the evgen state
38 struct iio_dummy_eventgen {
41 bool enabled[IIO_EVENTGEN_NO];
42 bool inuse[IIO_EVENTGEN_NO];
46 /* We can only ever have one instance of this 'device' */
47 static struct iio_dummy_eventgen *iio_evgen;
48 static const char *iio_evgen_name = "iio_dummy_evgen";
50 static void iio_dummy_event_irqmask(struct irq_data *d)
52 struct irq_chip *chip = irq_data_get_irq_chip(d);
53 struct iio_dummy_eventgen *evgen =
54 container_of(chip, struct iio_dummy_eventgen, chip);
56 evgen->enabled[d->irq - evgen->base] = false;
59 static void iio_dummy_event_irqunmask(struct irq_data *d)
61 struct irq_chip *chip = irq_data_get_irq_chip(d);
62 struct iio_dummy_eventgen *evgen =
63 container_of(chip, struct iio_dummy_eventgen, chip);
65 evgen->enabled[d->irq - evgen->base] = true;
68 static int iio_dummy_evgen_create(void)
72 iio_evgen = kzalloc(sizeof(*iio_evgen), GFP_KERNEL);
73 if (iio_evgen == NULL)
76 iio_evgen->base = irq_alloc_descs(-1, 0, IIO_EVENTGEN_NO, 0);
77 if (iio_evgen->base < 0) {
78 ret = iio_evgen->base;
82 iio_evgen->chip.name = iio_evgen_name;
83 iio_evgen->chip.irq_mask = &iio_dummy_event_irqmask;
84 iio_evgen->chip.irq_unmask = &iio_dummy_event_irqunmask;
85 for (i = 0; i < IIO_EVENTGEN_NO; i++) {
86 irq_set_chip(iio_evgen->base + i, &iio_evgen->chip);
87 irq_set_handler(iio_evgen->base + i, &handle_simple_irq);
88 irq_modify_status(iio_evgen->base + i,
89 IRQ_NOREQUEST | IRQ_NOAUTOEN,
92 mutex_init(&iio_evgen->lock);
97 * iio_dummy_evgen_get_irq() - get an evgen provided irq for a device
99 * This function will give a free allocated irq to a client device.
100 * That irq can then be caused to 'fire' by using the associated sysfs file.
102 int iio_dummy_evgen_get_irq(void)
105 mutex_lock(&iio_evgen->lock);
106 for (i = 0; i < IIO_EVENTGEN_NO; i++)
107 if (iio_evgen->inuse[i] == false) {
108 ret = iio_evgen->base + i;
109 iio_evgen->inuse[i] = true;
112 mutex_unlock(&iio_evgen->lock);
113 if (i == IIO_EVENTGEN_NO)
117 EXPORT_SYMBOL_GPL(iio_dummy_evgen_get_irq);
120 * iio_dummy_evgen_release_irq() - give the irq back.
121 * @irq: irq being returned to the pool
123 * Used by client driver instances to give the irqs back when they disconnect
125 int iio_dummy_evgen_release_irq(int irq)
127 mutex_lock(&iio_evgen->lock);
128 iio_evgen->inuse[irq - iio_evgen->base] = false;
129 mutex_unlock(&iio_evgen->lock);
133 EXPORT_SYMBOL_GPL(iio_dummy_evgen_release_irq);
135 static void iio_dummy_evgen_free(void)
137 irq_free_descs(iio_evgen->base, IIO_EVENTGEN_NO);
141 static void iio_evgen_release(struct device *dev)
143 iio_dummy_evgen_free();
146 static ssize_t iio_evgen_poke(struct device *dev,
147 struct device_attribute *attr,
151 struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
153 if (iio_evgen->enabled[this_attr->address])
154 handle_nested_irq(iio_evgen->base + this_attr->address);
159 static IIO_DEVICE_ATTR(poke_ev0, S_IWUSR, NULL, &iio_evgen_poke, 0);
160 static IIO_DEVICE_ATTR(poke_ev1, S_IWUSR, NULL, &iio_evgen_poke, 1);
161 static IIO_DEVICE_ATTR(poke_ev2, S_IWUSR, NULL, &iio_evgen_poke, 2);
162 static IIO_DEVICE_ATTR(poke_ev3, S_IWUSR, NULL, &iio_evgen_poke, 3);
163 static IIO_DEVICE_ATTR(poke_ev4, S_IWUSR, NULL, &iio_evgen_poke, 4);
164 static IIO_DEVICE_ATTR(poke_ev5, S_IWUSR, NULL, &iio_evgen_poke, 5);
165 static IIO_DEVICE_ATTR(poke_ev6, S_IWUSR, NULL, &iio_evgen_poke, 6);
166 static IIO_DEVICE_ATTR(poke_ev7, S_IWUSR, NULL, &iio_evgen_poke, 7);
167 static IIO_DEVICE_ATTR(poke_ev8, S_IWUSR, NULL, &iio_evgen_poke, 8);
168 static IIO_DEVICE_ATTR(poke_ev9, S_IWUSR, NULL, &iio_evgen_poke, 9);
170 static struct attribute *iio_evgen_attrs[] = {
171 &iio_dev_attr_poke_ev0.dev_attr.attr,
172 &iio_dev_attr_poke_ev1.dev_attr.attr,
173 &iio_dev_attr_poke_ev2.dev_attr.attr,
174 &iio_dev_attr_poke_ev3.dev_attr.attr,
175 &iio_dev_attr_poke_ev4.dev_attr.attr,
176 &iio_dev_attr_poke_ev5.dev_attr.attr,
177 &iio_dev_attr_poke_ev6.dev_attr.attr,
178 &iio_dev_attr_poke_ev7.dev_attr.attr,
179 &iio_dev_attr_poke_ev8.dev_attr.attr,
180 &iio_dev_attr_poke_ev9.dev_attr.attr,
184 static const struct attribute_group iio_evgen_group = {
185 .attrs = iio_evgen_attrs,
188 static const struct attribute_group *iio_evgen_groups[] = {
193 static struct device iio_evgen_dev = {
194 .bus = &iio_bus_type,
195 .groups = iio_evgen_groups,
196 .release = &iio_evgen_release,
198 static __init int iio_dummy_evgen_init(void)
200 int ret = iio_dummy_evgen_create();
203 device_initialize(&iio_evgen_dev);
204 dev_set_name(&iio_evgen_dev, "iio_evgen");
205 return device_add(&iio_evgen_dev);
207 module_init(iio_dummy_evgen_init);
209 static __exit void iio_dummy_evgen_exit(void)
211 device_unregister(&iio_evgen_dev);
213 module_exit(iio_dummy_evgen_exit);
215 MODULE_AUTHOR("Jonathan Cameron <jic23@cam.ac.uk>");
216 MODULE_DESCRIPTION("IIO dummy driver");
217 MODULE_LICENSE("GPL v2");