1/*
  2 * Copyright 2011 Analog Devices Inc.
  3 *
  4 * Licensed under the GPL-2.
  5 *
  6 */
  7
  8#include <linux/kernel.h>
  9#include <linux/module.h>
 10#include <linux/platform_device.h>
 11#include <linux/slab.h>
 12#include <linux/list.h>
 13#include <linux/irq_work.h>
 14
 15#include <linux/iio/iio.h>
 16#include <linux/iio/trigger.h>
 17
 18struct iio_sysfs_trig {
 19	struct iio_trigger *trig;
 20	struct irq_work work;
 21	int id;
 22	struct list_head l;
 23};
 24
 25static LIST_HEAD(iio_sysfs_trig_list);
 26static DEFINE_MUTEX(iio_sysfs_trig_list_mut);
 27
 28static int iio_sysfs_trigger_probe(int id);
 29static ssize_t iio_sysfs_trig_add(struct device *dev,
 30				  struct device_attribute *attr,
 31				  const char *buf,
 32				  size_t len)
 33{
 34	int ret;
 35	unsigned long input;
 36
 37	ret = kstrtoul(buf, 10, &input);
 38	if (ret)
 39		return ret;
 40	ret = iio_sysfs_trigger_probe(input);
 41	if (ret)
 42		return ret;
 43	return len;
 44}
 45static DEVICE_ATTR(add_trigger, S_IWUSR, NULL, &iio_sysfs_trig_add);
 46
 47static int iio_sysfs_trigger_remove(int id);
 48static ssize_t iio_sysfs_trig_remove(struct device *dev,
 49				     struct device_attribute *attr,
 50				     const char *buf,
 51				     size_t len)
 52{
 53	int ret;
 54	unsigned long input;
 55
 56	ret = kstrtoul(buf, 10, &input);
 57	if (ret)
 58		return ret;
 59	ret = iio_sysfs_trigger_remove(input);
 60	if (ret)
 61		return ret;
 62	return len;
 63}
 64
 65static DEVICE_ATTR(remove_trigger, S_IWUSR, NULL, &iio_sysfs_trig_remove);
 66
 67static struct attribute *iio_sysfs_trig_attrs[] = {
 68	&dev_attr_add_trigger.attr,
 69	&dev_attr_remove_trigger.attr,
 70	NULL,
 71};
 72
 73static const struct attribute_group iio_sysfs_trig_group = {
 74	.attrs = iio_sysfs_trig_attrs,
 75};
 76
 77static const struct attribute_group *iio_sysfs_trig_groups[] = {
 78	&iio_sysfs_trig_group,
 79	NULL
 80};
 81
 82
 83/* Nothing to actually do upon release */
 84static void iio_trigger_sysfs_release(struct device *dev)
 85{
 86}
 87
 88static struct device iio_sysfs_trig_dev = {
 89	.bus = &iio_bus_type,
 90	.groups = iio_sysfs_trig_groups,
 91	.release = &iio_trigger_sysfs_release,
 92};
 93
 94static void iio_sysfs_trigger_work(struct irq_work *work)
 95{
 96	struct iio_sysfs_trig *trig = container_of(work, struct iio_sysfs_trig,
 97							work);
 98
 99	iio_trigger_poll(trig->trig, 0);
100}
101
102static ssize_t iio_sysfs_trigger_poll(struct device *dev,
103		struct device_attribute *attr, const char *buf, size_t count)
104{
105	struct iio_trigger *trig = to_iio_trigger(dev);
106	struct iio_sysfs_trig *sysfs_trig = iio_trigger_get_drvdata(trig);
107
108	irq_work_queue(&sysfs_trig->work);
109
110	return count;
111}
112
113static DEVICE_ATTR(trigger_now, S_IWUSR, NULL, iio_sysfs_trigger_poll);
114
115static struct attribute *iio_sysfs_trigger_attrs[] = {
116	&dev_attr_trigger_now.attr,
117	NULL,
118};
119
120static const struct attribute_group iio_sysfs_trigger_attr_group = {
121	.attrs = iio_sysfs_trigger_attrs,
122};
123
124static const struct attribute_group *iio_sysfs_trigger_attr_groups[] = {
125	&iio_sysfs_trigger_attr_group,
126	NULL
127};
128
129static const struct iio_trigger_ops iio_sysfs_trigger_ops = {
130	.owner = THIS_MODULE,
131};
132
133static int iio_sysfs_trigger_probe(int id)
134{
135	struct iio_sysfs_trig *t;
136	int ret;
137	bool foundit = false;
138	mutex_lock(&iio_sysfs_trig_list_mut);
139	list_for_each_entry(t, &iio_sysfs_trig_list, l)
140		if (id == t->id) {
141			foundit = true;
142			break;
143		}
144	if (foundit) {
145		ret = -EINVAL;
146		goto out1;
147	}
148	t = kmalloc(sizeof(*t), GFP_KERNEL);
149	if (t == NULL) {
150		ret = -ENOMEM;
151		goto out1;
152	}
153	t->id = id;
154	t->trig = iio_trigger_alloc("sysfstrig%d", id);
155	if (!t->trig) {
156		ret = -ENOMEM;
157		goto free_t;
158	}
159
160	t->trig->dev.groups = iio_sysfs_trigger_attr_groups;
161	t->trig->ops = &iio_sysfs_trigger_ops;
162	t->trig->dev.parent = &iio_sysfs_trig_dev;
163	iio_trigger_set_drvdata(t->trig, t);
164
165	init_irq_work(&t->work, iio_sysfs_trigger_work);
166
167	ret = iio_trigger_register(t->trig);
168	if (ret)
169		goto out2;
170	list_add(&t->l, &iio_sysfs_trig_list);
171	__module_get(THIS_MODULE);
172	mutex_unlock(&iio_sysfs_trig_list_mut);
173	return 0;
174
175out2:
176	iio_trigger_put(t->trig);
177free_t:
178	kfree(t);
179out1:
180	mutex_unlock(&iio_sysfs_trig_list_mut);
181	return ret;
182}
183
184static int iio_sysfs_trigger_remove(int id)
185{
186	bool foundit = false;
187	struct iio_sysfs_trig *t;
188	mutex_lock(&iio_sysfs_trig_list_mut);
189	list_for_each_entry(t, &iio_sysfs_trig_list, l)
190		if (id == t->id) {
191			foundit = true;
192			break;
193		}
194	if (!foundit) {
195		mutex_unlock(&iio_sysfs_trig_list_mut);
196		return -EINVAL;
197	}
198
199	iio_trigger_unregister(t->trig);
200	iio_trigger_free(t->trig);
201
202	list_del(&t->l);
203	kfree(t);
204	module_put(THIS_MODULE);
205	mutex_unlock(&iio_sysfs_trig_list_mut);
206	return 0;
207}
208
209
210static int __init iio_sysfs_trig_init(void)
211{
212	device_initialize(&iio_sysfs_trig_dev);
213	dev_set_name(&iio_sysfs_trig_dev, "iio_sysfs_trigger");
214	return device_add(&iio_sysfs_trig_dev);
215}
216module_init(iio_sysfs_trig_init);
217
218static void __exit iio_sysfs_trig_exit(void)
219{
220	device_unregister(&iio_sysfs_trig_dev);
221}
222module_exit(iio_sysfs_trig_exit);
223
224MODULE_AUTHOR("Michael Hennerich <hennerich@blackfin.uclinux.org>");
225MODULE_DESCRIPTION("Sysfs based trigger for the iio subsystem");
226MODULE_LICENSE("GPL v2");
227MODULE_ALIAS("platform:iio-trig-sysfs");