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);
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
139	mutex_lock(&iio_sysfs_trig_list_mut);
140	list_for_each_entry(t, &iio_sysfs_trig_list, l)
141		if (id == t->id) {
142			foundit = true;
143			break;
144		}
145	if (foundit) {
146		ret = -EINVAL;
147		goto out1;
148	}
149	t = kmalloc(sizeof(*t), GFP_KERNEL);
150	if (t == NULL) {
151		ret = -ENOMEM;
152		goto out1;
153	}
154	t->id = id;
155	t->trig = iio_trigger_alloc("sysfstrig%d", id);
156	if (!t->trig) {
157		ret = -ENOMEM;
158		goto free_t;
159	}
160
161	t->trig->dev.groups = iio_sysfs_trigger_attr_groups;
162	t->trig->ops = &iio_sysfs_trigger_ops;
163	t->trig->dev.parent = &iio_sysfs_trig_dev;
164	iio_trigger_set_drvdata(t->trig, t);
165
166	init_irq_work(&t->work, iio_sysfs_trigger_work);
167
168	ret = iio_trigger_register(t->trig);
169	if (ret)
170		goto out2;
171	list_add(&t->l, &iio_sysfs_trig_list);
172	__module_get(THIS_MODULE);
173	mutex_unlock(&iio_sysfs_trig_list_mut);
174	return 0;
175
176out2:
177	iio_trigger_put(t->trig);
178free_t:
179	kfree(t);
180out1:
181	mutex_unlock(&iio_sysfs_trig_list_mut);
182	return ret;
183}
184
185static int iio_sysfs_trigger_remove(int id)
186{
187	bool foundit = false;
188	struct iio_sysfs_trig *t;
189
190	mutex_lock(&iio_sysfs_trig_list_mut);
191	list_for_each_entry(t, &iio_sysfs_trig_list, l)
192		if (id == t->id) {
193			foundit = true;
194			break;
195		}
196	if (!foundit) {
197		mutex_unlock(&iio_sysfs_trig_list_mut);
198		return -EINVAL;
199	}
200
201	iio_trigger_unregister(t->trig);
202	iio_trigger_free(t->trig);
203
204	list_del(&t->l);
205	kfree(t);
206	module_put(THIS_MODULE);
207	mutex_unlock(&iio_sysfs_trig_list_mut);
208	return 0;
209}
210
211
212static int __init iio_sysfs_trig_init(void)
213{
214	device_initialize(&iio_sysfs_trig_dev);
215	dev_set_name(&iio_sysfs_trig_dev, "iio_sysfs_trigger");
216	return device_add(&iio_sysfs_trig_dev);
217}
218module_init(iio_sysfs_trig_init);
219
220static void __exit iio_sysfs_trig_exit(void)
221{
222	device_unregister(&iio_sysfs_trig_dev);
223}
224module_exit(iio_sysfs_trig_exit);
225
226MODULE_AUTHOR("Michael Hennerich <hennerich@blackfin.uclinux.org>");
227MODULE_DESCRIPTION("Sysfs based trigger for the iio subsystem");
228MODULE_LICENSE("GPL v2");
229MODULE_ALIAS("platform:iio-trig-sysfs");