tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
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");