tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright 2011 Analog Devices Inc.
4 */
5
6#include <linux/kernel.h>
7#include <linux/module.h>
8#include <linux/platform_device.h>
9#include <linux/slab.h>
10#include <linux/list.h>
11#include <linux/irq_work.h>
12
13#include <linux/iio/iio.h>
14#include <linux/iio/trigger.h>
15
16struct iio_sysfs_trig {
17 struct iio_trigger *trig;
18 struct irq_work work;
19 int id;
20 struct list_head l;
21};
22
23static LIST_HEAD(iio_sysfs_trig_list);
24static DEFINE_MUTEX(iio_sysfs_trig_list_mut);
25
26static int iio_sysfs_trigger_probe(int id);
27static ssize_t iio_sysfs_trig_add(struct device *dev,
28 struct device_attribute *attr,
29 const char *buf,
30 size_t len)
31{
32 int ret;
33 unsigned long input;
34
35 ret = kstrtoul(buf, 10, &input);
36 if (ret)
37 return ret;
38 ret = iio_sysfs_trigger_probe(input);
39 if (ret)
40 return ret;
41 return len;
42}
43static DEVICE_ATTR(add_trigger, S_IWUSR, NULL, &iio_sysfs_trig_add);
44
45static int iio_sysfs_trigger_remove(int id);
46static ssize_t iio_sysfs_trig_remove(struct device *dev,
47 struct device_attribute *attr,
48 const char *buf,
49 size_t len)
50{
51 int ret;
52 unsigned long input;
53
54 ret = kstrtoul(buf, 10, &input);
55 if (ret)
56 return ret;
57 ret = iio_sysfs_trigger_remove(input);
58 if (ret)
59 return ret;
60 return len;
61}
62
63static DEVICE_ATTR(remove_trigger, S_IWUSR, NULL, &iio_sysfs_trig_remove);
64
65static struct attribute *iio_sysfs_trig_attrs[] = {
66 &dev_attr_add_trigger.attr,
67 &dev_attr_remove_trigger.attr,
68 NULL,
69};
70
71static const struct attribute_group iio_sysfs_trig_group = {
72 .attrs = iio_sysfs_trig_attrs,
73};
74
75static const struct attribute_group *iio_sysfs_trig_groups[] = {
76 &iio_sysfs_trig_group,
77 NULL
78};
79
80
81/* Nothing to actually do upon release */
82static void iio_trigger_sysfs_release(struct device *dev)
83{
84}
85
86static struct device iio_sysfs_trig_dev = {
87 .bus = &iio_bus_type,
88 .groups = iio_sysfs_trig_groups,
89 .release = &iio_trigger_sysfs_release,
90};
91
92static void iio_sysfs_trigger_work(struct irq_work *work)
93{
94 struct iio_sysfs_trig *trig = container_of(work, struct iio_sysfs_trig,
95 work);
96
97 iio_trigger_poll(trig->trig);
98}
99
100static ssize_t iio_sysfs_trigger_poll(struct device *dev,
101 struct device_attribute *attr, const char *buf, size_t count)
102{
103 struct iio_trigger *trig = to_iio_trigger(dev);
104 struct iio_sysfs_trig *sysfs_trig = iio_trigger_get_drvdata(trig);
105
106 irq_work_queue(&sysfs_trig->work);
107
108 return count;
109}
110
111static DEVICE_ATTR(trigger_now, S_IWUSR, NULL, iio_sysfs_trigger_poll);
112
113static struct attribute *iio_sysfs_trigger_attrs[] = {
114 &dev_attr_trigger_now.attr,
115 NULL,
116};
117
118static const struct attribute_group iio_sysfs_trigger_attr_group = {
119 .attrs = iio_sysfs_trigger_attrs,
120};
121
122static const struct attribute_group *iio_sysfs_trigger_attr_groups[] = {
123 &iio_sysfs_trigger_attr_group,
124 NULL
125};
126
127static const struct iio_trigger_ops iio_sysfs_trigger_ops = {
128};
129
130static int iio_sysfs_trigger_probe(int id)
131{
132 struct iio_sysfs_trig *t;
133 int ret;
134 bool foundit = false;
135
136 mutex_lock(&iio_sysfs_trig_list_mut);
137 list_for_each_entry(t, &iio_sysfs_trig_list, l)
138 if (id == t->id) {
139 foundit = true;
140 break;
141 }
142 if (foundit) {
143 ret = -EINVAL;
144 goto out1;
145 }
146 t = kmalloc(sizeof(*t), GFP_KERNEL);
147 if (t == NULL) {
148 ret = -ENOMEM;
149 goto out1;
150 }
151 t->id = id;
152 t->trig = iio_trigger_alloc(&iio_sysfs_trig_dev, "sysfstrig%d", id);
153 if (!t->trig) {
154 ret = -ENOMEM;
155 goto free_t;
156 }
157
158 t->trig->dev.groups = iio_sysfs_trigger_attr_groups;
159 t->trig->ops = &iio_sysfs_trigger_ops;
160 iio_trigger_set_drvdata(t->trig, t);
161
162 t->work = IRQ_WORK_INIT_HARD(iio_sysfs_trigger_work);
163
164 ret = iio_trigger_register(t->trig);
165 if (ret)
166 goto out2;
167 list_add(&t->l, &iio_sysfs_trig_list);
168 __module_get(THIS_MODULE);
169 mutex_unlock(&iio_sysfs_trig_list_mut);
170 return 0;
171
172out2:
173 iio_trigger_free(t->trig);
174free_t:
175 kfree(t);
176out1:
177 mutex_unlock(&iio_sysfs_trig_list_mut);
178 return ret;
179}
180
181static int iio_sysfs_trigger_remove(int id)
182{
183 bool foundit = false;
184 struct iio_sysfs_trig *t;
185
186 mutex_lock(&iio_sysfs_trig_list_mut);
187 list_for_each_entry(t, &iio_sysfs_trig_list, l)
188 if (id == t->id) {
189 foundit = true;
190 break;
191 }
192 if (!foundit) {
193 mutex_unlock(&iio_sysfs_trig_list_mut);
194 return -EINVAL;
195 }
196
197 iio_trigger_unregister(t->trig);
198 iio_trigger_free(t->trig);
199
200 list_del(&t->l);
201 kfree(t);
202 module_put(THIS_MODULE);
203 mutex_unlock(&iio_sysfs_trig_list_mut);
204 return 0;
205}
206
207
208static int __init iio_sysfs_trig_init(void)
209{
210 device_initialize(&iio_sysfs_trig_dev);
211 dev_set_name(&iio_sysfs_trig_dev, "iio_sysfs_trigger");
212 return device_add(&iio_sysfs_trig_dev);
213}
214module_init(iio_sysfs_trig_init);
215
216static void __exit iio_sysfs_trig_exit(void)
217{
218 device_unregister(&iio_sysfs_trig_dev);
219}
220module_exit(iio_sysfs_trig_exit);
221
222MODULE_AUTHOR("Michael Hennerich <michael.hennerich@analog.com>");
223MODULE_DESCRIPTION("Sysfs based trigger for the iio subsystem");
224MODULE_LICENSE("GPL v2");
225MODULE_ALIAS("platform:iio-trig-sysfs");