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
16 struct iio_sysfs_trig {
17 struct iio_trigger *trig;
18 struct irq_work work;
19 int id;
20 struct list_head l;
21 };
22
23 static LIST_HEAD(iio_sysfs_trig_list);
24 static DEFINE_MUTEX(iio_sysfs_trig_list_mut);
25
26 static int iio_sysfs_trigger_probe(int id);
iio_sysfs_trig_add(struct device * dev,struct device_attribute * attr,const char * buf,size_t len)27 static 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 }
43 static DEVICE_ATTR(add_trigger, S_IWUSR, NULL, &iio_sysfs_trig_add);
44
45 static int iio_sysfs_trigger_remove(int id);
iio_sysfs_trig_remove(struct device * dev,struct device_attribute * attr,const char * buf,size_t len)46 static 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
63 static DEVICE_ATTR(remove_trigger, S_IWUSR, NULL, &iio_sysfs_trig_remove);
64
65 static struct attribute *iio_sysfs_trig_attrs[] = {
66 &dev_attr_add_trigger.attr,
67 &dev_attr_remove_trigger.attr,
68 NULL,
69 };
70
71 static const struct attribute_group iio_sysfs_trig_group = {
72 .attrs = iio_sysfs_trig_attrs,
73 };
74
75 static 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 */
iio_trigger_sysfs_release(struct device * dev)82 static void iio_trigger_sysfs_release(struct device *dev)
83 {
84 }
85
86 static 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
iio_sysfs_trigger_work(struct irq_work * work)92 static 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
iio_sysfs_trigger_poll(struct device * dev,struct device_attribute * attr,const char * buf,size_t count)100 static 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
111 static DEVICE_ATTR(trigger_now, S_IWUSR, NULL, iio_sysfs_trigger_poll);
112
113 static struct attribute *iio_sysfs_trigger_attrs[] = {
114 &dev_attr_trigger_now.attr,
115 NULL,
116 };
117
118 static const struct attribute_group iio_sysfs_trigger_attr_group = {
119 .attrs = iio_sysfs_trigger_attrs,
120 };
121
122 static const struct attribute_group *iio_sysfs_trigger_attr_groups[] = {
123 &iio_sysfs_trigger_attr_group,
124 NULL
125 };
126
iio_sysfs_trigger_probe(int id)127 static int iio_sysfs_trigger_probe(int id)
128 {
129 struct iio_sysfs_trig *t;
130 int ret;
131 bool foundit = false;
132
133 mutex_lock(&iio_sysfs_trig_list_mut);
134 list_for_each_entry(t, &iio_sysfs_trig_list, l)
135 if (id == t->id) {
136 foundit = true;
137 break;
138 }
139 if (foundit) {
140 ret = -EINVAL;
141 goto err_unlock;
142 }
143 t = kmalloc(sizeof(*t), GFP_KERNEL);
144 if (t == NULL) {
145 ret = -ENOMEM;
146 goto err_unlock;
147 }
148 t->id = id;
149 t->trig = iio_trigger_alloc(&iio_sysfs_trig_dev, "sysfstrig%d", id);
150 if (!t->trig) {
151 ret = -ENOMEM;
152 goto err_free_sys_trig;
153 }
154
155 t->trig->dev.groups = iio_sysfs_trigger_attr_groups;
156 iio_trigger_set_drvdata(t->trig, t);
157
158 t->work = IRQ_WORK_INIT_HARD(iio_sysfs_trigger_work);
159
160 ret = iio_trigger_register(t->trig);
161 if (ret)
162 goto err_free_trig;
163 list_add(&t->l, &iio_sysfs_trig_list);
164 __module_get(THIS_MODULE);
165 mutex_unlock(&iio_sysfs_trig_list_mut);
166 return 0;
167
168 err_free_trig:
169 iio_trigger_free(t->trig);
170 err_free_sys_trig:
171 kfree(t);
172 err_unlock:
173 mutex_unlock(&iio_sysfs_trig_list_mut);
174 return ret;
175 }
176
iio_sysfs_trigger_remove(int id)177 static int iio_sysfs_trigger_remove(int id)
178 {
179 struct iio_sysfs_trig *t = NULL, *iter;
180
181 mutex_lock(&iio_sysfs_trig_list_mut);
182 list_for_each_entry(iter, &iio_sysfs_trig_list, l)
183 if (id == iter->id) {
184 t = iter;
185 break;
186 }
187 if (!t) {
188 mutex_unlock(&iio_sysfs_trig_list_mut);
189 return -EINVAL;
190 }
191
192 iio_trigger_unregister(t->trig);
193 irq_work_sync(&t->work);
194 iio_trigger_free(t->trig);
195
196 list_del(&t->l);
197 kfree(t);
198 module_put(THIS_MODULE);
199 mutex_unlock(&iio_sysfs_trig_list_mut);
200 return 0;
201 }
202
203
iio_sysfs_trig_init(void)204 static int __init iio_sysfs_trig_init(void)
205 {
206 int ret;
207 device_initialize(&iio_sysfs_trig_dev);
208 dev_set_name(&iio_sysfs_trig_dev, "iio_sysfs_trigger");
209 ret = device_add(&iio_sysfs_trig_dev);
210 if (ret)
211 put_device(&iio_sysfs_trig_dev);
212 return ret;
213 }
214 module_init(iio_sysfs_trig_init);
215
iio_sysfs_trig_exit(void)216 static void __exit iio_sysfs_trig_exit(void)
217 {
218 device_unregister(&iio_sysfs_trig_dev);
219 }
220 module_exit(iio_sysfs_trig_exit);
221
222 MODULE_AUTHOR("Michael Hennerich <michael.hennerich@analog.com>");
223 MODULE_DESCRIPTION("Sysfs based trigger for the iio subsystem");
224 MODULE_LICENSE("GPL v2");
225 MODULE_ALIAS("platform:iio-trig-sysfs");
226