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
14 #include "../iio.h"
15 #include "../trigger.h"
16
17 struct iio_sysfs_trig {
18 struct iio_trigger *trig;
19 int id;
20 struct list_head l;
21 };
22
23 static LIST_HEAD(iio_sysfs_trig_list);
24 static DEFINE_MUTEX(iio_syfs_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 = strict_strtoul(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 = strict_strtoul(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_poll(struct device * dev,struct device_attribute * attr,const char * buf,size_t count)92 static ssize_t iio_sysfs_trigger_poll(struct device *dev,
93 struct device_attribute *attr, const char *buf, size_t count)
94 {
95 struct iio_trigger *trig = dev_get_drvdata(dev);
96 iio_trigger_poll_chained(trig, 0);
97
98 return count;
99 }
100
101 static DEVICE_ATTR(trigger_now, S_IWUSR, NULL, iio_sysfs_trigger_poll);
102
103 static struct attribute *iio_sysfs_trigger_attrs[] = {
104 &dev_attr_trigger_now.attr,
105 NULL,
106 };
107
108 static const struct attribute_group iio_sysfs_trigger_attr_group = {
109 .attrs = iio_sysfs_trigger_attrs,
110 };
111
112 static const struct attribute_group *iio_sysfs_trigger_attr_groups[] = {
113 &iio_sysfs_trigger_attr_group,
114 NULL
115 };
116
117 static const struct iio_trigger_ops iio_sysfs_trigger_ops = {
118 .owner = THIS_MODULE,
119 };
120
iio_sysfs_trigger_probe(int id)121 static int iio_sysfs_trigger_probe(int id)
122 {
123 struct iio_sysfs_trig *t;
124 int ret;
125 bool foundit = false;
126 mutex_lock(&iio_syfs_trig_list_mut);
127 list_for_each_entry(t, &iio_sysfs_trig_list, l)
128 if (id == t->id) {
129 foundit = true;
130 break;
131 }
132 if (foundit) {
133 ret = -EINVAL;
134 goto out1;
135 }
136 t = kmalloc(sizeof(*t), GFP_KERNEL);
137 if (t == NULL) {
138 ret = -ENOMEM;
139 goto out1;
140 }
141 t->id = id;
142 t->trig = iio_allocate_trigger("sysfstrig%d", id);
143 if (!t->trig) {
144 ret = -ENOMEM;
145 goto free_t;
146 }
147
148 t->trig->dev.groups = iio_sysfs_trigger_attr_groups;
149 t->trig->ops = &iio_sysfs_trigger_ops;
150 t->trig->dev.parent = &iio_sysfs_trig_dev;
151
152 ret = iio_trigger_register(t->trig);
153 if (ret)
154 goto out2;
155 list_add(&t->l, &iio_sysfs_trig_list);
156 __module_get(THIS_MODULE);
157 mutex_unlock(&iio_syfs_trig_list_mut);
158 return 0;
159
160 out2:
161 iio_put_trigger(t->trig);
162 free_t:
163 kfree(t);
164 out1:
165 mutex_unlock(&iio_syfs_trig_list_mut);
166 return ret;
167 }
168
iio_sysfs_trigger_remove(int id)169 static int iio_sysfs_trigger_remove(int id)
170 {
171 bool foundit = false;
172 struct iio_sysfs_trig *t;
173 mutex_lock(&iio_syfs_trig_list_mut);
174 list_for_each_entry(t, &iio_sysfs_trig_list, l)
175 if (id == t->id) {
176 foundit = true;
177 break;
178 }
179 if (!foundit) {
180 mutex_unlock(&iio_syfs_trig_list_mut);
181 return -EINVAL;
182 }
183
184 iio_trigger_unregister(t->trig);
185 iio_free_trigger(t->trig);
186
187 list_del(&t->l);
188 kfree(t);
189 module_put(THIS_MODULE);
190 mutex_unlock(&iio_syfs_trig_list_mut);
191 return 0;
192 }
193
194
iio_sysfs_trig_init(void)195 static int __init iio_sysfs_trig_init(void)
196 {
197 device_initialize(&iio_sysfs_trig_dev);
198 dev_set_name(&iio_sysfs_trig_dev, "iio_sysfs_trigger");
199 return device_add(&iio_sysfs_trig_dev);
200 }
201 module_init(iio_sysfs_trig_init);
202
iio_sysfs_trig_exit(void)203 static void __exit iio_sysfs_trig_exit(void)
204 {
205 device_unregister(&iio_sysfs_trig_dev);
206 }
207 module_exit(iio_sysfs_trig_exit);
208
209 MODULE_AUTHOR("Michael Hennerich <hennerich@blackfin.uclinux.org>");
210 MODULE_DESCRIPTION("Sysfs based trigger for the iio subsystem");
211 MODULE_LICENSE("GPL v2");
212 MODULE_ALIAS("platform:iio-trig-sysfs");
213