1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
|
/*
* Industrial I/O - hrtimer trigger support
*
* Copyright 2014 STMicroelectronics Inc.
* Denis Ciocca <denis.ciocca@st.com>
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 as published by
* the Free Software Foundation.
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/hrtimer.h>
#include <linux/ktime.h>
#include <linux/slab.h>
#include <linux/list.h>
#include <linux/iio/iio.h>
#include <linux/iio/trigger.h>
struct iio_hrtimer_trigger_data {
struct iio_trigger *trig;
struct hrtimer timer;
struct list_head l;
ktime_t period;
u16 freq;
int id;
};
static LIST_HEAD(iio_hrtimer_trigger_list);
static DEFINE_MUTEX(iio_hrtimer_trigger_list_mut);
static int iio_hrtimer_trigger_probe(int id);
static int iio_hrtimer_trigger_remove(int id);
static ssize_t iio_sysfs_hrtimer_trig_add(struct device *dev,
struct device_attribute *attr, const char *buf, size_t len)
{
int ret;
unsigned int input;
ret = kstrtouint(buf, 10, &input);
if (ret)
return ret;
ret = iio_hrtimer_trigger_probe(input);
if (ret)
return ret;
return len;
}
static DEVICE_ATTR(add_trigger, S_IWUSR, NULL, &iio_sysfs_hrtimer_trig_add);
static ssize_t iio_sysfs_hrtimer_trig_remove(struct device *dev,
struct device_attribute *attr, const char *buf, size_t len)
{
int ret;
unsigned int input;
ret = kstrtouint(buf, 10, &input);
if (ret)
return ret;
ret = iio_hrtimer_trigger_remove(input);
if (ret)
return ret;
return len;
}
static DEVICE_ATTR(remove_trigger, S_IWUSR,
NULL, &iio_sysfs_hrtimer_trig_remove);
static struct attribute *iio_hrtimer_trig_attrs[] = {
&dev_attr_add_trigger.attr,
&dev_attr_remove_trigger.attr,
NULL,
};
static const struct attribute_group iio_hrtimer_trig_group = {
.attrs = iio_hrtimer_trig_attrs,
};
static const struct attribute_group *iio_hrtimer_trig_groups[] = {
&iio_hrtimer_trig_group,
NULL,
};
static struct device iio_hrtimer_trig_dev = {
.bus = &iio_bus_type,
.groups = iio_hrtimer_trig_groups,
};
static int iio_hrtimer_trig_set_state(struct iio_trigger *trig, bool state)
{
struct iio_hrtimer_trigger_data *trig_data =
iio_trigger_get_drvdata(trig);
if (trig_data->freq == 0)
return -EINVAL;
if (state)
hrtimer_start(&trig_data->timer,
trig_data->period, HRTIMER_MODE_REL);
else
hrtimer_cancel(&trig_data->timer);
return 0;
}
static ssize_t iio_hrtimer_trigger_set_freq_value(struct device *dev,
struct device_attribute *attr, const char *buf, size_t len)
{
int ret;
u16 frequency;
struct iio_trigger *trig = to_iio_trigger(dev);
struct iio_hrtimer_trigger_data *trig_data =
iio_trigger_get_drvdata(trig);
ret = kstrtou16(buf, 10, &frequency);
if (ret < 0)
return ret;
trig_data->freq = frequency;
if (frequency)
trig_data->period =
ktime_set(0, NSEC_PER_SEC / trig_data->freq);
return len;
}
static ssize_t iio_hrtimer_trigger_get_freq_value(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct iio_trigger *trig = to_iio_trigger(dev);
struct iio_hrtimer_trigger_data *trig_data =
iio_trigger_get_drvdata(trig);
return sprintf(buf, "%hu\n", trig_data->freq);
}
static DEVICE_ATTR(frequency, S_IWUSR | S_IRUGO,
iio_hrtimer_trigger_get_freq_value,
iio_hrtimer_trigger_set_freq_value);
static ssize_t iio_hrtimer_trigger_get_id(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct iio_trigger *trig = to_iio_trigger(dev);
struct iio_hrtimer_trigger_data *trig_data =
iio_trigger_get_drvdata(trig);
return sprintf(buf, "%d\n", trig_data->id);
}
static DEVICE_ATTR(id, S_IRUGO, iio_hrtimer_trigger_get_id, NULL);
static struct attribute *iio_hrtimer_trigger_attrs[] = {
&dev_attr_frequency.attr,
&dev_attr_id.attr,
NULL,
};
static const struct attribute_group iio_hrtimer_trigger_attr_group = {
.attrs = iio_hrtimer_trigger_attrs,
};
static const struct attribute_group *iio_hrtimer_trigger_attr_groups[] = {
&iio_hrtimer_trigger_attr_group,
NULL,
};
static const struct iio_trigger_ops iio_hrtimer_trigger_ops = {
.owner = THIS_MODULE,
.set_trigger_state = &iio_hrtimer_trig_set_state,
};
enum hrtimer_restart iio_hrtimer_trigger_func(struct hrtimer *timer)
{
struct iio_hrtimer_trigger_data *trig_data;
trig_data = container_of(timer, struct iio_hrtimer_trigger_data, timer);
hrtimer_forward_now(timer, trig_data->period);
iio_trigger_poll(trig_data->trig, iio_get_time_ns());
return HRTIMER_RESTART;
}
static int iio_hrtimer_trigger_probe(int id)
{
int err;
bool foundit = false;
struct iio_hrtimer_trigger_data *trig_data;
mutex_lock(&iio_hrtimer_trigger_list_mut);
list_for_each_entry(trig_data, &iio_hrtimer_trigger_list, l) {
if (id == trig_data->id) {
foundit = true;
break;
}
}
if (foundit) {
err = -EINVAL;
goto iio_hrtimer_mutex_unlock;
}
trig_data = kmalloc(sizeof(*trig_data), GFP_KERNEL);
if (trig_data == NULL) {
err = -ENOMEM;
goto iio_hrtimer_mutex_unlock;
}
trig_data->id = id;
trig_data->trig = iio_trigger_alloc("hrtimer_trig%d", id);
if (!trig_data->trig) {
err = -ENOMEM;
goto iio_hrtimer_free_trig_data;
}
trig_data->trig->dev.groups = iio_hrtimer_trigger_attr_groups;
trig_data->trig->ops = &iio_hrtimer_trigger_ops;
trig_data->trig->dev.parent = &iio_hrtimer_trig_dev;
iio_trigger_set_drvdata(trig_data->trig, trig_data);
trig_data->freq = 0;
hrtimer_init(&trig_data->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
trig_data->timer.function = &iio_hrtimer_trigger_func;
err = iio_trigger_register(trig_data->trig);
if (err)
goto iio_hrtimer_free_trig_data;
list_add(&trig_data->l, &iio_hrtimer_trigger_list);
__module_get(THIS_MODULE);
mutex_unlock(&iio_hrtimer_trigger_list_mut);
return 0;
iio_hrtimer_free_trig_data:
kfree(trig_data);
iio_hrtimer_mutex_unlock:
mutex_unlock(&iio_hrtimer_trigger_list_mut);
return err;
}
static int iio_hrtimer_trigger_remove(int id)
{
bool foundit = false;
struct iio_hrtimer_trigger_data *trig_data;
mutex_lock(&iio_hrtimer_trigger_list_mut);
list_for_each_entry(trig_data, &iio_hrtimer_trigger_list, l) {
if (id == trig_data->id) {
foundit = true;
break;
}
}
if (!foundit) {
mutex_unlock(&iio_hrtimer_trigger_list_mut);
return -EINVAL;
}
iio_trigger_unregister(trig_data->trig);
iio_trigger_free(trig_data->trig);
list_del(&trig_data->l);
kfree(trig_data);
module_put(THIS_MODULE);
mutex_unlock(&iio_hrtimer_trigger_list_mut);
return 0;
}
static int __init iio_hrtimer_trig_init(void)
{
device_initialize(&iio_hrtimer_trig_dev);
dev_set_name(&iio_hrtimer_trig_dev, "iio_hrtimer_trigger");
return device_add(&iio_hrtimer_trig_dev);
}
module_init(iio_hrtimer_trig_init);
static void __exit iio_hrtimer_trig_exit(void)
{
device_unregister(&iio_hrtimer_trig_dev);
}
module_exit(iio_hrtimer_trig_exit);
MODULE_AUTHOR("Denis Ciocca <denis.ciocca@st.com>");
MODULE_DESCRIPTION("Hrtimer trigger for the iio subsystem");
MODULE_LICENSE("GPL v2");
|
