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
|
// SPDX-License-Identifier: GPL-2.0-only
/**
* The industrial I/O periodic hrtimer trigger driver
*
* Copyright (C) Intuitive Aerial AB
* Written by Marten Svanfeldt, marten@intuitiveaerial.com
* Copyright (C) 2012, Analog Devices Inc.
* Author: Lars-Peter Clausen <lars@metafoo.de>
* Copyright (C) 2015, Intel Corporation
*/
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/hrtimer.h>
#include <linux/iio/iio.h>
#include <linux/iio/trigger.h>
#include <linux/iio/sw_trigger.h>
/* default sampling frequency - 100Hz */
#define HRTIMER_DEFAULT_SAMPLING_FREQUENCY 100
struct iio_hrtimer_info {
struct iio_sw_trigger swt;
struct hrtimer timer;
unsigned long sampling_frequency;
ktime_t period;
};
static const struct config_item_type iio_hrtimer_type = {
.ct_owner = THIS_MODULE,
};
static
ssize_t iio_hrtimer_show_sampling_frequency(struct device *dev,
struct device_attribute *attr,
char *buf)
{
struct iio_trigger *trig = to_iio_trigger(dev);
struct iio_hrtimer_info *info = iio_trigger_get_drvdata(trig);
return snprintf(buf, PAGE_SIZE, "%lu\n", info->sampling_frequency);
}
static
ssize_t iio_hrtimer_store_sampling_frequency(struct device *dev,
struct device_attribute *attr,
const char *buf, size_t len)
{
struct iio_trigger *trig = to_iio_trigger(dev);
struct iio_hrtimer_info *info = iio_trigger_get_drvdata(trig);
unsigned long val;
int ret;
ret = kstrtoul(buf, 10, &val);
if (ret)
return ret;
if (!val || val > NSEC_PER_SEC)
return -EINVAL;
info->sampling_frequency = val;
info->period = NSEC_PER_SEC / val;
return len;
}
static DEVICE_ATTR(sampling_frequency, S_IRUGO | S_IWUSR,
iio_hrtimer_show_sampling_frequency,
iio_hrtimer_store_sampling_frequency);
static struct attribute *iio_hrtimer_attrs[] = {
&dev_attr_sampling_frequency.attr,
NULL
};
static const struct attribute_group iio_hrtimer_attr_group = {
.attrs = iio_hrtimer_attrs,
};
static const struct attribute_group *iio_hrtimer_attr_groups[] = {
&iio_hrtimer_attr_group,
NULL
};
static enum hrtimer_restart iio_hrtimer_trig_handler(struct hrtimer *timer)
{
struct iio_hrtimer_info *info;
info = container_of(timer, struct iio_hrtimer_info, timer);
hrtimer_forward_now(timer, info->period);
iio_trigger_poll(info->swt.trigger);
return HRTIMER_RESTART;
}
static int iio_trig_hrtimer_set_state(struct iio_trigger *trig, bool state)
{
struct iio_hrtimer_info *trig_info;
trig_info = iio_trigger_get_drvdata(trig);
if (state)
hrtimer_start(&trig_info->timer, trig_info->period,
HRTIMER_MODE_REL);
else
hrtimer_cancel(&trig_info->timer);
return 0;
}
static const struct iio_trigger_ops iio_hrtimer_trigger_ops = {
.set_trigger_state = iio_trig_hrtimer_set_state,
};
static struct iio_sw_trigger *iio_trig_hrtimer_probe(const char *name)
{
struct iio_hrtimer_info *trig_info;
int ret;
trig_info = kzalloc(sizeof(*trig_info), GFP_KERNEL);
if (!trig_info)
return ERR_PTR(-ENOMEM);
trig_info->swt.trigger = iio_trigger_alloc("%s", name);
if (!trig_info->swt.trigger) {
ret = -ENOMEM;
goto err_free_trig_info;
}
iio_trigger_set_drvdata(trig_info->swt.trigger, trig_info);
trig_info->swt.trigger->ops = &iio_hrtimer_trigger_ops;
trig_info->swt.trigger->dev.groups = iio_hrtimer_attr_groups;
hrtimer_init(&trig_info->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
trig_info->timer.function = iio_hrtimer_trig_handler;
trig_info->sampling_frequency = HRTIMER_DEFAULT_SAMPLING_FREQUENCY;
trig_info->period = NSEC_PER_SEC / trig_info->sampling_frequency;
ret = iio_trigger_register(trig_info->swt.trigger);
if (ret)
goto err_free_trigger;
iio_swt_group_init_type_name(&trig_info->swt, name, &iio_hrtimer_type);
return &trig_info->swt;
err_free_trigger:
iio_trigger_free(trig_info->swt.trigger);
err_free_trig_info:
kfree(trig_info);
return ERR_PTR(ret);
}
static int iio_trig_hrtimer_remove(struct iio_sw_trigger *swt)
{
struct iio_hrtimer_info *trig_info;
trig_info = iio_trigger_get_drvdata(swt->trigger);
iio_trigger_unregister(swt->trigger);
/* cancel the timer after unreg to make sure no one rearms it */
hrtimer_cancel(&trig_info->timer);
iio_trigger_free(swt->trigger);
kfree(trig_info);
return 0;
}
static const struct iio_sw_trigger_ops iio_trig_hrtimer_ops = {
.probe = iio_trig_hrtimer_probe,
.remove = iio_trig_hrtimer_remove,
};
static struct iio_sw_trigger_type iio_trig_hrtimer = {
.name = "hrtimer",
.owner = THIS_MODULE,
.ops = &iio_trig_hrtimer_ops,
};
module_iio_sw_trigger_driver(iio_trig_hrtimer);
MODULE_AUTHOR("Marten Svanfeldt <marten@intuitiveaerial.com>");
MODULE_AUTHOR("Daniel Baluta <daniel.baluta@intel.com>");
MODULE_DESCRIPTION("Periodic hrtimer trigger for the IIO subsystem");
MODULE_LICENSE("GPL v2");
|
