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
|
/*
* Copyright 2016 Jonathan Cameron <jic23@kernel.org>
*
* Licensed under the GPL-2.
*
* Based on a mashup of the hrtimer trigger and continuous sampling proposal of
* Gregor Boirie <gregor.boirie@parrot.com>
*
* Note this is still rather experimental and may eat babies.
*
* Todo
* * Protect against connection of devices that 'need' the top half
* handler.
* * Work out how to run top half handlers in this context if it is
* safe to do so (timestamp grabbing for example)
*
* Tested against a max1363. Used about 33% cpu for the thread and 20%
* for generic_buffer piping to /dev/null. Watermark set at 64 on a 128
* element kfifo buffer.
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/irq_work.h>
#include <linux/kthread.h>
#include <linux/freezer.h>
#include <linux/iio/iio.h>
#include <linux/iio/trigger.h>
#include <linux/iio/sw_trigger.h>
struct iio_loop_info {
struct iio_sw_trigger swt;
struct task_struct *task;
};
static struct config_item_type iio_loop_type = {
.ct_owner = THIS_MODULE,
};
static int iio_loop_thread(void *data)
{
struct iio_trigger *trig = data;
set_freezable();
do {
iio_trigger_poll_chained(trig);
} while (likely(!kthread_freezable_should_stop(NULL)));
return 0;
}
static int iio_loop_trigger_set_state(struct iio_trigger *trig, bool state)
{
struct iio_loop_info *loop_trig = iio_trigger_get_drvdata(trig);
if (state) {
loop_trig->task = kthread_run(iio_loop_thread,
trig, trig->name);
if (unlikely(IS_ERR(loop_trig->task))) {
dev_err(&trig->dev,
"failed to create trigger loop thread\n");
return PTR_ERR(loop_trig->task);
}
} else {
kthread_stop(loop_trig->task);
}
return 0;
}
static const struct iio_trigger_ops iio_loop_trigger_ops = {
.set_trigger_state = iio_loop_trigger_set_state,
};
static struct iio_sw_trigger *iio_trig_loop_probe(const char *name)
{
struct iio_loop_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_loop_trigger_ops;
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_loop_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_loop_remove(struct iio_sw_trigger *swt)
{
struct iio_loop_info *trig_info;
trig_info = iio_trigger_get_drvdata(swt->trigger);
iio_trigger_unregister(swt->trigger);
iio_trigger_free(swt->trigger);
kfree(trig_info);
return 0;
}
static const struct iio_sw_trigger_ops iio_trig_loop_ops = {
.probe = iio_trig_loop_probe,
.remove = iio_trig_loop_remove,
};
static struct iio_sw_trigger_type iio_trig_loop = {
.name = "loop",
.owner = THIS_MODULE,
.ops = &iio_trig_loop_ops,
};
module_iio_sw_trigger_driver(iio_trig_loop);
MODULE_AUTHOR("Jonathan Cameron <jic23@kernel.org>");
MODULE_DESCRIPTION("Loop based trigger for the iio subsystem");
MODULE_LICENSE("GPL v2");
MODULE_ALIAS("platform:iio-trig-loop");
|
