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
|
// SPDX-License-Identifier: GPL-2.0
#include <linux/completion.h>
#include <linux/delay.h>
#include <linux/leds.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/tty.h>
#include <uapi/linux/serial.h>
#define LEDTRIG_TTY_INTERVAL 50
struct ledtrig_tty_data {
struct led_classdev *led_cdev;
struct delayed_work dwork;
struct completion sysfs;
const char *ttyname;
struct tty_struct *tty;
int rx, tx;
};
static int ledtrig_tty_wait_for_completion(struct device *dev)
{
struct ledtrig_tty_data *trigger_data = led_trigger_get_drvdata(dev);
int ret;
ret = wait_for_completion_timeout(&trigger_data->sysfs,
msecs_to_jiffies(LEDTRIG_TTY_INTERVAL * 20));
if (ret == 0)
return -ETIMEDOUT;
return ret;
}
static ssize_t ttyname_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
struct ledtrig_tty_data *trigger_data = led_trigger_get_drvdata(dev);
ssize_t len = 0;
int completion;
reinit_completion(&trigger_data->sysfs);
completion = ledtrig_tty_wait_for_completion(dev);
if (completion < 0)
return completion;
if (trigger_data->ttyname)
len = sprintf(buf, "%s\n", trigger_data->ttyname);
return len;
}
static ssize_t ttyname_store(struct device *dev,
struct device_attribute *attr, const char *buf,
size_t size)
{
struct ledtrig_tty_data *trigger_data = led_trigger_get_drvdata(dev);
char *ttyname;
ssize_t ret = size;
int completion;
if (size > 0 && buf[size - 1] == '\n')
size -= 1;
if (size) {
ttyname = kmemdup_nul(buf, size, GFP_KERNEL);
if (!ttyname)
return -ENOMEM;
} else {
ttyname = NULL;
}
reinit_completion(&trigger_data->sysfs);
completion = ledtrig_tty_wait_for_completion(dev);
if (completion < 0)
return completion;
kfree(trigger_data->ttyname);
tty_kref_put(trigger_data->tty);
trigger_data->tty = NULL;
trigger_data->ttyname = ttyname;
return ret;
}
static DEVICE_ATTR_RW(ttyname);
static void ledtrig_tty_work(struct work_struct *work)
{
struct ledtrig_tty_data *trigger_data =
container_of(work, struct ledtrig_tty_data, dwork.work);
struct serial_icounter_struct icount;
int ret;
if (!trigger_data->ttyname)
goto out;
/* try to get the tty corresponding to $ttyname */
if (!trigger_data->tty) {
dev_t devno;
struct tty_struct *tty;
int ret;
ret = tty_dev_name_to_number(trigger_data->ttyname, &devno);
if (ret < 0)
/*
* A device with this name might appear later, so keep
* retrying.
*/
goto out;
tty = tty_kopen_shared(devno);
if (IS_ERR(tty) || !tty)
/* What to do? retry or abort */
goto out;
trigger_data->tty = tty;
}
ret = tty_get_icount(trigger_data->tty, &icount);
if (ret)
goto out;
if (icount.rx != trigger_data->rx ||
icount.tx != trigger_data->tx) {
unsigned long interval = LEDTRIG_TTY_INTERVAL;
led_blink_set_oneshot(trigger_data->led_cdev, &interval,
&interval, 0);
trigger_data->rx = icount.rx;
trigger_data->tx = icount.tx;
}
out:
complete_all(&trigger_data->sysfs);
schedule_delayed_work(&trigger_data->dwork,
msecs_to_jiffies(LEDTRIG_TTY_INTERVAL * 2));
}
static struct attribute *ledtrig_tty_attrs[] = {
&dev_attr_ttyname.attr,
NULL
};
ATTRIBUTE_GROUPS(ledtrig_tty);
static int ledtrig_tty_activate(struct led_classdev *led_cdev)
{
struct ledtrig_tty_data *trigger_data;
trigger_data = kzalloc(sizeof(*trigger_data), GFP_KERNEL);
if (!trigger_data)
return -ENOMEM;
led_set_trigger_data(led_cdev, trigger_data);
INIT_DELAYED_WORK(&trigger_data->dwork, ledtrig_tty_work);
trigger_data->led_cdev = led_cdev;
init_completion(&trigger_data->sysfs);
schedule_delayed_work(&trigger_data->dwork, 0);
return 0;
}
static void ledtrig_tty_deactivate(struct led_classdev *led_cdev)
{
struct ledtrig_tty_data *trigger_data = led_get_trigger_data(led_cdev);
cancel_delayed_work_sync(&trigger_data->dwork);
kfree(trigger_data->ttyname);
tty_kref_put(trigger_data->tty);
trigger_data->tty = NULL;
kfree(trigger_data);
}
static struct led_trigger ledtrig_tty = {
.name = "tty",
.activate = ledtrig_tty_activate,
.deactivate = ledtrig_tty_deactivate,
.groups = ledtrig_tty_groups,
};
module_led_trigger(ledtrig_tty);
MODULE_AUTHOR("Uwe Kleine-König <u.kleine-koenig@pengutronix.de>");
MODULE_DESCRIPTION("UART LED trigger");
MODULE_LICENSE("GPL v2");
|
