summaryrefslogtreecommitdiff
path: root/arch/sparc/kernel/led.c
blob: a6292f8ed18024d542612d447a65967ccfe61ef6 (plain)
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
// SPDX-License-Identifier: GPL-2.0-only
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <linux/jiffies.h>
#include <linux/timer.h>
#include <linux/uaccess.h>
#include <linux/sched/loadavg.h>

#include <asm/auxio.h>

#define LED_MAX_LENGTH 8 /* maximum chars written to proc file */

static inline void led_toggle(void)
{
	unsigned char val = get_auxio();
	unsigned char on, off;

	if (val & AUXIO_LED) {
		on = 0;
		off = AUXIO_LED;
	} else {
		on = AUXIO_LED;
		off = 0;
	}

	set_auxio(on, off);
}

static struct timer_list led_blink_timer;
static unsigned long led_blink_timer_timeout;

static void led_blink(struct timer_list *unused)
{
	unsigned long timeout = led_blink_timer_timeout;

	led_toggle();

	/* reschedule */
	if (!timeout) { /* blink according to load */
		led_blink_timer.expires = jiffies +
			((1 + (avenrun[0] >> FSHIFT)) * HZ);
	} else { /* blink at user specified interval */
		led_blink_timer.expires = jiffies + (timeout * HZ);
	}
	add_timer(&led_blink_timer);
}

static int led_proc_show(struct seq_file *m, void *v)
{
	if (get_auxio() & AUXIO_LED)
		seq_puts(m, "on\n");
	else
		seq_puts(m, "off\n");
	return 0;
}

static int led_proc_open(struct inode *inode, struct file *file)
{
	return single_open(file, led_proc_show, NULL);
}

static ssize_t led_proc_write(struct file *file, const char __user *buffer,
			      size_t count, loff_t *ppos)
{
	char *buf = NULL;

	if (count > LED_MAX_LENGTH)
		count = LED_MAX_LENGTH;

	buf = memdup_user_nul(buffer, count);
	if (IS_ERR(buf))
		return PTR_ERR(buf);

	/* work around \n when echo'ing into proc */
	if (buf[count - 1] == '\n')
		buf[count - 1] = '\0';

	/* before we change anything we want to stop any running timers,
	 * otherwise calls such as on will have no persistent effect
	 */
	del_timer_sync(&led_blink_timer);

	if (!strcmp(buf, "on")) {
		auxio_set_led(AUXIO_LED_ON);
	} else if (!strcmp(buf, "toggle")) {
		led_toggle();
	} else if ((*buf > '0') && (*buf <= '9')) {
		led_blink_timer_timeout = simple_strtoul(buf, NULL, 10);
		led_blink(&led_blink_timer);
	} else if (!strcmp(buf, "load")) {
		led_blink_timer_timeout = 0;
		led_blink(&led_blink_timer);
	} else {
		auxio_set_led(AUXIO_LED_OFF);
	}

	kfree(buf);

	return count;
}

static const struct file_operations led_proc_fops = {
	.owner		= THIS_MODULE,
	.open		= led_proc_open,
	.read		= seq_read,
	.llseek		= seq_lseek,
	.release	= single_release,
	.write		= led_proc_write,
};

static struct proc_dir_entry *led;

#define LED_VERSION	"0.1"

static int __init led_init(void)
{
	timer_setup(&led_blink_timer, led_blink, 0);

	led = proc_create("led", 0, NULL, &led_proc_fops);
	if (!led)
		return -ENOMEM;

	printk(KERN_INFO
	       "led: version %s, Lars Kotthoff <metalhead@metalhead.ws>\n",
	       LED_VERSION);

	return 0;
}

static void __exit led_exit(void)
{
	remove_proc_entry("led", NULL);
	del_timer_sync(&led_blink_timer);
}

module_init(led_init);
module_exit(led_exit);

MODULE_AUTHOR("Lars Kotthoff <metalhead@metalhead.ws>");
MODULE_DESCRIPTION("Provides control of the front LED on SPARC systems.");
MODULE_LICENSE("GPL");
MODULE_VERSION(LED_VERSION);