summaryrefslogtreecommitdiff
path: root/arch/sparc/kernel/led.c
blob: 59e9344e7a0da2f5f0ccc8f4586e3ef89a85debe (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
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/proc_fs.h>
#include <linux/string.h>
#include <linux/jiffies.h>
#include <linux/timer.h>
#include <linux/uaccess.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 void led_blink(unsigned long timeout)
{
	led_toggle();

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

static int led_read_proc(char *buf, char **start, off_t offset, int count,
			 int *eof, void *data)
{
	int len = 0;

	if (get_auxio() & AUXIO_LED)
		len = sprintf(buf, "on\n");
	else
		len = sprintf(buf, "off\n");

	return len;
}

static int led_write_proc(struct file *file, const char __user *buffer,
			  unsigned long count, void *data)
{
	char *buf = NULL;

	if (count > LED_MAX_LENGTH)
		count = LED_MAX_LENGTH;

	buf = kmalloc(sizeof(char) * (count + 1), GFP_KERNEL);
	if (!buf)
		return -ENOMEM;

	if (copy_from_user(buf, buffer, count)) {
		kfree(buf);
		return -EFAULT;
	}

	buf[count] = '\0';

	/* 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(simple_strtoul(buf, NULL, 10));
	} else if (!strcmp(buf, "load")) {
		led_blink(0);
	} else {
		auxio_set_led(AUXIO_LED_OFF);
	}

	kfree(buf);

	return count;
}

static struct proc_dir_entry *led;

#define LED_VERSION	"0.1"

static int __init led_init(void)
{
	init_timer(&led_blink_timer);
	led_blink_timer.function = led_blink;

	led = create_proc_entry("led", 0, NULL);
	if (!led)
		return -ENOMEM;

	led->read_proc = led_read_proc; /* reader function */
	led->write_proc = led_write_proc; /* writer function */
	led->owner = THIS_MODULE;

	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);