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146 lines · 3.2 KiB

1// SPDX-License-Identifier: GPL-2.0-only
2#include <linux/kernel.h>
3#include <linux/module.h>
4#include <linux/init.h>
5#include <linux/proc_fs.h>
6#include <linux/seq_file.h>
7#include <linux/slab.h>
8#include <linux/string.h>
9#include <linux/jiffies.h>
10#include <linux/timer.h>
11#include <linux/uaccess.h>
12#include <linux/sched/loadavg.h>
13
14#include <asm/auxio.h>
15
16#define LED_MAX_LENGTH 8 /* maximum chars written to proc file */
17
18static inline void led_toggle(void)
19{
20 unsigned char val = get_auxio();
21 unsigned char on, off;
22
23 if (val & AUXIO_LED) {
24 on = 0;
25 off = AUXIO_LED;
26 } else {
27 on = AUXIO_LED;
28 off = 0;
29 }
30
31 set_auxio(on, off);
32}
33
34static struct timer_list led_blink_timer;
35static unsigned long led_blink_timer_timeout;
36
37static void led_blink(struct timer_list *unused)
38{
39 unsigned long timeout = led_blink_timer_timeout;
40
41 led_toggle();
42
43 /* reschedule */
44 if (!timeout) { /* blink according to load */
45 led_blink_timer.expires = jiffies +
46 ((1 + (avenrun[0] >> FSHIFT)) * HZ);
47 } else { /* blink at user specified interval */
48 led_blink_timer.expires = jiffies + (timeout * HZ);
49 }
50 add_timer(&led_blink_timer);
51}
52
53#ifdef CONFIG_PROC_FS
54static int led_proc_show(struct seq_file *m, void *v)
55{
56 if (get_auxio() & AUXIO_LED)
57 seq_puts(m, "on\n");
58 else
59 seq_puts(m, "off\n");
60 return 0;
61}
62
63static int led_proc_open(struct inode *inode, struct file *file)
64{
65 return single_open(file, led_proc_show, NULL);
66}
67
68static ssize_t led_proc_write(struct file *file, const char __user *buffer,
69 size_t count, loff_t *ppos)
70{
71 char *buf = NULL;
72
73 if (count > LED_MAX_LENGTH)
74 count = LED_MAX_LENGTH;
75
76 buf = memdup_user_nul(buffer, count);
77 if (IS_ERR(buf))
78 return PTR_ERR(buf);
79
80 /* work around \n when echo'ing into proc */
81 if (count > 0 && buf[count - 1] == '\n')
82 buf[count - 1] = '\0';
83
84 /* before we change anything we want to stop any running timers,
85 * otherwise calls such as on will have no persistent effect
86 */
87 timer_delete_sync(&led_blink_timer);
88
89 if (!strcmp(buf, "on")) {
90 auxio_set_led(AUXIO_LED_ON);
91 } else if (!strcmp(buf, "toggle")) {
92 led_toggle();
93 } else if ((*buf > '0') && (*buf <= '9')) {
94 led_blink_timer_timeout = simple_strtoul(buf, NULL, 10);
95 led_blink(&led_blink_timer);
96 } else if (!strcmp(buf, "load")) {
97 led_blink_timer_timeout = 0;
98 led_blink(&led_blink_timer);
99 } else {
100 auxio_set_led(AUXIO_LED_OFF);
101 }
102
103 kfree(buf);
104
105 return count;
106}
107
108static const struct proc_ops led_proc_ops = {
109 .proc_open = led_proc_open,
110 .proc_read = seq_read,
111 .proc_lseek = seq_lseek,
112 .proc_release = single_release,
113 .proc_write = led_proc_write,
114};
115#endif
116
117#define LED_VERSION "0.1"
118
119static int __init led_init(void)
120{
121 timer_setup(&led_blink_timer, led_blink, 0);
122
123#ifdef CONFIG_PROC_FS
124 if (!proc_create("led", 0, NULL, &led_proc_ops))
125 return -ENOMEM;
126#endif
127 printk(KERN_INFO
128 "led: version %s, Lars Kotthoff <[email protected]>\n",
129 LED_VERSION);
130
131 return 0;
132}
133
134static void __exit led_exit(void)
135{
136 remove_proc_entry("led", NULL);
137 timer_delete_sync(&led_blink_timer);
138}
139
140module_init(led_init);
141module_exit(led_exit);
142
143MODULE_AUTHOR("Lars Kotthoff <[email protected]>");
144MODULE_DESCRIPTION("Provides control of the front LED on SPARC systems.");
145MODULE_LICENSE("GPL");
146MODULE_VERSION(LED_VERSION);