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
18 static 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
34 static struct timer_list led_blink_timer;
35 static unsigned long led_blink_timer_timeout;
36
37 static 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
54 static 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
63 static int led_proc_open(struct inode *inode, struct file *file)
64 {
65 return single_open(file, led_proc_show, NULL);
66 }
67
68 static 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 (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 del_timer_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 > '') && (*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
108 static 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
119 static 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 <metalhead@metalhead.ws>\n",
129 LED_VERSION);
130
131 return 0;
132 }
133
134 static void __exit led_exit(void)
135 {
136 remove_proc_entry("led", NULL);
137 del_timer_sync(&led_blink_timer);
138 }
139
140 module_init(led_init);
141 module_exit(led_exit);
142
143 MODULE_AUTHOR("Lars Kotthoff <metalhead@metalhead.ws>");
144 MODULE_DESCRIPTION("Provides control of the front LED on SPARC systems.");
145 MODULE_LICENSE("GPL");
146 MODULE_VERSION(LED_VERSION);
147
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