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 (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 > '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 <metalhead@metalhead.ws>\n",
129	       LED_VERSION);
130
131	return 0;
132}
133
134static void __exit led_exit(void)
135{
136	remove_proc_entry("led", NULL);
137	del_timer_sync(&led_blink_timer);
138}
139
140module_init(led_init);
141module_exit(led_exit);
142
143MODULE_AUTHOR("Lars Kotthoff <metalhead@metalhead.ws>");
144MODULE_DESCRIPTION("Provides control of the front LED on SPARC systems.");
145MODULE_LICENSE("GPL");
146MODULE_VERSION(LED_VERSION);
147