LXR linux/arch/sparc/kernel/led.c

   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
  53static int led_proc_show(struct seq_file *m, void *v)
  54{
  55        if (get_auxio() & AUXIO_LED)
  56                seq_puts(m, "on\n");
  57        else
  58                seq_puts(m, "off\n");
  59        return 0;
  60}
  61
  62static int led_proc_open(struct inode *inode, struct file *file)
  63{
  64        return single_open(file, led_proc_show, NULL);
  65}
  66
  67static ssize_t led_proc_write(struct file *file, const char __user *buffer,
  68                              size_t count, loff_t *ppos)
  69{
  70        char *buf = NULL;
  71
  72        if (count > LED_MAX_LENGTH)
  73                count = LED_MAX_LENGTH;
  74
  75        buf = memdup_user_nul(buffer, count);
  76        if (IS_ERR(buf))
  77                return PTR_ERR(buf);
  78
  79        /* work around \n when echo'ing into proc */
  80        if (buf[count - 1] == '\n')
  81                buf[count - 1] = '\0';
  82
  83        /* before we change anything we want to stop any running timers,
  84         * otherwise calls such as on will have no persistent effect
  85         */
  86        del_timer_sync(&led_blink_timer);
  87
  88        if (!strcmp(buf, "on")) {
  89                auxio_set_led(AUXIO_LED_ON);
  90        } else if (!strcmp(buf, "toggle")) {
  91                led_toggle();
  92        } else if ((*buf > '0') && (*buf <= '9')) {
  93                led_blink_timer_timeout = simple_strtoul(buf, NULL, 10);
  94                led_blink(&led_blink_timer);
  95        } else if (!strcmp(buf, "load")) {
  96                led_blink_timer_timeout = 0;
  97                led_blink(&led_blink_timer);
  98        } else {
  99                auxio_set_led(AUXIO_LED_OFF);
 100        }
 101
 102        kfree(buf);
 103
 104        return count;
 105}
 106
 107static const struct proc_ops led_proc_ops = {
 108        .proc_open      = led_proc_open,
 109        .proc_read      = seq_read,
 110        .proc_lseek     = seq_lseek,
 111        .proc_release   = single_release,
 112        .proc_write     = led_proc_write,
 113};
 114
 115static struct proc_dir_entry *led;
 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        led = proc_create("led", 0, NULL, &led_proc_ops);
 124        if (!led)
 125                return -ENOMEM;
 126
 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