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

   1#include <linux/kernel.h>
   2#include <linux/module.h>
   3#include <linux/init.h>
   4#include <linux/proc_fs.h>
   5#include <linux/seq_file.h>
   6#include <linux/slab.h>
   7#include <linux/string.h>
   8#include <linux/jiffies.h>
   9#include <linux/timer.h>
  10#include <linux/uaccess.h>
  11#include <linux/sched/loadavg.h>
  12
  13#include <asm/auxio.h>
  14
  15#define LED_MAX_LENGTH 8 /* maximum chars written to proc file */
  16
  17static inline void led_toggle(void)
  18{
  19        unsigned char val = get_auxio();
  20        unsigned char on, off;
  21
  22        if (val & AUXIO_LED) {
  23                on = 0;
  24                off = AUXIO_LED;
  25        } else {
  26                on = AUXIO_LED;
  27                off = 0;
  28        }
  29
  30        set_auxio(on, off);
  31}
  32
  33static struct timer_list led_blink_timer;
  34static unsigned long led_blink_timer_timeout;
  35
  36static void led_blink(struct timer_list *unused)
  37{
  38        unsigned long timeout = led_blink_timer_timeout;
  39
  40        led_toggle();
  41
  42        /* reschedule */
  43        if (!timeout) { /* blink according to load */
  44                led_blink_timer.expires = jiffies +
  45                        ((1 + (avenrun[0] >> FSHIFT)) * HZ);
  46        } else { /* blink at user specified interval */
  47                led_blink_timer.expires = jiffies + (timeout * HZ);
  48        }
  49        add_timer(&led_blink_timer);
  50}
  51
  52static int led_proc_show(struct seq_file *m, void *v)
  53{
  54        if (get_auxio() & AUXIO_LED)
  55                seq_puts(m, "on\n");
  56        else
  57                seq_puts(m, "off\n");
  58        return 0;
  59}
  60
  61static int led_proc_open(struct inode *inode, struct file *file)
  62{
  63        return single_open(file, led_proc_show, NULL);
  64}
  65
  66static ssize_t led_proc_write(struct file *file, const char __user *buffer,
  67                              size_t count, loff_t *ppos)
  68{
  69        char *buf = NULL;
  70
  71        if (count > LED_MAX_LENGTH)
  72                count = LED_MAX_LENGTH;
  73
  74        buf = memdup_user_nul(buffer, count);
  75        if (IS_ERR(buf))
  76                return PTR_ERR(buf);
  77
  78        /* work around \n when echo'ing into proc */
  79        if (buf[count - 1] == '\n')
  80                buf[count - 1] = '\0';
  81
  82        /* before we change anything we want to stop any running timers,
  83         * otherwise calls such as on will have no persistent effect
  84         */
  85        del_timer_sync(&led_blink_timer);
  86
  87        if (!strcmp(buf, "on")) {
  88                auxio_set_led(AUXIO_LED_ON);
  89        } else if (!strcmp(buf, "toggle")) {
  90                led_toggle();
  91        } else if ((*buf > '0') && (*buf <= '9')) {
  92                led_blink_timer_timeout = simple_strtoul(buf, NULL, 10);
  93                led_blink(&led_blink_timer);
  94        } else if (!strcmp(buf, "load")) {
  95                led_blink_timer_timeout = 0;
  96                led_blink(&led_blink_timer);
  97        } else {
  98                auxio_set_led(AUXIO_LED_OFF);
  99        }
 100
 101        kfree(buf);
 102
 103        return count;
 104}
 105
 106static const struct file_operations led_proc_fops = {
 107        .owner          = THIS_MODULE,
 108        .open           = led_proc_open,
 109        .read           = seq_read,
 110        .llseek         = seq_lseek,
 111        .release        = single_release,
 112        .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_fops);
 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