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/string.h>
   6
   7#include <asm/auxio.h>
   8
   9#define LED_MAX_LENGTH 8 /* maximum chars written to proc file */
  10
  11static inline void led_toggle(void)
  12{
  13        unsigned char val = get_auxio();
  14        unsigned char on, off;
  15
  16        if (val & AUXIO_LED) {
  17                on = 0;
  18                off = AUXIO_LED;
  19        } else {
  20                on = AUXIO_LED;
  21                off = 0;
  22        }
  23
  24        set_auxio(on, off);
  25}
  26
  27static struct timer_list led_blink_timer;
  28
  29static void led_blink(unsigned long timeout)
  30{
  31        led_toggle();
  32
  33        /* reschedule */
  34        if (!timeout) { /* blink according to load */
  35                led_blink_timer.expires = jiffies +
  36                        ((1 + (avenrun[0] >> FSHIFT)) * HZ);
  37                led_blink_timer.data = 0;
  38        } else { /* blink at user specified interval */
  39                led_blink_timer.expires = jiffies + (timeout * HZ);
  40                led_blink_timer.data = timeout;
  41        }
  42        add_timer(&led_blink_timer);
  43}
  44
  45static int led_read_proc(char *buf, char **start, off_t offset, int count,
  46                         int *eof, void *data)
  47{
  48        int len = 0;
  49
  50        if (get_auxio() & AUXIO_LED)
  51                len = sprintf(buf, "on\n");
  52        else
  53                len = sprintf(buf, "off\n");
  54
  55        return len;
  56}
  57
  58static int led_write_proc(struct file *file, const char __user *buffer,
  59                          unsigned long count, void *data)
  60{
  61        char *buf = NULL;
  62
  63        if (count > LED_MAX_LENGTH)
  64                count = LED_MAX_LENGTH;
  65
  66        buf = kmalloc(sizeof(char) * (count + 1), GFP_KERNEL);
  67        if (!buf)
  68                return -ENOMEM;
  69
  70        if (copy_from_user(buf, buffer, count)) {
  71                kfree(buf);
  72                return -EFAULT;
  73        }
  74
  75        buf[count] = '\0';
  76
  77        /* work around \n when echo'ing into proc */
  78        if (buf[count - 1] == '\n')
  79                buf[count - 1] = '\0';
  80
  81        /* before we change anything we want to stop any running timers,
  82         * otherwise calls such as on will have no persistent effect
  83         */
  84        del_timer_sync(&led_blink_timer);
  85
  86        if (!strcmp(buf, "on")) {
  87                auxio_set_led(AUXIO_LED_ON);
  88        } else if (!strcmp(buf, "toggle")) {
  89                led_toggle();
  90        } else if ((*buf > '0') && (*buf <= '9')) {
  91                led_blink(simple_strtoul(buf, NULL, 10));
  92        } else if (!strcmp(buf, "load")) {
  93                led_blink(0);
  94        } else {
  95                auxio_set_led(AUXIO_LED_OFF);
  96        }
  97
  98        kfree(buf);
  99
 100        return count;
 101}
 102
 103static struct proc_dir_entry *led;
 104
 105#define LED_VERSION     "0.1"
 106
 107static int __init led_init(void)
 108{
 109        init_timer(&led_blink_timer);
 110        led_blink_timer.function = led_blink;
 111
 112        led = create_proc_entry("led", 0, NULL);
 113        if (!led)
 114                return -ENOMEM;
 115
 116        led->read_proc = led_read_proc; /* reader function */
 117        led->write_proc = led_write_proc; /* writer function */
 118        led->owner = THIS_MODULE;
 119
 120        printk(KERN_INFO
 121               "led: version %s, Lars Kotthoff <metalhead@metalhead.ws>\n",
 122               LED_VERSION);
 123
 124        return 0;
 125}
 126
 127static void __exit led_exit(void)
 128{
 129        remove_proc_entry("led", NULL);
 130        del_timer_sync(&led_blink_timer);
 131}
 132
 133module_init(led_init);
 134module_exit(led_exit);
 135
 136MODULE_AUTHOR("Lars Kotthoff <metalhead@metalhead.ws>");
 137MODULE_DESCRIPTION("Provides control of the front LED on SPARC systems.");
 138MODULE_LICENSE("GPL");
 139MODULE_VERSION(LED_VERSION);
 140