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
  11 static 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
  27 static struct timer_list led_blink_timer;
  28
  29 static 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
  45 static 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
  58 static 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
 103 static struct proc_dir_entry *led;
 104
 105 #define LED_VERSION     "0.1"
 106
 107 static 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
 127 static void __exit led_exit(void)
 128 {
 129         remove_proc_entry("led", NULL);
 130         del_timer_sync(&led_blink_timer);
 131 }
 132
 133 module_init(led_init);
 134 module_exit(led_exit);
 135
 136 MODULE_AUTHOR("Lars Kotthoff <metalhead@metalhead.ws>");
 137 MODULE_DESCRIPTION("Provides control of the front LED on SPARC systems.");
 138 MODULE_LICENSE("GPL");
 139 MODULE_VERSION(LED_VERSION);