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 #include <linux/jiffies.h>
   7 #include <linux/timer.h>
   8 #include <linux/uaccess.h>
   9
  10 #include <asm/auxio.h>
  11
  12 #define LED_MAX_LENGTH 8 /* maximum chars written to proc file */
  13
  14 static inline void led_toggle(void)
  15 {
  16         unsigned char val = get_auxio();
  17         unsigned char on, off;
  18
  19         if (val & AUXIO_LED) {
  20                 on = 0;
  21                 off = AUXIO_LED;
  22         } else {
  23                 on = AUXIO_LED;
  24                 off = 0;
  25         }
  26
  27         set_auxio(on, off);
  28 }
  29
  30 static struct timer_list led_blink_timer;
  31
  32 static void led_blink(unsigned long timeout)
  33 {
  34         led_toggle();
  35
  36         /* reschedule */
  37         if (!timeout) { /* blink according to load */
  38                 led_blink_timer.expires = jiffies +
  39                         ((1 + (avenrun[0] >> FSHIFT)) * HZ);
  40                 led_blink_timer.data = 0;
  41         } else { /* blink at user specified interval */
  42                 led_blink_timer.expires = jiffies + (timeout * HZ);
  43                 led_blink_timer.data = timeout;
  44         }
  45         add_timer(&led_blink_timer);
  46 }
  47
  48 static int led_read_proc(char *buf, char **start, off_t offset, int count,
  49                          int *eof, void *data)
  50 {
  51         int len = 0;
  52
  53         if (get_auxio() & AUXIO_LED)
  54                 len = sprintf(buf, "on\n");
  55         else
  56                 len = sprintf(buf, "off\n");
  57
  58         return len;
  59 }
  60
  61 static int led_write_proc(struct file *file, const char __user *buffer,
  62                           unsigned long count, void *data)
  63 {
  64         char *buf = NULL;
  65
  66         if (count > LED_MAX_LENGTH)
  67                 count = LED_MAX_LENGTH;
  68
  69         buf = kmalloc(sizeof(char) * (count + 1), GFP_KERNEL);
  70         if (!buf)
  71                 return -ENOMEM;
  72
  73         if (copy_from_user(buf, buffer, count)) {
  74                 kfree(buf);
  75                 return -EFAULT;
  76         }
  77
  78         buf[count] = '\0';
  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(simple_strtoul(buf, NULL, 10));
  95         } else if (!strcmp(buf, "load")) {
  96                 led_blink(0);
  97         } else {
  98                 auxio_set_led(AUXIO_LED_OFF);
  99         }
 100
 101         kfree(buf);
 102
 103         return count;
 104 }
 105
 106 static struct proc_dir_entry *led;
 107
 108 #define LED_VERSION     "0.1"
 109
 110 static int __init led_init(void)
 111 {
 112         init_timer(&led_blink_timer);
 113         led_blink_timer.function = led_blink;
 114
 115         led = create_proc_entry("led", 0, NULL);
 116         if (!led)
 117                 return -ENOMEM;
 118
 119         led->read_proc = led_read_proc; /* reader function */
 120         led->write_proc = led_write_proc; /* writer function */
 121         led->owner = THIS_MODULE;
 122
 123         printk(KERN_INFO
 124                "led: version %s, Lars Kotthoff <metalhead@metalhead.ws>\n",
 125                LED_VERSION);
 126
 127         return 0;
 128 }
 129
 130 static void __exit led_exit(void)
 131 {
 132         remove_proc_entry("led", NULL);
 133         del_timer_sync(&led_blink_timer);
 134 }
 135
 136 module_init(led_init);
 137 module_exit(led_exit);
 138
 139 MODULE_AUTHOR("Lars Kotthoff <metalhead@metalhead.ws>");
 140 MODULE_DESCRIPTION("Provides control of the front LED on SPARC systems.");
 141 MODULE_LICENSE("GPL");
 142 MODULE_VERSION(LED_VERSION);