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
  12 #include <asm/auxio.h>
  13
  14 #define LED_MAX_LENGTH 8 /* maximum chars written to proc file */
  15
  16 static inline void led_toggle(void)
  17 {
  18         unsigned char val = get_auxio();
  19         unsigned char on, off;
  20
  21         if (val & AUXIO_LED) {
  22                 on = 0;
  23                 off = AUXIO_LED;
  24         } else {
  25                 on = AUXIO_LED;
  26                 off = 0;
  27         }
  28
  29         set_auxio(on, off);
  30 }
  31
  32 static struct timer_list led_blink_timer;
  33
  34 static void led_blink(unsigned long timeout)
  35 {
  36         led_toggle();
  37
  38         /* reschedule */
  39         if (!timeout) { /* blink according to load */
  40                 led_blink_timer.expires = jiffies +
  41                         ((1 + (avenrun[0] >> FSHIFT)) * HZ);
  42                 led_blink_timer.data = 0;
  43         } else { /* blink at user specified interval */
  44                 led_blink_timer.expires = jiffies + (timeout * HZ);
  45                 led_blink_timer.data = timeout;
  46         }
  47         add_timer(&led_blink_timer);
  48 }
  49
  50 static int led_proc_show(struct seq_file *m, void *v)
  51 {
  52         if (get_auxio() & AUXIO_LED)
  53                 seq_puts(m, "on\n");
  54         else
  55                 seq_puts(m, "off\n");
  56         return 0;
  57 }
  58
  59 static int led_proc_open(struct inode *inode, struct file *file)
  60 {
  61         return single_open(file, led_proc_show, NULL);
  62 }
  63
  64 static ssize_t led_proc_write(struct file *file, const char __user *buffer,
  65                               size_t count, loff_t *ppos)
  66 {
  67         char *buf = NULL;
  68
  69         if (count > LED_MAX_LENGTH)
  70                 count = LED_MAX_LENGTH;
  71
  72         buf = kmalloc(sizeof(char) * (count + 1), GFP_KERNEL);
  73         if (!buf)
  74                 return -ENOMEM;
  75
  76         if (copy_from_user(buf, buffer, count)) {
  77                 kfree(buf);
  78                 return -EFAULT;
  79         }
  80
  81         buf[count] = '\0';
  82
  83         /* work around \n when echo'ing into proc */
  84         if (buf[count - 1] == '\n')
  85                 buf[count - 1] = '\0';
  86
  87         /* before we change anything we want to stop any running timers,
  88          * otherwise calls such as on will have no persistent effect
  89          */
  90         del_timer_sync(&led_blink_timer);
  91
  92         if (!strcmp(buf, "on")) {
  93                 auxio_set_led(AUXIO_LED_ON);
  94         } else if (!strcmp(buf, "toggle")) {
  95                 led_toggle();
  96         } else if ((*buf > '0') && (*buf <= '9')) {
  97                 led_blink(simple_strtoul(buf, NULL, 10));
  98         } else if (!strcmp(buf, "load")) {
  99                 led_blink(0);
 100         } else {
 101                 auxio_set_led(AUXIO_LED_OFF);
 102         }
 103
 104         kfree(buf);
 105
 106         return count;
 107 }
 108
 109 static const struct file_operations led_proc_fops = {
 110         .owner          = THIS_MODULE,
 111         .open           = led_proc_open,
 112         .read           = seq_read,
 113         .llseek         = seq_lseek,
 114         .release        = single_release,
 115         .write          = led_proc_write,
 116 };
 117
 118 static struct proc_dir_entry *led;
 119
 120 #define LED_VERSION     "0.1"
 121
 122 static int __init led_init(void)
 123 {
 124         init_timer(&led_blink_timer);
 125         led_blink_timer.function = led_blink;
 126
 127         led = proc_create("led", 0, NULL, &led_proc_fops);
 128         if (!led)
 129                 return -ENOMEM;
 130
 131         printk(KERN_INFO
 132                "led: version %s, Lars Kotthoff <metalhead@metalhead.ws>\n",
 133                LED_VERSION);
 134
 135         return 0;
 136 }
 137
 138 static void __exit led_exit(void)
 139 {
 140         remove_proc_entry("led", NULL);
 141         del_timer_sync(&led_blink_timer);
 142 }
 143
 144 module_init(led_init);
 145 module_exit(led_exit);
 146
 147 MODULE_AUTHOR("Lars Kotthoff <metalhead@metalhead.ws>");
 148 MODULE_DESCRIPTION("Provides control of the front LED on SPARC systems.");
 149 MODULE_LICENSE("GPL");
 150 MODULE_VERSION(LED_VERSION);