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