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