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
  35 static void led_blink(unsigned long timeout)
  36 {
  37         led_toggle();
  38
  39         /* reschedule */
  40         if (!timeout) { /* blink according to load */
  41                 led_blink_timer.expires = jiffies +
  42                         ((1 + (avenrun[0] >> FSHIFT)) * HZ);
  43                 led_blink_timer.data = 0;
  44         } else { /* blink at user specified interval */
  45                 led_blink_timer.expires = jiffies + (timeout * HZ);
  46                 led_blink_timer.data = timeout;
  47         }
  48         add_timer(&led_blink_timer);
  49 }
  50
  51 static int led_proc_show(struct seq_file *m, void *v)
  52 {
  53         if (get_auxio() & AUXIO_LED)
  54                 seq_puts(m, "on\n");
  55         else
  56                 seq_puts(m, "off\n");
  57         return 0;
  58 }
  59
  60 static int led_proc_open(struct inode *inode, struct file *file)
  61 {
  62         return single_open(file, led_proc_show, NULL);
  63 }
  64
  65 static ssize_t led_proc_write(struct file *file, const char __user *buffer,
  66                               size_t count, loff_t *ppos)
  67 {
  68         char *buf = NULL;
  69
  70         if (count > LED_MAX_LENGTH)
  71                 count = LED_MAX_LENGTH;
  72
  73         buf = memdup_user_nul(buffer, count);
  74         if (IS_ERR(buf))
  75                 return PTR_ERR(buf);
  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 const struct file_operations led_proc_fops = {
 104         .owner          = THIS_MODULE,
 105         .open           = led_proc_open,
 106         .read           = seq_read,
 107         .llseek         = seq_lseek,
 108         .release        = single_release,
 109         .write          = led_proc_write,
 110 };
 111
 112 static struct proc_dir_entry *led;
 113
 114 #define LED_VERSION     "0.1"
 115
 116 static int __init led_init(void)
 117 {
 118         init_timer(&led_blink_timer);
 119         led_blink_timer.function = led_blink;
 120
 121         led = proc_create("led", 0, NULL, &led_proc_fops);
 122         if (!led)
 123                 return -ENOMEM;
 124
 125         printk(KERN_INFO
 126                "led: version %s, Lars Kotthoff <metalhead@metalhead.ws>\n",
 127                LED_VERSION);
 128
 129         return 0;
 130 }
 131
 132 static void __exit led_exit(void)
 133 {
 134         remove_proc_entry("led", NULL);
 135         del_timer_sync(&led_blink_timer);
 136 }
 137
 138 module_init(led_init);
 139 module_exit(led_exit);
 140
 141 MODULE_AUTHOR("Lars Kotthoff <metalhead@metalhead.ws>");
 142 MODULE_DESCRIPTION("Provides control of the front LED on SPARC systems.");
 143 MODULE_LICENSE("GPL");
 144 MODULE_VERSION(LED_VERSION);