arch/arm/mach-shark/leds.c

   1 /*
   2  * DIGITAL Shark LED control routines.
   3  *
   4  * Driver for the 3 user LEDs found on the Shark
   5  * Based on Versatile and RealView machine LED code
   6  *
   7  * License terms: GNU General Public License (GPL) version 2
   8  * Author: Bryan Wu <bryan.wu@canonical.com>
   9  */
  10 #include <linux/kernel.h>
  11 #include <linux/init.h>
  12 #include <linux/io.h>
  13 #include <linux/ioport.h>
  14 #include <linux/slab.h>
  15 #include <linux/leds.h>
  16
  17 #include <asm/mach-types.h>
  18
  19 #if defined(CONFIG_NEW_LEDS) && defined(CONFIG_LEDS_CLASS)
  20 struct shark_led {
  21         struct led_classdev cdev;
  22         u8 mask;
  23 };
  24
  25 /*
  26  * The triggers lines up below will only be used if the
  27  * LED triggers are compiled in.
  28  */
  29 static const struct {
  30         const char *name;
  31         const char *trigger;
  32 } shark_leds[] = {
  33         { "shark:amber0", "default-on", },      /* Bit 5 */
  34         { "shark:green", "heartbeat", },        /* Bit 6 */
  35         { "shark:amber1", "cpu0" },             /* Bit 7 */
  36 };
  37
  38 static u16 led_reg_read(void)
  39 {
  40         outw(0x09, 0x24);
  41         return inw(0x26);
  42 }
  43
  44 static void led_reg_write(u16 value)
  45 {
  46         outw(0x09, 0x24);
  47         outw(value, 0x26);
  48 }
  49
  50 static void shark_led_set(struct led_classdev *cdev,
  51                               enum led_brightness b)
  52 {
  53         struct shark_led *led = container_of(cdev,
  54                                                  struct shark_led, cdev);
  55         u16 reg = led_reg_read();
  56
  57         if (b != LED_OFF)
  58                 reg |= led->mask;
  59         else
  60                 reg &= ~led->mask;
  61
  62         led_reg_write(reg);
  63 }
  64
  65 static enum led_brightness shark_led_get(struct led_classdev *cdev)
  66 {
  67         struct shark_led *led = container_of(cdev,
  68                                                  struct shark_led, cdev);
  69         u16 reg = led_reg_read();
  70
  71         return (reg & led->mask) ? LED_FULL : LED_OFF;
  72 }
  73
  74 static int __init shark_leds_init(void)
  75 {
  76         int i;
  77         u16 reg;
  78
  79         if (!machine_is_shark())
  80                 return -ENODEV;
  81
  82         for (i = 0; i < ARRAY_SIZE(shark_leds); i++) {
  83                 struct shark_led *led;
  84
  85                 led = kzalloc(sizeof(*led), GFP_KERNEL);
  86                 if (!led)
  87                         break;
  88
  89                 led->cdev.name = shark_leds[i].name;
  90                 led->cdev.brightness_set = shark_led_set;
  91                 led->cdev.brightness_get = shark_led_get;
  92                 led->cdev.default_trigger = shark_leds[i].trigger;
  93
  94                 /* Count in 5 bits offset */
  95                 led->mask = BIT(i + 5);
  96
  97                 if (led_classdev_register(NULL, &led->cdev) < 0) {
  98                         kfree(led);
  99                         break;
 100                 }
 101         }
 102
 103         /* Make LEDs independent of power-state */
 104         request_region(0x24, 4, "led_reg");
 105         reg = led_reg_read();
 106         reg |= 1 << 10;
 107         led_reg_write(reg);
 108
 109         return 0;
 110 }
 111
 112 /*
 113  * Since we may have triggers on any subsystem, defer registration
 114  * until after subsystem_init.
 115  */
 116 fs_initcall(shark_leds_init);
 117 #endif