arch/arm/plat-versatile/leds.c

   1 /*
   2  * Driver for the 8 user LEDs found on the RealViews and Versatiles
   3  * Based on DaVinci's DM365 board code
   4  *
   5  * License terms: GNU General Public License (GPL) version 2
   6  * Author: Linus Walleij <triad@df.lth.se>
   7  */
   8 #include <linux/kernel.h>
   9 #include <linux/init.h>
  10 #include <linux/io.h>
  11 #include <linux/slab.h>
  12 #include <linux/leds.h>
  13
  14 #include <mach/hardware.h>
  15 #include <mach/platform.h>
  16
  17 #ifdef VERSATILE_SYS_BASE
  18 #define LEDREG  (__io_address(VERSATILE_SYS_BASE) + VERSATILE_SYS_LED_OFFSET)
  19 #endif
  20
  21 #ifdef REALVIEW_SYS_BASE
  22 #define LEDREG  (__io_address(REALVIEW_SYS_BASE) + REALVIEW_SYS_LED_OFFSET)
  23 #endif
  24
  25 struct versatile_led {
  26         struct led_classdev     cdev;
  27         u8                      mask;
  28 };
  29
  30 /*
  31  * The triggers lines up below will only be used if the
  32  * LED triggers are compiled in.
  33  */
  34 static const struct {
  35         const char *name;
  36         const char *trigger;
  37 } versatile_leds[] = {
  38         { "versatile:0", "heartbeat", },
  39         { "versatile:1", "mmc0", },
  40         { "versatile:2", },
  41         { "versatile:3", },
  42         { "versatile:4", },
  43         { "versatile:5", },
  44         { "versatile:6", },
  45         { "versatile:7", },
  46 };
  47
  48 static void versatile_led_set(struct led_classdev *cdev,
  49                               enum led_brightness b)
  50 {
  51         struct versatile_led *led = container_of(cdev,
  52                                                  struct versatile_led, cdev);
  53         u32 reg = readl(LEDREG);
  54
  55         if (b != LED_OFF)
  56                 reg |= led->mask;
  57         else
  58                 reg &= ~led->mask;
  59         writel(reg, LEDREG);
  60 }
  61
  62 static enum led_brightness versatile_led_get(struct led_classdev *cdev)
  63 {
  64         struct versatile_led *led = container_of(cdev,
  65                                                  struct versatile_led, cdev);
  66         u32 reg = readl(LEDREG);
  67
  68         return (reg & led->mask) ? LED_FULL : LED_OFF;
  69 }
  70
  71 static int __init versatile_leds_init(void)
  72 {
  73         int i;
  74
  75         /* All ON */
  76         writel(0xff, LEDREG);
  77         for (i = 0; i < ARRAY_SIZE(versatile_leds); i++) {
  78                 struct versatile_led *led;
  79
  80                 led = kzalloc(sizeof(*led), GFP_KERNEL);
  81                 if (!led)
  82                         break;
  83
  84                 led->cdev.name = versatile_leds[i].name;
  85                 led->cdev.brightness_set = versatile_led_set;
  86                 led->cdev.brightness_get = versatile_led_get;
  87                 led->cdev.default_trigger = versatile_leds[i].trigger;
  88                 led->mask = BIT(i);
  89
  90                 if (led_classdev_register(NULL, &led->cdev) < 0) {
  91                         kfree(led);
  92                         break;
  93                 }
  94         }
  95
  96         return 0;
  97 }
  98
  99 /*
 100  * Since we may have triggers on any subsystem, defer registration
 101  * until after subsystem_init.
 102  */
 103 fs_initcall(versatile_leds_init);