leds.c

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/*
 * Driver for the 8 user LEDs found on the RealViews and Versatiles
 * Based on DaVinci's DM365 board code
 *
 * License terms: GNU General Public License (GPL) version 2
 * Author: Linus Walleij <[email protected]>
 */
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/io.h>
#include <linux/slab.h>
#include <linux/leds.h>

#include <mach/hardware.h>
#include <mach/platform.h>

#ifdef VERSATILE_SYS_BASE
#define LEDREG  (__io_address(VERSATILE_SYS_BASE) + VERSATILE_SYS_LED_OFFSET)
#endif

#ifdef REALVIEW_SYS_BASE
#define LEDREG  (__io_address(REALVIEW_SYS_BASE) + REALVIEW_SYS_LED_OFFSET)
#endif

struct versatile_led {
    struct led_classdev cdev;
    u8          mask;
};

/*
 * The triggers lines up below will only be used if the
 * LED triggers are compiled in.
 */
static const struct {
    const char *name;
    const char *trigger;
} versatile_leds[] = {
    { "versatile:0", "heartbeat", },
    { "versatile:1", "mmc0", },
    { "versatile:2", "cpu0" },
    { "versatile:3", "cpu1" },
    { "versatile:4", "cpu2" },
    { "versatile:5", "cpu3" },
    { "versatile:6", },
    { "versatile:7", },
};

static void versatile_led_set(struct led_classdev *cdev,
                  enum led_brightness b)
{
    struct versatile_led *led = container_of(cdev,
                         struct versatile_led, cdev);
    u32 reg = readl(LEDREG);

    if (b != LED_OFF)
        reg |= led->mask;
    else
        reg &= ~led->mask;
    writel(reg, LEDREG);
}

static enum led_brightness versatile_led_get(struct led_classdev *cdev)
{
    struct versatile_led *led = container_of(cdev,
                         struct versatile_led, cdev);
    u32 reg = readl(LEDREG);

    return (reg & led->mask) ? LED_FULL : LED_OFF;
}

static int __init versatile_leds_init(void)
{
    int i;

    /* All ON */
    writel(0xff, LEDREG);
    for (i = 0; i < ARRAY_SIZE(versatile_leds); i++) {
        struct versatile_led *led;

        led = kzalloc(sizeof(*led), GFP_KERNEL);
        if (!led)
            break;

        led->cdev.name = versatile_leds[i].name;
        led->cdev.brightness_set = versatile_led_set;
        led->cdev.brightness_get = versatile_led_get;
        led->cdev.default_trigger = versatile_leds[i].trigger;
        led->mask = BIT(i);

        if (led_classdev_register(NULL, &led->cdev) < 0) {
            kfree(led);
            break;
        }
    }

    return 0;
}

/*
 * Since we may have triggers on any subsystem, defer registration
 * until after subsystem_init.
 */
fs_initcall(versatile_leds_init);