leds.c

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/*
 * Driver for the 4 user LEDs found on the Integrator AP/CP baseboard
 * Based on Versatile and RealView machine LED code
 *
 * License terms: GNU General Public License (GPL) version 2
 * Author: Bryan Wu <[email protected]>
 */
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/io.h>
#include <linux/slab.h>
#include <linux/leds.h>

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

#if defined(CONFIG_NEW_LEDS) && defined(CONFIG_LEDS_CLASS)

#define ALPHA_REG __io_address(INTEGRATOR_DBG_BASE)
#define LEDREG  (__io_address(INTEGRATOR_DBG_BASE) + INTEGRATOR_DBG_LEDS_OFFSET)

struct integrator_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;
} integrator_leds[] = {
    { "integrator:green0", "heartbeat", },
    { "integrator:yellow", },
    { "integrator:red", },
    { "integrator:green1", },
    { "integrator:core_module", "cpu0", },
};

static void integrator_led_set(struct led_classdev *cdev,
                  enum led_brightness b)
{
    struct integrator_led *led = container_of(cdev,
                         struct integrator_led, cdev);
    u32 reg = __raw_readl(LEDREG);

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

    while (__raw_readl(ALPHA_REG) & 1)
        cpu_relax();

    __raw_writel(reg, LEDREG);
}

static enum led_brightness integrator_led_get(struct led_classdev *cdev)
{
    struct integrator_led *led = container_of(cdev,
                         struct integrator_led, cdev);
    u32 reg = __raw_readl(LEDREG);

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

static void cm_led_set(struct led_classdev *cdev,
                  enum led_brightness b)
{
    if (b != LED_OFF)
        cm_control(CM_CTRL_LED, CM_CTRL_LED);
    else
        cm_control(CM_CTRL_LED, 0);
}

static enum led_brightness cm_led_get(struct led_classdev *cdev)
{
    u32 reg = readl(CM_CTRL);

    return (reg & CM_CTRL_LED) ? LED_FULL : LED_OFF;
}

static int __init integrator_leds_init(void)
{
    int i;

    for (i = 0; i < ARRAY_SIZE(integrator_leds); i++) {
        struct integrator_led *led;

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


        led->cdev.name = integrator_leds[i].name;

        if (i == 4) { /* Setting for LED in core module */
            led->cdev.brightness_set = cm_led_set;
            led->cdev.brightness_get = cm_led_get;
        } else {
            led->cdev.brightness_set = integrator_led_set;
            led->cdev.brightness_get = integrator_led_get;
        }

        led->cdev.default_trigger = integrator_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(integrator_leds_init);
#endif