leds.c

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/*
 * DIGITAL Shark LED control routines.
 *
 * Driver for the 3 user LEDs found on the Shark
 * 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/ioport.h>
#include <linux/slab.h>
#include <linux/leds.h>

#include <asm/mach-types.h>

#if defined(CONFIG_NEW_LEDS) && defined(CONFIG_LEDS_CLASS)
struct shark_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;
} shark_leds[] = {
    { "shark:amber0", "default-on", },  /* Bit 5 */
    { "shark:green", "heartbeat", },    /* Bit 6 */
    { "shark:amber1", "cpu0" },     /* Bit 7 */
};

static u16 led_reg_read(void)
{
    outw(0x09, 0x24);
    return inw(0x26);
}

static void led_reg_write(u16 value)
{
    outw(0x09, 0x24);
    outw(value, 0x26);
}

static void shark_led_set(struct led_classdev *cdev,
                  enum led_brightness b)
{
    struct shark_led *led = container_of(cdev,
                         struct shark_led, cdev);
    u16 reg = led_reg_read();

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

    led_reg_write(reg);
}

static enum led_brightness shark_led_get(struct led_classdev *cdev)
{
    struct shark_led *led = container_of(cdev,
                         struct shark_led, cdev);
    u16 reg = led_reg_read();

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

static int __init shark_leds_init(void)
{
    int i;
    u16 reg;

    if (!machine_is_shark())
        return -ENODEV;

    for (i = 0; i < ARRAY_SIZE(shark_leds); i++) {
        struct shark_led *led;

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

        led->cdev.name = shark_leds[i].name;
        led->cdev.brightness_set = shark_led_set;
        led->cdev.brightness_get = shark_led_get;
        led->cdev.default_trigger = shark_leds[i].trigger;

        /* Count in 5 bits offset */
        led->mask = BIT(i + 5);

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

    /* Make LEDs independent of power-state */
    request_region(0x24, 4, "led_reg");
    reg = led_reg_read();
    reg |= 1 << 10;
    led_reg_write(reg);

    return 0;
}

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