linux_kernel/arch/arm/mach-integrator/leds.c

/*
 * 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 <bryan.wu@canonical.com>
 */
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/io.h>
#include <linux/slab.h>
#include <linux/leds.h>

#include "hardware.h"
#include "cm.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 = cm_get();

	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