arch/arm/mach-footbridge/netwinder-hw.c

Source file repositories/reference/linux-study-clean/arch/arm/mach-footbridge/netwinder-hw.c

File Facts

System
Linux kernel
Corpus path
arch/arm/mach-footbridge/netwinder-hw.c
Extension
.c
Size
14427 bytes
Lines
773
Domain
Architecture Layer
Bucket
arch/arm
Inferred role
Architecture Layer: exported/initcall integration point
Status
integration implementation candidate

Why This File Exists

CPU and platform-specific kernel glue: boot entry, traps, syscall entry, interrupts, page tables, context switch, and low-level barriers.

Dependency Surface

Detected Declarations

Annotated Snippet

struct netwinder_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;
} netwinder_leds[] = {
	{ "netwinder:green", "heartbeat", },
	{ "netwinder:red", "cpu0", },
};

/*
 * The LED control in Netwinder is reversed:
 *  - setting bit means turn off LED
 *  - clearing bit means turn on LED
 */
static void netwinder_led_set(struct led_classdev *cdev,
		enum led_brightness b)
{
	struct netwinder_led *led = container_of(cdev,
			struct netwinder_led, cdev);
	unsigned long flags;
	u32 reg;

	raw_spin_lock_irqsave(&nw_gpio_lock, flags);
	reg = nw_gpio_read();
	if (b != LED_OFF)
		reg &= ~led->mask;
	else
		reg |= led->mask;
	nw_gpio_modify_op(led->mask, reg);
	raw_spin_unlock_irqrestore(&nw_gpio_lock, flags);
}

static enum led_brightness netwinder_led_get(struct led_classdev *cdev)
{
	struct netwinder_led *led = container_of(cdev,
			struct netwinder_led, cdev);
	unsigned long flags;
	u32 reg;

	raw_spin_lock_irqsave(&nw_gpio_lock, flags);
	reg = nw_gpio_read();
	raw_spin_unlock_irqrestore(&nw_gpio_lock, flags);

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

static int __init netwinder_leds_init(void)
{
	int i;

	if (!machine_is_netwinder())
		return -ENODEV;

	for (i = 0; i < ARRAY_SIZE(netwinder_leds); i++) {
		struct netwinder_led *led;

		led = kzalloc_obj(*led);
		if (!led)
			break;

		led->cdev.name = netwinder_leds[i].name;
		led->cdev.brightness_set = netwinder_led_set;
		led->cdev.brightness_get = netwinder_led_get;
		led->cdev.default_trigger = netwinder_leds[i].trigger;

		if (i == 0)
			led->mask = GPIO_GREEN_LED;
		else
			led->mask = GPIO_RED_LED;

		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.

Annotation

Implementation Notes