drivers/extcon/extcon-gpio.c

Source file repositories/reference/linux-study-clean/drivers/extcon/extcon-gpio.c

File Facts

System
Linux kernel
Corpus path
drivers/extcon/extcon-gpio.c
Extension
.c
Size
4503 bytes
Lines
166
Domain
Driver Families
Bucket
drivers/extcon
Inferred role
Driver Families: implementation source
Status
source implementation candidate

Why This File Exists

Repeatable hardware-adapter layer. Deep compatibility for every driver is out of scope; this atlas records patterns, probe lifecycles, bus glue, IRQ/DMA usage, and links back to core abstractions.

Dependency Surface

Detected Declarations

Annotated Snippet

struct gpio_extcon_data {
	struct extcon_dev *edev;
	struct delayed_work work;
	unsigned long debounce_jiffies;
	struct gpio_desc *gpiod;
	unsigned int extcon_id;
	unsigned long debounce;
	bool check_on_resume;
};

static void gpio_extcon_work(struct work_struct *work)
{
	int state;
	struct gpio_extcon_data	*data =
		container_of(to_delayed_work(work), struct gpio_extcon_data,
			     work);

	state = gpiod_get_value_cansleep(data->gpiod);
	extcon_set_state_sync(data->edev, data->extcon_id, state);
}

static irqreturn_t gpio_irq_handler(int irq, void *dev_id)
{
	struct gpio_extcon_data *data = dev_id;

	queue_delayed_work(system_power_efficient_wq, &data->work,
			      data->debounce_jiffies);
	return IRQ_HANDLED;
}

static int gpio_extcon_probe(struct platform_device *pdev)
{
	struct gpio_extcon_data *data;
	struct device *dev = &pdev->dev;
	unsigned long irq_flags;
	int irq;
	int ret;

	data = devm_kzalloc(dev, sizeof(struct gpio_extcon_data), GFP_KERNEL);
	if (!data)
		return -ENOMEM;

	/*
	 * FIXME: extcon_id represents the unique identifier of external
	 * connectors such as EXTCON_USB, EXTCON_DISP_HDMI and so on. extcon_id
	 * is necessary to register the extcon device. But, it's not yet
	 * developed to get the extcon id from device-tree or others.
	 * On later, it have to be solved.
	 */
	if (data->extcon_id > EXTCON_NONE)
		return -EINVAL;

	data->gpiod = devm_gpiod_get(dev, "extcon", GPIOD_IN);
	if (IS_ERR(data->gpiod))
		return PTR_ERR(data->gpiod);
	irq = gpiod_to_irq(data->gpiod);
	if (irq <= 0)
		return irq;

	/*
	 * It is unlikely that this is an acknowledged interrupt that goes
	 * away after handling, what we are looking for are falling edges
	 * if the signal is active low, and rising edges if the signal is
	 * active high.
	 */
	if (gpiod_is_active_low(data->gpiod))
		irq_flags = IRQF_TRIGGER_FALLING;
	else
		irq_flags = IRQF_TRIGGER_RISING;

	/* Allocate the memory of extcon devie and register extcon device */
	data->edev = devm_extcon_dev_allocate(dev, &data->extcon_id);
	if (IS_ERR(data->edev)) {
		dev_err(dev, "failed to allocate extcon device\n");
		return -ENOMEM;
	}

	ret = devm_extcon_dev_register(dev, data->edev);
	if (ret < 0)
		return ret;

	ret = devm_delayed_work_autocancel(dev, &data->work, gpio_extcon_work);
	if (ret)
		return ret;

	/*
	 * Request the interrupt of gpio to detect whether external connector
	 * is attached or detached.
	 */
	ret = devm_request_any_context_irq(dev, irq,

Annotation

Implementation Notes