drivers/extcon/extcon-max3355.c

Source file repositories/reference/linux-study-clean/drivers/extcon/extcon-max3355.c

File Facts

System
Linux kernel
Corpus path
drivers/extcon/extcon-max3355.c
Extension
.c
Size
3569 bytes
Lines
142
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 max3355_data {
	struct extcon_dev *edev;
	struct gpio_desc *id_gpiod;
	struct gpio_desc *shdn_gpiod;
};

static const unsigned int max3355_cable[] = {
	EXTCON_USB,
	EXTCON_USB_HOST,
	EXTCON_NONE,
};

static irqreturn_t max3355_id_irq(int irq, void *dev_id)
{
	struct max3355_data *data = dev_id;
	int id = gpiod_get_value_cansleep(data->id_gpiod);

	if (id) {
		/*
		 * ID = 1 means USB HOST cable detached.
		 * As we don't have event for USB peripheral cable attached,
		 * we simulate USB peripheral attach here.
		 */
		extcon_set_state_sync(data->edev, EXTCON_USB_HOST, false);
		extcon_set_state_sync(data->edev, EXTCON_USB, true);
	} else {
		/*
		 * ID = 0 means USB HOST cable attached.
		 * As we don't have event for USB peripheral cable detached,
		 * we simulate USB peripheral detach here.
		 */
		extcon_set_state_sync(data->edev, EXTCON_USB, false);
		extcon_set_state_sync(data->edev, EXTCON_USB_HOST, true);
	}

	return IRQ_HANDLED;
}

static int max3355_probe(struct platform_device *pdev)
{
	struct max3355_data *data;
	struct gpio_desc *gpiod;
	int irq, err;

	data = devm_kzalloc(&pdev->dev, sizeof(struct max3355_data),
			    GFP_KERNEL);
	if (!data)
		return -ENOMEM;

	gpiod = devm_gpiod_get(&pdev->dev, "id", GPIOD_IN);
	if (IS_ERR(gpiod)) {
		dev_err(&pdev->dev, "failed to get ID_OUT GPIO\n");
		return PTR_ERR(gpiod);
	}
	data->id_gpiod = gpiod;

	gpiod = devm_gpiod_get(&pdev->dev, "maxim,shdn", GPIOD_OUT_HIGH);
	if (IS_ERR(gpiod)) {
		dev_err(&pdev->dev, "failed to get SHDN# GPIO\n");
		return PTR_ERR(gpiod);
	}
	data->shdn_gpiod = gpiod;

	data->edev = devm_extcon_dev_allocate(&pdev->dev, max3355_cable);
	if (IS_ERR(data->edev)) {
		dev_err(&pdev->dev, "failed to allocate extcon device\n");
		return PTR_ERR(data->edev);
	}

	err = devm_extcon_dev_register(&pdev->dev, data->edev);
	if (err < 0) {
		dev_err(&pdev->dev, "failed to register extcon device\n");
		return err;
	}

	irq = gpiod_to_irq(data->id_gpiod);
	if (irq < 0) {
		dev_err(&pdev->dev, "failed to translate ID_OUT GPIO to IRQ\n");
		return irq;
	}

	err = devm_request_threaded_irq(&pdev->dev, irq, NULL, max3355_id_irq,
					IRQF_ONESHOT | IRQF_NO_SUSPEND |
					IRQF_TRIGGER_RISING |
					IRQF_TRIGGER_FALLING,
					pdev->name, data);
	if (err < 0) {
		dev_err(&pdev->dev, "failed to request ID_OUT IRQ\n");
		return err;
	}

Annotation

Implementation Notes