drivers/input/misc/cpcap-pwrbutton.c

Source file repositories/reference/linux-study-clean/drivers/input/misc/cpcap-pwrbutton.c

File Facts

System
Linux kernel
Corpus path
drivers/input/misc/cpcap-pwrbutton.c
Extension
.c
Size
2677 bytes
Lines
113
Domain
Driver Families
Bucket
drivers/input
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 cpcap_power_button {
	struct regmap *regmap;
	struct input_dev *idev;
	struct device *dev;
};

static irqreturn_t powerbutton_irq(int irq, void *_button)
{
	struct cpcap_power_button *button = _button;
	int val;

	val = cpcap_sense_virq(button->regmap, irq);
	if (val < 0) {
		dev_err(button->dev, "irq read failed: %d", val);
		return IRQ_HANDLED;
	}

	pm_wakeup_event(button->dev, 0);
	input_report_key(button->idev, KEY_POWER, val);
	input_sync(button->idev);

	return IRQ_HANDLED;
}

static int cpcap_power_button_probe(struct platform_device *pdev)
{
	struct cpcap_power_button *button;
	int irq;
	int err;

	irq = platform_get_irq(pdev, 0);
	if (irq < 0)
		return irq;

	button = devm_kmalloc(&pdev->dev, sizeof(*button), GFP_KERNEL);
	if (!button)
		return -ENOMEM;

	button->idev = devm_input_allocate_device(&pdev->dev);
	if (!button->idev)
		return -ENOMEM;

	button->regmap = dev_get_regmap(pdev->dev.parent, NULL);
	if (!button->regmap)
		return -ENODEV;

	button->dev = &pdev->dev;

	button->idev->name = "cpcap-pwrbutton";
	button->idev->phys = "cpcap-pwrbutton/input0";
	input_set_capability(button->idev, EV_KEY, KEY_POWER);

	err = devm_request_threaded_irq(&pdev->dev, irq, NULL,
		powerbutton_irq, IRQF_ONESHOT, "cpcap_pwrbutton", button);
	if (err < 0) {
		dev_err(&pdev->dev, "IRQ request failed: %d\n", err);
		return err;
	}

	err = input_register_device(button->idev);
	if (err) {
		dev_err(&pdev->dev, "Input register failed: %d\n", err);
		return err;
	}

	device_init_wakeup(&pdev->dev, true);

	return 0;
}

#ifdef CONFIG_OF
static const struct of_device_id cpcap_pwrbutton_dt_match_table[] = {
	{ .compatible = "motorola,cpcap-pwrbutton" },
	{},
};
MODULE_DEVICE_TABLE(of, cpcap_pwrbutton_dt_match_table);
#endif

static struct platform_driver cpcap_power_button_driver = {
	.probe		= cpcap_power_button_probe,
	.driver		= {
		.name	= "cpcap-pwrbutton",
		.of_match_table = of_match_ptr(cpcap_pwrbutton_dt_match_table),
	},
};
module_platform_driver(cpcap_power_button_driver);

MODULE_ALIAS("platform:cpcap-pwrbutton");
MODULE_DESCRIPTION("CPCAP Power Button");
MODULE_LICENSE("GPL");

Annotation

Implementation Notes