1. 根目录:
2. drivers
3. input
4. misc
5. e3x0-button.c

/*
 * Copyright (c) 2014, National Instruments Corp. All rights reserved.
 *
 * Driver for NI Ettus Research USRP E3x0 Button Driver
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; version 2 of the License.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU General Public License for more details.
 */

#include <linux/device.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/input.h>
#include <linux/interrupt.h>
#include <linux/of.h>
#include <linux/slab.h>

static irqreturn_t e3x0_button_release_handler(int irq, void *data)
{
	struct input_dev *idev = data;

	input_report_key(idev, KEY_POWER, 0);
	input_sync(idev);

	return IRQ_HANDLED;
}

static irqreturn_t e3x0_button_press_handler(int irq, void *data)
{
	struct input_dev *idev = data;

	input_report_key(idev, KEY_POWER, 1);
	pm_wakeup_event(idev->dev.parent, 0);
	input_sync(idev);

	return IRQ_HANDLED;
}

static int __maybe_unused e3x0_button_suspend(struct device *dev)
{
	struct platform_device *pdev = to_platform_device(dev);

	if (device_may_wakeup(dev))
		enable_irq_wake(platform_get_irq_byname(pdev, "press"));

	return 0;
}

static int __maybe_unused e3x0_button_resume(struct device *dev)
{
	struct platform_device *pdev = to_platform_device(dev);

	if (device_may_wakeup(dev))
		disable_irq_wake(platform_get_irq_byname(pdev, "press"));

	return 0;
}

static SIMPLE_DEV_PM_OPS(e3x0_button_pm_ops,
			 e3x0_button_suspend, e3x0_button_resume);

static int e3x0_button_probe(struct platform_device *pdev)
{
	struct input_dev *input;
	int irq_press, irq_release;
	int error;

	irq_press = platform_get_irq_byname(pdev, "press");
	if (irq_press < 0) {
		dev_err(&pdev->dev, "No IRQ for 'press', error=%d\n",
			irq_press);
		return irq_press;
	}

	irq_release = platform_get_irq_byname(pdev, "release");
	if (irq_release < 0) {
		dev_err(&pdev->dev, "No IRQ for 'release', error=%d\n",
			irq_release);
		return irq_release;
	}

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

	input->name = "NI Ettus Research USRP E3x0 Button Driver";
	input->phys = "e3x0_button/input0";
	input->dev.parent = &pdev->dev;

	input_set_capability(input, EV_KEY, KEY_POWER);

	error = devm_request_irq(&pdev->dev, irq_press,
				 e3x0_button_press_handler, 0,
				 "e3x0-button", input);
	if (error) {
		dev_err(&pdev->dev, "Failed to request 'press' IRQ#%d: %d\n",
			irq_press, error);
		return error;
	}

	error = devm_request_irq(&pdev->dev, irq_release,
				 e3x0_button_release_handler, 0,
				 "e3x0-button", input);
	if (error) {
		dev_err(&pdev->dev, "Failed to request 'release' IRQ#%d: %d\n",
			irq_release, error);
		return error;
	}

	error = input_register_device(input);
	if (error) {
		dev_err(&pdev->dev, "Can't register input device: %d\n", error);
		return error;
	}

	platform_set_drvdata(pdev, input);
	device_init_wakeup(&pdev->dev, 1);
	return 0;
}

static int e3x0_button_remove(struct platform_device *pdev)
{
	device_init_wakeup(&pdev->dev, 0);
	return 0;
}

#ifdef CONFIG_OF
static const struct of_device_id e3x0_button_match[] = {
	{ .compatible = "ettus,e3x0-button", },
	{ }
};
MODULE_DEVICE_TABLE(of, e3x0_button_match);
#endif

static struct platform_driver e3x0_button_driver = {
	.driver		= {
		.name	= "e3x0-button",
		.of_match_table = of_match_ptr(e3x0_button_match),
		.pm	= &e3x0_button_pm_ops,
	},
	.probe		= e3x0_button_probe,
	.remove		= e3x0_button_remove,
};

module_platform_driver(e3x0_button_driver);

MODULE_LICENSE("GPL v2");
MODULE_AUTHOR("Moritz Fischer <moritz.fischer@ettus.com>");
MODULE_DESCRIPTION("NI Ettus Research USRP E3x0 Button driver");
MODULE_ALIAS("platform:e3x0-button");