1. 根目录:
2. drivers
3. input
4. misc
5. ixp4xx-beeper.c

/*
 * Generic IXP4xx beeper driver
 *
 * Copyright (C) 2005 Tower Technologies
 *
 * based on nslu2-io.c
 *  Copyright (C) 2004 Karen Spearel
 *
 * Author: Alessandro Zummo <a.zummo@towertech.it>
 * Maintainers: http://www.nslu2-linux.org/
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 */

#include <linux/module.h>
#include <linux/input.h>
#include <linux/delay.h>
#include <linux/platform_device.h>
#include <linux/interrupt.h>
#include <linux/gpio.h>
#include <mach/hardware.h>

MODULE_AUTHOR("Alessandro Zummo <a.zummo@towertech.it>");
MODULE_DESCRIPTION("ixp4xx beeper driver");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:ixp4xx-beeper");

static DEFINE_SPINLOCK(beep_lock);

static void ixp4xx_spkr_control(unsigned int pin, unsigned int count)
{
	unsigned long flags;

	spin_lock_irqsave(&beep_lock, flags);

	if (count) {
		gpio_direction_output(pin, 0);
		*IXP4XX_OSRT2 = (count & ~IXP4XX_OST_RELOAD_MASK) | IXP4XX_OST_ENABLE;
	} else {
		gpio_direction_output(pin, 1);
		gpio_direction_input(pin);
		*IXP4XX_OSRT2 = 0;
	}

	spin_unlock_irqrestore(&beep_lock, flags);
}

static int ixp4xx_spkr_event(struct input_dev *dev, unsigned int type, unsigned int code, int value)
{
	unsigned int pin = (unsigned int) input_get_drvdata(dev);
	unsigned int count = 0;

	if (type != EV_SND)
		return -1;

	switch (code) {
		case SND_BELL:
			if (value)
				value = 1000;
		case SND_TONE:
			break;
		default:
			return -1;
	}

	if (value > 20 && value < 32767)
		count = (IXP4XX_TIMER_FREQ / (value * 4)) - 1;

	ixp4xx_spkr_control(pin, count);

	return 0;
}

static irqreturn_t ixp4xx_spkr_interrupt(int irq, void *dev_id)
{
	unsigned int pin = (unsigned int) dev_id;

	/* clear interrupt */
	*IXP4XX_OSST = IXP4XX_OSST_TIMER_2_PEND;

	/* flip the beeper output */
	gpio_set_value(pin, !gpio_get_value(pin));

	return IRQ_HANDLED;
}

static int ixp4xx_spkr_probe(struct platform_device *dev)
{
	struct input_dev *input_dev;
	int err;

	input_dev = input_allocate_device();
	if (!input_dev)
		return -ENOMEM;

	input_set_drvdata(input_dev, (void *) dev->id);

	input_dev->name = "ixp4xx beeper",
	input_dev->phys = "ixp4xx/gpio";
	input_dev->id.bustype = BUS_HOST;
	input_dev->id.vendor  = 0x001f;
	input_dev->id.product = 0x0001;
	input_dev->id.version = 0x0100;
	input_dev->dev.parent = &dev->dev;

	input_dev->evbit[0] = BIT_MASK(EV_SND);
	input_dev->sndbit[0] = BIT_MASK(SND_BELL) | BIT_MASK(SND_TONE);
	input_dev->event = ixp4xx_spkr_event;

	err = gpio_request(dev->id, "ixp4-beeper");
	if (err)
		goto err_free_device;

	err = request_irq(IRQ_IXP4XX_TIMER2, &ixp4xx_spkr_interrupt,
			  IRQF_NO_SUSPEND, "ixp4xx-beeper",
			  (void *) dev->id);
	if (err)
		goto err_free_gpio;

	err = input_register_device(input_dev);
	if (err)
		goto err_free_irq;

	platform_set_drvdata(dev, input_dev);

	return 0;

 err_free_irq:
	free_irq(IRQ_IXP4XX_TIMER2, (void *)dev->id);
 err_free_gpio:
	gpio_free(dev->id);
 err_free_device:
	input_free_device(input_dev);

	return err;
}

static int ixp4xx_spkr_remove(struct platform_device *dev)
{
	struct input_dev *input_dev = platform_get_drvdata(dev);
	unsigned int pin = (unsigned int) input_get_drvdata(input_dev);

	input_unregister_device(input_dev);

	/* turn the speaker off */
	disable_irq(IRQ_IXP4XX_TIMER2);
	ixp4xx_spkr_control(pin, 0);

	free_irq(IRQ_IXP4XX_TIMER2, (void *)dev->id);
	gpio_free(dev->id);

	return 0;
}

static void ixp4xx_spkr_shutdown(struct platform_device *dev)
{
	struct input_dev *input_dev = platform_get_drvdata(dev);
	unsigned int pin = (unsigned int) input_get_drvdata(input_dev);

	/* turn off the speaker */
	disable_irq(IRQ_IXP4XX_TIMER2);
	ixp4xx_spkr_control(pin, 0);
}

static struct platform_driver ixp4xx_spkr_platform_driver = {
	.driver		= {
		.name	= "ixp4xx-beeper",
		.owner	= THIS_MODULE,
	},
	.probe		= ixp4xx_spkr_probe,
	.remove		= ixp4xx_spkr_remove,
	.shutdown	= ixp4xx_spkr_shutdown,
};
module_platform_driver(ixp4xx_spkr_platform_driver);