pwm-beeper.c

Go to the documentation of this file.

/*
 *  Copyright (C) 2010, Lars-Peter Clausen <[email protected]>
 *  PWM beeper 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;  either version 2 of the License, or (at your
 *  option) any later version.
 *
 *  You should have received a copy of the GNU General Public License along
 *  with this program; if not, write to the Free Software Foundation, Inc.,
 *  675 Mass Ave, Cambridge, MA 02139, USA.
 *
 */

#include <linux/input.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/platform_device.h>
#include <linux/pwm.h>
#include <linux/slab.h>

struct pwm_beeper {
    struct input_dev *input;
    struct pwm_device *pwm;
    unsigned long period;
};

#define HZ_TO_NANOSECONDS(x) (1000000000UL/(x))

static int pwm_beeper_event(struct input_dev *input,
                unsigned int type, unsigned int code, int value)
{
    int ret = 0;
    struct pwm_beeper *beeper = input_get_drvdata(input);
    unsigned long period;

    if (type != EV_SND || value < 0)
        return -EINVAL;

    switch (code) {
    case SND_BELL:
        value = value ? 1000 : 0;
        break;
    case SND_TONE:
        break;
    default:
        return -EINVAL;
    }

    if (value == 0) {
        pwm_config(beeper->pwm, 0, 0);
        pwm_disable(beeper->pwm);
    } else {
        period = HZ_TO_NANOSECONDS(value);
        ret = pwm_config(beeper->pwm, period / 2, period);
        if (ret)
            return ret;
        ret = pwm_enable(beeper->pwm);
        if (ret)
            return ret;
        beeper->period = period;
    }

    return 0;
}

static int __devinit pwm_beeper_probe(struct platform_device *pdev)
{
    unsigned long pwm_id = (unsigned long)pdev->dev.platform_data;
    struct pwm_beeper *beeper;
    int error;

    beeper = kzalloc(sizeof(*beeper), GFP_KERNEL);
    if (!beeper)
        return -ENOMEM;

    beeper->pwm = pwm_request(pwm_id, "pwm beeper");

    if (IS_ERR(beeper->pwm)) {
        error = PTR_ERR(beeper->pwm);
        dev_err(&pdev->dev, "Failed to request pwm device: %d\n", error);
        goto err_free;
    }

    beeper->input = input_allocate_device();
    if (!beeper->input) {
        dev_err(&pdev->dev, "Failed to allocate input device\n");
        error = -ENOMEM;
        goto err_pwm_free;
    }
    beeper->input->dev.parent = &pdev->dev;

    beeper->input->name = "pwm-beeper";
    beeper->input->phys = "pwm/input0";
    beeper->input->id.bustype = BUS_HOST;
    beeper->input->id.vendor = 0x001f;
    beeper->input->id.product = 0x0001;
    beeper->input->id.version = 0x0100;

    beeper->input->evbit[0] = BIT(EV_SND);
    beeper->input->sndbit[0] = BIT(SND_TONE) | BIT(SND_BELL);

    beeper->input->event = pwm_beeper_event;

    input_set_drvdata(beeper->input, beeper);

    error = input_register_device(beeper->input);
    if (error) {
        dev_err(&pdev->dev, "Failed to register input device: %d\n", error);
        goto err_input_free;
    }

    platform_set_drvdata(pdev, beeper);

    return 0;

err_input_free:
    input_free_device(beeper->input);
err_pwm_free:
    pwm_free(beeper->pwm);
err_free:
    kfree(beeper);

    return error;
}

static int __devexit pwm_beeper_remove(struct platform_device *pdev)
{
    struct pwm_beeper *beeper = platform_get_drvdata(pdev);

    platform_set_drvdata(pdev, NULL);
    input_unregister_device(beeper->input);

    pwm_disable(beeper->pwm);
    pwm_free(beeper->pwm);

    kfree(beeper);

    return 0;
}

#ifdef CONFIG_PM
static int pwm_beeper_suspend(struct device *dev)
{
    struct pwm_beeper *beeper = dev_get_drvdata(dev);

    if (beeper->period)
        pwm_disable(beeper->pwm);

    return 0;
}

static int pwm_beeper_resume(struct device *dev)
{
    struct pwm_beeper *beeper = dev_get_drvdata(dev);

    if (beeper->period) {
        pwm_config(beeper->pwm, beeper->period / 2, beeper->period);
        pwm_enable(beeper->pwm);
    }

    return 0;
}

static SIMPLE_DEV_PM_OPS(pwm_beeper_pm_ops,
             pwm_beeper_suspend, pwm_beeper_resume);

#define PWM_BEEPER_PM_OPS (&pwm_beeper_pm_ops)
#else
#define PWM_BEEPER_PM_OPS NULL
#endif

static struct platform_driver pwm_beeper_driver = {
    .probe  = pwm_beeper_probe,
    .remove = __devexit_p(pwm_beeper_remove),
    .driver = {
        .name   = "pwm-beeper",
        .owner  = THIS_MODULE,
        .pm = PWM_BEEPER_PM_OPS,
    },
};
module_platform_driver(pwm_beeper_driver);

MODULE_AUTHOR("Lars-Peter Clausen <[email protected]>");
MODULE_DESCRIPTION("PWM beeper driver");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:pwm-beeper");