pwm-beeper.c
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/*
* Copyright (C) 2010, Lars-Peter Clausen <lars@metafoo.de>
* 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/of.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 pwm_beeper_probe(struct platform_device *pdev)
{
unsigned long pwm_id = (unsigned long)dev_get_platdata(&pdev->dev);
struct pwm_beeper *beeper;
int error;
beeper = kzalloc(sizeof(*beeper), GFP_KERNEL);
if (!beeper)
return -ENOMEM;
beeper->pwm = pwm_get(&pdev->dev, NULL);
if (IS_ERR(beeper->pwm)) {
dev_dbg(&pdev->dev, "unable to request PWM, trying legacy API\n");
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 pwm_beeper_remove(struct platform_device *pdev)
{
struct pwm_beeper *beeper = platform_get_drvdata(pdev);
input_unregister_device(beeper->input);
pwm_disable(beeper->pwm);
pwm_free(beeper->pwm);
kfree(beeper);
return 0;
}
#ifdef CONFIG_PM_SLEEP
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
#ifdef CONFIG_OF
static const struct of_device_id pwm_beeper_match[] = {
{ .compatible = "pwm-beeper", },
{ },
};
#endif
static struct platform_driver pwm_beeper_driver = {
.probe = pwm_beeper_probe,
.remove = pwm_beeper_remove,
.driver = {
.name = "pwm-beeper",
.owner = THIS_MODULE,
.pm = PWM_BEEPER_PM_OPS,
.of_match_table = of_match_ptr(pwm_beeper_match),
},
};
module_platform_driver(pwm_beeper_driver);
MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
MODULE_DESCRIPTION("PWM beeper driver");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:pwm-beeper");