drivers/input/misc/pwm-beeper.c - third_party/kernel - Git at Google

 /*
  *  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/regulator/consumer.h>
 #include <linux/module.h>
 #include <linux/kernel.h>
 #include <linux/of.h>
 #include <linux/platform_device.h>
 #include <linux/property.h>
 #include <linux/pwm.h>
 #include <linux/slab.h>
 #include <linux/workqueue.h>

 struct pwm_beeper {
 	struct input_dev *input;
 	struct pwm_device *pwm;
 	struct regulator *amplifier;
 	struct work_struct work;
 	unsigned long period;
 	unsigned int bell_frequency;
 	bool suspended;
 	bool amplifier_on;
 };

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

 static int pwm_beeper_on(struct pwm_beeper *beeper, unsigned long period)
 {
 	struct pwm_state state;
 	int error;

 	pwm_get_state(beeper->pwm, &state);

 	state.enabled = true;
 	state.period = period;
 	pwm_set_relative_duty_cycle(&state, 50, 100);

 	error = pwm_apply_state(beeper->pwm, &state);
 	if (error)
 		return error;

 	if (!beeper->amplifier_on) {
 		error = regulator_enable(beeper->amplifier);
 		if (error) {
 			pwm_disable(beeper->pwm);
 			return error;
 		}

 		beeper->amplifier_on = true;
 	}

 	return 0;
 }

 static void pwm_beeper_off(struct pwm_beeper *beeper)
 {
 	if (beeper->amplifier_on) {
 		regulator_disable(beeper->amplifier);
 		beeper->amplifier_on = false;
 	}

 	pwm_disable(beeper->pwm);
 }

 static void pwm_beeper_work(struct work_struct *work)
 {
 	struct pwm_beeper *beeper = container_of(work, struct pwm_beeper, work);
 	unsigned long period = READ_ONCE(beeper->period);

 	if (period)
 		pwm_beeper_on(beeper, period);
 	else
 		pwm_beeper_off(beeper);
 }

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

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

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

 	if (value == 0)
 		beeper->period = 0;
 	else
 		beeper->period = HZ_TO_NANOSECONDS(value);

 	if (!beeper->suspended)
 		schedule_work(&beeper->work);

 	return 0;
 }

 static void pwm_beeper_stop(struct pwm_beeper *beeper)
 {
 	cancel_work_sync(&beeper->work);
 	pwm_beeper_off(beeper);
 }

 static void pwm_beeper_close(struct input_dev *input)
 {
 	struct pwm_beeper *beeper = input_get_drvdata(input);

 	pwm_beeper_stop(beeper);
 }

 static int pwm_beeper_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
 	struct pwm_beeper *beeper;
 	struct pwm_state state;
 	u32 bell_frequency;
 	int error;

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

 	beeper->pwm = devm_pwm_get(dev, NULL);
 	if (IS_ERR(beeper->pwm)) {
 		error = PTR_ERR(beeper->pwm);
 		if (error != -EPROBE_DEFER)
 			dev_err(dev, "Failed to request PWM device: %d\n",
 				error);
 		return error;
 	}

 	/* Sync up PWM state and ensure it is off. */
 	pwm_init_state(beeper->pwm, &state);
 	state.enabled = false;
 	error = pwm_apply_state(beeper->pwm, &state);
 	if (error) {
 		dev_err(dev, "failed to apply initial PWM state: %d\n",
 			error);
 		return error;
 	}

 	beeper->amplifier = devm_regulator_get(dev, "amp");
 	if (IS_ERR(beeper->amplifier)) {
 		error = PTR_ERR(beeper->amplifier);
 		if (error != -EPROBE_DEFER)
 			dev_err(dev, "Failed to get 'amp' regulator: %d\n",
 				error);
 		return error;
 	}

 	INIT_WORK(&beeper->work, pwm_beeper_work);

 	error = device_property_read_u32(dev, "beeper-hz", &bell_frequency);
 	if (error) {
 		bell_frequency = 1000;
 		dev_dbg(dev,
 			"failed to parse 'beeper-hz' property, using default: %uHz\n",
 			bell_frequency);
 	}

 	beeper->bell_frequency = bell_frequency;

 	beeper->input = devm_input_allocate_device(dev);
 	if (!beeper->input) {
 		dev_err(dev, "Failed to allocate input device\n");
 		return -ENOMEM;
 	}

 	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;

 	input_set_capability(beeper->input, EV_SND, SND_TONE);
 	input_set_capability(beeper->input, EV_SND, SND_BELL);

 	beeper->input->event = pwm_beeper_event;
 	beeper->input->close = pwm_beeper_close;

 	input_set_drvdata(beeper->input, beeper);

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

 	platform_set_drvdata(pdev, beeper);

 	return 0;
 }

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

 	/*
 	 * Spinlock is taken here is not to protect write to
 	 * beeper->suspended, but to ensure that pwm_beeper_event
 	 * does not re-submit work once flag is set.
 	 */
 	spin_lock_irq(&beeper->input->event_lock);
 	beeper->suspended = true;
 	spin_unlock_irq(&beeper->input->event_lock);

 	pwm_beeper_stop(beeper);

 	return 0;
 }

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

 	spin_lock_irq(&beeper->input->event_lock);
 	beeper->suspended = false;
 	spin_unlock_irq(&beeper->input->event_lock);

 	/* Let worker figure out if we should resume beeping */
 	schedule_work(&beeper->work);

 	return 0;
 }

 static SIMPLE_DEV_PM_OPS(pwm_beeper_pm_ops,
 			 pwm_beeper_suspend, pwm_beeper_resume);

 #ifdef CONFIG_OF
 static const struct of_device_id pwm_beeper_match[] = {
 	{ .compatible = "pwm-beeper", },
 	{ },
 };
 MODULE_DEVICE_TABLE(of, pwm_beeper_match);
 #endif

 static struct platform_driver pwm_beeper_driver = {
 	.probe	= pwm_beeper_probe,
 	.driver = {
 		.name	= "pwm-beeper",
 		.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");
	/*
	* 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/regulator/consumer.h>
	#include <linux/module.h>
	#include <linux/kernel.h>
	#include <linux/of.h>
	#include <linux/platform_device.h>
	#include <linux/property.h>
	#include <linux/pwm.h>
	#include <linux/slab.h>
	#include <linux/workqueue.h>

	struct pwm_beeper {
	struct input_dev *input;
	struct pwm_device *pwm;
	struct regulator *amplifier;
	struct work_struct work;
	unsigned long period;
	unsigned int bell_frequency;
	bool suspended;
	bool amplifier_on;
	};

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

	static int pwm_beeper_on(struct pwm_beeper *beeper, unsigned long period)
	{
	struct pwm_state state;
	int error;

	pwm_get_state(beeper->pwm, &state);

	state.enabled = true;
	state.period = period;
	pwm_set_relative_duty_cycle(&state, 50, 100);

	error = pwm_apply_state(beeper->pwm, &state);
	if (error)
	return error;

	if (!beeper->amplifier_on) {
	error = regulator_enable(beeper->amplifier);
	if (error) {
	pwm_disable(beeper->pwm);
	return error;
	}

	beeper->amplifier_on = true;
	}

	return 0;
	}

	static void pwm_beeper_off(struct pwm_beeper *beeper)
	{
	if (beeper->amplifier_on) {
	regulator_disable(beeper->amplifier);
	beeper->amplifier_on = false;
	}

	pwm_disable(beeper->pwm);
	}

	static void pwm_beeper_work(struct work_struct *work)
	{
	struct pwm_beeper *beeper = container_of(work, struct pwm_beeper, work);
	unsigned long period = READ_ONCE(beeper->period);

	if (period)
	pwm_beeper_on(beeper, period);
	else
	pwm_beeper_off(beeper);
	}

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

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

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

	if (value == 0)
	beeper->period = 0;
	else
	beeper->period = HZ_TO_NANOSECONDS(value);

	if (!beeper->suspended)
	schedule_work(&beeper->work);

	return 0;
	}

	static void pwm_beeper_stop(struct pwm_beeper *beeper)
	{
	cancel_work_sync(&beeper->work);
	pwm_beeper_off(beeper);
	}

	static void pwm_beeper_close(struct input_dev *input)
	{
	struct pwm_beeper *beeper = input_get_drvdata(input);

	pwm_beeper_stop(beeper);
	}

	static int pwm_beeper_probe(struct platform_device *pdev)
	{
	struct device *dev = &pdev->dev;
	struct pwm_beeper *beeper;
	struct pwm_state state;
	u32 bell_frequency;
	int error;

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

	beeper->pwm = devm_pwm_get(dev, NULL);
	if (IS_ERR(beeper->pwm)) {
	error = PTR_ERR(beeper->pwm);
	if (error != -EPROBE_DEFER)
	dev_err(dev, "Failed to request PWM device: %d\n",
	error);
	return error;
	}

	/* Sync up PWM state and ensure it is off. */
	pwm_init_state(beeper->pwm, &state);
	state.enabled = false;
	error = pwm_apply_state(beeper->pwm, &state);
	if (error) {
	dev_err(dev, "failed to apply initial PWM state: %d\n",
	error);
	return error;
	}

	beeper->amplifier = devm_regulator_get(dev, "amp");
	if (IS_ERR(beeper->amplifier)) {
	error = PTR_ERR(beeper->amplifier);
	if (error != -EPROBE_DEFER)
	dev_err(dev, "Failed to get 'amp' regulator: %d\n",
	error);
	return error;
	}

	INIT_WORK(&beeper->work, pwm_beeper_work);

	error = device_property_read_u32(dev, "beeper-hz", &bell_frequency);
	if (error) {
	bell_frequency = 1000;
	dev_dbg(dev,
	"failed to parse 'beeper-hz' property, using default: %uHz\n",
	bell_frequency);
	}

	beeper->bell_frequency = bell_frequency;

	beeper->input = devm_input_allocate_device(dev);
	if (!beeper->input) {
	dev_err(dev, "Failed to allocate input device\n");
	return -ENOMEM;
	}

	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;

	input_set_capability(beeper->input, EV_SND, SND_TONE);
	input_set_capability(beeper->input, EV_SND, SND_BELL);

	beeper->input->event = pwm_beeper_event;
	beeper->input->close = pwm_beeper_close;

	input_set_drvdata(beeper->input, beeper);

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

	platform_set_drvdata(pdev, beeper);

	return 0;
	}

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

	/*
	* Spinlock is taken here is not to protect write to
	* beeper->suspended, but to ensure that pwm_beeper_event
	* does not re-submit work once flag is set.
	*/
	spin_lock_irq(&beeper->input->event_lock);
	beeper->suspended = true;
	spin_unlock_irq(&beeper->input->event_lock);

	pwm_beeper_stop(beeper);

	return 0;
	}

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

	spin_lock_irq(&beeper->input->event_lock);
	beeper->suspended = false;
	spin_unlock_irq(&beeper->input->event_lock);

	/* Let worker figure out if we should resume beeping */
	schedule_work(&beeper->work);

	return 0;
	}

	static SIMPLE_DEV_PM_OPS(pwm_beeper_pm_ops,
	pwm_beeper_suspend, pwm_beeper_resume);

	#ifdef CONFIG_OF
	static const struct of_device_id pwm_beeper_match[] = {
	{ .compatible = "pwm-beeper", },
	{ },
	};
	MODULE_DEVICE_TABLE(of, pwm_beeper_match);
	#endif

	static struct platform_driver pwm_beeper_driver = {
	.probe = pwm_beeper_probe,
	.driver = {
	.name = "pwm-beeper",
	.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");