// SPDX-License-Identifier: GPL-2.0-or-later/* *  Copyright (C) 2010, Lars-Peter Clausen <lars@metafoo.de> *  PWM beeper driver */ #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_might_sleep(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))		return dev_err_probe(dev, PTR_ERR(beeper->pwm), "Failed to request PWM device\n"); 	/* Sync up PWM state and ensure it is off. */	pwm_init_state(beeper->pwm, &state);	state.enabled = false;	error = pwm_apply_might_sleep(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))		return dev_err_probe(dev, PTR_ERR(beeper->amplifier),				     "Failed to get 'amp' regulator\n"); 	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 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.	 */	scoped_guard(spinlock_irq, &beeper->input->event_lock) {		beeper->suspended = true;	} 	pwm_beeper_stop(beeper); 	return 0;} static int pwm_beeper_resume(struct device *dev){	struct pwm_beeper *beeper = dev_get_drvdata(dev); 	scoped_guard(spinlock_irq, &beeper->input->event_lock) {		beeper->suspended = false;	} 	/* Let worker figure out if we should resume beeping */	schedule_work(&beeper->work); 	return 0;} static DEFINE_SIMPLE_DEV_PM_OPS(pwm_beeper_pm_ops,				pwm_beeper_suspend, pwm_beeper_resume); #ifdef CONFIG_OFstatic 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	= pm_sleep_ptr(&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");