text: /*
   * Regulator haptic driver
   *
   * Copyright (c) 2014 Samsung Electronics Co., Ltd.
   * Author: Jaewon Kim <jaewon02.kim@samsung.com>
   * Author: Hyunhee Kim <hyunhee.kim@samsung.com>
   *
   * 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/input.h>
  #include <linux/module.h>
  #include <linux/of.h>
  #include <linux/platform_data/regulator-haptic.h>
  #include <linux/platform_device.h>
  #include <linux/regulator/consumer.h>
  #include <linux/slab.h>
  
  #define MAX_MAGNITUDE_SHIFT	16
  
  struct regulator_haptic {
  	struct device *dev;
  	struct input_dev *input_dev;
  	struct regulator *regulator;
  
  	struct work_struct work;
  	struct mutex mutex;
  
  	bool active;
  	bool suspended;
  
  	unsigned int max_volt;
  	unsigned int min_volt;
  	unsigned int magnitude;
  };
  
  static int regulator_haptic_toggle(struct regulator_haptic *haptic, bool on)
  {
  	int error;
  
  	if (haptic->active != on) {
  
  		error = on ? regulator_enable(haptic->regulator) :
  			     regulator_disable(haptic->regulator);
  		if (error) {
  			dev_err(haptic->dev,
  				"failed to switch regulator %s: %d\n",
  				on ? "on" : "off", error);
  			return error;
  		}
  
  		haptic->active = on;
  	}
  
  	return 0;
  }
  
  static int regulator_haptic_set_voltage(struct regulator_haptic *haptic,
  					 unsigned int magnitude)
  {
  	u64 volt_mag_multi;
  	unsigned int intensity;
  	int error;
  
  	volt_mag_multi = (u64)(haptic->max_volt - haptic->min_volt) * magnitude;
  	intensity = (unsigned int)(volt_mag_multi >> MAX_MAGNITUDE_SHIFT);
  
  	error = regulator_set_voltage(haptic->regulator,
  				      intensity + haptic->min_volt,
  				      haptic->max_volt);
  	if (error) {
  		dev_err(haptic->dev, "cannot set regulator voltage to %d: %d\n",
  			intensity + haptic->min_volt, error);
  		return error;
  	}
  
  	regulator_haptic_toggle(haptic, !!magnitude);
  
  	return 0;
  }
  
  static void regulator_haptic_work(struct work_struct *work)
  {
  	struct regulator_haptic *haptic = container_of(work,
  					struct regulator_haptic, work);
  
  	mutex_lock(&haptic->mutex);
  
  	if (!haptic->suspended)
  		regulator_haptic_set_voltage(haptic, haptic->magnitude);
  
  	mutex_unlock(&haptic->mutex);
  }
  
  static int regulator_haptic_play_effect(struct input_dev *input, void *data,
  					struct ff_effect *effect)
  {
  	struct regulator_haptic *haptic = input_get_drvdata(input);
  
  	haptic->magnitude = effect->u.rumble.strong_magnitude;
  	if (!haptic->magnitude)
  		haptic->magnitude = effect->u.rumble.weak_magnitude;
  
  	schedule_work(&haptic->work);
  
  	return 0;
  }
  
  static void regulator_haptic_close(struct input_dev *input)
  {
  	struct regulator_haptic *haptic = input_get_drvdata(input);
  
  	cancel_work_sync(&haptic->work);
  	regulator_haptic_set_voltage(haptic, 0);
  }
  
  static int __maybe_unused
  regulator_haptic_parse_dt(struct device *dev, struct regulator_haptic *haptic)
  {
  	struct device_node *node;
  	int error;
  
  	node = dev->of_node;
  	if(!node) {
  		dev_err(dev, "Missing dveice tree data\n");
  		return -EINVAL;
  	}
  
  	error = of_property_read_u32(node, "max-microvolt", &haptic->max_volt);
  	if (error) {
  		dev_err(dev, "cannot parse max-microvolt\n");
  		return error;
  	}
  
  	error = of_property_read_u32(node, "min-microvolt", &haptic->min_volt);
  	if (error) {
  		dev_err(dev, "cannot parse min-microvolt\n");
  		return error;
  	}
  
  	return 0;
  }
  
  static int regulator_haptic_probe(struct platform_device *pdev)
  {
  	const struct regulator_haptic_data *pdata = dev_get_platdata(&pdev->dev);
  	struct regulator_haptic *haptic;
  	struct input_dev *input_dev;
  	int error;
  
  	haptic = devm_kzalloc(&pdev->dev, sizeof(*haptic), GFP_KERNEL);
  	if (!haptic)
  		return -ENOMEM;
  
  	platform_set_drvdata(pdev, haptic);
  	haptic->dev = &pdev->dev;
  	mutex_init(&haptic->mutex);
  	INIT_WORK(&haptic->work, regulator_haptic_work);
  
  	if (pdata) {
  		haptic->max_volt = pdata->max_volt;
  		haptic->min_volt = pdata->min_volt;
  	} else if (IS_ENABLED(CONFIG_OF)) {
  		error = regulator_haptic_parse_dt(&pdev->dev, haptic);
  		if (error)
  			return error;
  	} else {
  		dev_err(&pdev->dev, "Missing platform data\n");
  		return -EINVAL;
  	}
  
  	haptic->regulator = devm_regulator_get_exclusive(&pdev->dev, "haptic");
  	if (IS_ERR(haptic->regulator)) {
  		dev_err(&pdev->dev, "failed to get regulator\n");
  		return PTR_ERR(haptic->regulator);
  	}
  
  	input_dev = devm_input_allocate_device(&pdev->dev);
  	if (!input_dev)
  		return	-ENOMEM;
  
  	haptic->input_dev = input_dev;
  	haptic->input_dev->name = "regulator-haptic";
  	haptic->input_dev->dev.parent = &pdev->dev;
  	haptic->input_dev->close = regulator_haptic_close;
  	input_set_drvdata(haptic->input_dev, haptic);
  	input_set_capability(haptic->input_dev, EV_FF, FF_RUMBLE);
  
  	error = input_ff_create_memless(input_dev, NULL,
  					regulator_haptic_play_effect);
  	if (error) {
  		dev_err(&pdev->dev, "failed to create force-feedback\n");
  		return error;
  	}
  
  	error = input_register_device(haptic->input_dev);
  	if (error) {
  		dev_err(&pdev->dev, "failed to register input device\n");
  		return error;
  	}
  
  	return 0;
  }
  
  static int __maybe_unused regulator_haptic_suspend(struct device *dev)
  {
  	struct platform_device *pdev = to_platform_device(dev);
  	struct regulator_haptic *haptic = platform_get_drvdata(pdev);
  	int error;
  
  	error = mutex_lock_interruptible(&haptic->mutex);
  	if (error)
  		return error;
  
  	regulator_haptic_set_voltage(haptic, 0);
  
  	haptic->suspended = true;
  
  	mutex_unlock(&haptic->mutex);
  
  	return 0;
  }
  
  static int __maybe_unused regulator_haptic_resume(struct device *dev)
  {
  	struct platform_device *pdev = to_platform_device(dev);
  	struct regulator_haptic *haptic = platform_get_drvdata(pdev);
  	unsigned int magnitude;
  
  	mutex_lock(&haptic->mutex);
  
  	haptic->suspended = false;
  
  	magnitude = ACCESS_ONCE(haptic->magnitude);
  	if (magnitude)
  		regulator_haptic_set_voltage(haptic, magnitude);
  
  	mutex_unlock(&haptic->mutex);
  
  	return 0;
  }
  
  static SIMPLE_DEV_PM_OPS(regulator_haptic_pm_ops,
  		regulator_haptic_suspend, regulator_haptic_resume);
  
  static const struct of_device_id regulator_haptic_dt_match[] = {
  	{ .compatible = "regulator-haptic" },
  	{ /* sentinel */ },
  };
  MODULE_DEVICE_TABLE(of, regulator_haptic_dt_match);
  
  static struct platform_driver regulator_haptic_driver = {
  	.probe		= regulator_haptic_probe,
  	.driver		= {
  		.name		= "regulator-haptic",
  		.of_match_table = regulator_haptic_dt_match,
  		.pm		= &regulator_haptic_pm_ops,
  	},
  };
  module_platform_driver(regulator_haptic_driver);
  
  MODULE_AUTHOR("Jaewon Kim <jaewon02.kim@samsung.com>");
  MODULE_AUTHOR("Hyunhee Kim <hyunhee.kim@samsung.com>");
  MODULE_DESCRIPTION("Regulator haptic driver");
  MODULE_LICENSE("GPL");
  