/*
   * fixed.c
   *
   * Copyright 2008 Wolfson Microelectronics PLC.
   *
   * Author: Mark Brown <broonie@opensource.wolfsonmicro.com>
   *

   * Copyright (c) 2009 Nokia Corporation
   * Roger Quadros <ext-roger.quadros@nokia.com>
   *

   * 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.
   *
   * This is useful for systems with mixed controllable and
   * non-controllable regulators, as well as for allowing testing on
   * systems with no controllable regulators.
   */
  
  #include <linux/err.h>
  #include <linux/mutex.h>

  #include <linux/module.h>

  #include <linux/platform_device.h>
  #include <linux/regulator/driver.h>
  #include <linux/regulator/fixed.h>

  #include <linux/gpio.h>

  #include <linux/slab.h>

  #include <linux/of.h>
  #include <linux/of_gpio.h>
  #include <linux/regulator/of_regulator.h>
  #include <linux/regulator/machine.h>

  #include <linux/pinctrl/consumer.h>

  
  struct fixed_voltage_data {
  	struct regulator_desc desc;
  	struct regulator_dev *dev;

  };

  
  /**
   * of_get_fixed_voltage_config - extract fixed_voltage_config structure info
   * @dev: device requesting for fixed_voltage_config

   * @desc: regulator description

   *
   * Populates fixed_voltage_config structure by extracting data from device
   * tree node, returns a pointer to the populated structure of NULL if memory
   * alloc fails.
   */

  static struct fixed_voltage_config *

  of_get_fixed_voltage_config(struct device *dev,
  			    const struct regulator_desc *desc)

  {
  	struct fixed_voltage_config *config;
  	struct device_node *np = dev->of_node;

  	struct regulator_init_data *init_data;
  
  	config = devm_kzalloc(dev, sizeof(struct fixed_voltage_config),
  								 GFP_KERNEL);
  	if (!config)

  		return ERR_PTR(-ENOMEM);

  	config->init_data = of_get_regulator_init_data(dev, dev->of_node, desc);

  	if (!config->init_data)

  		return ERR_PTR(-EINVAL);

  	init_data = config->init_data;

  	init_data->constraints.apply_uV = 0;

  
  	config->supply_name = init_data->constraints.name;
  	if (init_data->constraints.min_uV == init_data->constraints.max_uV) {
  		config->microvolts = init_data->constraints.min_uV;
  	} else {
  		dev_err(dev,
  			 "Fixed regulator specified with variable voltages
  ");

  		return ERR_PTR(-EINVAL);

  	}
  
  	if (init_data->constraints.boot_on)
  		config->enabled_at_boot = true;
  
  	config->gpio = of_get_named_gpio(np, "gpio", 0);

  	if ((config->gpio < 0) && (config->gpio != -ENOENT))
  		return ERR_PTR(config->gpio);

  	of_property_read_u32(np, "startup-delay-us", &config->startup_delay);

  	of_property_read_u32(np, "off-on-delay", &config->off_on_delay);

  	config->enable_high = of_property_read_bool(np, "enable-active-high");
  	config->gpio_is_open_drain = of_property_read_bool(np,
  							   "gpio-open-drain");

  	if (of_find_property(np, "vin-supply", NULL))
  		config->input_supply = "vin";

  	return config;
  }

  static struct regulator_ops fixed_voltage_ops = {

  };

  static int reg_fixed_voltage_probe(struct platform_device *pdev)

  {

  	struct fixed_voltage_config *config;

  	struct fixed_voltage_data *drvdata;

  	struct regulator_config cfg = { };

  	int ret;

  	drvdata = devm_kzalloc(&pdev->dev, sizeof(struct fixed_voltage_data),
  			       GFP_KERNEL);
  	if (!drvdata)
  		return -ENOMEM;

  	if (pdev->dev.of_node) {

  		config = of_get_fixed_voltage_config(&pdev->dev,
  						     &drvdata->desc);

  		if (IS_ERR(config))
  			return PTR_ERR(config);
  	} else {

  		config = dev_get_platdata(&pdev->dev);

  	}

  
  	if (!config)
  		return -ENOMEM;

  	drvdata->desc.name = devm_kstrdup(&pdev->dev,
  					  config->supply_name,
  					  GFP_KERNEL);

  	if (drvdata->desc.name == NULL) {

  		dev_err(&pdev->dev, "Failed to allocate supply name
  ");

  		return -ENOMEM;

  	}
  	drvdata->desc.type = REGULATOR_VOLTAGE;
  	drvdata->desc.owner = THIS_MODULE;

  	drvdata->desc.ops = &fixed_voltage_ops;

  	drvdata->desc.enable_time = config->startup_delay;

  	drvdata->desc.off_on_delay = config->off_on_delay;

  	if (config->input_supply) {

  		drvdata->desc.supply_name = devm_kstrdup(&pdev->dev,
  					    config->input_supply,
  					    GFP_KERNEL);

  		if (!drvdata->desc.supply_name) {
  			dev_err(&pdev->dev,
  				"Failed to allocate input supply
  ");

  			return -ENOMEM;

  		}
  	}

  	if (config->microvolts)
  		drvdata->desc.n_voltages = 1;

  	drvdata->desc.fixed_uV = config->microvolts;

  	if (gpio_is_valid(config->gpio)) {

  		cfg.ena_gpio = config->gpio;

  		if (pdev->dev.of_node)
  			cfg.ena_gpio_initialized = true;
  	}

  	cfg.ena_gpio_invert = !config->enable_high;
  	if (config->enabled_at_boot) {

  		if (config->enable_high)

  			cfg.ena_gpio_flags |= GPIOF_OUT_INIT_HIGH;

  		else

  			cfg.ena_gpio_flags |= GPIOF_OUT_INIT_LOW;

  	} else {

  		if (config->enable_high)

  			cfg.ena_gpio_flags |= GPIOF_OUT_INIT_LOW;

  		else

  			cfg.ena_gpio_flags |= GPIOF_OUT_INIT_HIGH;

  	}

  	if (config->gpio_is_open_drain)
  		cfg.ena_gpio_flags |= GPIOF_OPEN_DRAIN;

  	cfg.dev = &pdev->dev;
  	cfg.init_data = config->init_data;
  	cfg.driver_data = drvdata;
  	cfg.of_node = pdev->dev.of_node;

  	drvdata->dev = devm_regulator_register(&pdev->dev, &drvdata->desc,
  					       &cfg);

  	if (IS_ERR(drvdata->dev)) {
  		ret = PTR_ERR(drvdata->dev);

  		dev_err(&pdev->dev, "Failed to register regulator: %d
  ", ret);

  		return ret;

  	}
  
  	platform_set_drvdata(pdev, drvdata);
  
  	dev_dbg(&pdev->dev, "%s supplying %duV
  ", drvdata->desc.name,

  		drvdata->desc.fixed_uV);

  
  	return 0;

  }

  #if defined(CONFIG_OF)

  static const struct of_device_id fixed_of_match[] = {

  	{ .compatible = "regulator-fixed", },
  	{},
  };
  MODULE_DEVICE_TABLE(of, fixed_of_match);

  #endif

  #ifdef CONFIG_PM_SLEEP
  static int reg_fixed_voltage_suspend(struct device *dev)
  {
  	pinctrl_pm_select_sleep_state(dev);
  
  	return 0;
  }
  static int reg_fixed_voltage_resume(struct device *dev)
  {
  	pinctrl_pm_select_default_state(dev);
  
  	return 0;
  }
  #endif
  
  static const struct dev_pm_ops reg_fixed_voltage_pm_ops = {
  	SET_LATE_SYSTEM_SLEEP_PM_OPS(reg_fixed_voltage_suspend,
  		reg_fixed_voltage_resume)
  };

  static struct platform_driver regulator_fixed_voltage_driver = {

  	.probe		= reg_fixed_voltage_probe,

  	.driver		= {
  		.name		= "reg-fixed-voltage",

  		.of_match_table = of_match_ptr(fixed_of_match),

  		.pm = &reg_fixed_voltage_pm_ops,

  	},
  };
  
  static int __init regulator_fixed_voltage_init(void)
  {
  	return platform_driver_register(&regulator_fixed_voltage_driver);
  }

  subsys_initcall(regulator_fixed_voltage_init);

  
  static void __exit regulator_fixed_voltage_exit(void)
  {
  	platform_driver_unregister(&regulator_fixed_voltage_driver);
  }
  module_exit(regulator_fixed_voltage_exit);
  
  MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com>");
  MODULE_DESCRIPTION("Fixed voltage regulator");
  MODULE_LICENSE("GPL");

  MODULE_ALIAS("platform:reg-fixed-voltage");