/*
   * userspace-consumer.c
   *
   * Copyright 2009 CompuLab, Ltd.
   *
   * Author: Mike Rapoport <mike@compulab.co.il>
   *
   * Based of virtual consumer driver:
   *   Copyright 2008 Wolfson Microelectronics PLC.
   *   Author: Mark Brown <broonie@opensource.wolfsonmicro.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.
   *
   */
  
  #include <linux/err.h>
  #include <linux/mutex.h>

  #include <linux/module.h>

  #include <linux/platform_device.h>
  #include <linux/regulator/consumer.h>
  #include <linux/regulator/userspace-consumer.h>

  #include <linux/slab.h>

  
  struct userspace_consumer_data {
  	const char *name;
  
  	struct mutex lock;
  	bool enabled;
  
  	int num_supplies;
  	struct regulator_bulk_data *supplies;
  };

  static ssize_t reg_show_name(struct device *dev,

  			  struct device_attribute *attr, char *buf)
  {
  	struct userspace_consumer_data *data = dev_get_drvdata(dev);
  
  	return sprintf(buf, "%s
  ", data->name);
  }

  static ssize_t reg_show_state(struct device *dev,

  			  struct device_attribute *attr, char *buf)
  {
  	struct userspace_consumer_data *data = dev_get_drvdata(dev);
  
  	if (data->enabled)
  		return sprintf(buf, "enabled
  ");
  
  	return sprintf(buf, "disabled
  ");
  }

  static ssize_t reg_set_state(struct device *dev, struct device_attribute *attr,

  			 const char *buf, size_t count)
  {
  	struct userspace_consumer_data *data = dev_get_drvdata(dev);
  	bool enabled;
  	int ret;
  
  	/*
  	 * sysfs_streq() doesn't need the 
  's, but we add them so the strings
  	 * will be shared with show_state(), above.
  	 */
  	if (sysfs_streq(buf, "enabled
  ") || sysfs_streq(buf, "1"))
  		enabled = true;
  	else if (sysfs_streq(buf, "disabled
  ") || sysfs_streq(buf, "0"))
  		enabled = false;
  	else {
  		dev_err(dev, "Configuring invalid mode
  ");
  		return count;
  	}
  
  	mutex_lock(&data->lock);
  	if (enabled != data->enabled) {
  		if (enabled)
  			ret = regulator_bulk_enable(data->num_supplies,
  						    data->supplies);
  		else
  			ret = regulator_bulk_disable(data->num_supplies,
  						     data->supplies);
  
  		if (ret == 0)
  			data->enabled = enabled;
  		else
  			dev_err(dev, "Failed to configure state: %d
  ", ret);
  	}
  	mutex_unlock(&data->lock);
  
  	return count;
  }

  static DEVICE_ATTR(name, 0444, reg_show_name, NULL);
  static DEVICE_ATTR(state, 0644, reg_show_state, reg_set_state);

  static struct attribute *attributes[] = {
  	&dev_attr_name.attr,
  	&dev_attr_state.attr,
  	NULL,
  };
  
  static const struct attribute_group attr_group = {
  	.attrs	= attributes,

  };
  
  static int regulator_userspace_consumer_probe(struct platform_device *pdev)
  {
  	struct regulator_userspace_consumer_data *pdata;
  	struct userspace_consumer_data *drvdata;

  	int ret;

  
  	pdata = pdev->dev.platform_data;
  	if (!pdata)
  		return -EINVAL;
  
  	drvdata = kzalloc(sizeof(struct userspace_consumer_data), GFP_KERNEL);
  	if (drvdata == NULL)
  		return -ENOMEM;
  
  	drvdata->name = pdata->name;
  	drvdata->num_supplies = pdata->num_supplies;
  	drvdata->supplies = pdata->supplies;
  
  	mutex_init(&drvdata->lock);
  
  	ret = regulator_bulk_get(&pdev->dev, drvdata->num_supplies,
  				 drvdata->supplies);
  	if (ret) {
  		dev_err(&pdev->dev, "Failed to get supplies: %d
  ", ret);
  		goto err_alloc_supplies;
  	}

  	ret = sysfs_create_group(&pdev->dev.kobj, &attr_group);
  	if (ret != 0)
  		goto err_create_attrs;

  	if (pdata->init_on) {

  		ret = regulator_bulk_enable(drvdata->num_supplies,
  					    drvdata->supplies);

  		if (ret) {
  			dev_err(&pdev->dev,
  				"Failed to set initial state: %d
  ", ret);
  			goto err_enable;
  		}

  	}

  	drvdata->enabled = pdata->init_on;

  	platform_set_drvdata(pdev, drvdata);
  
  	return 0;

  err_enable:
  	sysfs_remove_group(&pdev->dev.kobj, &attr_group);

  err_create_attrs:

  	regulator_bulk_free(drvdata->num_supplies, drvdata->supplies);
  
  err_alloc_supplies:
  	kfree(drvdata);
  	return ret;
  }
  
  static int regulator_userspace_consumer_remove(struct platform_device *pdev)
  {
  	struct userspace_consumer_data *data = platform_get_drvdata(pdev);

  	sysfs_remove_group(&pdev->dev.kobj, &attr_group);

  
  	if (data->enabled)
  		regulator_bulk_disable(data->num_supplies, data->supplies);
  
  	regulator_bulk_free(data->num_supplies, data->supplies);
  	kfree(data);
  
  	return 0;
  }
  
  static struct platform_driver regulator_userspace_consumer_driver = {
  	.probe		= regulator_userspace_consumer_probe,
  	.remove		= regulator_userspace_consumer_remove,
  	.driver		= {
  		.name		= "reg-userspace-consumer",
  	},
  };

  module_platform_driver(regulator_userspace_consumer_driver);

  
  MODULE_AUTHOR("Mike Rapoport <mike@compulab.co.il>");
  MODULE_DESCRIPTION("Userspace consumer for voltage and current regulators");
  MODULE_LICENSE("GPL");