/*
   * System Control Driver
   *
   * Copyright (C) 2012 Freescale Semiconductor, Inc.
   * Copyright (C) 2012 Linaro Ltd.
   *
   * Author: Dong Aisheng <dong.aisheng@linaro.org>
   *
   * 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/io.h>
  #include <linux/module.h>
  #include <linux/of.h>
  #include <linux/of_address.h>
  #include <linux/of_platform.h>
  #include <linux/platform_device.h>
  #include <linux/regmap.h>

  #include <linux/mfd/syscon.h>

  
  static struct platform_driver syscon_driver;
  
  struct syscon {

  	struct regmap *regmap;
  };

  static int syscon_match_node(struct device *dev, void *data)

  {

  	struct device_node *dn = data;

  	return (dev->of_node == dn) ? 1 : 0;

  }
  
  struct regmap *syscon_node_to_regmap(struct device_node *np)
  {
  	struct syscon *syscon;
  	struct device *dev;
  
  	dev = driver_find_device(&syscon_driver.driver, NULL, np,

  				 syscon_match_node);

  	if (!dev)
  		return ERR_PTR(-EPROBE_DEFER);
  
  	syscon = dev_get_drvdata(dev);
  
  	return syscon->regmap;
  }
  EXPORT_SYMBOL_GPL(syscon_node_to_regmap);
  
  struct regmap *syscon_regmap_lookup_by_compatible(const char *s)
  {
  	struct device_node *syscon_np;
  	struct regmap *regmap;
  
  	syscon_np = of_find_compatible_node(NULL, NULL, s);
  	if (!syscon_np)
  		return ERR_PTR(-ENODEV);
  
  	regmap = syscon_node_to_regmap(syscon_np);
  	of_node_put(syscon_np);
  
  	return regmap;
  }
  EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_compatible);

  static int syscon_match_pdevname(struct device *dev, void *data)
  {

  	return !strcmp(dev_name(dev), (const char *)data);
  }
  
  struct regmap *syscon_regmap_lookup_by_pdevname(const char *s)
  {
  	struct device *dev;
  	struct syscon *syscon;
  
  	dev = driver_find_device(&syscon_driver.driver, NULL, (void *)s,
  				 syscon_match_pdevname);
  	if (!dev)
  		return ERR_PTR(-EPROBE_DEFER);
  
  	syscon = dev_get_drvdata(dev);
  
  	return syscon->regmap;
  }
  EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_pdevname);

  struct regmap *syscon_regmap_lookup_by_phandle(struct device_node *np,
  					const char *property)
  {
  	struct device_node *syscon_np;
  	struct regmap *regmap;
  
  	syscon_np = of_parse_phandle(np, property, 0);
  	if (!syscon_np)
  		return ERR_PTR(-ENODEV);
  
  	regmap = syscon_node_to_regmap(syscon_np);
  	of_node_put(syscon_np);
  
  	return regmap;
  }
  EXPORT_SYMBOL_GPL(syscon_regmap_lookup_by_phandle);
  
  static const struct of_device_id of_syscon_match[] = {
  	{ .compatible = "syscon", },
  	{ },
  };
  
  static struct regmap_config syscon_regmap_config = {
  	.reg_bits = 32,
  	.val_bits = 32,
  	.reg_stride = 4,
  };

  static int syscon_probe(struct platform_device *pdev)

  {
  	struct device *dev = &pdev->dev;

  	struct syscon *syscon;

  	struct resource *res;

  	void __iomem *base;

  	syscon = devm_kzalloc(dev, sizeof(*syscon), GFP_KERNEL);

  	if (!syscon)
  		return -ENOMEM;

  	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
  	if (!res)
  		return -ENOENT;

  	base = devm_ioremap(dev, res->start, resource_size(res));
  	if (!base)

  		return -ENOMEM;

  	syscon_regmap_config.max_register = res->end - res->start - 3;

  	syscon->regmap = devm_regmap_init_mmio(dev, base,

  					&syscon_regmap_config);
  	if (IS_ERR(syscon->regmap)) {
  		dev_err(dev, "regmap init failed
  ");
  		return PTR_ERR(syscon->regmap);
  	}

  	platform_set_drvdata(pdev, syscon);

  	dev_dbg(dev, "regmap %pR registered
  ", res);

  
  	return 0;
  }

  static const struct platform_device_id syscon_ids[] = {
  	{ "syscon", },
  	{ }
  };

  
  static struct platform_driver syscon_driver = {
  	.driver = {
  		.name = "syscon",
  		.owner = THIS_MODULE,
  		.of_match_table = of_syscon_match,
  	},
  	.probe		= syscon_probe,

  	.id_table	= syscon_ids,

  };
  
  static int __init syscon_init(void)
  {
  	return platform_driver_register(&syscon_driver);
  }
  postcore_initcall(syscon_init);
  
  static void __exit syscon_exit(void)
  {
  	platform_driver_unregister(&syscon_driver);
  }
  module_exit(syscon_exit);
  
  MODULE_AUTHOR("Dong Aisheng <dong.aisheng@linaro.org>");
  MODULE_DESCRIPTION("System Control driver");
  MODULE_LICENSE("GPL v2");