/*
   * Copyright (C) 2011 Sascha Hauer, Pengutronix <s.hauer@pengutronix.de>
   *
   * 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.
   *
   * Standard functionality for the common clock API.
   */
  #include <linux/module.h>
  #include <linux/clk-provider.h>
  #include <linux/slab.h>
  #include <linux/err.h>

  #include <linux/of.h>

  #include <linux/platform_device.h>

  
  /*
   * DOC: basic fixed multiplier and divider clock that cannot gate
   *
   * Traits of this clock:
   * prepare - clk_prepare only ensures that parents are prepared
   * enable - clk_enable only ensures that parents are enabled
   * rate - rate is fixed.  clk->rate = parent->rate / div * mult
   * parent - fixed parent.  No clk_set_parent support
   */

  static unsigned long clk_factor_recalc_rate(struct clk_hw *hw,
  		unsigned long parent_rate)
  {
  	struct clk_fixed_factor *fix = to_clk_fixed_factor(hw);

  	unsigned long long int rate;

  	rate = (unsigned long long int)parent_rate * fix->mult;
  	do_div(rate, fix->div);
  	return (unsigned long)rate;

  }
  
  static long clk_factor_round_rate(struct clk_hw *hw, unsigned long rate,
  				unsigned long *prate)
  {
  	struct clk_fixed_factor *fix = to_clk_fixed_factor(hw);

  	if (clk_hw_get_flags(hw) & CLK_SET_RATE_PARENT) {

  		unsigned long best_parent;
  
  		best_parent = (rate / fix->mult) * fix->div;

  		*prate = clk_hw_round_rate(clk_hw_get_parent(hw), best_parent);

  	}
  
  	return (*prate / fix->div) * fix->mult;
  }
  
  static int clk_factor_set_rate(struct clk_hw *hw, unsigned long rate,
  				unsigned long parent_rate)
  {

  	/*
  	 * We must report success but we can do so unconditionally because
  	 * clk_factor_round_rate returns values that ensure this call is a
  	 * nop.
  	 */

  	return 0;
  }

  const struct clk_ops clk_fixed_factor_ops = {

  	.round_rate = clk_factor_round_rate,
  	.set_rate = clk_factor_set_rate,
  	.recalc_rate = clk_factor_recalc_rate,
  };
  EXPORT_SYMBOL_GPL(clk_fixed_factor_ops);

  struct clk_hw *clk_hw_register_fixed_factor(struct device *dev,
  		const char *name, const char *parent_name, unsigned long flags,

  		unsigned int mult, unsigned int div)
  {
  	struct clk_fixed_factor *fix;
  	struct clk_init_data init;

  	struct clk_hw *hw;
  	int ret;

  
  	fix = kmalloc(sizeof(*fix), GFP_KERNEL);

  	if (!fix)

  		return ERR_PTR(-ENOMEM);

  
  	/* struct clk_fixed_factor assignments */
  	fix->mult = mult;
  	fix->div = div;
  	fix->hw.init = &init;
  
  	init.name = name;
  	init.ops = &clk_fixed_factor_ops;

  	init.flags = flags | CLK_IS_BASIC;

  	init.parent_names = &parent_name;
  	init.num_parents = 1;

  	hw = &fix->hw;
  	ret = clk_hw_register(dev, hw);
  	if (ret) {

  		kfree(fix);

  		hw = ERR_PTR(ret);
  	}

  	return hw;
  }
  EXPORT_SYMBOL_GPL(clk_hw_register_fixed_factor);
  
  struct clk *clk_register_fixed_factor(struct device *dev, const char *name,
  		const char *parent_name, unsigned long flags,
  		unsigned int mult, unsigned int div)
  {
  	struct clk_hw *hw;
  
  	hw = clk_hw_register_fixed_factor(dev, name, parent_name, flags, mult,
  					  div);
  	if (IS_ERR(hw))
  		return ERR_CAST(hw);
  	return hw->clk;

  }

  EXPORT_SYMBOL_GPL(clk_register_fixed_factor);

  
  void clk_unregister_fixed_factor(struct clk *clk)
  {
  	struct clk_hw *hw;
  
  	hw = __clk_get_hw(clk);
  	if (!hw)
  		return;
  
  	clk_unregister(clk);
  	kfree(to_clk_fixed_factor(hw));
  }
  EXPORT_SYMBOL_GPL(clk_unregister_fixed_factor);

  
  void clk_hw_unregister_fixed_factor(struct clk_hw *hw)
  {
  	struct clk_fixed_factor *fix;
  
  	fix = to_clk_fixed_factor(hw);
  
  	clk_hw_unregister(hw);
  	kfree(fix);
  }
  EXPORT_SYMBOL_GPL(clk_hw_unregister_fixed_factor);

  #ifdef CONFIG_OF

  static const struct of_device_id set_rate_parent_matches[] = {
  	{ .compatible = "allwinner,sun4i-a10-pll3-2x-clk" },
  	{ /* Sentinel */ },
  };

  static struct clk *_of_fixed_factor_clk_setup(struct device_node *node)

  {
  	struct clk *clk;
  	const char *clk_name = node->name;
  	const char *parent_name;

  	unsigned long flags = 0;

  	u32 div, mult;

  	int ret;

  
  	if (of_property_read_u32(node, "clock-div", &div)) {
  		pr_err("%s Fixed factor clock <%s> must have a clock-div property
  ",
  			__func__, node->name);

  		return ERR_PTR(-EIO);

  	}
  
  	if (of_property_read_u32(node, "clock-mult", &mult)) {

  		pr_err("%s Fixed factor clock <%s> must have a clock-mult property
  ",

  			__func__, node->name);

  		return ERR_PTR(-EIO);

  	}
  
  	of_property_read_string(node, "clock-output-names", &clk_name);
  	parent_name = of_clk_get_parent_name(node, 0);

  	if (of_match_node(set_rate_parent_matches, node))
  		flags |= CLK_SET_RATE_PARENT;
  
  	clk = clk_register_fixed_factor(NULL, clk_name, parent_name, flags,

  					mult, div);

  	if (IS_ERR(clk))
  		return clk;
  
  	ret = of_clk_add_provider(node, of_clk_src_simple_get, clk);
  	if (ret) {
  		clk_unregister(clk);
  		return ERR_PTR(ret);
  	}
  
  	return clk;
  }
  
  /**
   * of_fixed_factor_clk_setup() - Setup function for simple fixed factor clock
   */
  void __init of_fixed_factor_clk_setup(struct device_node *node)
  {
  	_of_fixed_factor_clk_setup(node);

  }

  CLK_OF_DECLARE(fixed_factor_clk, "fixed-factor-clock",
  		of_fixed_factor_clk_setup);

  
  static int of_fixed_factor_clk_remove(struct platform_device *pdev)
  {
  	struct clk *clk = platform_get_drvdata(pdev);
  
  	clk_unregister_fixed_factor(clk);
  
  	return 0;
  }
  
  static int of_fixed_factor_clk_probe(struct platform_device *pdev)
  {
  	struct clk *clk;
  
  	/*
  	 * This function is not executed when of_fixed_factor_clk_setup
  	 * succeeded.
  	 */
  	clk = _of_fixed_factor_clk_setup(pdev->dev.of_node);
  	if (IS_ERR(clk))
  		return PTR_ERR(clk);
  
  	platform_set_drvdata(pdev, clk);
  
  	return 0;
  }
  
  static const struct of_device_id of_fixed_factor_clk_ids[] = {
  	{ .compatible = "fixed-factor-clock" },
  	{ }
  };
  MODULE_DEVICE_TABLE(of, of_fixed_factor_clk_ids);
  
  static struct platform_driver of_fixed_factor_clk_driver = {
  	.driver = {
  		.name = "of_fixed_factor_clk",
  		.of_match_table = of_fixed_factor_clk_ids,
  	},
  	.probe = of_fixed_factor_clk_probe,
  	.remove = of_fixed_factor_clk_remove,
  };
  builtin_platform_driver(of_fixed_factor_clk_driver);

  #endif