/*
   * Copyright (C) 2010-2011 Canonical Ltd <jeremy.kerr@canonical.com>
   * Copyright (C) 2011-2012 Mike Turquette, Linaro Ltd <mturquette@linaro.org>
   *
   * 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.
   *
   * Fixed rate clock implementation
   */
  
  #include <linux/clk-provider.h>
  #include <linux/module.h>
  #include <linux/slab.h>
  #include <linux/io.h>
  #include <linux/err.h>
  #include <linux/of.h>
  
  /*
   * DOC: basic fixed-rate clock that cannot gate
   *
   * Traits of this clock:
   * prepare - clk_(un)prepare only ensures parents are prepared
   * enable - clk_enable only ensures parents are enabled
   * rate - rate is always a fixed value.  No clk_set_rate support
   * parent - fixed parent.  No clk_set_parent support
   */
  
  #define to_clk_fixed_rate(_hw) container_of(_hw, struct clk_fixed_rate, hw)
  
  static unsigned long clk_fixed_rate_recalc_rate(struct clk_hw *hw,
  		unsigned long parent_rate)
  {
  	return to_clk_fixed_rate(hw)->fixed_rate;
  }
  
  static unsigned long clk_fixed_rate_recalc_accuracy(struct clk_hw *hw,
  		unsigned long parent_accuracy)
  {
  	return to_clk_fixed_rate(hw)->fixed_accuracy;
  }
  
  const struct clk_ops clk_fixed_rate_ops = {
  	.recalc_rate = clk_fixed_rate_recalc_rate,
  	.recalc_accuracy = clk_fixed_rate_recalc_accuracy,
  };
  EXPORT_SYMBOL_GPL(clk_fixed_rate_ops);
  
  /**
   * clk_register_fixed_rate_with_accuracy - register fixed-rate clock with the
   *					   clock framework
   * @dev: device that is registering this clock
   * @name: name of this clock
   * @parent_name: name of clock's parent
   * @flags: framework-specific flags
   * @fixed_rate: non-adjustable clock rate
   * @fixed_accuracy: non-adjustable clock rate
   */
  struct clk *clk_register_fixed_rate_with_accuracy(struct device *dev,
  		const char *name, const char *parent_name, unsigned long flags,
  		unsigned long fixed_rate, unsigned long fixed_accuracy)
  {
  	struct clk_fixed_rate *fixed;
  	struct clk *clk;
  	struct clk_init_data init;
  
  	/* allocate fixed-rate clock */
  	fixed = kzalloc(sizeof(struct clk_fixed_rate), GFP_KERNEL);
  	if (!fixed) {
  		pr_err("%s: could not allocate fixed clk
  ", __func__);
  		return ERR_PTR(-ENOMEM);
  	}
  
  	init.name = name;
  	init.ops = &clk_fixed_rate_ops;
  	init.flags = flags | CLK_IS_BASIC;
  	init.parent_names = (parent_name ? &parent_name: NULL);
  	init.num_parents = (parent_name ? 1 : 0);
  
  	/* struct clk_fixed_rate assignments */
  	fixed->fixed_rate = fixed_rate;
  	fixed->fixed_accuracy = fixed_accuracy;
  	fixed->hw.init = &init;
  
  	/* register the clock */
  	clk = clk_register(dev, &fixed->hw);
  	if (IS_ERR(clk))
  		kfree(fixed);
  
  	return clk;
  }
  EXPORT_SYMBOL_GPL(clk_register_fixed_rate_with_accuracy);
  
  /**
   * clk_register_fixed_rate - register fixed-rate clock with the clock framework
   * @dev: device that is registering this clock
   * @name: name of this clock
   * @parent_name: name of clock's parent
   * @flags: framework-specific flags
   * @fixed_rate: non-adjustable clock rate
   */
  struct clk *clk_register_fixed_rate(struct device *dev, const char *name,
  		const char *parent_name, unsigned long flags,
  		unsigned long fixed_rate)
  {
  	return clk_register_fixed_rate_with_accuracy(dev, name, parent_name,
  						     flags, fixed_rate, 0);
  }
  EXPORT_SYMBOL_GPL(clk_register_fixed_rate);
  
  #ifdef CONFIG_OF
  /**
   * of_fixed_clk_setup() - Setup function for simple fixed rate clock
   */
  void of_fixed_clk_setup(struct device_node *node)
  {
  	struct clk *clk;
  	const char *clk_name = node->name;
  	u32 rate;
  	u32 accuracy = 0;
  
  	if (of_property_read_u32(node, "clock-frequency", &rate))
  		return;
  
  	of_property_read_u32(node, "clock-accuracy", &accuracy);
  
  	of_property_read_string(node, "clock-output-names", &clk_name);
  
  	clk = clk_register_fixed_rate_with_accuracy(NULL, clk_name, NULL,
  						    CLK_IS_ROOT, rate,
  						    accuracy);
  	if (!IS_ERR(clk))
  		of_clk_add_provider(node, of_clk_src_simple_get, clk);
  }
  EXPORT_SYMBOL_GPL(of_fixed_clk_setup);
  CLK_OF_DECLARE(fixed_clk, "fixed-clock", of_fixed_clk_setup);
  #endif