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kernel/linux-imx6_3.14.28/drivers/clk/clk-fixed-factor.c 3.6 KB
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  /*
   * 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>
  
  /*
   * 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
   */
  
  #define to_clk_fixed_factor(_hw) container_of(_hw, struct clk_fixed_factor, hw)
  
  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_get_flags(hw->clk) & CLK_SET_RATE_PARENT) {
  		unsigned long best_parent;
  
  		best_parent = (rate / fix->mult) * fix->div;
  		*prate = __clk_round_rate(__clk_get_parent(hw->clk),
  				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)
  {
  	return 0;
  }
  
  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 *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_fixed_factor *fix;
  	struct clk_init_data init;
  	struct clk *clk;
  
  	fix = kmalloc(sizeof(*fix), GFP_KERNEL);
  	if (!fix) {
  		pr_err("%s: could not allocate fixed factor clk
  ", __func__);
  		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;
  
  	clk = clk_register(dev, &fix->hw);
  
  	if (IS_ERR(clk))
  		kfree(fix);
  
  	return clk;
  }
  EXPORT_SYMBOL_GPL(clk_register_fixed_factor);
  
  #ifdef CONFIG_OF
  /**
   * of_fixed_factor_clk_setup() - Setup function for simple fixed factor clock
   */
  void __init of_fixed_factor_clk_setup(struct device_node *node)
  {
  	struct clk *clk;
  	const char *clk_name = node->name;
  	const char *parent_name;
  	u32 div, mult;
  
  	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;
  	}
  
  	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;
  	}
  
  	of_property_read_string(node, "clock-output-names", &clk_name);
  	parent_name = of_clk_get_parent_name(node, 0);
  
  	clk = clk_register_fixed_factor(NULL, clk_name, parent_name, 0,
  					mult, div);
  	if (!IS_ERR(clk))
  		of_clk_add_provider(node, of_clk_src_simple_get, clk);
  }
  EXPORT_SYMBOL_GPL(of_fixed_factor_clk_setup);
  CLK_OF_DECLARE(fixed_factor_clk, "fixed-factor-clock",
  		of_fixed_factor_clk_setup);
  #endif