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kernel/linux-imx6_3.14.28/drivers/clk/mxs/clk-div.c 2.62 KB
6b13f685e   김민수   BSP 최초 추가
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  /*
   * Copyright 2012 Freescale Semiconductor, Inc.
   *
   * The code contained herein is licensed under the GNU General Public
   * License. You may obtain a copy of the GNU General Public License
   * Version 2 or later at the following locations:
   *
   * http://www.opensource.org/licenses/gpl-license.html
   * http://www.gnu.org/copyleft/gpl.html
   */
  
  #include <linux/clk.h>
  #include <linux/clk-provider.h>
  #include <linux/err.h>
  #include <linux/slab.h>
  #include "clk.h"
  
  /**
   * struct clk_div - mxs integer divider clock
   * @divider: the parent class
   * @ops: pointer to clk_ops of parent class
   * @reg: register address
   * @busy: busy bit shift
   *
   * The mxs divider clock is a subclass of basic clk_divider with an
   * addtional busy bit.
   */
  struct clk_div {
  	struct clk_divider divider;
  	const struct clk_ops *ops;
  	void __iomem *reg;
  	u8 busy;
  };
  
  static inline struct clk_div *to_clk_div(struct clk_hw *hw)
  {
  	struct clk_divider *divider = container_of(hw, struct clk_divider, hw);
  
  	return container_of(divider, struct clk_div, divider);
  }
  
  static unsigned long clk_div_recalc_rate(struct clk_hw *hw,
  					 unsigned long parent_rate)
  {
  	struct clk_div *div = to_clk_div(hw);
  
  	return div->ops->recalc_rate(&div->divider.hw, parent_rate);
  }
  
  static long clk_div_round_rate(struct clk_hw *hw, unsigned long rate,
  			       unsigned long *prate)
  {
  	struct clk_div *div = to_clk_div(hw);
  
  	return div->ops->round_rate(&div->divider.hw, rate, prate);
  }
  
  static int clk_div_set_rate(struct clk_hw *hw, unsigned long rate,
  			    unsigned long parent_rate)
  {
  	struct clk_div *div = to_clk_div(hw);
  	int ret;
  
  	ret = div->ops->set_rate(&div->divider.hw, rate, parent_rate);
  	if (!ret)
  		ret = mxs_clk_wait(div->reg, div->busy);
  
  	return ret;
  }
  
  static struct clk_ops clk_div_ops = {
  	.recalc_rate = clk_div_recalc_rate,
  	.round_rate = clk_div_round_rate,
  	.set_rate = clk_div_set_rate,
  };
  
  struct clk *mxs_clk_div(const char *name, const char *parent_name,
  			void __iomem *reg, u8 shift, u8 width, u8 busy)
  {
  	struct clk_div *div;
  	struct clk *clk;
  	struct clk_init_data init;
  
  	div = kzalloc(sizeof(*div), GFP_KERNEL);
  	if (!div)
  		return ERR_PTR(-ENOMEM);
  
  	init.name = name;
  	init.ops = &clk_div_ops;
  	init.flags = CLK_SET_RATE_PARENT;
  	init.parent_names = (parent_name ? &parent_name: NULL);
  	init.num_parents = (parent_name ? 1 : 0);
  
  	div->reg = reg;
  	div->busy = busy;
  
  	div->divider.reg = reg;
  	div->divider.shift = shift;
  	div->divider.width = width;
  	div->divider.flags = CLK_DIVIDER_ONE_BASED;
  	div->divider.lock = &mxs_lock;
  	div->divider.hw.init = &init;
  	div->ops = &clk_divider_ops;
  
  	clk = clk_register(NULL, &div->divider.hw);
  	if (IS_ERR(clk))
  		kfree(div);
  
  	return clk;
  }