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kernel/linux-imx6_3.14.28/arch/arm/mach-imx/clk-fixup-div.c 3.28 KB
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  /*
   * Copyright (C) 2013 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-provider.h>
  #include <linux/err.h>
  #include <linux/io.h>
  #include <linux/slab.h>
  #include "clk.h"
  
  #define to_clk_div(_hw) container_of(_hw, struct clk_divider, hw)
  #define div_mask(d)	((1 << (d->width)) - 1)
  
  /**
   * struct clk_fixup_div - imx integer fixup divider clock
   * @divider: the parent class
   * @ops: pointer to clk_ops of parent class
   * @fixup: a hook to fixup the write value
   *
   * The imx fixup divider clock is a subclass of basic clk_divider
   * with an addtional fixup hook.
   */
  struct clk_fixup_div {
  	struct clk_divider divider;
  	const struct clk_ops *ops;
  	void (*fixup)(u32 *val);
  };
  
  static inline struct clk_fixup_div *to_clk_fixup_div(struct clk_hw *hw)
  {
  	struct clk_divider *divider = to_clk_div(hw);
  
  	return container_of(divider, struct clk_fixup_div, divider);
  }
  
  static unsigned long clk_fixup_div_recalc_rate(struct clk_hw *hw,
  					 unsigned long parent_rate)
  {
  	struct clk_fixup_div *fixup_div = to_clk_fixup_div(hw);
  
  	return fixup_div->ops->recalc_rate(&fixup_div->divider.hw, parent_rate);
  }
  
  static long clk_fixup_div_round_rate(struct clk_hw *hw, unsigned long rate,
  			       unsigned long *prate)
  {
  	struct clk_fixup_div *fixup_div = to_clk_fixup_div(hw);
  
  	return fixup_div->ops->round_rate(&fixup_div->divider.hw, rate, prate);
  }
  
  static int clk_fixup_div_set_rate(struct clk_hw *hw, unsigned long rate,
  			    unsigned long parent_rate)
  {
  	struct clk_fixup_div *fixup_div = to_clk_fixup_div(hw);
  	struct clk_divider *div = to_clk_div(hw);
  	unsigned int divider, value;
  	unsigned long flags = 0;
  	u32 val;
  
  	divider = parent_rate / rate;
  
  	/* Zero based divider */
  	value = divider - 1;
  
  	if (value > div_mask(div))
  		value = div_mask(div);
  
  	spin_lock_irqsave(div->lock, flags);
  
  	val = readl(div->reg);
  	val &= ~(div_mask(div) << div->shift);
  	val |= value << div->shift;
  	fixup_div->fixup(&val);
  	writel(val, div->reg);
  
  	spin_unlock_irqrestore(div->lock, flags);
  
  	return 0;
  }
  
  static const struct clk_ops clk_fixup_div_ops = {
  	.recalc_rate = clk_fixup_div_recalc_rate,
  	.round_rate = clk_fixup_div_round_rate,
  	.set_rate = clk_fixup_div_set_rate,
  };
  
  struct clk *imx_clk_fixup_divider(const char *name, const char *parent,
  				  void __iomem *reg, u8 shift, u8 width,
  				  void (*fixup)(u32 *val))
  {
  	struct clk_fixup_div *fixup_div;
  	struct clk *clk;
  	struct clk_init_data init;
  
  	if (!fixup)
  		return ERR_PTR(-EINVAL);
  
  	fixup_div = kzalloc(sizeof(*fixup_div), GFP_KERNEL);
  	if (!fixup_div)
  		return ERR_PTR(-ENOMEM);
  
  	init.name = name;
  	init.ops = &clk_fixup_div_ops;
  	init.flags = CLK_SET_RATE_PARENT;
  	init.parent_names = parent ? &parent : NULL;
  	init.num_parents = parent ? 1 : 0;
  
  	fixup_div->divider.reg = reg;
  	fixup_div->divider.shift = shift;
  	fixup_div->divider.width = width;
  	fixup_div->divider.lock = &imx_ccm_lock;
  	fixup_div->divider.hw.init = &init;
  	fixup_div->ops = &clk_divider_ops;
  	fixup_div->fixup = fixup;
  
  	clk = clk_register(NULL, &fixup_div->divider.hw);
  	if (IS_ERR(clk))
  		kfree(fixup_div);
  
  	return clk;
  }