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kernel/linux-imx6_3.14.28/arch/arm/mach-imx/clk-pllv1.c 2.4 KB
6b13f685e   김민수   BSP 최초 추가
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  #include <linux/clk.h>
  #include <linux/clk-provider.h>
  #include <linux/io.h>
  #include <linux/slab.h>
  #include <linux/kernel.h>
  #include <linux/err.h>
  
  #include "clk.h"
  #include "common.h"
  #include "hardware.h"
  
  /**
   * pll v1
   *
   * @clk_hw	clock source
   * @parent	the parent clock name
   * @base	base address of pll registers
   *
   * PLL clock version 1, found on i.MX1/21/25/27/31/35
   */
  
  #define MFN_BITS	(10)
  #define MFN_SIGN	(BIT(MFN_BITS - 1))
  #define MFN_MASK	(MFN_SIGN - 1)
  
  struct clk_pllv1 {
  	struct clk_hw	hw;
  	void __iomem	*base;
  };
  
  #define to_clk_pllv1(clk) (container_of(clk, struct clk_pllv1, clk))
  
  static inline bool mfn_is_negative(unsigned int mfn)
  {
  	return !cpu_is_mx1() && !cpu_is_mx21() && (mfn & MFN_SIGN);
  }
  
  static unsigned long clk_pllv1_recalc_rate(struct clk_hw *hw,
  		unsigned long parent_rate)
  {
  	struct clk_pllv1 *pll = to_clk_pllv1(hw);
  	long long ll;
  	int mfn_abs;
  	unsigned int mfi, mfn, mfd, pd;
  	u32 reg;
  	unsigned long rate;
  
  	reg = readl(pll->base);
  
  	/*
  	 * Get the resulting clock rate from a PLL register value and the input
  	 * frequency. PLLs with this register layout can be found on i.MX1,
  	 * i.MX21, i.MX27 and i,MX31
  	 *
  	 *                  mfi + mfn / (mfd + 1)
  	 *  f = 2 * f_ref * --------------------
  	 *                        pd + 1
  	 */
  
  	mfi = (reg >> 10) & 0xf;
  	mfn = reg & 0x3ff;
  	mfd = (reg >> 16) & 0x3ff;
  	pd =  (reg >> 26) & 0xf;
  
  	mfi = mfi <= 5 ? 5 : mfi;
  
  	mfn_abs = mfn;
  
  	/*
  	 * On all i.MXs except i.MX1 and i.MX21 mfn is a 10bit
  	 * 2's complements number.
  	 * On i.MX27 the bit 9 is the sign bit.
  	 */
  	if (mfn_is_negative(mfn)) {
  		if (cpu_is_mx27())
  			mfn_abs = mfn & MFN_MASK;
  		else
  			mfn_abs = BIT(MFN_BITS) - mfn;
  	}
  
  	rate = parent_rate * 2;
  	rate /= pd + 1;
  
  	ll = (unsigned long long)rate * mfn_abs;
  
  	do_div(ll, mfd + 1);
  
  	if (mfn_is_negative(mfn))
  		ll = -ll;
  
  	ll = (rate * mfi) + ll;
  
  	return ll;
  }
  
  static struct clk_ops clk_pllv1_ops = {
  	.recalc_rate = clk_pllv1_recalc_rate,
  };
  
  struct clk *imx_clk_pllv1(const char *name, const char *parent,
  		void __iomem *base)
  {
  	struct clk_pllv1 *pll;
  	struct clk *clk;
  	struct clk_init_data init;
  
  	pll = kmalloc(sizeof(*pll), GFP_KERNEL);
  	if (!pll)
  		return ERR_PTR(-ENOMEM);
  
  	pll->base = base;
  
  	init.name = name;
  	init.ops = &clk_pllv1_ops;
  	init.flags = 0;
  	init.parent_names = &parent;
  	init.num_parents = 1;
  
  	pll->hw.init = &init;
  
  	clk = clk_register(NULL, &pll->hw);
  	if (IS_ERR(clk))
  		kfree(pll);
  
  	return clk;
  }