drivers/clk/imx/clk-pllv1.c

   1 #include <linux/clk-provider.h>
   2 #include <linux/io.h>
   3 #include <linux/slab.h>
   4 #include <linux/kernel.h>
   5 #include <linux/err.h>
   6
   7 #include "clk.h"
   8
   9 /**
  10  * pll v1
  11  *
  12  * @clk_hw      clock source
  13  * @parent      the parent clock name
  14  * @base        base address of pll registers
  15  *
  16  * PLL clock version 1, found on i.MX1/21/25/27/31/35
  17  */
  18
  19 #define MFN_BITS        (10)
  20 #define MFN_SIGN        (BIT(MFN_BITS - 1))
  21 #define MFN_MASK        (MFN_SIGN - 1)
  22
  23 struct clk_pllv1 {
  24         struct clk_hw   hw;
  25         void __iomem    *base;
  26         enum imx_pllv1_type type;
  27 };
  28
  29 #define to_clk_pllv1(clk) (container_of(clk, struct clk_pllv1, clk))
  30
  31 static inline bool is_imx1_pllv1(struct clk_pllv1 *pll)
  32 {
  33         return pll->type == IMX_PLLV1_IMX1;
  34 }
  35
  36 static inline bool is_imx21_pllv1(struct clk_pllv1 *pll)
  37 {
  38         return pll->type == IMX_PLLV1_IMX21;
  39 }
  40
  41 static inline bool is_imx27_pllv1(struct clk_pllv1 *pll)
  42 {
  43         return pll->type == IMX_PLLV1_IMX27;
  44 }
  45
  46 static inline bool mfn_is_negative(struct clk_pllv1 *pll, unsigned int mfn)
  47 {
  48         return !is_imx1_pllv1(pll) && !is_imx21_pllv1(pll) && (mfn & MFN_SIGN);
  49 }
  50
  51 static unsigned long clk_pllv1_recalc_rate(struct clk_hw *hw,
  52                 unsigned long parent_rate)
  53 {
  54         struct clk_pllv1 *pll = to_clk_pllv1(hw);
  55         unsigned long long ull;
  56         int mfn_abs;
  57         unsigned int mfi, mfn, mfd, pd;
  58         u32 reg;
  59         unsigned long rate;
  60
  61         reg = readl(pll->base);
  62
  63         /*
  64          * Get the resulting clock rate from a PLL register value and the input
  65          * frequency. PLLs with this register layout can be found on i.MX1,
  66          * i.MX21, i.MX27 and i,MX31
  67          *
  68          *                  mfi + mfn / (mfd + 1)
  69          *  f = 2 * f_ref * --------------------
  70          *                        pd + 1
  71          */
  72
  73         mfi = (reg >> 10) & 0xf;
  74         mfn = reg & 0x3ff;
  75         mfd = (reg >> 16) & 0x3ff;
  76         pd =  (reg >> 26) & 0xf;
  77
  78         mfi = mfi <= 5 ? 5 : mfi;
  79
  80         mfn_abs = mfn;
  81
  82         /*
  83          * On all i.MXs except i.MX1 and i.MX21 mfn is a 10bit
  84          * 2's complements number.
  85          * On i.MX27 the bit 9 is the sign bit.
  86          */
  87         if (mfn_is_negative(pll, mfn)) {
  88                 if (is_imx27_pllv1(pll))
  89                         mfn_abs = mfn & MFN_MASK;
  90                 else
  91                         mfn_abs = BIT(MFN_BITS) - mfn;
  92         }
  93
  94         rate = parent_rate * 2;
  95         rate /= pd + 1;
  96
  97         ull = (unsigned long long)rate * mfn_abs;
  98
  99         do_div(ull, mfd + 1);
 100
 101         if (mfn_is_negative(pll, mfn))
 102                 ull = (rate * mfi) - ull;
 103         else
 104                 ull = (rate * mfi) + ull;
 105
 106         return ull;
 107 }
 108
 109 static struct clk_ops clk_pllv1_ops = {
 110         .recalc_rate = clk_pllv1_recalc_rate,
 111 };
 112
 113 struct clk *imx_clk_pllv1(enum imx_pllv1_type type, const char *name,
 114                 const char *parent, void __iomem *base)
 115 {
 116         struct clk_pllv1 *pll;
 117         struct clk *clk;
 118         struct clk_init_data init;
 119
 120         pll = kmalloc(sizeof(*pll), GFP_KERNEL);
 121         if (!pll)
 122                 return ERR_PTR(-ENOMEM);
 123
 124         pll->base = base;
 125         pll->type = type;
 126
 127         init.name = name;
 128         init.ops = &clk_pllv1_ops;
 129         init.flags = 0;
 130         init.parent_names = &parent;
 131         init.num_parents = 1;
 132
 133         pll->hw.init = &init;
 134
 135         clk = clk_register(NULL, &pll->hw);
 136         if (IS_ERR(clk))
 137                 kfree(pll);
 138
 139         return clk;
 140 }