drivers/clk/imx/clk-pllv1.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 #include <linux/clk-provider.h>
   3 #include <linux/io.h>
   4 #include <linux/slab.h>
   5 #include <linux/kernel.h>
   6 #include <linux/err.h>
   7
   8 #include "clk.h"
   9
  10 /**
  11  * pll v1
  12  *
  13  * @clk_hw      clock source
  14  * @parent      the parent clock name
  15  * @base        base address of pll registers
  16  *
  17  * PLL clock version 1, found on i.MX1/21/25/27/31/35
  18  */
  19
  20 #define MFN_BITS        (10)
  21 #define MFN_SIGN        (BIT(MFN_BITS - 1))
  22 #define MFN_MASK        (MFN_SIGN - 1)
  23
  24 struct clk_pllv1 {
  25         struct clk_hw   hw;
  26         void __iomem    *base;
  27         enum imx_pllv1_type type;
  28 };
  29
  30 #define to_clk_pllv1(clk) (container_of(clk, struct clk_pllv1, clk))
  31
  32 static inline bool is_imx1_pllv1(struct clk_pllv1 *pll)
  33 {
  34         return pll->type == IMX_PLLV1_IMX1;
  35 }
  36
  37 static inline bool is_imx21_pllv1(struct clk_pllv1 *pll)
  38 {
  39         return pll->type == IMX_PLLV1_IMX21;
  40 }
  41
  42 static inline bool is_imx27_pllv1(struct clk_pllv1 *pll)
  43 {
  44         return pll->type == IMX_PLLV1_IMX27;
  45 }
  46
  47 static inline bool mfn_is_negative(struct clk_pllv1 *pll, unsigned int mfn)
  48 {
  49         return !is_imx1_pllv1(pll) && !is_imx21_pllv1(pll) && (mfn & MFN_SIGN);
  50 }
  51
  52 static unsigned long clk_pllv1_recalc_rate(struct clk_hw *hw,
  53                 unsigned long parent_rate)
  54 {
  55         struct clk_pllv1 *pll = to_clk_pllv1(hw);
  56         unsigned long long ull;
  57         int mfn_abs;
  58         unsigned int mfi, mfn, mfd, pd;
  59         u32 reg;
  60         unsigned long rate;
  61
  62         reg = readl(pll->base);
  63
  64         /*
  65          * Get the resulting clock rate from a PLL register value and the input
  66          * frequency. PLLs with this register layout can be found on i.MX1,
  67          * i.MX21, i.MX27 and i,MX31
  68          *
  69          *                  mfi + mfn / (mfd + 1)
  70          *  f = 2 * f_ref * --------------------
  71          *                        pd + 1
  72          */
  73
  74         mfi = (reg >> 10) & 0xf;
  75         mfn = reg & 0x3ff;
  76         mfd = (reg >> 16) & 0x3ff;
  77         pd =  (reg >> 26) & 0xf;
  78
  79         mfi = mfi <= 5 ? 5 : mfi;
  80
  81         mfn_abs = mfn;
  82
  83         /*
  84          * On all i.MXs except i.MX1 and i.MX21 mfn is a 10bit
  85          * 2's complements number.
  86          * On i.MX27 the bit 9 is the sign bit.
  87          */
  88         if (mfn_is_negative(pll, mfn)) {
  89                 if (is_imx27_pllv1(pll))
  90                         mfn_abs = mfn & MFN_MASK;
  91                 else
  92                         mfn_abs = BIT(MFN_BITS) - mfn;
  93         }
  94
  95         rate = parent_rate * 2;
  96         rate /= pd + 1;
  97
  98         ull = (unsigned long long)rate * mfn_abs;
  99
 100         do_div(ull, mfd + 1);
 101
 102         if (mfn_is_negative(pll, mfn))
 103                 ull = (rate * mfi) - ull;
 104         else
 105                 ull = (rate * mfi) + ull;
 106
 107         return ull;
 108 }
 109
 110 static struct clk_ops clk_pllv1_ops = {
 111         .recalc_rate = clk_pllv1_recalc_rate,
 112 };
 113
 114 struct clk *imx_clk_pllv1(enum imx_pllv1_type type, const char *name,
 115                 const char *parent, void __iomem *base)
 116 {
 117         struct clk_pllv1 *pll;
 118         struct clk *clk;
 119         struct clk_init_data init;
 120
 121         pll = kmalloc(sizeof(*pll), GFP_KERNEL);
 122         if (!pll)
 123                 return ERR_PTR(-ENOMEM);
 124
 125         pll->base = base;
 126         pll->type = type;
 127
 128         init.name = name;
 129         init.ops = &clk_pllv1_ops;
 130         init.flags = 0;
 131         init.parent_names = &parent;
 132         init.num_parents = 1;
 133
 134         pll->hw.init = &init;
 135
 136         clk = clk_register(NULL, &pll->hw);
 137         if (IS_ERR(clk))
 138                 kfree(pll);
 139
 140         return clk;
 141 }