drivers/clk/mmp/clk-frac.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * mmp factor clock operation source file
   4  *
   5  * Copyright (C) 2012 Marvell
   6  * Chao Xie <xiechao.mail@gmail.com>
   7  */
   8
   9 #include <linux/clk-provider.h>
  10 #include <linux/slab.h>
  11 #include <linux/io.h>
  12 #include <linux/err.h>
  13
  14 #include "clk.h"
  15 /*
  16  * It is M/N clock
  17  *
  18  * Fout from synthesizer can be given from two equations:
  19  * numerator/denominator = Fin / (Fout * factor)
  20  */
  21
  22 #define to_clk_factor(hw) container_of(hw, struct mmp_clk_factor, hw)
  23
  24 static long clk_factor_round_rate(struct clk_hw *hw, unsigned long drate,
  25                 unsigned long *prate)
  26 {
  27         struct mmp_clk_factor *factor = to_clk_factor(hw);
  28         u64 rate = 0, prev_rate;
  29         int i;
  30
  31         for (i = 0; i < factor->ftbl_cnt; i++) {
  32                 prev_rate = rate;
  33                 rate = *prate;
  34                 rate *= factor->ftbl[i].den;
  35                 do_div(rate, factor->ftbl[i].num * factor->masks->factor);
  36
  37                 if (rate > drate)
  38                         break;
  39         }
  40         if ((i == 0) || (i == factor->ftbl_cnt)) {
  41                 return rate;
  42         } else {
  43                 if ((drate - prev_rate) > (rate - drate))
  44                         return rate;
  45                 else
  46                         return prev_rate;
  47         }
  48 }
  49
  50 static unsigned long clk_factor_recalc_rate(struct clk_hw *hw,
  51                 unsigned long parent_rate)
  52 {
  53         struct mmp_clk_factor *factor = to_clk_factor(hw);
  54         struct mmp_clk_factor_masks *masks = factor->masks;
  55         unsigned int val, num, den;
  56         u64 rate;
  57
  58         val = readl_relaxed(factor->base);
  59
  60         /* calculate numerator */
  61         num = (val >> masks->num_shift) & masks->num_mask;
  62
  63         /* calculate denominator */
  64         den = (val >> masks->den_shift) & masks->den_mask;
  65
  66         if (!den)
  67                 return 0;
  68
  69         rate = parent_rate;
  70         rate *= den;
  71         do_div(rate, num * factor->masks->factor);
  72
  73         return rate;
  74 }
  75
  76 /* Configures new clock rate*/
  77 static int clk_factor_set_rate(struct clk_hw *hw, unsigned long drate,
  78                                 unsigned long prate)
  79 {
  80         struct mmp_clk_factor *factor = to_clk_factor(hw);
  81         struct mmp_clk_factor_masks *masks = factor->masks;
  82         int i;
  83         unsigned long val;
  84         unsigned long flags = 0;
  85         u64 rate = 0;
  86
  87         for (i = 0; i < factor->ftbl_cnt; i++) {
  88                 rate = prate;
  89                 rate *= factor->ftbl[i].den;
  90                 do_div(rate, factor->ftbl[i].num * factor->masks->factor);
  91
  92                 if (rate > drate)
  93                         break;
  94         }
  95         if (i > 0)
  96                 i--;
  97
  98         if (factor->lock)
  99                 spin_lock_irqsave(factor->lock, flags);
 100
 101         val = readl_relaxed(factor->base);
 102
 103         val &= ~(masks->num_mask << masks->num_shift);
 104         val |= (factor->ftbl[i].num & masks->num_mask) << masks->num_shift;
 105
 106         val &= ~(masks->den_mask << masks->den_shift);
 107         val |= (factor->ftbl[i].den & masks->den_mask) << masks->den_shift;
 108
 109         writel_relaxed(val, factor->base);
 110
 111         if (factor->lock)
 112                 spin_unlock_irqrestore(factor->lock, flags);
 113
 114         return 0;
 115 }
 116
 117 static int clk_factor_init(struct clk_hw *hw)
 118 {
 119         struct mmp_clk_factor *factor = to_clk_factor(hw);
 120         struct mmp_clk_factor_masks *masks = factor->masks;
 121         u32 val, num, den;
 122         int i;
 123         unsigned long flags = 0;
 124
 125         if (factor->lock)
 126                 spin_lock_irqsave(factor->lock, flags);
 127
 128         val = readl(factor->base);
 129
 130         /* calculate numerator */
 131         num = (val >> masks->num_shift) & masks->num_mask;
 132
 133         /* calculate denominator */
 134         den = (val >> masks->den_shift) & masks->den_mask;
 135
 136         for (i = 0; i < factor->ftbl_cnt; i++)
 137                 if (den == factor->ftbl[i].den && num == factor->ftbl[i].num)
 138                         break;
 139
 140         if (i >= factor->ftbl_cnt) {
 141                 val &= ~(masks->num_mask << masks->num_shift);
 142                 val |= (factor->ftbl[0].num & masks->num_mask) <<
 143                         masks->num_shift;
 144
 145                 val &= ~(masks->den_mask << masks->den_shift);
 146                 val |= (factor->ftbl[0].den & masks->den_mask) <<
 147                         masks->den_shift;
 148         }
 149
 150         if (!(val & masks->enable_mask) || i >= factor->ftbl_cnt) {
 151                 val |= masks->enable_mask;
 152                 writel(val, factor->base);
 153         }
 154
 155         if (factor->lock)
 156                 spin_unlock_irqrestore(factor->lock, flags);
 157
 158         return 0;
 159 }
 160
 161 static const struct clk_ops clk_factor_ops = {
 162         .recalc_rate = clk_factor_recalc_rate,
 163         .round_rate = clk_factor_round_rate,
 164         .set_rate = clk_factor_set_rate,
 165         .init = clk_factor_init,
 166 };
 167
 168 struct clk *mmp_clk_register_factor(const char *name, const char *parent_name,
 169                 unsigned long flags, void __iomem *base,
 170                 struct mmp_clk_factor_masks *masks,
 171                 struct mmp_clk_factor_tbl *ftbl,
 172                 unsigned int ftbl_cnt, spinlock_t *lock)
 173 {
 174         struct mmp_clk_factor *factor;
 175         struct clk_init_data init;
 176         struct clk *clk;
 177
 178         if (!masks) {
 179                 pr_err("%s: must pass a clk_factor_mask\n", __func__);
 180                 return ERR_PTR(-EINVAL);
 181         }
 182
 183         factor = kzalloc(sizeof(*factor), GFP_KERNEL);
 184         if (!factor)
 185                 return ERR_PTR(-ENOMEM);
 186
 187         /* struct clk_aux assignments */
 188         factor->base = base;
 189         factor->masks = masks;
 190         factor->ftbl = ftbl;
 191         factor->ftbl_cnt = ftbl_cnt;
 192         factor->hw.init = &init;
 193         factor->lock = lock;
 194
 195         init.name = name;
 196         init.ops = &clk_factor_ops;
 197         init.flags = flags;
 198         init.parent_names = &parent_name;
 199         init.num_parents = 1;
 200
 201         clk = clk_register(NULL, &factor->hw);
 202         if (IS_ERR_OR_NULL(clk))
 203                 kfree(factor);
 204
 205         return clk;
 206 }