drivers/clk/actions/owl-factor.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 //
   3 // OWL factor clock driver
   4 //
   5 // Copyright (c) 2014 Actions Semi Inc.
   6 // Author: David Liu <liuwei@actions-semi.com>
   7 //
   8 // Copyright (c) 2018 Linaro Ltd.
   9 // Author: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
  10
  11 #include <linux/clk-provider.h>
  12 #include <linux/regmap.h>
  13 #include <linux/slab.h>
  14
  15 #include "owl-factor.h"
  16
  17 static unsigned int _get_table_maxval(const struct clk_factor_table *table)
  18 {
  19         unsigned int maxval = 0;
  20         const struct clk_factor_table *clkt;
  21
  22         for (clkt = table; clkt->div; clkt++)
  23                 if (clkt->val > maxval)
  24                         maxval = clkt->val;
  25         return maxval;
  26 }
  27
  28 static int _get_table_div_mul(const struct clk_factor_table *table,
  29                         unsigned int val, unsigned int *mul, unsigned int *div)
  30 {
  31         const struct clk_factor_table *clkt;
  32
  33         for (clkt = table; clkt->div; clkt++) {
  34                 if (clkt->val == val) {
  35                         *mul = clkt->mul;
  36                         *div = clkt->div;
  37                         return 1;
  38                 }
  39         }
  40
  41         return 0;
  42 }
  43
  44 static unsigned int _get_table_val(const struct clk_factor_table *table,
  45                         unsigned long rate, unsigned long parent_rate)
  46 {
  47         const struct clk_factor_table *clkt;
  48         int val = -1;
  49         u64 calc_rate;
  50
  51         for (clkt = table; clkt->div; clkt++) {
  52                 calc_rate = parent_rate * clkt->mul;
  53                 do_div(calc_rate, clkt->div);
  54
  55                 if ((unsigned long)calc_rate <= rate) {
  56                         val = clkt->val;
  57                         break;
  58                 }
  59         }
  60
  61         if (val == -1)
  62                 val = _get_table_maxval(table);
  63
  64         return val;
  65 }
  66
  67 static int owl_clk_val_best(const struct owl_factor_hw *factor_hw,
  68                         struct clk_hw *hw, unsigned long rate,
  69                         unsigned long *best_parent_rate)
  70 {
  71         const struct clk_factor_table *clkt = factor_hw->table;
  72         unsigned long parent_rate, try_parent_rate, best = 0, cur_rate;
  73         unsigned long parent_rate_saved = *best_parent_rate;
  74         int bestval = 0;
  75
  76         if (!rate)
  77                 rate = 1;
  78
  79         if (!(clk_hw_get_flags(hw) & CLK_SET_RATE_PARENT)) {
  80                 parent_rate = *best_parent_rate;
  81                 bestval = _get_table_val(clkt, rate, parent_rate);
  82                 return bestval;
  83         }
  84
  85         for (clkt = factor_hw->table; clkt->div; clkt++) {
  86                 try_parent_rate = rate * clkt->div / clkt->mul;
  87
  88                 if (try_parent_rate == parent_rate_saved) {
  89                         pr_debug("%s: [%d %d %d] found try_parent_rate %ld\n",
  90                                 __func__, clkt->val, clkt->mul, clkt->div,
  91                                 try_parent_rate);
  92                         /*
  93                          * It's the most ideal case if the requested rate can be
  94                          * divided from parent clock without any need to change
  95                          * parent rate, so return the divider immediately.
  96                          */
  97                         *best_parent_rate = parent_rate_saved;
  98                         return clkt->val;
  99                 }
 100
 101                 parent_rate = clk_hw_round_rate(clk_hw_get_parent(hw),
 102                                 try_parent_rate);
 103                 cur_rate = DIV_ROUND_UP(parent_rate, clkt->div) * clkt->mul;
 104                 if (cur_rate <= rate && cur_rate > best) {
 105                         bestval = clkt->val;
 106                         best = cur_rate;
 107                         *best_parent_rate = parent_rate;
 108                 }
 109         }
 110
 111         if (!bestval) {
 112                 bestval = _get_table_maxval(clkt);
 113                 *best_parent_rate = clk_hw_round_rate(
 114                                 clk_hw_get_parent(hw), 1);
 115         }
 116
 117         return bestval;
 118 }
 119
 120 long owl_factor_helper_round_rate(struct owl_clk_common *common,
 121                                 const struct owl_factor_hw *factor_hw,
 122                                 unsigned long rate,
 123                                 unsigned long *parent_rate)
 124 {
 125         const struct clk_factor_table *clkt = factor_hw->table;
 126         unsigned int val, mul = 0, div = 1;
 127
 128         val = owl_clk_val_best(factor_hw, &common->hw, rate, parent_rate);
 129         _get_table_div_mul(clkt, val, &mul, &div);
 130
 131         return *parent_rate * mul / div;
 132 }
 133
 134 static long owl_factor_round_rate(struct clk_hw *hw, unsigned long rate,
 135                         unsigned long *parent_rate)
 136 {
 137         struct owl_factor *factor = hw_to_owl_factor(hw);
 138         struct owl_factor_hw *factor_hw = &factor->factor_hw;
 139
 140         return owl_factor_helper_round_rate(&factor->common, factor_hw,
 141                                         rate, parent_rate);
 142 }
 143
 144 unsigned long owl_factor_helper_recalc_rate(struct owl_clk_common *common,
 145                                          const struct owl_factor_hw *factor_hw,
 146                                          unsigned long parent_rate)
 147 {
 148         const struct clk_factor_table *clkt = factor_hw->table;
 149         unsigned long long int rate;
 150         u32 reg, val, mul, div;
 151
 152         div = 0;
 153         mul = 0;
 154
 155         regmap_read(common->regmap, factor_hw->reg, &reg);
 156
 157         val = reg >> factor_hw->shift;
 158         val &= div_mask(factor_hw);
 159
 160         _get_table_div_mul(clkt, val, &mul, &div);
 161         if (!div) {
 162                 WARN(!(factor_hw->fct_flags & CLK_DIVIDER_ALLOW_ZERO),
 163                         "%s: Zero divisor and CLK_DIVIDER_ALLOW_ZERO not set\n",
 164                         __clk_get_name(common->hw.clk));
 165                 return parent_rate;
 166         }
 167
 168         rate = (unsigned long long int)parent_rate * mul;
 169         do_div(rate, div);
 170
 171         return rate;
 172 }
 173
 174 static unsigned long owl_factor_recalc_rate(struct clk_hw *hw,
 175                         unsigned long parent_rate)
 176 {
 177         struct owl_factor *factor = hw_to_owl_factor(hw);
 178         struct owl_factor_hw *factor_hw = &factor->factor_hw;
 179         struct owl_clk_common *common = &factor->common;
 180
 181         return owl_factor_helper_recalc_rate(common, factor_hw, parent_rate);
 182 }
 183
 184 int owl_factor_helper_set_rate(const struct owl_clk_common *common,
 185                                 const struct owl_factor_hw *factor_hw,
 186                                 unsigned long rate,
 187                                 unsigned long parent_rate)
 188 {
 189         u32 val, reg;
 190
 191         val = _get_table_val(factor_hw->table, rate, parent_rate);
 192
 193         if (val > div_mask(factor_hw))
 194                 val = div_mask(factor_hw);
 195
 196         regmap_read(common->regmap, factor_hw->reg, &reg);
 197
 198         reg &= ~(div_mask(factor_hw) << factor_hw->shift);
 199         reg |= val << factor_hw->shift;
 200
 201         regmap_write(common->regmap, factor_hw->reg, reg);
 202
 203         return 0;
 204 }
 205
 206 static int owl_factor_set_rate(struct clk_hw *hw, unsigned long rate,
 207                                unsigned long parent_rate)
 208 {
 209         struct owl_factor *factor = hw_to_owl_factor(hw);
 210         struct owl_factor_hw *factor_hw = &factor->factor_hw;
 211         struct owl_clk_common *common = &factor->common;
 212
 213         return owl_factor_helper_set_rate(common, factor_hw,
 214                                         rate, parent_rate);
 215 }
 216
 217 const struct clk_ops owl_factor_ops = {
 218         .round_rate     = owl_factor_round_rate,
 219         .recalc_rate    = owl_factor_recalc_rate,
 220         .set_rate       = owl_factor_set_rate,
 221 };