drivers/clk/sunxi-ng/ccu_nm.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * Copyright (C) 2016 Maxime Ripard
   4  * Maxime Ripard <maxime.ripard@free-electrons.com>
   5  */
   6
   7 #include <linux/clk-provider.h>
   8 #include <linux/io.h>
   9
  10 #include "ccu_frac.h"
  11 #include "ccu_gate.h"
  12 #include "ccu_nm.h"
  13
  14 struct _ccu_nm {
  15         unsigned long   n, min_n, max_n;
  16         unsigned long   m, min_m, max_m;
  17 };
  18
  19 static unsigned long ccu_nm_calc_rate(unsigned long parent,
  20                                       unsigned long n, unsigned long m)
  21 {
  22         u64 rate = parent;
  23
  24         rate *= n;
  25         do_div(rate, m);
  26
  27         return rate;
  28 }
  29
  30 static unsigned long ccu_nm_find_best(struct ccu_common *common, unsigned long parent,
  31                                       unsigned long rate, struct _ccu_nm *nm)
  32 {
  33         unsigned long best_rate = 0;
  34         unsigned long best_n = 0, best_m = 0;
  35         unsigned long _n, _m;
  36
  37         for (_n = nm->min_n; _n <= nm->max_n; _n++) {
  38                 for (_m = nm->min_m; _m <= nm->max_m; _m++) {
  39                         unsigned long tmp_rate = ccu_nm_calc_rate(parent,
  40                                                                   _n, _m);
  41
  42                         if (ccu_is_better_rate(common, rate, tmp_rate, best_rate)) {
  43                                 best_rate = tmp_rate;
  44                                 best_n = _n;
  45                                 best_m = _m;
  46                         }
  47                 }
  48         }
  49
  50         nm->n = best_n;
  51         nm->m = best_m;
  52
  53         return best_rate;
  54 }
  55
  56 static void ccu_nm_disable(struct clk_hw *hw)
  57 {
  58         struct ccu_nm *nm = hw_to_ccu_nm(hw);
  59
  60         return ccu_gate_helper_disable(&nm->common, nm->enable);
  61 }
  62
  63 static int ccu_nm_enable(struct clk_hw *hw)
  64 {
  65         struct ccu_nm *nm = hw_to_ccu_nm(hw);
  66
  67         return ccu_gate_helper_enable(&nm->common, nm->enable);
  68 }
  69
  70 static int ccu_nm_is_enabled(struct clk_hw *hw)
  71 {
  72         struct ccu_nm *nm = hw_to_ccu_nm(hw);
  73
  74         return ccu_gate_helper_is_enabled(&nm->common, nm->enable);
  75 }
  76
  77 static unsigned long ccu_nm_recalc_rate(struct clk_hw *hw,
  78                                         unsigned long parent_rate)
  79 {
  80         struct ccu_nm *nm = hw_to_ccu_nm(hw);
  81         unsigned long rate;
  82         unsigned long n, m;
  83         u32 reg;
  84
  85         if (ccu_frac_helper_is_enabled(&nm->common, &nm->frac)) {
  86                 rate = ccu_frac_helper_read_rate(&nm->common, &nm->frac);
  87
  88                 if (nm->common.features & CCU_FEATURE_FIXED_POSTDIV)
  89                         rate /= nm->fixed_post_div;
  90
  91                 return rate;
  92         }
  93
  94         reg = readl(nm->common.base + nm->common.reg);
  95
  96         n = reg >> nm->n.shift;
  97         n &= (1 << nm->n.width) - 1;
  98         n += nm->n.offset;
  99         if (!n)
 100                 n++;
 101
 102         m = reg >> nm->m.shift;
 103         m &= (1 << nm->m.width) - 1;
 104         m += nm->m.offset;
 105         if (!m)
 106                 m++;
 107
 108         if (ccu_sdm_helper_is_enabled(&nm->common, &nm->sdm))
 109                 rate = ccu_sdm_helper_read_rate(&nm->common, &nm->sdm, m, n);
 110         else
 111                 rate = ccu_nm_calc_rate(parent_rate, n, m);
 112
 113         if (nm->common.features & CCU_FEATURE_FIXED_POSTDIV)
 114                 rate /= nm->fixed_post_div;
 115
 116         return rate;
 117 }
 118
 119 static long ccu_nm_round_rate(struct clk_hw *hw, unsigned long rate,
 120                               unsigned long *parent_rate)
 121 {
 122         struct ccu_nm *nm = hw_to_ccu_nm(hw);
 123         struct _ccu_nm _nm;
 124
 125         if (nm->common.features & CCU_FEATURE_FIXED_POSTDIV)
 126                 rate *= nm->fixed_post_div;
 127
 128         if (rate < nm->min_rate) {
 129                 rate = nm->min_rate;
 130                 if (nm->common.features & CCU_FEATURE_FIXED_POSTDIV)
 131                         rate /= nm->fixed_post_div;
 132                 return rate;
 133         }
 134
 135         if (nm->max_rate && rate > nm->max_rate) {
 136                 rate = nm->max_rate;
 137                 if (nm->common.features & CCU_FEATURE_FIXED_POSTDIV)
 138                         rate /= nm->fixed_post_div;
 139                 return rate;
 140         }
 141
 142         if (ccu_frac_helper_has_rate(&nm->common, &nm->frac, rate)) {
 143                 if (nm->common.features & CCU_FEATURE_FIXED_POSTDIV)
 144                         rate /= nm->fixed_post_div;
 145                 return rate;
 146         }
 147
 148         if (ccu_sdm_helper_has_rate(&nm->common, &nm->sdm, rate)) {
 149                 if (nm->common.features & CCU_FEATURE_FIXED_POSTDIV)
 150                         rate /= nm->fixed_post_div;
 151                 return rate;
 152         }
 153
 154         _nm.min_n = nm->n.min ?: 1;
 155         _nm.max_n = nm->n.max ?: 1 << nm->n.width;
 156         _nm.min_m = 1;
 157         _nm.max_m = nm->m.max ?: 1 << nm->m.width;
 158
 159         rate = ccu_nm_find_best(&nm->common, *parent_rate, rate, &_nm);
 160
 161         if (nm->common.features & CCU_FEATURE_FIXED_POSTDIV)
 162                 rate /= nm->fixed_post_div;
 163
 164         return rate;
 165 }
 166
 167 static int ccu_nm_set_rate(struct clk_hw *hw, unsigned long rate,
 168                            unsigned long parent_rate)
 169 {
 170         struct ccu_nm *nm = hw_to_ccu_nm(hw);
 171         struct _ccu_nm _nm;
 172         unsigned long flags;
 173         u32 reg;
 174
 175         /* Adjust target rate according to post-dividers */
 176         if (nm->common.features & CCU_FEATURE_FIXED_POSTDIV)
 177                 rate = rate * nm->fixed_post_div;
 178
 179         if (ccu_frac_helper_has_rate(&nm->common, &nm->frac, rate)) {
 180                 spin_lock_irqsave(nm->common.lock, flags);
 181
 182                 /* most SoCs require M to be 0 if fractional mode is used */
 183                 reg = readl(nm->common.base + nm->common.reg);
 184                 reg &= ~GENMASK(nm->m.width + nm->m.shift - 1, nm->m.shift);
 185                 writel(reg, nm->common.base + nm->common.reg);
 186
 187                 spin_unlock_irqrestore(nm->common.lock, flags);
 188
 189                 ccu_frac_helper_enable(&nm->common, &nm->frac);
 190
 191                 return ccu_frac_helper_set_rate(&nm->common, &nm->frac,
 192                                                 rate, nm->lock);
 193         } else {
 194                 ccu_frac_helper_disable(&nm->common, &nm->frac);
 195         }
 196
 197         _nm.min_n = nm->n.min ?: 1;
 198         _nm.max_n = nm->n.max ?: 1 << nm->n.width;
 199         _nm.min_m = 1;
 200         _nm.max_m = nm->m.max ?: 1 << nm->m.width;
 201
 202         if (ccu_sdm_helper_has_rate(&nm->common, &nm->sdm, rate)) {
 203                 ccu_sdm_helper_enable(&nm->common, &nm->sdm, rate);
 204
 205                 /* Sigma delta modulation requires specific N and M factors */
 206                 ccu_sdm_helper_get_factors(&nm->common, &nm->sdm, rate,
 207                                            &_nm.m, &_nm.n);
 208         } else {
 209                 ccu_sdm_helper_disable(&nm->common, &nm->sdm);
 210                 ccu_nm_find_best(&nm->common, parent_rate, rate, &_nm);
 211         }
 212
 213         spin_lock_irqsave(nm->common.lock, flags);
 214
 215         reg = readl(nm->common.base + nm->common.reg);
 216         reg &= ~GENMASK(nm->n.width + nm->n.shift - 1, nm->n.shift);
 217         reg &= ~GENMASK(nm->m.width + nm->m.shift - 1, nm->m.shift);
 218
 219         reg |= (_nm.n - nm->n.offset) << nm->n.shift;
 220         reg |= (_nm.m - nm->m.offset) << nm->m.shift;
 221         writel(reg, nm->common.base + nm->common.reg);
 222
 223         spin_unlock_irqrestore(nm->common.lock, flags);
 224
 225         ccu_helper_wait_for_lock(&nm->common, nm->lock);
 226
 227         return 0;
 228 }
 229
 230 const struct clk_ops ccu_nm_ops = {
 231         .disable        = ccu_nm_disable,
 232         .enable         = ccu_nm_enable,
 233         .is_enabled     = ccu_nm_is_enabled,
 234
 235         .recalc_rate    = ccu_nm_recalc_rate,
 236         .round_rate     = ccu_nm_round_rate,
 237         .set_rate       = ccu_nm_set_rate,
 238 };
 239 EXPORT_SYMBOL_NS_GPL(ccu_nm_ops, SUNXI_CCU);