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 void ccu_nm_find_best(unsigned long parent, unsigned long rate,
  31                              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 (tmp_rate > rate)
  43                                 continue;
  44
  45                         if ((rate - tmp_rate) < (rate - best_rate)) {
  46                                 best_rate = tmp_rate;
  47                                 best_n = _n;
  48                                 best_m = _m;
  49                         }
  50                 }
  51         }
  52
  53         nm->n = best_n;
  54         nm->m = best_m;
  55 }
  56
  57 static void ccu_nm_disable(struct clk_hw *hw)
  58 {
  59         struct ccu_nm *nm = hw_to_ccu_nm(hw);
  60
  61         return ccu_gate_helper_disable(&nm->common, nm->enable);
  62 }
  63
  64 static int ccu_nm_enable(struct clk_hw *hw)
  65 {
  66         struct ccu_nm *nm = hw_to_ccu_nm(hw);
  67
  68         return ccu_gate_helper_enable(&nm->common, nm->enable);
  69 }
  70
  71 static int ccu_nm_is_enabled(struct clk_hw *hw)
  72 {
  73         struct ccu_nm *nm = hw_to_ccu_nm(hw);
  74
  75         return ccu_gate_helper_is_enabled(&nm->common, nm->enable);
  76 }
  77
  78 static unsigned long ccu_nm_recalc_rate(struct clk_hw *hw,
  79                                         unsigned long parent_rate)
  80 {
  81         struct ccu_nm *nm = hw_to_ccu_nm(hw);
  82         unsigned long rate;
  83         unsigned long n, m;
  84         u32 reg;
  85
  86         if (ccu_frac_helper_is_enabled(&nm->common, &nm->frac)) {
  87                 rate = ccu_frac_helper_read_rate(&nm->common, &nm->frac);
  88
  89                 if (nm->common.features & CCU_FEATURE_FIXED_POSTDIV)
  90                         rate /= nm->fixed_post_div;
  91
  92                 return rate;
  93         }
  94
  95         reg = readl(nm->common.base + nm->common.reg);
  96
  97         n = reg >> nm->n.shift;
  98         n &= (1 << nm->n.width) - 1;
  99         n += nm->n.offset;
 100         if (!n)
 101                 n++;
 102
 103         m = reg >> nm->m.shift;
 104         m &= (1 << nm->m.width) - 1;
 105         m += nm->m.offset;
 106         if (!m)
 107                 m++;
 108
 109         if (ccu_sdm_helper_is_enabled(&nm->common, &nm->sdm))
 110                 rate = ccu_sdm_helper_read_rate(&nm->common, &nm->sdm, m, n);
 111         else
 112                 rate = ccu_nm_calc_rate(parent_rate, n, m);
 113
 114         if (nm->common.features & CCU_FEATURE_FIXED_POSTDIV)
 115                 rate /= nm->fixed_post_div;
 116
 117         return rate;
 118 }
 119
 120 static long ccu_nm_round_rate(struct clk_hw *hw, unsigned long rate,
 121                               unsigned long *parent_rate)
 122 {
 123         struct ccu_nm *nm = hw_to_ccu_nm(hw);
 124         struct _ccu_nm _nm;
 125
 126         if (nm->common.features & CCU_FEATURE_FIXED_POSTDIV)
 127                 rate *= nm->fixed_post_div;
 128
 129         if (rate < nm->min_rate) {
 130                 rate = nm->min_rate;
 131                 if (nm->common.features & CCU_FEATURE_FIXED_POSTDIV)
 132                         rate /= nm->fixed_post_div;
 133                 return rate;
 134         }
 135
 136         if (nm->max_rate && rate > nm->max_rate) {
 137                 rate = nm->max_rate;
 138                 if (nm->common.features & CCU_FEATURE_FIXED_POSTDIV)
 139                         rate /= nm->fixed_post_div;
 140                 return rate;
 141         }
 142
 143         if (ccu_frac_helper_has_rate(&nm->common, &nm->frac, rate)) {
 144                 if (nm->common.features & CCU_FEATURE_FIXED_POSTDIV)
 145                         rate /= nm->fixed_post_div;
 146                 return rate;
 147         }
 148
 149         if (ccu_sdm_helper_has_rate(&nm->common, &nm->sdm, rate)) {
 150                 if (nm->common.features & CCU_FEATURE_FIXED_POSTDIV)
 151                         rate /= nm->fixed_post_div;
 152                 return rate;
 153         }
 154
 155         _nm.min_n = nm->n.min ?: 1;
 156         _nm.max_n = nm->n.max ?: 1 << nm->n.width;
 157         _nm.min_m = 1;
 158         _nm.max_m = nm->m.max ?: 1 << nm->m.width;
 159
 160         ccu_nm_find_best(*parent_rate, rate, &_nm);
 161         rate = ccu_nm_calc_rate(*parent_rate, _nm.n, _nm.m);
 162
 163         if (nm->common.features & CCU_FEATURE_FIXED_POSTDIV)
 164                 rate /= nm->fixed_post_div;
 165
 166         return rate;
 167 }
 168
 169 static int ccu_nm_set_rate(struct clk_hw *hw, unsigned long rate,
 170                            unsigned long parent_rate)
 171 {
 172         struct ccu_nm *nm = hw_to_ccu_nm(hw);
 173         struct _ccu_nm _nm;
 174         unsigned long flags;
 175         u32 reg;
 176
 177         /* Adjust target rate according to post-dividers */
 178         if (nm->common.features & CCU_FEATURE_FIXED_POSTDIV)
 179                 rate = rate * nm->fixed_post_div;
 180
 181         if (ccu_frac_helper_has_rate(&nm->common, &nm->frac, rate)) {
 182                 spin_lock_irqsave(nm->common.lock, flags);
 183
 184                 /* most SoCs require M to be 0 if fractional mode is used */
 185                 reg = readl(nm->common.base + nm->common.reg);
 186                 reg &= ~GENMASK(nm->m.width + nm->m.shift - 1, nm->m.shift);
 187                 writel(reg, nm->common.base + nm->common.reg);
 188
 189                 spin_unlock_irqrestore(nm->common.lock, flags);
 190
 191                 ccu_frac_helper_enable(&nm->common, &nm->frac);
 192
 193                 return ccu_frac_helper_set_rate(&nm->common, &nm->frac,
 194                                                 rate, nm->lock);
 195         } else {
 196                 ccu_frac_helper_disable(&nm->common, &nm->frac);
 197         }
 198
 199         _nm.min_n = nm->n.min ?: 1;
 200         _nm.max_n = nm->n.max ?: 1 << nm->n.width;
 201         _nm.min_m = 1;
 202         _nm.max_m = nm->m.max ?: 1 << nm->m.width;
 203
 204         if (ccu_sdm_helper_has_rate(&nm->common, &nm->sdm, rate)) {
 205                 ccu_sdm_helper_enable(&nm->common, &nm->sdm, rate);
 206
 207                 /* Sigma delta modulation requires specific N and M factors */
 208                 ccu_sdm_helper_get_factors(&nm->common, &nm->sdm, rate,
 209                                            &_nm.m, &_nm.n);
 210         } else {
 211                 ccu_sdm_helper_disable(&nm->common, &nm->sdm);
 212                 ccu_nm_find_best(parent_rate, rate, &_nm);
 213         }
 214
 215         spin_lock_irqsave(nm->common.lock, flags);
 216
 217         reg = readl(nm->common.base + nm->common.reg);
 218         reg &= ~GENMASK(nm->n.width + nm->n.shift - 1, nm->n.shift);
 219         reg &= ~GENMASK(nm->m.width + nm->m.shift - 1, nm->m.shift);
 220
 221         reg |= (_nm.n - nm->n.offset) << nm->n.shift;
 222         reg |= (_nm.m - nm->m.offset) << nm->m.shift;
 223         writel(reg, nm->common.base + nm->common.reg);
 224
 225         spin_unlock_irqrestore(nm->common.lock, flags);
 226
 227         ccu_helper_wait_for_lock(&nm->common, nm->lock);
 228
 229         return 0;
 230 }
 231
 232 const struct clk_ops ccu_nm_ops = {
 233         .disable        = ccu_nm_disable,
 234         .enable         = ccu_nm_enable,
 235         .is_enabled     = ccu_nm_is_enabled,
 236
 237         .recalc_rate    = ccu_nm_recalc_rate,
 238         .round_rate     = ccu_nm_round_rate,
 239         .set_rate       = ccu_nm_set_rate,
 240 };