drivers/clk/sunxi-ng/ccu_nm.c

   1 /*
   2  * Copyright (C) 2016 Maxime Ripard
   3  * Maxime Ripard <maxime.ripard@free-electrons.com>
   4  *
   5  * This program is free software; you can redistribute it and/or
   6  * modify it under the terms of the GNU General Public License as
   7  * published by the Free Software Foundation; either version 2 of
   8  * the License, or (at your option) any later version.
   9  */
  10
  11 #include <linux/clk-provider.h>
  12 #include <linux/io.h>
  13
  14 #include "ccu_frac.h"
  15 #include "ccu_gate.h"
  16 #include "ccu_nm.h"
  17
  18 struct _ccu_nm {
  19         unsigned long   n, min_n, max_n;
  20         unsigned long   m, min_m, max_m;
  21 };
  22
  23 static unsigned long ccu_nm_calc_rate(unsigned long parent,
  24                                       unsigned long n, unsigned long m)
  25 {
  26         u64 rate = parent;
  27
  28         rate *= n;
  29         do_div(rate, m);
  30
  31         return rate;
  32 }
  33
  34 static void ccu_nm_find_best(unsigned long parent, unsigned long rate,
  35                              struct _ccu_nm *nm)
  36 {
  37         unsigned long best_rate = 0;
  38         unsigned long best_n = 0, best_m = 0;
  39         unsigned long _n, _m;
  40
  41         for (_n = nm->min_n; _n <= nm->max_n; _n++) {
  42                 for (_m = nm->min_m; _m <= nm->max_m; _m++) {
  43                         unsigned long tmp_rate = ccu_nm_calc_rate(parent,
  44                                                                   _n, _m);
  45
  46                         if (tmp_rate > rate)
  47                                 continue;
  48
  49                         if ((rate - tmp_rate) < (rate - best_rate)) {
  50                                 best_rate = tmp_rate;
  51                                 best_n = _n;
  52                                 best_m = _m;
  53                         }
  54                 }
  55         }
  56
  57         nm->n = best_n;
  58         nm->m = best_m;
  59 }
  60
  61 static void ccu_nm_disable(struct clk_hw *hw)
  62 {
  63         struct ccu_nm *nm = hw_to_ccu_nm(hw);
  64
  65         return ccu_gate_helper_disable(&nm->common, nm->enable);
  66 }
  67
  68 static int ccu_nm_enable(struct clk_hw *hw)
  69 {
  70         struct ccu_nm *nm = hw_to_ccu_nm(hw);
  71
  72         return ccu_gate_helper_enable(&nm->common, nm->enable);
  73 }
  74
  75 static int ccu_nm_is_enabled(struct clk_hw *hw)
  76 {
  77         struct ccu_nm *nm = hw_to_ccu_nm(hw);
  78
  79         return ccu_gate_helper_is_enabled(&nm->common, nm->enable);
  80 }
  81
  82 static unsigned long ccu_nm_recalc_rate(struct clk_hw *hw,
  83                                         unsigned long parent_rate)
  84 {
  85         struct ccu_nm *nm = hw_to_ccu_nm(hw);
  86         unsigned long rate;
  87         unsigned long n, m;
  88         u32 reg;
  89
  90         if (ccu_frac_helper_is_enabled(&nm->common, &nm->frac)) {
  91                 rate = ccu_frac_helper_read_rate(&nm->common, &nm->frac);
  92
  93                 if (nm->common.features & CCU_FEATURE_FIXED_POSTDIV)
  94                         rate /= nm->fixed_post_div;
  95
  96                 return rate;
  97         }
  98
  99         reg = readl(nm->common.base + nm->common.reg);
 100
 101         n = reg >> nm->n.shift;
 102         n &= (1 << nm->n.width) - 1;
 103         n += nm->n.offset;
 104         if (!n)
 105                 n++;
 106
 107         m = reg >> nm->m.shift;
 108         m &= (1 << nm->m.width) - 1;
 109         m += nm->m.offset;
 110         if (!m)
 111                 m++;
 112
 113         if (ccu_sdm_helper_is_enabled(&nm->common, &nm->sdm))
 114                 rate = ccu_sdm_helper_read_rate(&nm->common, &nm->sdm, m, n);
 115         else
 116                 rate = ccu_nm_calc_rate(parent_rate, n, m);
 117
 118         if (nm->common.features & CCU_FEATURE_FIXED_POSTDIV)
 119                 rate /= nm->fixed_post_div;
 120
 121         return rate;
 122 }
 123
 124 static long ccu_nm_round_rate(struct clk_hw *hw, unsigned long rate,
 125                               unsigned long *parent_rate)
 126 {
 127         struct ccu_nm *nm = hw_to_ccu_nm(hw);
 128         struct _ccu_nm _nm;
 129
 130         if (nm->common.features & CCU_FEATURE_FIXED_POSTDIV)
 131                 rate *= nm->fixed_post_div;
 132
 133         if (rate < nm->min_rate) {
 134                 rate = nm->min_rate;
 135                 if (nm->common.features & CCU_FEATURE_FIXED_POSTDIV)
 136                         rate /= nm->fixed_post_div;
 137                 return rate;
 138         }
 139
 140         if (nm->max_rate && rate > nm->max_rate) {
 141                 rate = nm->max_rate;
 142                 if (nm->common.features & CCU_FEATURE_FIXED_POSTDIV)
 143                         rate /= nm->fixed_post_div;
 144                 return rate;
 145         }
 146
 147         if (ccu_frac_helper_has_rate(&nm->common, &nm->frac, rate)) {
 148                 if (nm->common.features & CCU_FEATURE_FIXED_POSTDIV)
 149                         rate /= nm->fixed_post_div;
 150                 return rate;
 151         }
 152
 153         if (ccu_sdm_helper_has_rate(&nm->common, &nm->sdm, rate)) {
 154                 if (nm->common.features & CCU_FEATURE_FIXED_POSTDIV)
 155                         rate /= nm->fixed_post_div;
 156                 return rate;
 157         }
 158
 159         _nm.min_n = nm->n.min ?: 1;
 160         _nm.max_n = nm->n.max ?: 1 << nm->n.width;
 161         _nm.min_m = 1;
 162         _nm.max_m = nm->m.max ?: 1 << nm->m.width;
 163
 164         ccu_nm_find_best(*parent_rate, rate, &_nm);
 165         rate = ccu_nm_calc_rate(*parent_rate, _nm.n, _nm.m);
 166
 167         if (nm->common.features & CCU_FEATURE_FIXED_POSTDIV)
 168                 rate /= nm->fixed_post_div;
 169
 170         return rate;
 171 }
 172
 173 static int ccu_nm_set_rate(struct clk_hw *hw, unsigned long rate,
 174                            unsigned long parent_rate)
 175 {
 176         struct ccu_nm *nm = hw_to_ccu_nm(hw);
 177         struct _ccu_nm _nm;
 178         unsigned long flags;
 179         u32 reg;
 180
 181         /* Adjust target rate according to post-dividers */
 182         if (nm->common.features & CCU_FEATURE_FIXED_POSTDIV)
 183                 rate = rate * nm->fixed_post_div;
 184
 185         if (ccu_frac_helper_has_rate(&nm->common, &nm->frac, rate)) {
 186                 spin_lock_irqsave(nm->common.lock, flags);
 187
 188                 /* most SoCs require M to be 0 if fractional mode is used */
 189                 reg = readl(nm->common.base + nm->common.reg);
 190                 reg &= ~GENMASK(nm->m.width + nm->m.shift - 1, nm->m.shift);
 191                 writel(reg, nm->common.base + nm->common.reg);
 192
 193                 spin_unlock_irqrestore(nm->common.lock, flags);
 194
 195                 ccu_frac_helper_enable(&nm->common, &nm->frac);
 196
 197                 return ccu_frac_helper_set_rate(&nm->common, &nm->frac,
 198                                                 rate, nm->lock);
 199         } else {
 200                 ccu_frac_helper_disable(&nm->common, &nm->frac);
 201         }
 202
 203         _nm.min_n = nm->n.min ?: 1;
 204         _nm.max_n = nm->n.max ?: 1 << nm->n.width;
 205         _nm.min_m = 1;
 206         _nm.max_m = nm->m.max ?: 1 << nm->m.width;
 207
 208         if (ccu_sdm_helper_has_rate(&nm->common, &nm->sdm, rate)) {
 209                 ccu_sdm_helper_enable(&nm->common, &nm->sdm, rate);
 210
 211                 /* Sigma delta modulation requires specific N and M factors */
 212                 ccu_sdm_helper_get_factors(&nm->common, &nm->sdm, rate,
 213                                            &_nm.m, &_nm.n);
 214         } else {
 215                 ccu_sdm_helper_disable(&nm->common, &nm->sdm);
 216                 ccu_nm_find_best(parent_rate, rate, &_nm);
 217         }
 218
 219         spin_lock_irqsave(nm->common.lock, flags);
 220
 221         reg = readl(nm->common.base + nm->common.reg);
 222         reg &= ~GENMASK(nm->n.width + nm->n.shift - 1, nm->n.shift);
 223         reg &= ~GENMASK(nm->m.width + nm->m.shift - 1, nm->m.shift);
 224
 225         reg |= (_nm.n - nm->n.offset) << nm->n.shift;
 226         reg |= (_nm.m - nm->m.offset) << nm->m.shift;
 227         writel(reg, nm->common.base + nm->common.reg);
 228
 229         spin_unlock_irqrestore(nm->common.lock, flags);
 230
 231         ccu_helper_wait_for_lock(&nm->common, nm->lock);
 232
 233         return 0;
 234 }
 235
 236 const struct clk_ops ccu_nm_ops = {
 237         .disable        = ccu_nm_disable,
 238         .enable         = ccu_nm_enable,
 239         .is_enabled     = ccu_nm_is_enabled,
 240
 241         .recalc_rate    = ccu_nm_recalc_rate,
 242         .round_rate     = ccu_nm_round_rate,
 243         .set_rate       = ccu_nm_set_rate,
 244 };