drivers/clk/sunxi-ng/ccu_mux.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.h>
   8 #include <linux/clk-provider.h>
   9 #include <linux/delay.h>
  10 #include <linux/io.h>
  11
  12 #include "ccu_gate.h"
  13 #include "ccu_mux.h"
  14
  15 static u16 ccu_mux_get_prediv(struct ccu_common *common,
  16                               struct ccu_mux_internal *cm,
  17                               int parent_index)
  18 {
  19         u16 prediv = 1;
  20         u32 reg;
  21
  22         if (!((common->features & CCU_FEATURE_FIXED_PREDIV) ||
  23               (common->features & CCU_FEATURE_VARIABLE_PREDIV) ||
  24               (common->features & CCU_FEATURE_ALL_PREDIV)))
  25                 return 1;
  26
  27         if (common->features & CCU_FEATURE_ALL_PREDIV)
  28                 return common->prediv;
  29
  30         reg = readl(common->base + common->reg);
  31         if (parent_index < 0) {
  32                 parent_index = reg >> cm->shift;
  33                 parent_index &= (1 << cm->width) - 1;
  34         }
  35
  36         if (common->features & CCU_FEATURE_FIXED_PREDIV) {
  37                 int i;
  38
  39                 for (i = 0; i < cm->n_predivs; i++)
  40                         if (parent_index == cm->fixed_predivs[i].index)
  41                                 prediv = cm->fixed_predivs[i].div;
  42         }
  43
  44         if (common->features & CCU_FEATURE_VARIABLE_PREDIV) {
  45                 int i;
  46
  47                 for (i = 0; i < cm->n_var_predivs; i++)
  48                         if (parent_index == cm->var_predivs[i].index) {
  49                                 u8 div;
  50
  51                                 div = reg >> cm->var_predivs[i].shift;
  52                                 div &= (1 << cm->var_predivs[i].width) - 1;
  53                                 prediv = div + 1;
  54                         }
  55         }
  56
  57         return prediv;
  58 }
  59
  60 unsigned long ccu_mux_helper_apply_prediv(struct ccu_common *common,
  61                                           struct ccu_mux_internal *cm,
  62                                           int parent_index,
  63                                           unsigned long parent_rate)
  64 {
  65         return parent_rate / ccu_mux_get_prediv(common, cm, parent_index);
  66 }
  67
  68 static unsigned long ccu_mux_helper_unapply_prediv(struct ccu_common *common,
  69                                             struct ccu_mux_internal *cm,
  70                                             int parent_index,
  71                                             unsigned long parent_rate)
  72 {
  73         return parent_rate * ccu_mux_get_prediv(common, cm, parent_index);
  74 }
  75
  76 int ccu_mux_helper_determine_rate(struct ccu_common *common,
  77                                   struct ccu_mux_internal *cm,
  78                                   struct clk_rate_request *req,
  79                                   unsigned long (*round)(struct ccu_mux_internal *,
  80                                                          struct clk_hw *,
  81                                                          unsigned long *,
  82                                                          unsigned long,
  83                                                          void *),
  84                                   void *data)
  85 {
  86         unsigned long best_parent_rate = 0, best_rate = 0;
  87         struct clk_hw *best_parent, *hw = &common->hw;
  88         unsigned int i;
  89
  90         if (clk_hw_get_flags(hw) & CLK_SET_RATE_NO_REPARENT) {
  91                 unsigned long adj_parent_rate;
  92
  93                 best_parent = clk_hw_get_parent(hw);
  94                 best_parent_rate = clk_hw_get_rate(best_parent);
  95                 adj_parent_rate = ccu_mux_helper_apply_prediv(common, cm, -1,
  96                                                               best_parent_rate);
  97
  98                 best_rate = round(cm, best_parent, &adj_parent_rate,
  99                                   req->rate, data);
 100
 101                 /*
 102                  * adj_parent_rate might have been modified by our clock.
 103                  * Unapply the pre-divider if there's one, and give
 104                  * the actual frequency the parent needs to run at.
 105                  */
 106                 best_parent_rate = ccu_mux_helper_unapply_prediv(common, cm, -1,
 107                                                                  adj_parent_rate);
 108
 109                 goto out;
 110         }
 111
 112         for (i = 0; i < clk_hw_get_num_parents(hw); i++) {
 113                 unsigned long tmp_rate, parent_rate;
 114                 struct clk_hw *parent;
 115
 116                 parent = clk_hw_get_parent_by_index(hw, i);
 117                 if (!parent)
 118                         continue;
 119
 120                 parent_rate = ccu_mux_helper_apply_prediv(common, cm, i,
 121                                                           clk_hw_get_rate(parent));
 122
 123                 tmp_rate = round(cm, parent, &parent_rate, req->rate, data);
 124
 125                 /*
 126                  * parent_rate might have been modified by our clock.
 127                  * Unapply the pre-divider if there's one, and give
 128                  * the actual frequency the parent needs to run at.
 129                  */
 130                 parent_rate = ccu_mux_helper_unapply_prediv(common, cm, i,
 131                                                             parent_rate);
 132                 if (tmp_rate == req->rate) {
 133                         best_parent = parent;
 134                         best_parent_rate = parent_rate;
 135                         best_rate = tmp_rate;
 136                         goto out;
 137                 }
 138
 139                 if ((req->rate - tmp_rate) < (req->rate - best_rate)) {
 140                         best_rate = tmp_rate;
 141                         best_parent_rate = parent_rate;
 142                         best_parent = parent;
 143                 }
 144         }
 145
 146         if (best_rate == 0)
 147                 return -EINVAL;
 148
 149 out:
 150         req->best_parent_hw = best_parent;
 151         req->best_parent_rate = best_parent_rate;
 152         req->rate = best_rate;
 153         return 0;
 154 }
 155
 156 u8 ccu_mux_helper_get_parent(struct ccu_common *common,
 157                              struct ccu_mux_internal *cm)
 158 {
 159         u32 reg;
 160         u8 parent;
 161
 162         reg = readl(common->base + common->reg);
 163         parent = reg >> cm->shift;
 164         parent &= (1 << cm->width) - 1;
 165
 166         if (cm->table) {
 167                 int num_parents = clk_hw_get_num_parents(&common->hw);
 168                 int i;
 169
 170                 for (i = 0; i < num_parents; i++)
 171                         if (cm->table[i] == parent)
 172                                 return i;
 173         }
 174
 175         return parent;
 176 }
 177
 178 int ccu_mux_helper_set_parent(struct ccu_common *common,
 179                               struct ccu_mux_internal *cm,
 180                               u8 index)
 181 {
 182         unsigned long flags;
 183         u32 reg;
 184
 185         if (cm->table)
 186                 index = cm->table[index];
 187
 188         spin_lock_irqsave(common->lock, flags);
 189
 190         reg = readl(common->base + common->reg);
 191         reg &= ~GENMASK(cm->width + cm->shift - 1, cm->shift);
 192         writel(reg | (index << cm->shift), common->base + common->reg);
 193
 194         spin_unlock_irqrestore(common->lock, flags);
 195
 196         return 0;
 197 }
 198
 199 static void ccu_mux_disable(struct clk_hw *hw)
 200 {
 201         struct ccu_mux *cm = hw_to_ccu_mux(hw);
 202
 203         return ccu_gate_helper_disable(&cm->common, cm->enable);
 204 }
 205
 206 static int ccu_mux_enable(struct clk_hw *hw)
 207 {
 208         struct ccu_mux *cm = hw_to_ccu_mux(hw);
 209
 210         return ccu_gate_helper_enable(&cm->common, cm->enable);
 211 }
 212
 213 static int ccu_mux_is_enabled(struct clk_hw *hw)
 214 {
 215         struct ccu_mux *cm = hw_to_ccu_mux(hw);
 216
 217         return ccu_gate_helper_is_enabled(&cm->common, cm->enable);
 218 }
 219
 220 static u8 ccu_mux_get_parent(struct clk_hw *hw)
 221 {
 222         struct ccu_mux *cm = hw_to_ccu_mux(hw);
 223
 224         return ccu_mux_helper_get_parent(&cm->common, &cm->mux);
 225 }
 226
 227 static int ccu_mux_set_parent(struct clk_hw *hw, u8 index)
 228 {
 229         struct ccu_mux *cm = hw_to_ccu_mux(hw);
 230
 231         return ccu_mux_helper_set_parent(&cm->common, &cm->mux, index);
 232 }
 233
 234 static unsigned long ccu_mux_recalc_rate(struct clk_hw *hw,
 235                                          unsigned long parent_rate)
 236 {
 237         struct ccu_mux *cm = hw_to_ccu_mux(hw);
 238
 239         return ccu_mux_helper_apply_prediv(&cm->common, &cm->mux, -1,
 240                                            parent_rate);
 241 }
 242
 243 const struct clk_ops ccu_mux_ops = {
 244         .disable        = ccu_mux_disable,
 245         .enable         = ccu_mux_enable,
 246         .is_enabled     = ccu_mux_is_enabled,
 247
 248         .get_parent     = ccu_mux_get_parent,
 249         .set_parent     = ccu_mux_set_parent,
 250
 251         .determine_rate = __clk_mux_determine_rate,
 252         .recalc_rate    = ccu_mux_recalc_rate,
 253 };
 254
 255 /*
 256  * This clock notifier is called when the frequency of the of the parent
 257  * PLL clock is to be changed. The idea is to switch the parent to a
 258  * stable clock, such as the main oscillator, while the PLL frequency
 259  * stabilizes.
 260  */
 261 static int ccu_mux_notifier_cb(struct notifier_block *nb,
 262                                unsigned long event, void *data)
 263 {
 264         struct ccu_mux_nb *mux = to_ccu_mux_nb(nb);
 265         int ret = 0;
 266
 267         if (event == PRE_RATE_CHANGE) {
 268                 mux->original_index = ccu_mux_helper_get_parent(mux->common,
 269                                                                 mux->cm);
 270                 ret = ccu_mux_helper_set_parent(mux->common, mux->cm,
 271                                                 mux->bypass_index);
 272         } else if (event == POST_RATE_CHANGE) {
 273                 ret = ccu_mux_helper_set_parent(mux->common, mux->cm,
 274                                                 mux->original_index);
 275         }
 276
 277         udelay(mux->delay_us);
 278
 279         return notifier_from_errno(ret);
 280 }
 281
 282 int ccu_mux_notifier_register(struct clk *clk, struct ccu_mux_nb *mux_nb)
 283 {
 284         mux_nb->clk_nb.notifier_call = ccu_mux_notifier_cb;
 285
 286         return clk_notifier_register(clk, &mux_nb->clk_nb);
 287 }