drivers/clk/sunxi-ng/ccu_mux.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.h>
  12 #include <linux/clk-provider.h>
  13 #include <linux/delay.h>
  14 #include <linux/io.h>
  15
  16 #include "ccu_gate.h"
  17 #include "ccu_mux.h"
  18
  19 static u16 ccu_mux_get_prediv(struct ccu_common *common,
  20                               struct ccu_mux_internal *cm,
  21                               int parent_index)
  22 {
  23         u16 prediv = 1;
  24         u32 reg;
  25
  26         if (!((common->features & CCU_FEATURE_FIXED_PREDIV) ||
  27               (common->features & CCU_FEATURE_VARIABLE_PREDIV) ||
  28               (common->features & CCU_FEATURE_ALL_PREDIV)))
  29                 return 1;
  30
  31         if (common->features & CCU_FEATURE_ALL_PREDIV)
  32                 return common->prediv;
  33
  34         reg = readl(common->base + common->reg);
  35         if (parent_index < 0) {
  36                 parent_index = reg >> cm->shift;
  37                 parent_index &= (1 << cm->width) - 1;
  38         }
  39
  40         if (common->features & CCU_FEATURE_FIXED_PREDIV) {
  41                 int i;
  42
  43                 for (i = 0; i < cm->n_predivs; i++)
  44                         if (parent_index == cm->fixed_predivs[i].index)
  45                                 prediv = cm->fixed_predivs[i].div;
  46         }
  47
  48         if (common->features & CCU_FEATURE_VARIABLE_PREDIV) {
  49                 int i;
  50
  51                 for (i = 0; i < cm->n_var_predivs; i++)
  52                         if (parent_index == cm->var_predivs[i].index) {
  53                                 u8 div;
  54
  55                                 div = reg >> cm->var_predivs[i].shift;
  56                                 div &= (1 << cm->var_predivs[i].width) - 1;
  57                                 prediv = div + 1;
  58                         }
  59         }
  60
  61         return prediv;
  62 }
  63
  64 unsigned long ccu_mux_helper_apply_prediv(struct ccu_common *common,
  65                                           struct ccu_mux_internal *cm,
  66                                           int parent_index,
  67                                           unsigned long parent_rate)
  68 {
  69         return parent_rate / ccu_mux_get_prediv(common, cm, parent_index);
  70 }
  71
  72 static unsigned long ccu_mux_helper_unapply_prediv(struct ccu_common *common,
  73                                             struct ccu_mux_internal *cm,
  74                                             int parent_index,
  75                                             unsigned long parent_rate)
  76 {
  77         return parent_rate * ccu_mux_get_prediv(common, cm, parent_index);
  78 }
  79
  80 int ccu_mux_helper_determine_rate(struct ccu_common *common,
  81                                   struct ccu_mux_internal *cm,
  82                                   struct clk_rate_request *req,
  83                                   unsigned long (*round)(struct ccu_mux_internal *,
  84                                                          struct clk_hw *,
  85                                                          unsigned long *,
  86                                                          unsigned long,
  87                                                          void *),
  88                                   void *data)
  89 {
  90         unsigned long best_parent_rate = 0, best_rate = 0;
  91         struct clk_hw *best_parent, *hw = &common->hw;
  92         unsigned int i;
  93
  94         if (clk_hw_get_flags(hw) & CLK_SET_RATE_NO_REPARENT) {
  95                 unsigned long adj_parent_rate;
  96
  97                 best_parent = clk_hw_get_parent(hw);
  98                 best_parent_rate = clk_hw_get_rate(best_parent);
  99                 adj_parent_rate = ccu_mux_helper_apply_prediv(common, cm, -1,
 100                                                               best_parent_rate);
 101
 102                 best_rate = round(cm, best_parent, &adj_parent_rate,
 103                                   req->rate, data);
 104
 105                 /*
 106                  * adj_parent_rate might have been modified by our clock.
 107                  * Unapply the pre-divider if there's one, and give
 108                  * the actual frequency the parent needs to run at.
 109                  */
 110                 best_parent_rate = ccu_mux_helper_unapply_prediv(common, cm, -1,
 111                                                                  adj_parent_rate);
 112
 113                 goto out;
 114         }
 115
 116         for (i = 0; i < clk_hw_get_num_parents(hw); i++) {
 117                 unsigned long tmp_rate, parent_rate;
 118                 struct clk_hw *parent;
 119
 120                 parent = clk_hw_get_parent_by_index(hw, i);
 121                 if (!parent)
 122                         continue;
 123
 124                 parent_rate = ccu_mux_helper_apply_prediv(common, cm, i,
 125                                                           clk_hw_get_rate(parent));
 126
 127                 tmp_rate = round(cm, parent, &parent_rate, req->rate, data);
 128
 129                 /*
 130                  * parent_rate might have been modified by our clock.
 131                  * Unapply the pre-divider if there's one, and give
 132                  * the actual frequency the parent needs to run at.
 133                  */
 134                 parent_rate = ccu_mux_helper_unapply_prediv(common, cm, i,
 135                                                             parent_rate);
 136                 if (tmp_rate == req->rate) {
 137                         best_parent = parent;
 138                         best_parent_rate = parent_rate;
 139                         best_rate = tmp_rate;
 140                         goto out;
 141                 }
 142
 143                 if ((req->rate - tmp_rate) < (req->rate - best_rate)) {
 144                         best_rate = tmp_rate;
 145                         best_parent_rate = parent_rate;
 146                         best_parent = parent;
 147                 }
 148         }
 149
 150         if (best_rate == 0)
 151                 return -EINVAL;
 152
 153 out:
 154         req->best_parent_hw = best_parent;
 155         req->best_parent_rate = best_parent_rate;
 156         req->rate = best_rate;
 157         return 0;
 158 }
 159
 160 u8 ccu_mux_helper_get_parent(struct ccu_common *common,
 161                              struct ccu_mux_internal *cm)
 162 {
 163         u32 reg;
 164         u8 parent;
 165
 166         reg = readl(common->base + common->reg);
 167         parent = reg >> cm->shift;
 168         parent &= (1 << cm->width) - 1;
 169
 170         if (cm->table) {
 171                 int num_parents = clk_hw_get_num_parents(&common->hw);
 172                 int i;
 173
 174                 for (i = 0; i < num_parents; i++)
 175                         if (cm->table[i] == parent)
 176                                 return i;
 177         }
 178
 179         return parent;
 180 }
 181
 182 int ccu_mux_helper_set_parent(struct ccu_common *common,
 183                               struct ccu_mux_internal *cm,
 184                               u8 index)
 185 {
 186         unsigned long flags;
 187         u32 reg;
 188
 189         if (cm->table)
 190                 index = cm->table[index];
 191
 192         spin_lock_irqsave(common->lock, flags);
 193
 194         reg = readl(common->base + common->reg);
 195         reg &= ~GENMASK(cm->width + cm->shift - 1, cm->shift);
 196         writel(reg | (index << cm->shift), common->base + common->reg);
 197
 198         spin_unlock_irqrestore(common->lock, flags);
 199
 200         return 0;
 201 }
 202
 203 static void ccu_mux_disable(struct clk_hw *hw)
 204 {
 205         struct ccu_mux *cm = hw_to_ccu_mux(hw);
 206
 207         return ccu_gate_helper_disable(&cm->common, cm->enable);
 208 }
 209
 210 static int ccu_mux_enable(struct clk_hw *hw)
 211 {
 212         struct ccu_mux *cm = hw_to_ccu_mux(hw);
 213
 214         return ccu_gate_helper_enable(&cm->common, cm->enable);
 215 }
 216
 217 static int ccu_mux_is_enabled(struct clk_hw *hw)
 218 {
 219         struct ccu_mux *cm = hw_to_ccu_mux(hw);
 220
 221         return ccu_gate_helper_is_enabled(&cm->common, cm->enable);
 222 }
 223
 224 static u8 ccu_mux_get_parent(struct clk_hw *hw)
 225 {
 226         struct ccu_mux *cm = hw_to_ccu_mux(hw);
 227
 228         return ccu_mux_helper_get_parent(&cm->common, &cm->mux);
 229 }
 230
 231 static int ccu_mux_set_parent(struct clk_hw *hw, u8 index)
 232 {
 233         struct ccu_mux *cm = hw_to_ccu_mux(hw);
 234
 235         return ccu_mux_helper_set_parent(&cm->common, &cm->mux, index);
 236 }
 237
 238 static unsigned long ccu_mux_recalc_rate(struct clk_hw *hw,
 239                                          unsigned long parent_rate)
 240 {
 241         struct ccu_mux *cm = hw_to_ccu_mux(hw);
 242
 243         return ccu_mux_helper_apply_prediv(&cm->common, &cm->mux, -1,
 244                                            parent_rate);
 245 }
 246
 247 const struct clk_ops ccu_mux_ops = {
 248         .disable        = ccu_mux_disable,
 249         .enable         = ccu_mux_enable,
 250         .is_enabled     = ccu_mux_is_enabled,
 251
 252         .get_parent     = ccu_mux_get_parent,
 253         .set_parent     = ccu_mux_set_parent,
 254
 255         .determine_rate = __clk_mux_determine_rate,
 256         .recalc_rate    = ccu_mux_recalc_rate,
 257 };
 258
 259 /*
 260  * This clock notifier is called when the frequency of the of the parent
 261  * PLL clock is to be changed. The idea is to switch the parent to a
 262  * stable clock, such as the main oscillator, while the PLL frequency
 263  * stabilizes.
 264  */
 265 static int ccu_mux_notifier_cb(struct notifier_block *nb,
 266                                unsigned long event, void *data)
 267 {
 268         struct ccu_mux_nb *mux = to_ccu_mux_nb(nb);
 269         int ret = 0;
 270
 271         if (event == PRE_RATE_CHANGE) {
 272                 mux->original_index = ccu_mux_helper_get_parent(mux->common,
 273                                                                 mux->cm);
 274                 ret = ccu_mux_helper_set_parent(mux->common, mux->cm,
 275                                                 mux->bypass_index);
 276         } else if (event == POST_RATE_CHANGE) {
 277                 ret = ccu_mux_helper_set_parent(mux->common, mux->cm,
 278                                                 mux->original_index);
 279         }
 280
 281         udelay(mux->delay_us);
 282
 283         return notifier_from_errno(ret);
 284 }
 285
 286 int ccu_mux_notifier_register(struct clk *clk, struct ccu_mux_nb *mux_nb)
 287 {
 288         mux_nb->clk_nb.notifier_call = ccu_mux_notifier_cb;
 289
 290         return clk_notifier_register(clk, &mux_nb->clk_nb);
 291 }