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