drivers/clk/clk-composite.c

   1 /*
   2  * Copyright (c) 2013 NVIDIA CORPORATION.  All rights reserved.
   3  *
   4  * This program is free software; you can redistribute it and/or modify it
   5  * under the terms and conditions of the GNU General Public License,
   6  * version 2, as published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope it will be useful, but WITHOUT
   9  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  10  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  11  * more details.
  12  *
  13  * You should have received a copy of the GNU General Public License
  14  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  15  */
  16
  17 #include <linux/clk.h>
  18 #include <linux/clk-provider.h>
  19 #include <linux/err.h>
  20 #include <linux/slab.h>
  21
  22 static u8 clk_composite_get_parent(struct clk_hw *hw)
  23 {
  24         struct clk_composite *composite = to_clk_composite(hw);
  25         const struct clk_ops *mux_ops = composite->mux_ops;
  26         struct clk_hw *mux_hw = composite->mux_hw;
  27
  28         __clk_hw_set_clk(mux_hw, hw);
  29
  30         return mux_ops->get_parent(mux_hw);
  31 }
  32
  33 static int clk_composite_set_parent(struct clk_hw *hw, u8 index)
  34 {
  35         struct clk_composite *composite = to_clk_composite(hw);
  36         const struct clk_ops *mux_ops = composite->mux_ops;
  37         struct clk_hw *mux_hw = composite->mux_hw;
  38
  39         __clk_hw_set_clk(mux_hw, hw);
  40
  41         return mux_ops->set_parent(mux_hw, index);
  42 }
  43
  44 static unsigned long clk_composite_recalc_rate(struct clk_hw *hw,
  45                                             unsigned long parent_rate)
  46 {
  47         struct clk_composite *composite = to_clk_composite(hw);
  48         const struct clk_ops *rate_ops = composite->rate_ops;
  49         struct clk_hw *rate_hw = composite->rate_hw;
  50
  51         __clk_hw_set_clk(rate_hw, hw);
  52
  53         return rate_ops->recalc_rate(rate_hw, parent_rate);
  54 }
  55
  56 static int clk_composite_determine_rate(struct clk_hw *hw,
  57                                         struct clk_rate_request *req)
  58 {
  59         struct clk_composite *composite = to_clk_composite(hw);
  60         const struct clk_ops *rate_ops = composite->rate_ops;
  61         const struct clk_ops *mux_ops = composite->mux_ops;
  62         struct clk_hw *rate_hw = composite->rate_hw;
  63         struct clk_hw *mux_hw = composite->mux_hw;
  64         struct clk_hw *parent;
  65         unsigned long parent_rate;
  66         long tmp_rate, best_rate = 0;
  67         unsigned long rate_diff;
  68         unsigned long best_rate_diff = ULONG_MAX;
  69         long rate;
  70         int i;
  71
  72         if (rate_hw && rate_ops && rate_ops->determine_rate) {
  73                 __clk_hw_set_clk(rate_hw, hw);
  74                 return rate_ops->determine_rate(rate_hw, req);
  75         } else if (rate_hw && rate_ops && rate_ops->round_rate &&
  76                    mux_hw && mux_ops && mux_ops->set_parent) {
  77                 req->best_parent_hw = NULL;
  78
  79                 if (clk_hw_get_flags(hw) & CLK_SET_RATE_NO_REPARENT) {
  80                         parent = clk_hw_get_parent(mux_hw);
  81                         req->best_parent_hw = parent;
  82                         req->best_parent_rate = clk_hw_get_rate(parent);
  83
  84                         rate = rate_ops->round_rate(rate_hw, req->rate,
  85                                                     &req->best_parent_rate);
  86                         if (rate < 0)
  87                                 return rate;
  88
  89                         req->rate = rate;
  90                         return 0;
  91                 }
  92
  93                 for (i = 0; i < clk_hw_get_num_parents(mux_hw); i++) {
  94                         parent = clk_hw_get_parent_by_index(mux_hw, i);
  95                         if (!parent)
  96                                 continue;
  97
  98                         parent_rate = clk_hw_get_rate(parent);
  99
 100                         tmp_rate = rate_ops->round_rate(rate_hw, req->rate,
 101                                                         &parent_rate);
 102                         if (tmp_rate < 0)
 103                                 continue;
 104
 105                         rate_diff = abs(req->rate - tmp_rate);
 106
 107                         if (!rate_diff || !req->best_parent_hw
 108                                        || best_rate_diff > rate_diff) {
 109                                 req->best_parent_hw = parent;
 110                                 req->best_parent_rate = parent_rate;
 111                                 best_rate_diff = rate_diff;
 112                                 best_rate = tmp_rate;
 113                         }
 114
 115                         if (!rate_diff)
 116                                 return 0;
 117                 }
 118
 119                 req->rate = best_rate;
 120                 return 0;
 121         } else if (mux_hw && mux_ops && mux_ops->determine_rate) {
 122                 __clk_hw_set_clk(mux_hw, hw);
 123                 return mux_ops->determine_rate(mux_hw, req);
 124         } else {
 125                 pr_err("clk: clk_composite_determine_rate function called, but no mux or rate callback set!\n");
 126                 return -EINVAL;
 127         }
 128 }
 129
 130 static long clk_composite_round_rate(struct clk_hw *hw, unsigned long rate,
 131                                   unsigned long *prate)
 132 {
 133         struct clk_composite *composite = to_clk_composite(hw);
 134         const struct clk_ops *rate_ops = composite->rate_ops;
 135         struct clk_hw *rate_hw = composite->rate_hw;
 136
 137         __clk_hw_set_clk(rate_hw, hw);
 138
 139         return rate_ops->round_rate(rate_hw, rate, prate);
 140 }
 141
 142 static int clk_composite_set_rate(struct clk_hw *hw, unsigned long rate,
 143                                unsigned long parent_rate)
 144 {
 145         struct clk_composite *composite = to_clk_composite(hw);
 146         const struct clk_ops *rate_ops = composite->rate_ops;
 147         struct clk_hw *rate_hw = composite->rate_hw;
 148
 149         __clk_hw_set_clk(rate_hw, hw);
 150
 151         return rate_ops->set_rate(rate_hw, rate, parent_rate);
 152 }
 153
 154 static int clk_composite_set_rate_and_parent(struct clk_hw *hw,
 155                                              unsigned long rate,
 156                                              unsigned long parent_rate,
 157                                              u8 index)
 158 {
 159         struct clk_composite *composite = to_clk_composite(hw);
 160         const struct clk_ops *rate_ops = composite->rate_ops;
 161         const struct clk_ops *mux_ops = composite->mux_ops;
 162         struct clk_hw *rate_hw = composite->rate_hw;
 163         struct clk_hw *mux_hw = composite->mux_hw;
 164         unsigned long temp_rate;
 165
 166         __clk_hw_set_clk(rate_hw, hw);
 167         __clk_hw_set_clk(mux_hw, hw);
 168
 169         temp_rate = rate_ops->recalc_rate(rate_hw, parent_rate);
 170         if (temp_rate > rate) {
 171                 rate_ops->set_rate(rate_hw, rate, parent_rate);
 172                 mux_ops->set_parent(mux_hw, index);
 173         } else {
 174                 mux_ops->set_parent(mux_hw, index);
 175                 rate_ops->set_rate(rate_hw, rate, parent_rate);
 176         }
 177
 178         return 0;
 179 }
 180
 181 static int clk_composite_is_enabled(struct clk_hw *hw)
 182 {
 183         struct clk_composite *composite = to_clk_composite(hw);
 184         const struct clk_ops *gate_ops = composite->gate_ops;
 185         struct clk_hw *gate_hw = composite->gate_hw;
 186
 187         __clk_hw_set_clk(gate_hw, hw);
 188
 189         return gate_ops->is_enabled(gate_hw);
 190 }
 191
 192 static int clk_composite_enable(struct clk_hw *hw)
 193 {
 194         struct clk_composite *composite = to_clk_composite(hw);
 195         const struct clk_ops *gate_ops = composite->gate_ops;
 196         struct clk_hw *gate_hw = composite->gate_hw;
 197
 198         __clk_hw_set_clk(gate_hw, hw);
 199
 200         return gate_ops->enable(gate_hw);
 201 }
 202
 203 static void clk_composite_disable(struct clk_hw *hw)
 204 {
 205         struct clk_composite *composite = to_clk_composite(hw);
 206         const struct clk_ops *gate_ops = composite->gate_ops;
 207         struct clk_hw *gate_hw = composite->gate_hw;
 208
 209         __clk_hw_set_clk(gate_hw, hw);
 210
 211         gate_ops->disable(gate_hw);
 212 }
 213
 214 struct clk_hw *clk_hw_register_composite(struct device *dev, const char *name,
 215                         const char * const *parent_names, int num_parents,
 216                         struct clk_hw *mux_hw, const struct clk_ops *mux_ops,
 217                         struct clk_hw *rate_hw, const struct clk_ops *rate_ops,
 218                         struct clk_hw *gate_hw, const struct clk_ops *gate_ops,
 219                         unsigned long flags)
 220 {
 221         struct clk_hw *hw;
 222         struct clk_init_data init;
 223         struct clk_composite *composite;
 224         struct clk_ops *clk_composite_ops;
 225         int ret;
 226
 227         composite = kzalloc(sizeof(*composite), GFP_KERNEL);
 228         if (!composite)
 229                 return ERR_PTR(-ENOMEM);
 230
 231         init.name = name;
 232         init.flags = flags | CLK_IS_BASIC;
 233         init.parent_names = parent_names;
 234         init.num_parents = num_parents;
 235         hw = &composite->hw;
 236
 237         clk_composite_ops = &composite->ops;
 238
 239         if (mux_hw && mux_ops) {
 240                 if (!mux_ops->get_parent) {
 241                         hw = ERR_PTR(-EINVAL);
 242                         goto err;
 243                 }
 244
 245                 composite->mux_hw = mux_hw;
 246                 composite->mux_ops = mux_ops;
 247                 clk_composite_ops->get_parent = clk_composite_get_parent;
 248                 if (mux_ops->set_parent)
 249                         clk_composite_ops->set_parent = clk_composite_set_parent;
 250                 if (mux_ops->determine_rate)
 251                         clk_composite_ops->determine_rate = clk_composite_determine_rate;
 252         }
 253
 254         if (rate_hw && rate_ops) {
 255                 if (!rate_ops->recalc_rate) {
 256                         hw = ERR_PTR(-EINVAL);
 257                         goto err;
 258                 }
 259                 clk_composite_ops->recalc_rate = clk_composite_recalc_rate;
 260
 261                 if (rate_ops->determine_rate)
 262                         clk_composite_ops->determine_rate =
 263                                 clk_composite_determine_rate;
 264                 else if (rate_ops->round_rate)
 265                         clk_composite_ops->round_rate =
 266                                 clk_composite_round_rate;
 267
 268                 /* .set_rate requires either .round_rate or .determine_rate */
 269                 if (rate_ops->set_rate) {
 270                         if (rate_ops->determine_rate || rate_ops->round_rate)
 271                                 clk_composite_ops->set_rate =
 272                                                 clk_composite_set_rate;
 273                         else
 274                                 WARN(1, "%s: missing round_rate op is required\n",
 275                                                 __func__);
 276                 }
 277
 278                 composite->rate_hw = rate_hw;
 279                 composite->rate_ops = rate_ops;
 280         }
 281
 282         if (mux_hw && mux_ops && rate_hw && rate_ops) {
 283                 if (mux_ops->set_parent && rate_ops->set_rate)
 284                         clk_composite_ops->set_rate_and_parent =
 285                         clk_composite_set_rate_and_parent;
 286         }
 287
 288         if (gate_hw && gate_ops) {
 289                 if (!gate_ops->is_enabled || !gate_ops->enable ||
 290                     !gate_ops->disable) {
 291                         hw = ERR_PTR(-EINVAL);
 292                         goto err;
 293                 }
 294
 295                 composite->gate_hw = gate_hw;
 296                 composite->gate_ops = gate_ops;
 297                 clk_composite_ops->is_enabled = clk_composite_is_enabled;
 298                 clk_composite_ops->enable = clk_composite_enable;
 299                 clk_composite_ops->disable = clk_composite_disable;
 300         }
 301
 302         init.ops = clk_composite_ops;
 303         composite->hw.init = &init;
 304
 305         ret = clk_hw_register(dev, hw);
 306         if (ret) {
 307                 hw = ERR_PTR(ret);
 308                 goto err;
 309         }
 310
 311         if (composite->mux_hw)
 312                 composite->mux_hw->clk = hw->clk;
 313
 314         if (composite->rate_hw)
 315                 composite->rate_hw->clk = hw->clk;
 316
 317         if (composite->gate_hw)
 318                 composite->gate_hw->clk = hw->clk;
 319
 320         return hw;
 321
 322 err:
 323         kfree(composite);
 324         return hw;
 325 }
 326
 327 struct clk *clk_register_composite(struct device *dev, const char *name,
 328                         const char * const *parent_names, int num_parents,
 329                         struct clk_hw *mux_hw, const struct clk_ops *mux_ops,
 330                         struct clk_hw *rate_hw, const struct clk_ops *rate_ops,
 331                         struct clk_hw *gate_hw, const struct clk_ops *gate_ops,
 332                         unsigned long flags)
 333 {
 334         struct clk_hw *hw;
 335
 336         hw = clk_hw_register_composite(dev, name, parent_names, num_parents,
 337                         mux_hw, mux_ops, rate_hw, rate_ops, gate_hw, gate_ops,
 338                         flags);
 339         if (IS_ERR(hw))
 340                 return ERR_CAST(hw);
 341         return hw->clk;
 342 }
 343
 344 void clk_unregister_composite(struct clk *clk)
 345 {
 346         struct clk_composite *composite;
 347         struct clk_hw *hw;
 348
 349         hw = __clk_get_hw(clk);
 350         if (!hw)
 351                 return;
 352
 353         composite = to_clk_composite(hw);
 354
 355         clk_unregister(clk);
 356         kfree(composite);
 357 }