kernel/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 #define to_clk_composite(_hw) container_of(_hw, struct clk_composite, hw)
  23
  24 static u8 clk_composite_get_parent(struct clk_hw *hw)
  25 {
  26         struct clk_composite *composite = to_clk_composite(hw);
  27         const struct clk_ops *mux_ops = composite->mux_ops;
  28         struct clk_hw *mux_hw = composite->mux_hw;
  29
  30         __clk_hw_set_clk(mux_hw, hw);
  31
  32         return mux_ops->get_parent(mux_hw);
  33 }
  34
  35 static int clk_composite_set_parent(struct clk_hw *hw, u8 index)
  36 {
  37         struct clk_composite *composite = to_clk_composite(hw);
  38         const struct clk_ops *mux_ops = composite->mux_ops;
  39         struct clk_hw *mux_hw = composite->mux_hw;
  40
  41         __clk_hw_set_clk(mux_hw, hw);
  42
  43         return mux_ops->set_parent(mux_hw, index);
  44 }
  45
  46 static unsigned long clk_composite_recalc_rate(struct clk_hw *hw,
  47                                             unsigned long parent_rate)
  48 {
  49         struct clk_composite *composite = to_clk_composite(hw);
  50         const struct clk_ops *rate_ops = composite->rate_ops;
  51         struct clk_hw *rate_hw = composite->rate_hw;
  52
  53         __clk_hw_set_clk(rate_hw, hw);
  54
  55         return rate_ops->recalc_rate(rate_hw, parent_rate);
  56 }
  57
  58 static long clk_composite_determine_rate(struct clk_hw *hw, unsigned long rate,
  59                                         unsigned long min_rate,
  60                                         unsigned long max_rate,
  61                                         unsigned long *best_parent_rate,
  62                                         struct clk_hw **best_parent_p)
  63 {
  64         struct clk_composite *composite = to_clk_composite(hw);
  65         const struct clk_ops *rate_ops = composite->rate_ops;
  66         const struct clk_ops *mux_ops = composite->mux_ops;
  67         struct clk_hw *rate_hw = composite->rate_hw;
  68         struct clk_hw *mux_hw = composite->mux_hw;
  69         struct clk *parent;
  70         unsigned long parent_rate;
  71         long tmp_rate, best_rate = 0;
  72         unsigned long rate_diff;
  73         unsigned long best_rate_diff = ULONG_MAX;
  74         int i;
  75
  76         if (rate_hw && rate_ops && rate_ops->determine_rate) {
  77                 __clk_hw_set_clk(rate_hw, hw);
  78                 return rate_ops->determine_rate(rate_hw, rate, min_rate,
  79                                                 max_rate,
  80                                                 best_parent_rate,
  81                                                 best_parent_p);
  82         } else if (rate_hw && rate_ops && rate_ops->round_rate &&
  83                    mux_hw && mux_ops && mux_ops->set_parent) {
  84                 *best_parent_p = NULL;
  85
  86                 if (__clk_get_flags(hw->clk) & CLK_SET_RATE_NO_REPARENT) {
  87                         parent = clk_get_parent(mux_hw->clk);
  88                         *best_parent_p = __clk_get_hw(parent);
  89                         *best_parent_rate = __clk_get_rate(parent);
  90
  91                         return rate_ops->round_rate(rate_hw, rate,
  92                                                     best_parent_rate);
  93                 }
  94
  95                 for (i = 0; i < __clk_get_num_parents(mux_hw->clk); i++) {
  96                         parent = clk_get_parent_by_index(mux_hw->clk, i);
  97                         if (!parent)
  98                                 continue;
  99
 100                         parent_rate = __clk_get_rate(parent);
 101
 102                         tmp_rate = rate_ops->round_rate(rate_hw, rate,
 103                                                         &parent_rate);
 104                         if (tmp_rate < 0)
 105                                 continue;
 106
 107                         rate_diff = abs(rate - tmp_rate);
 108
 109                         if (!rate_diff || !*best_parent_p
 110                                        || best_rate_diff > rate_diff) {
 111                                 *best_parent_p = __clk_get_hw(parent);
 112                                 *best_parent_rate = parent_rate;
 113                                 best_rate_diff = rate_diff;
 114                                 best_rate = tmp_rate;
 115                         }
 116
 117                         if (!rate_diff)
 118                                 return rate;
 119                 }
 120
 121                 return best_rate;
 122         } else if (mux_hw && mux_ops && mux_ops->determine_rate) {
 123                 __clk_hw_set_clk(mux_hw, hw);
 124                 return mux_ops->determine_rate(mux_hw, rate, min_rate,
 125                                                max_rate, best_parent_rate,
 126                                                best_parent_p);
 127         } else {
 128                 pr_err("clk: clk_composite_determine_rate function called, but no mux or rate callback set!\n");
 129                 return 0;
 130         }
 131 }
 132
 133 static long clk_composite_round_rate(struct clk_hw *hw, unsigned long rate,
 134                                   unsigned long *prate)
 135 {
 136         struct clk_composite *composite = to_clk_composite(hw);
 137         const struct clk_ops *rate_ops = composite->rate_ops;
 138         struct clk_hw *rate_hw = composite->rate_hw;
 139
 140         __clk_hw_set_clk(rate_hw, hw);
 141
 142         return rate_ops->round_rate(rate_hw, rate, prate);
 143 }
 144
 145 static int clk_composite_set_rate(struct clk_hw *hw, unsigned long rate,
 146                                unsigned long parent_rate)
 147 {
 148         struct clk_composite *composite = to_clk_composite(hw);
 149         const struct clk_ops *rate_ops = composite->rate_ops;
 150         struct clk_hw *rate_hw = composite->rate_hw;
 151
 152         __clk_hw_set_clk(rate_hw, hw);
 153
 154         return rate_ops->set_rate(rate_hw, rate, parent_rate);
 155 }
 156
 157 static int clk_composite_is_enabled(struct clk_hw *hw)
 158 {
 159         struct clk_composite *composite = to_clk_composite(hw);
 160         const struct clk_ops *gate_ops = composite->gate_ops;
 161         struct clk_hw *gate_hw = composite->gate_hw;
 162
 163         __clk_hw_set_clk(gate_hw, hw);
 164
 165         return gate_ops->is_enabled(gate_hw);
 166 }
 167
 168 static int clk_composite_enable(struct clk_hw *hw)
 169 {
 170         struct clk_composite *composite = to_clk_composite(hw);
 171         const struct clk_ops *gate_ops = composite->gate_ops;
 172         struct clk_hw *gate_hw = composite->gate_hw;
 173
 174         __clk_hw_set_clk(gate_hw, hw);
 175
 176         return gate_ops->enable(gate_hw);
 177 }
 178
 179 static void clk_composite_disable(struct clk_hw *hw)
 180 {
 181         struct clk_composite *composite = to_clk_composite(hw);
 182         const struct clk_ops *gate_ops = composite->gate_ops;
 183         struct clk_hw *gate_hw = composite->gate_hw;
 184
 185         __clk_hw_set_clk(gate_hw, hw);
 186
 187         gate_ops->disable(gate_hw);
 188 }
 189
 190 struct clk *clk_register_composite(struct device *dev, const char *name,
 191                         const char **parent_names, int num_parents,
 192                         struct clk_hw *mux_hw, const struct clk_ops *mux_ops,
 193                         struct clk_hw *rate_hw, const struct clk_ops *rate_ops,
 194                         struct clk_hw *gate_hw, const struct clk_ops *gate_ops,
 195                         unsigned long flags)
 196 {
 197         struct clk *clk;
 198         struct clk_init_data init;
 199         struct clk_composite *composite;
 200         struct clk_ops *clk_composite_ops;
 201
 202         composite = kzalloc(sizeof(*composite), GFP_KERNEL);
 203         if (!composite) {
 204                 pr_err("%s: could not allocate composite clk\n", __func__);
 205                 return ERR_PTR(-ENOMEM);
 206         }
 207
 208         init.name = name;
 209         init.flags = flags | CLK_IS_BASIC;
 210         init.parent_names = parent_names;
 211         init.num_parents = num_parents;
 212
 213         clk_composite_ops = &composite->ops;
 214
 215         if (mux_hw && mux_ops) {
 216                 if (!mux_ops->get_parent) {
 217                         clk = ERR_PTR(-EINVAL);
 218                         goto err;
 219                 }
 220
 221                 composite->mux_hw = mux_hw;
 222                 composite->mux_ops = mux_ops;
 223                 clk_composite_ops->get_parent = clk_composite_get_parent;
 224                 if (mux_ops->set_parent)
 225                         clk_composite_ops->set_parent = clk_composite_set_parent;
 226                 if (mux_ops->determine_rate)
 227                         clk_composite_ops->determine_rate = clk_composite_determine_rate;
 228         }
 229
 230         if (rate_hw && rate_ops) {
 231                 if (!rate_ops->recalc_rate) {
 232                         clk = ERR_PTR(-EINVAL);
 233                         goto err;
 234                 }
 235                 clk_composite_ops->recalc_rate = clk_composite_recalc_rate;
 236
 237                 if (rate_ops->determine_rate)
 238                         clk_composite_ops->determine_rate =
 239                                 clk_composite_determine_rate;
 240                 else if (rate_ops->round_rate)
 241                         clk_composite_ops->round_rate =
 242                                 clk_composite_round_rate;
 243
 244                 /* .set_rate requires either .round_rate or .determine_rate */
 245                 if (rate_ops->set_rate) {
 246                         if (rate_ops->determine_rate || rate_ops->round_rate)
 247                                 clk_composite_ops->set_rate =
 248                                                 clk_composite_set_rate;
 249                         else
 250                                 WARN(1, "%s: missing round_rate op is required\n",
 251                                                 __func__);
 252                 }
 253
 254                 composite->rate_hw = rate_hw;
 255                 composite->rate_ops = rate_ops;
 256         }
 257
 258         if (gate_hw && gate_ops) {
 259                 if (!gate_ops->is_enabled || !gate_ops->enable ||
 260                     !gate_ops->disable) {
 261                         clk = ERR_PTR(-EINVAL);
 262                         goto err;
 263                 }
 264
 265                 composite->gate_hw = gate_hw;
 266                 composite->gate_ops = gate_ops;
 267                 clk_composite_ops->is_enabled = clk_composite_is_enabled;
 268                 clk_composite_ops->enable = clk_composite_enable;
 269                 clk_composite_ops->disable = clk_composite_disable;
 270         }
 271
 272         init.ops = clk_composite_ops;
 273         composite->hw.init = &init;
 274
 275         clk = clk_register(dev, &composite->hw);
 276         if (IS_ERR(clk))
 277                 goto err;
 278
 279         if (composite->mux_hw)
 280                 composite->mux_hw->clk = clk;
 281
 282         if (composite->rate_hw)
 283                 composite->rate_hw->clk = clk;
 284
 285         if (composite->gate_hw)
 286                 composite->gate_hw->clk = clk;
 287
 288         return clk;
 289
 290 err:
 291         kfree(composite);
 292         return clk;
 293 }