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 int clk_composite_determine_rate(struct clk_hw *hw,
  59                                         struct clk_rate_request *req)
  60 {
  61         struct clk_composite *composite = to_clk_composite(hw);
  62         const struct clk_ops *rate_ops = composite->rate_ops;
  63         const struct clk_ops *mux_ops = composite->mux_ops;
  64         struct clk_hw *rate_hw = composite->rate_hw;
  65         struct clk_hw *mux_hw = composite->mux_hw;
  66         struct clk_hw *parent;
  67         unsigned long parent_rate;
  68         long tmp_rate, best_rate = 0;
  69         unsigned long rate_diff;
  70         unsigned long best_rate_diff = ULONG_MAX;
  71         long rate;
  72         int i;
  73
  74         if (rate_hw && rate_ops && rate_ops->determine_rate) {
  75                 __clk_hw_set_clk(rate_hw, hw);
  76                 return rate_ops->determine_rate(rate_hw, req);
  77         } else if (rate_hw && rate_ops && rate_ops->round_rate &&
  78                    mux_hw && mux_ops && mux_ops->set_parent) {
  79                 req->best_parent_hw = NULL;
  80
  81                 if (clk_hw_get_flags(hw) & CLK_SET_RATE_NO_REPARENT) {
  82                         parent = clk_hw_get_parent(mux_hw);
  83                         req->best_parent_hw = parent;
  84                         req->best_parent_rate = clk_hw_get_rate(parent);
  85
  86                         rate = rate_ops->round_rate(rate_hw, req->rate,
  87                                                     &req->best_parent_rate);
  88                         if (rate < 0)
  89                                 return rate;
  90
  91                         req->rate = rate;
  92                         return 0;
  93                 }
  94
  95                 for (i = 0; i < clk_hw_get_num_parents(mux_hw); i++) {
  96                         parent = clk_hw_get_parent_by_index(mux_hw, i);
  97                         if (!parent)
  98                                 continue;
  99
 100                         parent_rate = clk_hw_get_rate(parent);
 101
 102                         tmp_rate = rate_ops->round_rate(rate_hw, req->rate,
 103                                                         &parent_rate);
 104                         if (tmp_rate < 0)
 105                                 continue;
 106
 107                         rate_diff = abs(req->rate - tmp_rate);
 108
 109                         if (!rate_diff || !req->best_parent_hw
 110                                        || best_rate_diff > rate_diff) {
 111                                 req->best_parent_hw = parent;
 112                                 req->best_parent_rate = parent_rate;
 113                                 best_rate_diff = rate_diff;
 114                                 best_rate = tmp_rate;
 115                         }
 116
 117                         if (!rate_diff)
 118                                 return 0;
 119                 }
 120
 121                 req->rate = best_rate;
 122                 return 0;
 123         } else if (mux_hw && mux_ops && mux_ops->determine_rate) {
 124                 __clk_hw_set_clk(mux_hw, hw);
 125                 return mux_ops->determine_rate(mux_hw, req);
 126         } else {
 127                 pr_err("clk: clk_composite_determine_rate function called, but no mux or rate callback set!\n");
 128                 return -EINVAL;
 129         }
 130 }
 131
 132 static long clk_composite_round_rate(struct clk_hw *hw, unsigned long rate,
 133                                   unsigned long *prate)
 134 {
 135         struct clk_composite *composite = to_clk_composite(hw);
 136         const struct clk_ops *rate_ops = composite->rate_ops;
 137         struct clk_hw *rate_hw = composite->rate_hw;
 138
 139         __clk_hw_set_clk(rate_hw, hw);
 140
 141         return rate_ops->round_rate(rate_hw, rate, prate);
 142 }
 143
 144 static int clk_composite_set_rate(struct clk_hw *hw, unsigned long rate,
 145                                unsigned long parent_rate)
 146 {
 147         struct clk_composite *composite = to_clk_composite(hw);
 148         const struct clk_ops *rate_ops = composite->rate_ops;
 149         struct clk_hw *rate_hw = composite->rate_hw;
 150
 151         __clk_hw_set_clk(rate_hw, hw);
 152
 153         return rate_ops->set_rate(rate_hw, rate, parent_rate);
 154 }
 155
 156 static int clk_composite_is_enabled(struct clk_hw *hw)
 157 {
 158         struct clk_composite *composite = to_clk_composite(hw);
 159         const struct clk_ops *gate_ops = composite->gate_ops;
 160         struct clk_hw *gate_hw = composite->gate_hw;
 161
 162         __clk_hw_set_clk(gate_hw, hw);
 163
 164         return gate_ops->is_enabled(gate_hw);
 165 }
 166
 167 static int clk_composite_enable(struct clk_hw *hw)
 168 {
 169         struct clk_composite *composite = to_clk_composite(hw);
 170         const struct clk_ops *gate_ops = composite->gate_ops;
 171         struct clk_hw *gate_hw = composite->gate_hw;
 172
 173         __clk_hw_set_clk(gate_hw, hw);
 174
 175         return gate_ops->enable(gate_hw);
 176 }
 177
 178 static void clk_composite_disable(struct clk_hw *hw)
 179 {
 180         struct clk_composite *composite = to_clk_composite(hw);
 181         const struct clk_ops *gate_ops = composite->gate_ops;
 182         struct clk_hw *gate_hw = composite->gate_hw;
 183
 184         __clk_hw_set_clk(gate_hw, hw);
 185
 186         gate_ops->disable(gate_hw);
 187 }
 188
 189 struct clk *clk_register_composite(struct device *dev, const char *name,
 190                         const char * const *parent_names, int num_parents,
 191                         struct clk_hw *mux_hw, const struct clk_ops *mux_ops,
 192                         struct clk_hw *rate_hw, const struct clk_ops *rate_ops,
 193                         struct clk_hw *gate_hw, const struct clk_ops *gate_ops,
 194                         unsigned long flags)
 195 {
 196         struct clk *clk;
 197         struct clk_init_data init;
 198         struct clk_composite *composite;
 199         struct clk_ops *clk_composite_ops;
 200
 201         composite = kzalloc(sizeof(*composite), GFP_KERNEL);
 202         if (!composite)
 203                 return ERR_PTR(-ENOMEM);
 204
 205         init.name = name;
 206         init.flags = flags | CLK_IS_BASIC;
 207         init.parent_names = parent_names;
 208         init.num_parents = num_parents;
 209
 210         clk_composite_ops = &composite->ops;
 211
 212         if (mux_hw && mux_ops) {
 213                 if (!mux_ops->get_parent) {
 214                         clk = ERR_PTR(-EINVAL);
 215                         goto err;
 216                 }
 217
 218                 composite->mux_hw = mux_hw;
 219                 composite->mux_ops = mux_ops;
 220                 clk_composite_ops->get_parent = clk_composite_get_parent;
 221                 if (mux_ops->set_parent)
 222                         clk_composite_ops->set_parent = clk_composite_set_parent;
 223                 if (mux_ops->determine_rate)
 224                         clk_composite_ops->determine_rate = clk_composite_determine_rate;
 225         }
 226
 227         if (rate_hw && rate_ops) {
 228                 if (!rate_ops->recalc_rate) {
 229                         clk = ERR_PTR(-EINVAL);
 230                         goto err;
 231                 }
 232                 clk_composite_ops->recalc_rate = clk_composite_recalc_rate;
 233
 234                 if (rate_ops->determine_rate)
 235                         clk_composite_ops->determine_rate =
 236                                 clk_composite_determine_rate;
 237                 else if (rate_ops->round_rate)
 238                         clk_composite_ops->round_rate =
 239                                 clk_composite_round_rate;
 240
 241                 /* .set_rate requires either .round_rate or .determine_rate */
 242                 if (rate_ops->set_rate) {
 243                         if (rate_ops->determine_rate || rate_ops->round_rate)
 244                                 clk_composite_ops->set_rate =
 245                                                 clk_composite_set_rate;
 246                         else
 247                                 WARN(1, "%s: missing round_rate op is required\n",
 248                                                 __func__);
 249                 }
 250
 251                 composite->rate_hw = rate_hw;
 252                 composite->rate_ops = rate_ops;
 253         }
 254
 255         if (gate_hw && gate_ops) {
 256                 if (!gate_ops->is_enabled || !gate_ops->enable ||
 257                     !gate_ops->disable) {
 258                         clk = ERR_PTR(-EINVAL);
 259                         goto err;
 260                 }
 261
 262                 composite->gate_hw = gate_hw;
 263                 composite->gate_ops = gate_ops;
 264                 clk_composite_ops->is_enabled = clk_composite_is_enabled;
 265                 clk_composite_ops->enable = clk_composite_enable;
 266                 clk_composite_ops->disable = clk_composite_disable;
 267         }
 268
 269         init.ops = clk_composite_ops;
 270         composite->hw.init = &init;
 271
 272         clk = clk_register(dev, &composite->hw);
 273         if (IS_ERR(clk))
 274                 goto err;
 275
 276         if (composite->mux_hw)
 277                 composite->mux_hw->clk = clk;
 278
 279         if (composite->rate_hw)
 280                 composite->rate_hw->clk = clk;
 281
 282         if (composite->gate_hw)
 283                 composite->gate_hw->clk = clk;
 284
 285         return clk;
 286
 287 err:
 288         kfree(composite);
 289         return clk;
 290 }