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