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_is_enabled(struct clk_hw *hw)
 155 {
 156         struct clk_composite *composite = to_clk_composite(hw);
 157         const struct clk_ops *gate_ops = composite->gate_ops;
 158         struct clk_hw *gate_hw = composite->gate_hw;
 159
 160         __clk_hw_set_clk(gate_hw, hw);
 161
 162         return gate_ops->is_enabled(gate_hw);
 163 }
 164
 165 static int clk_composite_enable(struct clk_hw *hw)
 166 {
 167         struct clk_composite *composite = to_clk_composite(hw);
 168         const struct clk_ops *gate_ops = composite->gate_ops;
 169         struct clk_hw *gate_hw = composite->gate_hw;
 170
 171         __clk_hw_set_clk(gate_hw, hw);
 172
 173         return gate_ops->enable(gate_hw);
 174 }
 175
 176 static void clk_composite_disable(struct clk_hw *hw)
 177 {
 178         struct clk_composite *composite = to_clk_composite(hw);
 179         const struct clk_ops *gate_ops = composite->gate_ops;
 180         struct clk_hw *gate_hw = composite->gate_hw;
 181
 182         __clk_hw_set_clk(gate_hw, hw);
 183
 184         gate_ops->disable(gate_hw);
 185 }
 186
 187 struct clk *clk_register_composite(struct device *dev, const char *name,
 188                         const char * const *parent_names, int num_parents,
 189                         struct clk_hw *mux_hw, const struct clk_ops *mux_ops,
 190                         struct clk_hw *rate_hw, const struct clk_ops *rate_ops,
 191                         struct clk_hw *gate_hw, const struct clk_ops *gate_ops,
 192                         unsigned long flags)
 193 {
 194         struct clk *clk;
 195         struct clk_init_data init;
 196         struct clk_composite *composite;
 197         struct clk_ops *clk_composite_ops;
 198
 199         composite = kzalloc(sizeof(*composite), GFP_KERNEL);
 200         if (!composite)
 201                 return ERR_PTR(-ENOMEM);
 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 }