drivers/clk/clk-divider.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright (C) 2011 Sascha Hauer, Pengutronix <[email protected]>
   4  * Copyright (C) 2011 Richard Zhao, Linaro <[email protected]>
   5  * Copyright (C) 2011-2012 Mike Turquette, Linaro Ltd <[email protected]>
   6  *
   7  * Adjustable divider clock implementation
   8  */
   9
  10 #include <linux/clk-provider.h>
  11 #include <linux/device.h>
  12 #include <linux/module.h>
  13 #include <linux/slab.h>
  14 #include <linux/io.h>
  15 #include <linux/err.h>
  16 #include <linux/string.h>
  17 #include <linux/log2.h>
  18
  19 /*
  20  * DOC: basic adjustable divider clock that cannot gate
  21  *
  22  * Traits of this clock:
  23  * prepare - clk_prepare only ensures that parents are prepared
  24  * enable - clk_enable only ensures that parents are enabled
  25  * rate - rate is adjustable.  clk->rate = ceiling(parent->rate / divisor)
  26  * parent - fixed parent.  No clk_set_parent support
  27  */
  28
  29 static inline u32 clk_div_readl(struct clk_divider *divider)
  30 {
  31         if (divider->flags & CLK_DIVIDER_BIG_ENDIAN)
  32                 return ioread32be(divider->reg);
  33
  34         return readl(divider->reg);
  35 }
  36
  37 static inline void clk_div_writel(struct clk_divider *divider, u32 val)
  38 {
  39         if (divider->flags & CLK_DIVIDER_BIG_ENDIAN)
  40                 iowrite32be(val, divider->reg);
  41         else
  42                 writel(val, divider->reg);
  43 }
  44
  45 static unsigned int _get_table_maxdiv(const struct clk_div_table *table,
  46                                       u8 width)
  47 {
  48         unsigned int maxdiv = 0, mask = clk_div_mask(width);
  49         const struct clk_div_table *clkt;
  50
  51         for (clkt = table; clkt->div; clkt++)
  52                 if (clkt->div > maxdiv && clkt->val <= mask)
  53                         maxdiv = clkt->div;
  54         return maxdiv;
  55 }
  56
  57 static unsigned int _get_table_mindiv(const struct clk_div_table *table)
  58 {
  59         unsigned int mindiv = UINT_MAX;
  60         const struct clk_div_table *clkt;
  61
  62         for (clkt = table; clkt->div; clkt++)
  63                 if (clkt->div < mindiv)
  64                         mindiv = clkt->div;
  65         return mindiv;
  66 }
  67
  68 static unsigned int _get_maxdiv(const struct clk_div_table *table, u8 width,
  69                                 unsigned long flags)
  70 {
  71         if (flags & CLK_DIVIDER_ONE_BASED)
  72                 return clk_div_mask(width);
  73         if (flags & CLK_DIVIDER_POWER_OF_TWO)
  74                 return 1 << clk_div_mask(width);
  75         if (flags & CLK_DIVIDER_EVEN_INTEGERS)
  76                 return 2 * (clk_div_mask(width) + 1);
  77         if (table)
  78                 return _get_table_maxdiv(table, width);
  79         return clk_div_mask(width) + 1;
  80 }
  81
  82 static unsigned int _get_table_div(const struct clk_div_table *table,
  83                                                         unsigned int val)
  84 {
  85         const struct clk_div_table *clkt;
  86
  87         for (clkt = table; clkt->div; clkt++)
  88                 if (clkt->val == val)
  89                         return clkt->div;
  90         return 0;
  91 }
  92
  93 static unsigned int _get_div(const struct clk_div_table *table,
  94                              unsigned int val, unsigned long flags, u8 width)
  95 {
  96         if (flags & CLK_DIVIDER_ONE_BASED)
  97                 return val;
  98         if (flags & CLK_DIVIDER_POWER_OF_TWO)
  99                 return 1 << val;
 100         if (flags & CLK_DIVIDER_MAX_AT_ZERO)
 101                 return val ? val : clk_div_mask(width) + 1;
 102         if (flags & CLK_DIVIDER_EVEN_INTEGERS)
 103                 return 2 * (val + 1);
 104         if (table)
 105                 return _get_table_div(table, val);
 106         return val + 1;
 107 }
 108
 109 static unsigned int _get_table_val(const struct clk_div_table *table,
 110                                                         unsigned int div)
 111 {
 112         const struct clk_div_table *clkt;
 113
 114         for (clkt = table; clkt->div; clkt++)
 115                 if (clkt->div == div)
 116                         return clkt->val;
 117         return 0;
 118 }
 119
 120 static unsigned int _get_val(const struct clk_div_table *table,
 121                              unsigned int div, unsigned long flags, u8 width)
 122 {
 123         if (flags & CLK_DIVIDER_ONE_BASED)
 124                 return div;
 125         if (flags & CLK_DIVIDER_POWER_OF_TWO)
 126                 return __ffs(div);
 127         if (flags & CLK_DIVIDER_MAX_AT_ZERO)
 128                 return (div == clk_div_mask(width) + 1) ? 0 : div;
 129         if (flags & CLK_DIVIDER_EVEN_INTEGERS)
 130                 return (div >> 1) - 1;
 131         if (table)
 132                 return  _get_table_val(table, div);
 133         return div - 1;
 134 }
 135
 136 unsigned long divider_recalc_rate(struct clk_hw *hw, unsigned long parent_rate,
 137                                   unsigned int val,
 138                                   const struct clk_div_table *table,
 139                                   unsigned long flags, unsigned long width)
 140 {
 141         unsigned int div;
 142
 143         div = _get_div(table, val, flags, width);
 144         if (!div) {
 145                 WARN(!(flags & CLK_DIVIDER_ALLOW_ZERO),
 146                         "%s: Zero divisor and CLK_DIVIDER_ALLOW_ZERO not set\n",
 147                         clk_hw_get_name(hw));
 148                 return parent_rate;
 149         }
 150
 151         return DIV_ROUND_UP_ULL((u64)parent_rate, div);
 152 }
 153 EXPORT_SYMBOL_GPL(divider_recalc_rate);
 154
 155 static unsigned long clk_divider_recalc_rate(struct clk_hw *hw,
 156                 unsigned long parent_rate)
 157 {
 158         struct clk_divider *divider = to_clk_divider(hw);
 159         unsigned int val;
 160
 161         val = clk_div_readl(divider) >> divider->shift;
 162         val &= clk_div_mask(divider->width);
 163
 164         return divider_recalc_rate(hw, parent_rate, val, divider->table,
 165                                    divider->flags, divider->width);
 166 }
 167
 168 static bool _is_valid_table_div(const struct clk_div_table *table,
 169                                                          unsigned int div)
 170 {
 171         const struct clk_div_table *clkt;
 172
 173         for (clkt = table; clkt->div; clkt++)
 174                 if (clkt->div == div)
 175                         return true;
 176         return false;
 177 }
 178
 179 static bool _is_valid_div(const struct clk_div_table *table, unsigned int div,
 180                           unsigned long flags)
 181 {
 182         if (flags & CLK_DIVIDER_POWER_OF_TWO)
 183                 return is_power_of_2(div);
 184         if (table)
 185                 return _is_valid_table_div(table, div);
 186         return true;
 187 }
 188
 189 static int _round_up_table(const struct clk_div_table *table, int div)
 190 {
 191         const struct clk_div_table *clkt;
 192         int up = INT_MAX;
 193
 194         for (clkt = table; clkt->div; clkt++) {
 195                 if (clkt->div == div)
 196                         return clkt->div;
 197                 else if (clkt->div < div)
 198                         continue;
 199
 200                 if ((clkt->div - div) < (up - div))
 201                         up = clkt->div;
 202         }
 203
 204         return up;
 205 }
 206
 207 static int _round_down_table(const struct clk_div_table *table, int div)
 208 {
 209         const struct clk_div_table *clkt;
 210         int down = _get_table_mindiv(table);
 211
 212         for (clkt = table; clkt->div; clkt++) {
 213                 if (clkt->div == div)
 214                         return clkt->div;
 215                 else if (clkt->div > div)
 216                         continue;
 217
 218                 if ((div - clkt->div) < (div - down))
 219                         down = clkt->div;
 220         }
 221
 222         return down;
 223 }
 224
 225 static int _div_round_up(const struct clk_div_table *table,
 226                          unsigned long parent_rate, unsigned long rate,
 227                          unsigned long flags)
 228 {
 229         int div = DIV_ROUND_UP_ULL((u64)parent_rate, rate);
 230
 231         if (flags & CLK_DIVIDER_POWER_OF_TWO)
 232                 div = __roundup_pow_of_two(div);
 233         if (table)
 234                 div = _round_up_table(table, div);
 235
 236         return div;
 237 }
 238
 239 static int _div_round_closest(const struct clk_div_table *table,
 240                               unsigned long parent_rate, unsigned long rate,
 241                               unsigned long flags)
 242 {
 243         int up, down;
 244         unsigned long up_rate, down_rate;
 245
 246         up = DIV_ROUND_UP_ULL((u64)parent_rate, rate);
 247         down = parent_rate / rate;
 248
 249         if (flags & CLK_DIVIDER_POWER_OF_TWO) {
 250                 up = __roundup_pow_of_two(up);
 251                 down = __rounddown_pow_of_two(down);
 252         } else if (table) {
 253                 up = _round_up_table(table, up);
 254                 down = _round_down_table(table, down);
 255         }
 256
 257         up_rate = DIV_ROUND_UP_ULL((u64)parent_rate, up);
 258         down_rate = DIV_ROUND_UP_ULL((u64)parent_rate, down);
 259
 260         return (rate - up_rate) <= (down_rate - rate) ? up : down;
 261 }
 262
 263 static int _div_round(const struct clk_div_table *table,
 264                       unsigned long parent_rate, unsigned long rate,
 265                       unsigned long flags)
 266 {
 267         if (flags & CLK_DIVIDER_ROUND_CLOSEST)
 268                 return _div_round_closest(table, parent_rate, rate, flags);
 269
 270         return _div_round_up(table, parent_rate, rate, flags);
 271 }
 272
 273 static bool _is_best_div(unsigned long rate, unsigned long now,
 274                          unsigned long best, unsigned long flags)
 275 {
 276         if (flags & CLK_DIVIDER_ROUND_CLOSEST)
 277                 return abs(rate - now) < abs(rate - best);
 278
 279         return now <= rate && now > best;
 280 }
 281
 282 static int _next_div(const struct clk_div_table *table, int div,
 283                      unsigned long flags)
 284 {
 285         div++;
 286
 287         if (flags & CLK_DIVIDER_POWER_OF_TWO)
 288                 return __roundup_pow_of_two(div);
 289         if (table)
 290                 return _round_up_table(table, div);
 291
 292         return div;
 293 }
 294
 295 static int clk_divider_bestdiv(struct clk_hw *hw, struct clk_hw *parent,
 296                                unsigned long rate,
 297                                unsigned long *best_parent_rate,
 298                                const struct clk_div_table *table, u8 width,
 299                                unsigned long flags)
 300 {
 301         int i, bestdiv = 0;
 302         unsigned long parent_rate, best = 0, now, maxdiv;
 303         unsigned long parent_rate_saved = *best_parent_rate;
 304
 305         if (!rate)
 306                 rate = 1;
 307
 308         maxdiv = _get_maxdiv(table, width, flags);
 309
 310         if (!(clk_hw_get_flags(hw) & CLK_SET_RATE_PARENT)) {
 311                 parent_rate = *best_parent_rate;
 312                 bestdiv = _div_round(table, parent_rate, rate, flags);
 313                 bestdiv = bestdiv == 0 ? 1 : bestdiv;
 314                 bestdiv = bestdiv > maxdiv ? maxdiv : bestdiv;
 315                 return bestdiv;
 316         }
 317
 318         /*
 319          * The maximum divider we can use without overflowing
 320          * unsigned long in rate * i below
 321          */
 322         maxdiv = min(ULONG_MAX / rate, maxdiv);
 323
 324         for (i = _next_div(table, 0, flags); i <= maxdiv;
 325                                              i = _next_div(table, i, flags)) {
 326                 if (rate * i == parent_rate_saved) {
 327                         /*
 328                          * It's the most ideal case if the requested rate can be
 329                          * divided from parent clock without needing to change
 330                          * parent rate, so return the divider immediately.
 331                          */
 332                         *best_parent_rate = parent_rate_saved;
 333                         return i;
 334                 }
 335                 parent_rate = clk_hw_round_rate(parent, rate * i);
 336                 now = DIV_ROUND_UP_ULL((u64)parent_rate, i);
 337                 if (_is_best_div(rate, now, best, flags)) {
 338                         bestdiv = i;
 339                         best = now;
 340                         *best_parent_rate = parent_rate;
 341                 }
 342         }
 343
 344         if (!bestdiv) {
 345                 bestdiv = _get_maxdiv(table, width, flags);
 346                 *best_parent_rate = clk_hw_round_rate(parent, 1);
 347         }
 348
 349         return bestdiv;
 350 }
 351
 352 int divider_determine_rate(struct clk_hw *hw, struct clk_rate_request *req,
 353                            const struct clk_div_table *table, u8 width,
 354                            unsigned long flags)
 355 {
 356         int div;
 357
 358         div = clk_divider_bestdiv(hw, req->best_parent_hw, req->rate,
 359                                   &req->best_parent_rate, table, width, flags);
 360
 361         req->rate = DIV_ROUND_UP_ULL((u64)req->best_parent_rate, div);
 362
 363         return 0;
 364 }
 365 EXPORT_SYMBOL_GPL(divider_determine_rate);
 366
 367 int divider_ro_determine_rate(struct clk_hw *hw, struct clk_rate_request *req,
 368                               const struct clk_div_table *table, u8 width,
 369                               unsigned long flags, unsigned int val)
 370 {
 371         int div;
 372
 373         div = _get_div(table, val, flags, width);
 374
 375         /* Even a read-only clock can propagate a rate change */
 376         if (clk_hw_get_flags(hw) & CLK_SET_RATE_PARENT) {
 377                 if (!req->best_parent_hw)
 378                         return -EINVAL;
 379
 380                 req->best_parent_rate = clk_hw_round_rate(req->best_parent_hw,
 381                                                           req->rate * div);
 382         }
 383
 384         req->rate = DIV_ROUND_UP_ULL((u64)req->best_parent_rate, div);
 385
 386         return 0;
 387 }
 388 EXPORT_SYMBOL_GPL(divider_ro_determine_rate);
 389
 390 long divider_round_rate_parent(struct clk_hw *hw, struct clk_hw *parent,
 391                                unsigned long rate, unsigned long *prate,
 392                                const struct clk_div_table *table,
 393                                u8 width, unsigned long flags)
 394 {
 395         struct clk_rate_request req;
 396         int ret;
 397
 398         clk_hw_init_rate_request(hw, &req, rate);
 399         req.best_parent_rate = *prate;
 400         req.best_parent_hw = parent;
 401
 402         ret = divider_determine_rate(hw, &req, table, width, flags);
 403         if (ret)
 404                 return ret;
 405
 406         *prate = req.best_parent_rate;
 407
 408         return req.rate;
 409 }
 410 EXPORT_SYMBOL_GPL(divider_round_rate_parent);
 411
 412 long divider_ro_round_rate_parent(struct clk_hw *hw, struct clk_hw *parent,
 413                                   unsigned long rate, unsigned long *prate,
 414                                   const struct clk_div_table *table, u8 width,
 415                                   unsigned long flags, unsigned int val)
 416 {
 417         struct clk_rate_request req;
 418         int ret;
 419
 420         clk_hw_init_rate_request(hw, &req, rate);
 421         req.best_parent_rate = *prate;
 422         req.best_parent_hw = parent;
 423
 424         ret = divider_ro_determine_rate(hw, &req, table, width, flags, val);
 425         if (ret)
 426                 return ret;
 427
 428         *prate = req.best_parent_rate;
 429
 430         return req.rate;
 431 }
 432 EXPORT_SYMBOL_GPL(divider_ro_round_rate_parent);
 433
 434 static long clk_divider_round_rate(struct clk_hw *hw, unsigned long rate,
 435                                 unsigned long *prate)
 436 {
 437         struct clk_divider *divider = to_clk_divider(hw);
 438
 439         /* if read only, just return current value */
 440         if (divider->flags & CLK_DIVIDER_READ_ONLY) {
 441                 u32 val;
 442
 443                 val = clk_div_readl(divider) >> divider->shift;
 444                 val &= clk_div_mask(divider->width);
 445
 446                 return divider_ro_round_rate(hw, rate, prate, divider->table,
 447                                              divider->width, divider->flags,
 448                                              val);
 449         }
 450
 451         return divider_round_rate(hw, rate, prate, divider->table,
 452                                   divider->width, divider->flags);
 453 }
 454
 455 static int clk_divider_determine_rate(struct clk_hw *hw,
 456                                       struct clk_rate_request *req)
 457 {
 458         struct clk_divider *divider = to_clk_divider(hw);
 459
 460         /* if read only, just return current value */
 461         if (divider->flags & CLK_DIVIDER_READ_ONLY) {
 462                 u32 val;
 463
 464                 val = clk_div_readl(divider) >> divider->shift;
 465                 val &= clk_div_mask(divider->width);
 466
 467                 return divider_ro_determine_rate(hw, req, divider->table,
 468                                                  divider->width,
 469                                                  divider->flags, val);
 470         }
 471
 472         return divider_determine_rate(hw, req, divider->table, divider->width,
 473                                       divider->flags);
 474 }
 475
 476 int divider_get_val(unsigned long rate, unsigned long parent_rate,
 477                     const struct clk_div_table *table, u8 width,
 478                     unsigned long flags)
 479 {
 480         unsigned int div, value;
 481
 482         div = DIV_ROUND_UP_ULL((u64)parent_rate, rate);
 483
 484         if (!_is_valid_div(table, div, flags))
 485                 return -EINVAL;
 486
 487         value = _get_val(table, div, flags, width);
 488
 489         return min_t(unsigned int, value, clk_div_mask(width));
 490 }
 491 EXPORT_SYMBOL_GPL(divider_get_val);
 492
 493 static int clk_divider_set_rate(struct clk_hw *hw, unsigned long rate,
 494                                 unsigned long parent_rate)
 495 {
 496         struct clk_divider *divider = to_clk_divider(hw);
 497         int value;
 498         unsigned long flags = 0;
 499         u32 val;
 500
 501         value = divider_get_val(rate, parent_rate, divider->table,
 502                                 divider->width, divider->flags);
 503         if (value < 0)
 504                 return value;
 505
 506         if (divider->lock)
 507                 spin_lock_irqsave(divider->lock, flags);
 508         else
 509                 __acquire(divider->lock);
 510
 511         if (divider->flags & CLK_DIVIDER_HIWORD_MASK) {
 512                 val = clk_div_mask(divider->width) << (divider->shift + 16);
 513         } else {
 514                 val = clk_div_readl(divider);
 515                 val &= ~(clk_div_mask(divider->width) << divider->shift);
 516         }
 517         val |= (u32)value << divider->shift;
 518         clk_div_writel(divider, val);
 519
 520         if (divider->lock)
 521                 spin_unlock_irqrestore(divider->lock, flags);
 522         else
 523                 __release(divider->lock);
 524
 525         return 0;
 526 }
 527
 528 const struct clk_ops clk_divider_ops = {
 529         .recalc_rate = clk_divider_recalc_rate,
 530         .round_rate = clk_divider_round_rate,
 531         .determine_rate = clk_divider_determine_rate,
 532         .set_rate = clk_divider_set_rate,
 533 };
 534 EXPORT_SYMBOL_GPL(clk_divider_ops);
 535
 536 const struct clk_ops clk_divider_ro_ops = {
 537         .recalc_rate = clk_divider_recalc_rate,
 538         .round_rate = clk_divider_round_rate,
 539         .determine_rate = clk_divider_determine_rate,
 540 };
 541 EXPORT_SYMBOL_GPL(clk_divider_ro_ops);
 542
 543 struct clk_hw *__clk_hw_register_divider(struct device *dev,
 544                 struct device_node *np, const char *name,
 545                 const char *parent_name, const struct clk_hw *parent_hw,
 546                 const struct clk_parent_data *parent_data, unsigned long flags,
 547                 void __iomem *reg, u8 shift, u8 width,
 548                 unsigned long clk_divider_flags,
 549                 const struct clk_div_table *table, spinlock_t *lock)
 550 {
 551         struct clk_divider *div;
 552         struct clk_hw *hw;
 553         struct clk_init_data init = {};
 554         int ret;
 555
 556         if (clk_divider_flags & CLK_DIVIDER_HIWORD_MASK) {
 557                 if (width + shift > 16) {
 558                         pr_warn("divider value exceeds LOWORD field\n");
 559                         return ERR_PTR(-EINVAL);
 560                 }
 561         }
 562
 563         /* allocate the divider */
 564         div = kzalloc(sizeof(*div), GFP_KERNEL);
 565         if (!div)
 566                 return ERR_PTR(-ENOMEM);
 567
 568         init.name = name;
 569         if (clk_divider_flags & CLK_DIVIDER_READ_ONLY)
 570                 init.ops = &clk_divider_ro_ops;
 571         else
 572                 init.ops = &clk_divider_ops;
 573         init.flags = flags;
 574         init.parent_names = parent_name ? &parent_name : NULL;
 575         init.parent_hws = parent_hw ? &parent_hw : NULL;
 576         init.parent_data = parent_data;
 577         if (parent_name || parent_hw || parent_data)
 578                 init.num_parents = 1;
 579         else
 580                 init.num_parents = 0;
 581
 582         /* struct clk_divider assignments */
 583         div->reg = reg;
 584         div->shift = shift;
 585         div->width = width;
 586         div->flags = clk_divider_flags;
 587         div->lock = lock;
 588         div->hw.init = &init;
 589         div->table = table;
 590
 591         /* register the clock */
 592         hw = &div->hw;
 593         ret = clk_hw_register(dev, hw);
 594         if (ret) {
 595                 kfree(div);
 596                 hw = ERR_PTR(ret);
 597         }
 598
 599         return hw;
 600 }
 601 EXPORT_SYMBOL_GPL(__clk_hw_register_divider);
 602
 603 /**
 604  * clk_register_divider_table - register a table based divider clock with
 605  * the clock framework
 606  * @dev: device registering this clock
 607  * @name: name of this clock
 608  * @parent_name: name of clock's parent
 609  * @flags: framework-specific flags
 610  * @reg: register address to adjust divider
 611  * @shift: number of bits to shift the bitfield
 612  * @width: width of the bitfield
 613  * @clk_divider_flags: divider-specific flags for this clock
 614  * @table: array of divider/value pairs ending with a div set to 0
 615  * @lock: shared register lock for this clock
 616  */
 617 struct clk *clk_register_divider_table(struct device *dev, const char *name,
 618                 const char *parent_name, unsigned long flags,
 619                 void __iomem *reg, u8 shift, u8 width,
 620                 unsigned long clk_divider_flags,
 621                 const struct clk_div_table *table, spinlock_t *lock)
 622 {
 623         struct clk_hw *hw;
 624
 625         hw =  __clk_hw_register_divider(dev, NULL, name, parent_name, NULL,
 626                         NULL, flags, reg, shift, width, clk_divider_flags,
 627                         table, lock);
 628         if (IS_ERR(hw))
 629                 return ERR_CAST(hw);
 630         return hw->clk;
 631 }
 632 EXPORT_SYMBOL_GPL(clk_register_divider_table);
 633
 634 void clk_unregister_divider(struct clk *clk)
 635 {
 636         struct clk_divider *div;
 637         struct clk_hw *hw;
 638
 639         hw = __clk_get_hw(clk);
 640         if (!hw)
 641                 return;
 642
 643         div = to_clk_divider(hw);
 644
 645         clk_unregister(clk);
 646         kfree(div);
 647 }
 648 EXPORT_SYMBOL_GPL(clk_unregister_divider);
 649
 650 /**
 651  * clk_hw_unregister_divider - unregister a clk divider
 652  * @hw: hardware-specific clock data to unregister
 653  */
 654 void clk_hw_unregister_divider(struct clk_hw *hw)
 655 {
 656         struct clk_divider *div;
 657
 658         div = to_clk_divider(hw);
 659
 660         clk_hw_unregister(hw);
 661         kfree(div);
 662 }
 663 EXPORT_SYMBOL_GPL(clk_hw_unregister_divider);
 664
 665 static void devm_clk_hw_release_divider(struct device *dev, void *res)
 666 {
 667         clk_hw_unregister_divider(*(struct clk_hw **)res);
 668 }
 669
 670 struct clk_hw *__devm_clk_hw_register_divider(struct device *dev,
 671                 struct device_node *np, const char *name,
 672                 const char *parent_name, const struct clk_hw *parent_hw,
 673                 const struct clk_parent_data *parent_data, unsigned long flags,
 674                 void __iomem *reg, u8 shift, u8 width,
 675                 unsigned long clk_divider_flags,
 676                 const struct clk_div_table *table, spinlock_t *lock)
 677 {
 678         struct clk_hw **ptr, *hw;
 679
 680         ptr = devres_alloc(devm_clk_hw_release_divider, sizeof(*ptr), GFP_KERNEL);
 681         if (!ptr)
 682                 return ERR_PTR(-ENOMEM);
 683
 684         hw = __clk_hw_register_divider(dev, np, name, parent_name, parent_hw,
 685                                        parent_data, flags, reg, shift, width,
 686                                        clk_divider_flags, table, lock);
 687
 688         if (!IS_ERR(hw)) {
 689                 *ptr = hw;
 690                 devres_add(dev, ptr);
 691         } else {
 692                 devres_free(ptr);
 693         }
 694
 695         return hw;
 696 }
 697 EXPORT_SYMBOL_GPL(__devm_clk_hw_register_divider);