drivers/clk/ti/divider.c

   1 /*
   2  * TI Divider Clock
   3  *
   4  * Copyright (C) 2013 Texas Instruments, Inc.
   5  *
   6  * Tero Kristo <t-kristo@ti.com>
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License version 2 as
  10  * published by the Free Software Foundation.
  11  *
  12  * This program is distributed "as is" WITHOUT ANY WARRANTY of any
  13  * kind, whether express or implied; without even the implied warranty
  14  * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  */
  17
  18 #include <linux/clk-provider.h>
  19 #include <linux/slab.h>
  20 #include <linux/err.h>
  21 #include <linux/of.h>
  22 #include <linux/of_address.h>
  23 #include <linux/clk/ti.h>
  24 #include "clock.h"
  25
  26 #undef pr_fmt
  27 #define pr_fmt(fmt) "%s: " fmt, __func__
  28
  29 #define div_mask(d)     ((1 << ((d)->width)) - 1)
  30
  31 static unsigned int _get_table_maxdiv(const struct clk_div_table *table)
  32 {
  33         unsigned int maxdiv = 0;
  34         const struct clk_div_table *clkt;
  35
  36         for (clkt = table; clkt->div; clkt++)
  37                 if (clkt->div > maxdiv)
  38                         maxdiv = clkt->div;
  39         return maxdiv;
  40 }
  41
  42 static unsigned int _get_maxdiv(struct clk_omap_divider *divider)
  43 {
  44         if (divider->flags & CLK_DIVIDER_ONE_BASED)
  45                 return div_mask(divider);
  46         if (divider->flags & CLK_DIVIDER_POWER_OF_TWO)
  47                 return 1 << div_mask(divider);
  48         if (divider->table)
  49                 return _get_table_maxdiv(divider->table);
  50         return div_mask(divider) + 1;
  51 }
  52
  53 static unsigned int _get_table_div(const struct clk_div_table *table,
  54                                    unsigned int val)
  55 {
  56         const struct clk_div_table *clkt;
  57
  58         for (clkt = table; clkt->div; clkt++)
  59                 if (clkt->val == val)
  60                         return clkt->div;
  61         return 0;
  62 }
  63
  64 static unsigned int _get_div(struct clk_omap_divider *divider, unsigned int val)
  65 {
  66         if (divider->flags & CLK_DIVIDER_ONE_BASED)
  67                 return val;
  68         if (divider->flags & CLK_DIVIDER_POWER_OF_TWO)
  69                 return 1 << val;
  70         if (divider->table)
  71                 return _get_table_div(divider->table, val);
  72         return val + 1;
  73 }
  74
  75 static unsigned int _get_table_val(const struct clk_div_table *table,
  76                                    unsigned int div)
  77 {
  78         const struct clk_div_table *clkt;
  79
  80         for (clkt = table; clkt->div; clkt++)
  81                 if (clkt->div == div)
  82                         return clkt->val;
  83         return 0;
  84 }
  85
  86 static unsigned int _get_val(struct clk_omap_divider *divider, u8 div)
  87 {
  88         if (divider->flags & CLK_DIVIDER_ONE_BASED)
  89                 return div;
  90         if (divider->flags & CLK_DIVIDER_POWER_OF_TWO)
  91                 return __ffs(div);
  92         if (divider->table)
  93                 return  _get_table_val(divider->table, div);
  94         return div - 1;
  95 }
  96
  97 static unsigned long ti_clk_divider_recalc_rate(struct clk_hw *hw,
  98                                                 unsigned long parent_rate)
  99 {
 100         struct clk_omap_divider *divider = to_clk_omap_divider(hw);
 101         unsigned int div, val;
 102
 103         val = ti_clk_ll_ops->clk_readl(&divider->reg) >> divider->shift;
 104         val &= div_mask(divider);
 105
 106         div = _get_div(divider, val);
 107         if (!div) {
 108                 WARN(!(divider->flags & CLK_DIVIDER_ALLOW_ZERO),
 109                      "%s: Zero divisor and CLK_DIVIDER_ALLOW_ZERO not set\n",
 110                      clk_hw_get_name(hw));
 111                 return parent_rate;
 112         }
 113
 114         return DIV_ROUND_UP(parent_rate, div);
 115 }
 116
 117 /*
 118  * The reverse of DIV_ROUND_UP: The maximum number which
 119  * divided by m is r
 120  */
 121 #define MULT_ROUND_UP(r, m) ((r) * (m) + (m) - 1)
 122
 123 static bool _is_valid_table_div(const struct clk_div_table *table,
 124                                 unsigned int div)
 125 {
 126         const struct clk_div_table *clkt;
 127
 128         for (clkt = table; clkt->div; clkt++)
 129                 if (clkt->div == div)
 130                         return true;
 131         return false;
 132 }
 133
 134 static bool _is_valid_div(struct clk_omap_divider *divider, unsigned int div)
 135 {
 136         if (divider->flags & CLK_DIVIDER_POWER_OF_TWO)
 137                 return is_power_of_2(div);
 138         if (divider->table)
 139                 return _is_valid_table_div(divider->table, div);
 140         return true;
 141 }
 142
 143 static int _div_round_up(const struct clk_div_table *table,
 144                          unsigned long parent_rate, unsigned long rate)
 145 {
 146         const struct clk_div_table *clkt;
 147         int up = INT_MAX;
 148         int div = DIV_ROUND_UP_ULL((u64)parent_rate, rate);
 149
 150         for (clkt = table; clkt->div; clkt++) {
 151                 if (clkt->div == div)
 152                         return clkt->div;
 153                 else if (clkt->div < div)
 154                         continue;
 155
 156                 if ((clkt->div - div) < (up - div))
 157                         up = clkt->div;
 158         }
 159
 160         return up;
 161 }
 162
 163 static int _div_round(const struct clk_div_table *table,
 164                       unsigned long parent_rate, unsigned long rate)
 165 {
 166         if (!table)
 167                 return DIV_ROUND_UP(parent_rate, rate);
 168
 169         return _div_round_up(table, parent_rate, rate);
 170 }
 171
 172 static int ti_clk_divider_bestdiv(struct clk_hw *hw, unsigned long rate,
 173                                   unsigned long *best_parent_rate)
 174 {
 175         struct clk_omap_divider *divider = to_clk_omap_divider(hw);
 176         int i, bestdiv = 0;
 177         unsigned long parent_rate, best = 0, now, maxdiv;
 178         unsigned long parent_rate_saved = *best_parent_rate;
 179
 180         if (!rate)
 181                 rate = 1;
 182
 183         maxdiv = _get_maxdiv(divider);
 184
 185         if (!(clk_hw_get_flags(hw) & CLK_SET_RATE_PARENT)) {
 186                 parent_rate = *best_parent_rate;
 187                 bestdiv = _div_round(divider->table, parent_rate, rate);
 188                 bestdiv = bestdiv == 0 ? 1 : bestdiv;
 189                 bestdiv = bestdiv > maxdiv ? maxdiv : bestdiv;
 190                 return bestdiv;
 191         }
 192
 193         /*
 194          * The maximum divider we can use without overflowing
 195          * unsigned long in rate * i below
 196          */
 197         maxdiv = min(ULONG_MAX / rate, maxdiv);
 198
 199         for (i = 1; i <= maxdiv; i++) {
 200                 if (!_is_valid_div(divider, i))
 201                         continue;
 202                 if (rate * i == parent_rate_saved) {
 203                         /*
 204                          * It's the most ideal case if the requested rate can be
 205                          * divided from parent clock without needing to change
 206                          * parent rate, so return the divider immediately.
 207                          */
 208                         *best_parent_rate = parent_rate_saved;
 209                         return i;
 210                 }
 211                 parent_rate = clk_hw_round_rate(clk_hw_get_parent(hw),
 212                                 MULT_ROUND_UP(rate, i));
 213                 now = DIV_ROUND_UP(parent_rate, i);
 214                 if (now <= rate && now > best) {
 215                         bestdiv = i;
 216                         best = now;
 217                         *best_parent_rate = parent_rate;
 218                 }
 219         }
 220
 221         if (!bestdiv) {
 222                 bestdiv = _get_maxdiv(divider);
 223                 *best_parent_rate =
 224                         clk_hw_round_rate(clk_hw_get_parent(hw), 1);
 225         }
 226
 227         return bestdiv;
 228 }
 229
 230 static long ti_clk_divider_round_rate(struct clk_hw *hw, unsigned long rate,
 231                                       unsigned long *prate)
 232 {
 233         int div;
 234         div = ti_clk_divider_bestdiv(hw, rate, prate);
 235
 236         return DIV_ROUND_UP(*prate, div);
 237 }
 238
 239 static int ti_clk_divider_set_rate(struct clk_hw *hw, unsigned long rate,
 240                                    unsigned long parent_rate)
 241 {
 242         struct clk_omap_divider *divider;
 243         unsigned int div, value;
 244         u32 val;
 245
 246         if (!hw || !rate)
 247                 return -EINVAL;
 248
 249         divider = to_clk_omap_divider(hw);
 250
 251         div = DIV_ROUND_UP(parent_rate, rate);
 252         value = _get_val(divider, div);
 253
 254         if (value > div_mask(divider))
 255                 value = div_mask(divider);
 256
 257         if (divider->flags & CLK_DIVIDER_HIWORD_MASK) {
 258                 val = div_mask(divider) << (divider->shift + 16);
 259         } else {
 260                 val = ti_clk_ll_ops->clk_readl(&divider->reg);
 261                 val &= ~(div_mask(divider) << divider->shift);
 262         }
 263         val |= value << divider->shift;
 264         ti_clk_ll_ops->clk_writel(val, &divider->reg);
 265
 266         ti_clk_latch(&divider->reg, divider->latch);
 267
 268         return 0;
 269 }
 270
 271 const struct clk_ops ti_clk_divider_ops = {
 272         .recalc_rate = ti_clk_divider_recalc_rate,
 273         .round_rate = ti_clk_divider_round_rate,
 274         .set_rate = ti_clk_divider_set_rate,
 275 };
 276
 277 static struct clk *_register_divider(struct device *dev, const char *name,
 278                                      const char *parent_name,
 279                                      unsigned long flags,
 280                                      struct clk_omap_reg *reg,
 281                                      u8 shift, u8 width, s8 latch,
 282                                      u8 clk_divider_flags,
 283                                      const struct clk_div_table *table)
 284 {
 285         struct clk_omap_divider *div;
 286         struct clk *clk;
 287         struct clk_init_data init;
 288
 289         if (clk_divider_flags & CLK_DIVIDER_HIWORD_MASK) {
 290                 if (width + shift > 16) {
 291                         pr_warn("divider value exceeds LOWORD field\n");
 292                         return ERR_PTR(-EINVAL);
 293                 }
 294         }
 295
 296         /* allocate the divider */
 297         div = kzalloc(sizeof(*div), GFP_KERNEL);
 298         if (!div)
 299                 return ERR_PTR(-ENOMEM);
 300
 301         init.name = name;
 302         init.ops = &ti_clk_divider_ops;
 303         init.flags = flags | CLK_IS_BASIC;
 304         init.parent_names = (parent_name ? &parent_name : NULL);
 305         init.num_parents = (parent_name ? 1 : 0);
 306
 307         /* struct clk_divider assignments */
 308         memcpy(&div->reg, reg, sizeof(*reg));
 309         div->shift = shift;
 310         div->width = width;
 311         div->latch = latch;
 312         div->flags = clk_divider_flags;
 313         div->hw.init = &init;
 314         div->table = table;
 315
 316         /* register the clock */
 317         clk = ti_clk_register(dev, &div->hw, name);
 318
 319         if (IS_ERR(clk))
 320                 kfree(div);
 321
 322         return clk;
 323 }
 324
 325 int ti_clk_parse_divider_data(int *div_table, int num_dividers, int max_div,
 326                               u8 flags, u8 *width,
 327                               const struct clk_div_table **table)
 328 {
 329         int valid_div = 0;
 330         u32 val;
 331         int div;
 332         int i;
 333         struct clk_div_table *tmp;
 334
 335         if (!div_table) {
 336                 if (flags & CLKF_INDEX_STARTS_AT_ONE)
 337                         val = 1;
 338                 else
 339                         val = 0;
 340
 341                 div = 1;
 342
 343                 while (div < max_div) {
 344                         if (flags & CLKF_INDEX_POWER_OF_TWO)
 345                                 div <<= 1;
 346                         else
 347                                 div++;
 348                         val++;
 349                 }
 350
 351                 *width = fls(val);
 352                 *table = NULL;
 353
 354                 return 0;
 355         }
 356
 357         i = 0;
 358
 359         while (!num_dividers || i < num_dividers) {
 360                 if (div_table[i] == -1)
 361                         break;
 362                 if (div_table[i])
 363                         valid_div++;
 364                 i++;
 365         }
 366
 367         num_dividers = i;
 368
 369         tmp = kzalloc(sizeof(*tmp) * (valid_div + 1), GFP_KERNEL);
 370         if (!tmp)
 371                 return -ENOMEM;
 372
 373         valid_div = 0;
 374         *width = 0;
 375
 376         for (i = 0; i < num_dividers; i++)
 377                 if (div_table[i] > 0) {
 378                         tmp[valid_div].div = div_table[i];
 379                         tmp[valid_div].val = i;
 380                         valid_div++;
 381                         *width = i;
 382                 }
 383
 384         *width = fls(*width);
 385         *table = tmp;
 386
 387         return 0;
 388 }
 389
 390 static const struct clk_div_table *
 391 _get_div_table_from_setup(struct ti_clk_divider *setup, u8 *width)
 392 {
 393         const struct clk_div_table *table = NULL;
 394
 395         ti_clk_parse_divider_data(setup->dividers, setup->num_dividers,
 396                                   setup->max_div, setup->flags, width,
 397                                   &table);
 398
 399         return table;
 400 }
 401
 402 struct clk_hw *ti_clk_build_component_div(struct ti_clk_divider *setup)
 403 {
 404         struct clk_omap_divider *div;
 405         struct clk_omap_reg *reg;
 406
 407         if (!setup)
 408                 return NULL;
 409
 410         div = kzalloc(sizeof(*div), GFP_KERNEL);
 411         if (!div)
 412                 return ERR_PTR(-ENOMEM);
 413
 414         reg = (struct clk_omap_reg *)&div->reg;
 415         reg->index = setup->module;
 416         reg->offset = setup->reg;
 417
 418         if (setup->flags & CLKF_INDEX_STARTS_AT_ONE)
 419                 div->flags |= CLK_DIVIDER_ONE_BASED;
 420
 421         if (setup->flags & CLKF_INDEX_POWER_OF_TWO)
 422                 div->flags |= CLK_DIVIDER_POWER_OF_TWO;
 423
 424         div->table = _get_div_table_from_setup(setup, &div->width);
 425
 426         div->shift = setup->bit_shift;
 427         div->latch = -EINVAL;
 428
 429         return &div->hw;
 430 }
 431
 432 struct clk *ti_clk_register_divider(struct ti_clk *setup)
 433 {
 434         struct ti_clk_divider *div = setup->data;
 435         struct clk_omap_reg reg = {
 436                 .index = div->module,
 437                 .offset = div->reg,
 438         };
 439         u8 width;
 440         u32 flags = 0;
 441         u8 div_flags = 0;
 442         const struct clk_div_table *table;
 443         struct clk *clk;
 444
 445         if (div->flags & CLKF_INDEX_STARTS_AT_ONE)
 446                 div_flags |= CLK_DIVIDER_ONE_BASED;
 447
 448         if (div->flags & CLKF_INDEX_POWER_OF_TWO)
 449                 div_flags |= CLK_DIVIDER_POWER_OF_TWO;
 450
 451         if (div->flags & CLKF_SET_RATE_PARENT)
 452                 flags |= CLK_SET_RATE_PARENT;
 453
 454         table = _get_div_table_from_setup(div, &width);
 455         if (IS_ERR(table))
 456                 return (struct clk *)table;
 457
 458         clk = _register_divider(NULL, setup->name, div->parent,
 459                                 flags, &reg, div->bit_shift,
 460                                 width, -EINVAL, div_flags, table);
 461
 462         if (IS_ERR(clk))
 463                 kfree(table);
 464
 465         return clk;
 466 }
 467
 468 static struct clk_div_table *
 469 __init ti_clk_get_div_table(struct device_node *node)
 470 {
 471         struct clk_div_table *table;
 472         const __be32 *divspec;
 473         u32 val;
 474         u32 num_div;
 475         u32 valid_div;
 476         int i;
 477
 478         divspec = of_get_property(node, "ti,dividers", &num_div);
 479
 480         if (!divspec)
 481                 return NULL;
 482
 483         num_div /= 4;
 484
 485         valid_div = 0;
 486
 487         /* Determine required size for divider table */
 488         for (i = 0; i < num_div; i++) {
 489                 of_property_read_u32_index(node, "ti,dividers", i, &val);
 490                 if (val)
 491                         valid_div++;
 492         }
 493
 494         if (!valid_div) {
 495                 pr_err("no valid dividers for %s table\n", node->name);
 496                 return ERR_PTR(-EINVAL);
 497         }
 498
 499         table = kzalloc(sizeof(*table) * (valid_div + 1), GFP_KERNEL);
 500
 501         if (!table)
 502                 return ERR_PTR(-ENOMEM);
 503
 504         valid_div = 0;
 505
 506         for (i = 0; i < num_div; i++) {
 507                 of_property_read_u32_index(node, "ti,dividers", i, &val);
 508                 if (val) {
 509                         table[valid_div].div = val;
 510                         table[valid_div].val = i;
 511                         valid_div++;
 512                 }
 513         }
 514
 515         return table;
 516 }
 517
 518 static int _get_divider_width(struct device_node *node,
 519                               const struct clk_div_table *table,
 520                               u8 flags)
 521 {
 522         u32 min_div;
 523         u32 max_div;
 524         u32 val = 0;
 525         u32 div;
 526
 527         if (!table) {
 528                 /* Clk divider table not provided, determine min/max divs */
 529                 if (of_property_read_u32(node, "ti,min-div", &min_div))
 530                         min_div = 1;
 531
 532                 if (of_property_read_u32(node, "ti,max-div", &max_div)) {
 533                         pr_err("no max-div for %s!\n", node->name);
 534                         return -EINVAL;
 535                 }
 536
 537                 /* Determine bit width for the field */
 538                 if (flags & CLK_DIVIDER_ONE_BASED)
 539                         val = 1;
 540
 541                 div = min_div;
 542
 543                 while (div < max_div) {
 544                         if (flags & CLK_DIVIDER_POWER_OF_TWO)
 545                                 div <<= 1;
 546                         else
 547                                 div++;
 548                         val++;
 549                 }
 550         } else {
 551                 div = 0;
 552
 553                 while (table[div].div) {
 554                         val = table[div].val;
 555                         div++;
 556                 }
 557         }
 558
 559         return fls(val);
 560 }
 561
 562 static int __init ti_clk_divider_populate(struct device_node *node,
 563         struct clk_omap_reg *reg, const struct clk_div_table **table,
 564         u32 *flags, u8 *div_flags, u8 *width, u8 *shift, s8 *latch)
 565 {
 566         u32 val;
 567         int ret;
 568
 569         ret = ti_clk_get_reg_addr(node, 0, reg);
 570         if (ret)
 571                 return ret;
 572
 573         if (!of_property_read_u32(node, "ti,bit-shift", &val))
 574                 *shift = val;
 575         else
 576                 *shift = 0;
 577
 578         if (latch) {
 579                 if (!of_property_read_u32(node, "ti,latch-bit", &val))
 580                         *latch = val;
 581                 else
 582                         *latch = -EINVAL;
 583         }
 584
 585         *flags = 0;
 586         *div_flags = 0;
 587
 588         if (of_property_read_bool(node, "ti,index-starts-at-one"))
 589                 *div_flags |= CLK_DIVIDER_ONE_BASED;
 590
 591         if (of_property_read_bool(node, "ti,index-power-of-two"))
 592                 *div_flags |= CLK_DIVIDER_POWER_OF_TWO;
 593
 594         if (of_property_read_bool(node, "ti,set-rate-parent"))
 595                 *flags |= CLK_SET_RATE_PARENT;
 596
 597         *table = ti_clk_get_div_table(node);
 598
 599         if (IS_ERR(*table))
 600                 return PTR_ERR(*table);
 601
 602         *width = _get_divider_width(node, *table, *div_flags);
 603
 604         return 0;
 605 }
 606
 607 /**
 608  * of_ti_divider_clk_setup - Setup function for simple div rate clock
 609  * @node: device node for this clock
 610  *
 611  * Sets up a basic divider clock.
 612  */
 613 static void __init of_ti_divider_clk_setup(struct device_node *node)
 614 {
 615         struct clk *clk;
 616         const char *parent_name;
 617         struct clk_omap_reg reg;
 618         u8 clk_divider_flags = 0;
 619         u8 width = 0;
 620         u8 shift = 0;
 621         s8 latch = -EINVAL;
 622         const struct clk_div_table *table = NULL;
 623         u32 flags = 0;
 624
 625         parent_name = of_clk_get_parent_name(node, 0);
 626
 627         if (ti_clk_divider_populate(node, &reg, &table, &flags,
 628                                     &clk_divider_flags, &width, &shift, &latch))
 629                 goto cleanup;
 630
 631         clk = _register_divider(NULL, node->name, parent_name, flags, &reg,
 632                                 shift, width, latch, clk_divider_flags, table);
 633
 634         if (!IS_ERR(clk)) {
 635                 of_clk_add_provider(node, of_clk_src_simple_get, clk);
 636                 of_ti_clk_autoidle_setup(node);
 637                 return;
 638         }
 639
 640 cleanup:
 641         kfree(table);
 642 }
 643 CLK_OF_DECLARE(divider_clk, "ti,divider-clock", of_ti_divider_clk_setup);
 644
 645 static void __init of_ti_composite_divider_clk_setup(struct device_node *node)
 646 {
 647         struct clk_omap_divider *div;
 648         u32 val;
 649
 650         div = kzalloc(sizeof(*div), GFP_KERNEL);
 651         if (!div)
 652                 return;
 653
 654         if (ti_clk_divider_populate(node, &div->reg, &div->table, &val,
 655                                     &div->flags, &div->width, &div->shift,
 656                                     NULL) < 0)
 657                 goto cleanup;
 658
 659         if (!ti_clk_add_component(node, &div->hw, CLK_COMPONENT_TYPE_DIVIDER))
 660                 return;
 661
 662 cleanup:
 663         kfree(div->table);
 664         kfree(div);
 665 }
 666 CLK_OF_DECLARE(ti_composite_divider_clk, "ti,composite-divider-clock",
 667                of_ti_composite_divider_clk_setup);