drivers/opp/of.c

   1 /*
   2  * Generic OPP OF helpers
   3  *
   4  * Copyright (C) 2009-2010 Texas Instruments Incorporated.
   5  *      Nishanth Menon
   6  *      Romit Dasgupta
   7  *      Kevin Hilman
   8  *
   9  * This program is free software; you can redistribute it and/or modify
  10  * it under the terms of the GNU General Public License version 2 as
  11  * published by the Free Software Foundation.
  12  */
  13
  14 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  15
  16 #include <linux/cpu.h>
  17 #include <linux/errno.h>
  18 #include <linux/device.h>
  19 #include <linux/of_device.h>
  20 #include <linux/pm_domain.h>
  21 #include <linux/slab.h>
  22 #include <linux/export.h>
  23
  24 #include "opp.h"
  25
  26 /*
  27  * Returns opp descriptor node for a device node, caller must
  28  * do of_node_put().
  29  */
  30 static struct device_node *_opp_of_get_opp_desc_node(struct device_node *np,
  31                                                      int index)
  32 {
  33         /* "operating-points-v2" can be an array for power domain providers */
  34         return of_parse_phandle(np, "operating-points-v2", index);
  35 }
  36
  37 /* Returns opp descriptor node for a device, caller must do of_node_put() */
  38 struct device_node *dev_pm_opp_of_get_opp_desc_node(struct device *dev)
  39 {
  40         return _opp_of_get_opp_desc_node(dev->of_node, 0);
  41 }
  42 EXPORT_SYMBOL_GPL(dev_pm_opp_of_get_opp_desc_node);
  43
  44 struct opp_table *_managed_opp(struct device *dev, int index)
  45 {
  46         struct opp_table *opp_table, *managed_table = NULL;
  47         struct device_node *np;
  48
  49         np = _opp_of_get_opp_desc_node(dev->of_node, index);
  50         if (!np)
  51                 return NULL;
  52
  53         list_for_each_entry(opp_table, &opp_tables, node) {
  54                 if (opp_table->np == np) {
  55                         /*
  56                          * Multiple devices can point to the same OPP table and
  57                          * so will have same node-pointer, np.
  58                          *
  59                          * But the OPPs will be considered as shared only if the
  60                          * OPP table contains a "opp-shared" property.
  61                          */
  62                         if (opp_table->shared_opp == OPP_TABLE_ACCESS_SHARED) {
  63                                 _get_opp_table_kref(opp_table);
  64                                 managed_table = opp_table;
  65                         }
  66
  67                         break;
  68                 }
  69         }
  70
  71         of_node_put(np);
  72
  73         return managed_table;
  74 }
  75
  76 void _of_init_opp_table(struct opp_table *opp_table, struct device *dev,
  77                         int index)
  78 {
  79         struct device_node *np, *opp_np;
  80         u32 val;
  81
  82         /*
  83          * Only required for backward compatibility with v1 bindings, but isn't
  84          * harmful for other cases. And so we do it unconditionally.
  85          */
  86         np = of_node_get(dev->of_node);
  87         if (!np)
  88                 return;
  89
  90         if (!of_property_read_u32(np, "clock-latency", &val))
  91                 opp_table->clock_latency_ns_max = val;
  92         of_property_read_u32(np, "voltage-tolerance",
  93                              &opp_table->voltage_tolerance_v1);
  94
  95         /* Get OPP table node */
  96         opp_np = _opp_of_get_opp_desc_node(np, index);
  97         of_node_put(np);
  98
  99         if (!opp_np)
 100                 return;
 101
 102         if (of_property_read_bool(opp_np, "opp-shared"))
 103                 opp_table->shared_opp = OPP_TABLE_ACCESS_SHARED;
 104         else
 105                 opp_table->shared_opp = OPP_TABLE_ACCESS_EXCLUSIVE;
 106
 107         opp_table->np = opp_np;
 108
 109         of_node_put(opp_np);
 110 }
 111
 112 static bool _opp_is_supported(struct device *dev, struct opp_table *opp_table,
 113                               struct device_node *np)
 114 {
 115         unsigned int count = opp_table->supported_hw_count;
 116         u32 version;
 117         int ret;
 118
 119         if (!opp_table->supported_hw) {
 120                 /*
 121                  * In the case that no supported_hw has been set by the
 122                  * platform but there is an opp-supported-hw value set for
 123                  * an OPP then the OPP should not be enabled as there is
 124                  * no way to see if the hardware supports it.
 125                  */
 126                 if (of_find_property(np, "opp-supported-hw", NULL))
 127                         return false;
 128                 else
 129                         return true;
 130         }
 131
 132         while (count--) {
 133                 ret = of_property_read_u32_index(np, "opp-supported-hw", count,
 134                                                  &version);
 135                 if (ret) {
 136                         dev_warn(dev, "%s: failed to read opp-supported-hw property at index %d: %d\n",
 137                                  __func__, count, ret);
 138                         return false;
 139                 }
 140
 141                 /* Both of these are bitwise masks of the versions */
 142                 if (!(version & opp_table->supported_hw[count]))
 143                         return false;
 144         }
 145
 146         return true;
 147 }
 148
 149 static int opp_parse_supplies(struct dev_pm_opp *opp, struct device *dev,
 150                               struct opp_table *opp_table)
 151 {
 152         u32 *microvolt, *microamp = NULL;
 153         int supplies, vcount, icount, ret, i, j;
 154         struct property *prop = NULL;
 155         char name[NAME_MAX];
 156
 157         supplies = opp_table->regulator_count ? opp_table->regulator_count : 1;
 158
 159         /* Search for "opp-microvolt-<name>" */
 160         if (opp_table->prop_name) {
 161                 snprintf(name, sizeof(name), "opp-microvolt-%s",
 162                          opp_table->prop_name);
 163                 prop = of_find_property(opp->np, name, NULL);
 164         }
 165
 166         if (!prop) {
 167                 /* Search for "opp-microvolt" */
 168                 sprintf(name, "opp-microvolt");
 169                 prop = of_find_property(opp->np, name, NULL);
 170
 171                 /* Missing property isn't a problem, but an invalid entry is */
 172                 if (!prop) {
 173                         if (!opp_table->regulator_count)
 174                                 return 0;
 175
 176                         dev_err(dev, "%s: opp-microvolt missing although OPP managing regulators\n",
 177                                 __func__);
 178                         return -EINVAL;
 179                 }
 180         }
 181
 182         vcount = of_property_count_u32_elems(opp->np, name);
 183         if (vcount < 0) {
 184                 dev_err(dev, "%s: Invalid %s property (%d)\n",
 185                         __func__, name, vcount);
 186                 return vcount;
 187         }
 188
 189         /* There can be one or three elements per supply */
 190         if (vcount != supplies && vcount != supplies * 3) {
 191                 dev_err(dev, "%s: Invalid number of elements in %s property (%d) with supplies (%d)\n",
 192                         __func__, name, vcount, supplies);
 193                 return -EINVAL;
 194         }
 195
 196         microvolt = kmalloc_array(vcount, sizeof(*microvolt), GFP_KERNEL);
 197         if (!microvolt)
 198                 return -ENOMEM;
 199
 200         ret = of_property_read_u32_array(opp->np, name, microvolt, vcount);
 201         if (ret) {
 202                 dev_err(dev, "%s: error parsing %s: %d\n", __func__, name, ret);
 203                 ret = -EINVAL;
 204                 goto free_microvolt;
 205         }
 206
 207         /* Search for "opp-microamp-<name>" */
 208         prop = NULL;
 209         if (opp_table->prop_name) {
 210                 snprintf(name, sizeof(name), "opp-microamp-%s",
 211                          opp_table->prop_name);
 212                 prop = of_find_property(opp->np, name, NULL);
 213         }
 214
 215         if (!prop) {
 216                 /* Search for "opp-microamp" */
 217                 sprintf(name, "opp-microamp");
 218                 prop = of_find_property(opp->np, name, NULL);
 219         }
 220
 221         if (prop) {
 222                 icount = of_property_count_u32_elems(opp->np, name);
 223                 if (icount < 0) {
 224                         dev_err(dev, "%s: Invalid %s property (%d)\n", __func__,
 225                                 name, icount);
 226                         ret = icount;
 227                         goto free_microvolt;
 228                 }
 229
 230                 if (icount != supplies) {
 231                         dev_err(dev, "%s: Invalid number of elements in %s property (%d) with supplies (%d)\n",
 232                                 __func__, name, icount, supplies);
 233                         ret = -EINVAL;
 234                         goto free_microvolt;
 235                 }
 236
 237                 microamp = kmalloc_array(icount, sizeof(*microamp), GFP_KERNEL);
 238                 if (!microamp) {
 239                         ret = -EINVAL;
 240                         goto free_microvolt;
 241                 }
 242
 243                 ret = of_property_read_u32_array(opp->np, name, microamp,
 244                                                  icount);
 245                 if (ret) {
 246                         dev_err(dev, "%s: error parsing %s: %d\n", __func__,
 247                                 name, ret);
 248                         ret = -EINVAL;
 249                         goto free_microamp;
 250                 }
 251         }
 252
 253         for (i = 0, j = 0; i < supplies; i++) {
 254                 opp->supplies[i].u_volt = microvolt[j++];
 255
 256                 if (vcount == supplies) {
 257                         opp->supplies[i].u_volt_min = opp->supplies[i].u_volt;
 258                         opp->supplies[i].u_volt_max = opp->supplies[i].u_volt;
 259                 } else {
 260                         opp->supplies[i].u_volt_min = microvolt[j++];
 261                         opp->supplies[i].u_volt_max = microvolt[j++];
 262                 }
 263
 264                 if (microamp)
 265                         opp->supplies[i].u_amp = microamp[i];
 266         }
 267
 268 free_microamp:
 269         kfree(microamp);
 270 free_microvolt:
 271         kfree(microvolt);
 272
 273         return ret;
 274 }
 275
 276 /**
 277  * dev_pm_opp_of_remove_table() - Free OPP table entries created from static DT
 278  *                                entries
 279  * @dev:        device pointer used to lookup OPP table.
 280  *
 281  * Free OPPs created using static entries present in DT.
 282  */
 283 void dev_pm_opp_of_remove_table(struct device *dev)
 284 {
 285         _dev_pm_opp_find_and_remove_table(dev);
 286 }
 287 EXPORT_SYMBOL_GPL(dev_pm_opp_of_remove_table);
 288
 289 /**
 290  * _opp_add_static_v2() - Allocate static OPPs (As per 'v2' DT bindings)
 291  * @opp_table:  OPP table
 292  * @dev:        device for which we do this operation
 293  * @np:         device node
 294  *
 295  * This function adds an opp definition to the opp table and returns status. The
 296  * opp can be controlled using dev_pm_opp_enable/disable functions and may be
 297  * removed by dev_pm_opp_remove.
 298  *
 299  * Return:
 300  * Valid OPP pointer:
 301  *              On success
 302  * NULL:
 303  *              Duplicate OPPs (both freq and volt are same) and opp->available
 304  *              OR if the OPP is not supported by hardware.
 305  * ERR_PTR(-EEXIST):
 306  *              Freq are same and volt are different OR
 307  *              Duplicate OPPs (both freq and volt are same) and !opp->available
 308  * ERR_PTR(-ENOMEM):
 309  *              Memory allocation failure
 310  * ERR_PTR(-EINVAL):
 311  *              Failed parsing the OPP node
 312  */
 313 static struct dev_pm_opp *_opp_add_static_v2(struct opp_table *opp_table,
 314                 struct device *dev, struct device_node *np)
 315 {
 316         struct dev_pm_opp *new_opp;
 317         u64 rate = 0;
 318         u32 val;
 319         int ret;
 320         bool rate_not_available = false;
 321
 322         new_opp = _opp_allocate(opp_table);
 323         if (!new_opp)
 324                 return ERR_PTR(-ENOMEM);
 325
 326         ret = of_property_read_u64(np, "opp-hz", &rate);
 327         if (ret < 0) {
 328                 /* "opp-hz" is optional for devices like power domains. */
 329                 if (!of_find_property(dev->of_node, "#power-domain-cells",
 330                                       NULL)) {
 331                         dev_err(dev, "%s: opp-hz not found\n", __func__);
 332                         goto free_opp;
 333                 }
 334
 335                 rate_not_available = true;
 336         } else {
 337                 /*
 338                  * Rate is defined as an unsigned long in clk API, and so
 339                  * casting explicitly to its type. Must be fixed once rate is 64
 340                  * bit guaranteed in clk API.
 341                  */
 342                 new_opp->rate = (unsigned long)rate;
 343         }
 344
 345         /* Check if the OPP supports hardware's hierarchy of versions or not */
 346         if (!_opp_is_supported(dev, opp_table, np)) {
 347                 dev_dbg(dev, "OPP not supported by hardware: %llu\n", rate);
 348                 goto free_opp;
 349         }
 350
 351         new_opp->turbo = of_property_read_bool(np, "turbo-mode");
 352
 353         new_opp->np = np;
 354         new_opp->dynamic = false;
 355         new_opp->available = true;
 356
 357         if (!of_property_read_u32(np, "clock-latency-ns", &val))
 358                 new_opp->clock_latency_ns = val;
 359
 360         new_opp->pstate = of_genpd_opp_to_performance_state(dev, np);
 361
 362         ret = opp_parse_supplies(new_opp, dev, opp_table);
 363         if (ret)
 364                 goto free_opp;
 365
 366         ret = _opp_add(dev, new_opp, opp_table, rate_not_available);
 367         if (ret) {
 368                 /* Don't return error for duplicate OPPs */
 369                 if (ret == -EBUSY)
 370                         ret = 0;
 371                 goto free_opp;
 372         }
 373
 374         /* OPP to select on device suspend */
 375         if (of_property_read_bool(np, "opp-suspend")) {
 376                 if (opp_table->suspend_opp) {
 377                         dev_warn(dev, "%s: Multiple suspend OPPs found (%lu %lu)\n",
 378                                  __func__, opp_table->suspend_opp->rate,
 379                                  new_opp->rate);
 380                 } else {
 381                         new_opp->suspend = true;
 382                         opp_table->suspend_opp = new_opp;
 383                 }
 384         }
 385
 386         if (new_opp->clock_latency_ns > opp_table->clock_latency_ns_max)
 387                 opp_table->clock_latency_ns_max = new_opp->clock_latency_ns;
 388
 389         pr_debug("%s: turbo:%d rate:%lu uv:%lu uvmin:%lu uvmax:%lu latency:%lu\n",
 390                  __func__, new_opp->turbo, new_opp->rate,
 391                  new_opp->supplies[0].u_volt, new_opp->supplies[0].u_volt_min,
 392                  new_opp->supplies[0].u_volt_max, new_opp->clock_latency_ns);
 393
 394         /*
 395          * Notify the changes in the availability of the operable
 396          * frequency/voltage list.
 397          */
 398         blocking_notifier_call_chain(&opp_table->head, OPP_EVENT_ADD, new_opp);
 399         return new_opp;
 400
 401 free_opp:
 402         _opp_free(new_opp);
 403
 404         return ERR_PTR(ret);
 405 }
 406
 407 /* Initializes OPP tables based on new bindings */
 408 static int _of_add_opp_table_v2(struct device *dev, struct opp_table *opp_table)
 409 {
 410         struct device_node *np;
 411         int ret, count = 0, pstate_count = 0;
 412         struct dev_pm_opp *opp;
 413
 414         /* OPP table is already initialized for the device */
 415         if (opp_table->parsed_static_opps) {
 416                 kref_get(&opp_table->list_kref);
 417                 return 0;
 418         }
 419
 420         kref_init(&opp_table->list_kref);
 421
 422         /* We have opp-table node now, iterate over it and add OPPs */
 423         for_each_available_child_of_node(opp_table->np, np) {
 424                 opp = _opp_add_static_v2(opp_table, dev, np);
 425                 if (IS_ERR(opp)) {
 426                         ret = PTR_ERR(opp);
 427                         dev_err(dev, "%s: Failed to add OPP, %d\n", __func__,
 428                                 ret);
 429                         of_node_put(np);
 430                         goto put_list_kref;
 431                 } else if (opp) {
 432                         count++;
 433                 }
 434         }
 435
 436         /* There should be one of more OPP defined */
 437         if (WARN_ON(!count)) {
 438                 ret = -ENOENT;
 439                 goto put_list_kref;
 440         }
 441
 442         list_for_each_entry(opp, &opp_table->opp_list, node)
 443                 pstate_count += !!opp->pstate;
 444
 445         /* Either all or none of the nodes shall have performance state set */
 446         if (pstate_count && pstate_count != count) {
 447                 dev_err(dev, "Not all nodes have performance state set (%d: %d)\n",
 448                         count, pstate_count);
 449                 ret = -ENOENT;
 450                 goto put_list_kref;
 451         }
 452
 453         if (pstate_count)
 454                 opp_table->genpd_performance_state = true;
 455
 456         opp_table->parsed_static_opps = true;
 457
 458         return 0;
 459
 460 put_list_kref:
 461         _put_opp_list_kref(opp_table);
 462
 463         return ret;
 464 }
 465
 466 /* Initializes OPP tables based on old-deprecated bindings */
 467 static int _of_add_opp_table_v1(struct device *dev, struct opp_table *opp_table)
 468 {
 469         const struct property *prop;
 470         const __be32 *val;
 471         int nr, ret = 0;
 472
 473         prop = of_find_property(dev->of_node, "operating-points", NULL);
 474         if (!prop)
 475                 return -ENODEV;
 476         if (!prop->value)
 477                 return -ENODATA;
 478
 479         /*
 480          * Each OPP is a set of tuples consisting of frequency and
 481          * voltage like <freq-kHz vol-uV>.
 482          */
 483         nr = prop->length / sizeof(u32);
 484         if (nr % 2) {
 485                 dev_err(dev, "%s: Invalid OPP table\n", __func__);
 486                 return -EINVAL;
 487         }
 488
 489         kref_init(&opp_table->list_kref);
 490
 491         val = prop->value;
 492         while (nr) {
 493                 unsigned long freq = be32_to_cpup(val++) * 1000;
 494                 unsigned long volt = be32_to_cpup(val++);
 495
 496                 ret = _opp_add_v1(opp_table, dev, freq, volt, false);
 497                 if (ret) {
 498                         dev_err(dev, "%s: Failed to add OPP %ld (%d)\n",
 499                                 __func__, freq, ret);
 500                         _put_opp_list_kref(opp_table);
 501                         return ret;
 502                 }
 503                 nr -= 2;
 504         }
 505
 506         return ret;
 507 }
 508
 509 /**
 510  * dev_pm_opp_of_add_table() - Initialize opp table from device tree
 511  * @dev:        device pointer used to lookup OPP table.
 512  *
 513  * Register the initial OPP table with the OPP library for given device.
 514  *
 515  * Return:
 516  * 0            On success OR
 517  *              Duplicate OPPs (both freq and volt are same) and opp->available
 518  * -EEXIST      Freq are same and volt are different OR
 519  *              Duplicate OPPs (both freq and volt are same) and !opp->available
 520  * -ENOMEM      Memory allocation failure
 521  * -ENODEV      when 'operating-points' property is not found or is invalid data
 522  *              in device node.
 523  * -ENODATA     when empty 'operating-points' property is found
 524  * -EINVAL      when invalid entries are found in opp-v2 table
 525  */
 526 int dev_pm_opp_of_add_table(struct device *dev)
 527 {
 528         struct opp_table *opp_table;
 529         int ret;
 530
 531         opp_table = dev_pm_opp_get_opp_table_indexed(dev, 0);
 532         if (!opp_table)
 533                 return -ENOMEM;
 534
 535         /*
 536          * OPPs have two version of bindings now. Also try the old (v1)
 537          * bindings for backward compatibility with older dtbs.
 538          */
 539         if (opp_table->np)
 540                 ret = _of_add_opp_table_v2(dev, opp_table);
 541         else
 542                 ret = _of_add_opp_table_v1(dev, opp_table);
 543
 544         if (ret)
 545                 dev_pm_opp_put_opp_table(opp_table);
 546
 547         return ret;
 548 }
 549 EXPORT_SYMBOL_GPL(dev_pm_opp_of_add_table);
 550
 551 /**
 552  * dev_pm_opp_of_add_table_indexed() - Initialize indexed opp table from device tree
 553  * @dev:        device pointer used to lookup OPP table.
 554  * @index:      Index number.
 555  *
 556  * Register the initial OPP table with the OPP library for given device only
 557  * using the "operating-points-v2" property.
 558  *
 559  * Return:
 560  * 0            On success OR
 561  *              Duplicate OPPs (both freq and volt are same) and opp->available
 562  * -EEXIST      Freq are same and volt are different OR
 563  *              Duplicate OPPs (both freq and volt are same) and !opp->available
 564  * -ENOMEM      Memory allocation failure
 565  * -ENODEV      when 'operating-points' property is not found or is invalid data
 566  *              in device node.
 567  * -ENODATA     when empty 'operating-points' property is found
 568  * -EINVAL      when invalid entries are found in opp-v2 table
 569  */
 570 int dev_pm_opp_of_add_table_indexed(struct device *dev, int index)
 571 {
 572         struct opp_table *opp_table;
 573         int ret, count;
 574
 575         if (index) {
 576                 /*
 577                  * If only one phandle is present, then the same OPP table
 578                  * applies for all index requests.
 579                  */
 580                 count = of_count_phandle_with_args(dev->of_node,
 581                                                    "operating-points-v2", NULL);
 582                 if (count == 1)
 583                         index = 0;
 584         }
 585
 586         opp_table = dev_pm_opp_get_opp_table_indexed(dev, index);
 587         if (!opp_table)
 588                 return -ENOMEM;
 589
 590         ret = _of_add_opp_table_v2(dev, opp_table);
 591         if (ret)
 592                 dev_pm_opp_put_opp_table(opp_table);
 593
 594         return ret;
 595 }
 596 EXPORT_SYMBOL_GPL(dev_pm_opp_of_add_table_indexed);
 597
 598 /* CPU device specific helpers */
 599
 600 /**
 601  * dev_pm_opp_of_cpumask_remove_table() - Removes OPP table for @cpumask
 602  * @cpumask:    cpumask for which OPP table needs to be removed
 603  *
 604  * This removes the OPP tables for CPUs present in the @cpumask.
 605  * This should be used only to remove static entries created from DT.
 606  */
 607 void dev_pm_opp_of_cpumask_remove_table(const struct cpumask *cpumask)
 608 {
 609         _dev_pm_opp_cpumask_remove_table(cpumask, -1);
 610 }
 611 EXPORT_SYMBOL_GPL(dev_pm_opp_of_cpumask_remove_table);
 612
 613 /**
 614  * dev_pm_opp_of_cpumask_add_table() - Adds OPP table for @cpumask
 615  * @cpumask:    cpumask for which OPP table needs to be added.
 616  *
 617  * This adds the OPP tables for CPUs present in the @cpumask.
 618  */
 619 int dev_pm_opp_of_cpumask_add_table(const struct cpumask *cpumask)
 620 {
 621         struct device *cpu_dev;
 622         int cpu, ret;
 623
 624         if (WARN_ON(cpumask_empty(cpumask)))
 625                 return -ENODEV;
 626
 627         for_each_cpu(cpu, cpumask) {
 628                 cpu_dev = get_cpu_device(cpu);
 629                 if (!cpu_dev) {
 630                         pr_err("%s: failed to get cpu%d device\n", __func__,
 631                                cpu);
 632                         ret = -ENODEV;
 633                         goto remove_table;
 634                 }
 635
 636                 ret = dev_pm_opp_of_add_table(cpu_dev);
 637                 if (ret) {
 638                         /*
 639                          * OPP may get registered dynamically, don't print error
 640                          * message here.
 641                          */
 642                         pr_debug("%s: couldn't find opp table for cpu:%d, %d\n",
 643                                  __func__, cpu, ret);
 644
 645                         goto remove_table;
 646                 }
 647         }
 648
 649         return 0;
 650
 651 remove_table:
 652         /* Free all other OPPs */
 653         _dev_pm_opp_cpumask_remove_table(cpumask, cpu);
 654
 655         return ret;
 656 }
 657 EXPORT_SYMBOL_GPL(dev_pm_opp_of_cpumask_add_table);
 658
 659 /*
 660  * Works only for OPP v2 bindings.
 661  *
 662  * Returns -ENOENT if operating-points-v2 bindings aren't supported.
 663  */
 664 /**
 665  * dev_pm_opp_of_get_sharing_cpus() - Get cpumask of CPUs sharing OPPs with
 666  *                                    @cpu_dev using operating-points-v2
 667  *                                    bindings.
 668  *
 669  * @cpu_dev:    CPU device for which we do this operation
 670  * @cpumask:    cpumask to update with information of sharing CPUs
 671  *
 672  * This updates the @cpumask with CPUs that are sharing OPPs with @cpu_dev.
 673  *
 674  * Returns -ENOENT if operating-points-v2 isn't present for @cpu_dev.
 675  */
 676 int dev_pm_opp_of_get_sharing_cpus(struct device *cpu_dev,
 677                                    struct cpumask *cpumask)
 678 {
 679         struct device_node *np, *tmp_np, *cpu_np;
 680         int cpu, ret = 0;
 681
 682         /* Get OPP descriptor node */
 683         np = dev_pm_opp_of_get_opp_desc_node(cpu_dev);
 684         if (!np) {
 685                 dev_dbg(cpu_dev, "%s: Couldn't find opp node.\n", __func__);
 686                 return -ENOENT;
 687         }
 688
 689         cpumask_set_cpu(cpu_dev->id, cpumask);
 690
 691         /* OPPs are shared ? */
 692         if (!of_property_read_bool(np, "opp-shared"))
 693                 goto put_cpu_node;
 694
 695         for_each_possible_cpu(cpu) {
 696                 if (cpu == cpu_dev->id)
 697                         continue;
 698
 699                 cpu_np = of_cpu_device_node_get(cpu);
 700                 if (!cpu_np) {
 701                         dev_err(cpu_dev, "%s: failed to get cpu%d node\n",
 702                                 __func__, cpu);
 703                         ret = -ENOENT;
 704                         goto put_cpu_node;
 705                 }
 706
 707                 /* Get OPP descriptor node */
 708                 tmp_np = _opp_of_get_opp_desc_node(cpu_np, 0);
 709                 of_node_put(cpu_np);
 710                 if (!tmp_np) {
 711                         pr_err("%pOF: Couldn't find opp node\n", cpu_np);
 712                         ret = -ENOENT;
 713                         goto put_cpu_node;
 714                 }
 715
 716                 /* CPUs are sharing opp node */
 717                 if (np == tmp_np)
 718                         cpumask_set_cpu(cpu, cpumask);
 719
 720                 of_node_put(tmp_np);
 721         }
 722
 723 put_cpu_node:
 724         of_node_put(np);
 725         return ret;
 726 }
 727 EXPORT_SYMBOL_GPL(dev_pm_opp_of_get_sharing_cpus);
 728
 729 /**
 730  * of_dev_pm_opp_find_required_opp() - Search for required OPP.
 731  * @dev: The device whose OPP node is referenced by the 'np' DT node.
 732  * @np: Node that contains the "required-opps" property.
 733  *
 734  * Returns the OPP of the device 'dev', whose phandle is present in the "np"
 735  * node. Although the "required-opps" property supports having multiple
 736  * phandles, this helper routine only parses the very first phandle in the list.
 737  *
 738  * Return: Matching opp, else returns ERR_PTR in case of error and should be
 739  * handled using IS_ERR.
 740  *
 741  * The callers are required to call dev_pm_opp_put() for the returned OPP after
 742  * use.
 743  */
 744 struct dev_pm_opp *of_dev_pm_opp_find_required_opp(struct device *dev,
 745                                                    struct device_node *np)
 746 {
 747         struct dev_pm_opp *temp_opp, *opp = ERR_PTR(-ENODEV);
 748         struct device_node *required_np;
 749         struct opp_table *opp_table;
 750
 751         opp_table = _find_opp_table(dev);
 752         if (IS_ERR(opp_table))
 753                 return ERR_CAST(opp_table);
 754
 755         required_np = of_parse_phandle(np, "required-opps", 0);
 756         if (unlikely(!required_np)) {
 757                 dev_err(dev, "Unable to parse required-opps\n");
 758                 goto put_opp_table;
 759         }
 760
 761         mutex_lock(&opp_table->lock);
 762
 763         list_for_each_entry(temp_opp, &opp_table->opp_list, node) {
 764                 if (temp_opp->available && temp_opp->np == required_np) {
 765                         opp = temp_opp;
 766
 767                         /* Increment the reference count of OPP */
 768                         dev_pm_opp_get(opp);
 769                         break;
 770                 }
 771         }
 772
 773         mutex_unlock(&opp_table->lock);
 774
 775         of_node_put(required_np);
 776 put_opp_table:
 777         dev_pm_opp_put_opp_table(opp_table);
 778
 779         return opp;
 780 }
 781 EXPORT_SYMBOL_GPL(of_dev_pm_opp_find_required_opp);
 782
 783 /**
 784  * dev_pm_opp_get_of_node() - Gets the DT node corresponding to an opp
 785  * @opp:        opp for which DT node has to be returned for
 786  *
 787  * Return: DT node corresponding to the opp, else 0 on success.
 788  *
 789  * The caller needs to put the node with of_node_put() after using it.
 790  */
 791 struct device_node *dev_pm_opp_get_of_node(struct dev_pm_opp *opp)
 792 {
 793         if (IS_ERR_OR_NULL(opp)) {
 794                 pr_err("%s: Invalid parameters\n", __func__);
 795                 return NULL;
 796         }
 797
 798         return of_node_get(opp->np);
 799 }
 800 EXPORT_SYMBOL_GPL(dev_pm_opp_get_of_node);