linux/drivers/clk/clk.c
<<
>>
Prefs
   1/*
   2 * Copyright (C) 2010-2011 Canonical Ltd <jeremy.kerr@canonical.com>
   3 * Copyright (C) 2011-2012 Linaro Ltd <mturquette@linaro.org>
   4 *
   5 * This program is free software; you can redistribute it and/or modify
   6 * it under the terms of the GNU General Public License version 2 as
   7 * published by the Free Software Foundation.
   8 *
   9 * Standard functionality for the common clock API.  See Documentation/clk.txt
  10 */
  11
  12#include <linux/clk-private.h>
  13#include <linux/module.h>
  14#include <linux/mutex.h>
  15#include <linux/spinlock.h>
  16#include <linux/err.h>
  17#include <linux/list.h>
  18#include <linux/slab.h>
  19#include <linux/of.h>
  20#include <linux/device.h>
  21#include <linux/init.h>
  22
  23static DEFINE_SPINLOCK(enable_lock);
  24static DEFINE_MUTEX(prepare_lock);
  25
  26static HLIST_HEAD(clk_root_list);
  27static HLIST_HEAD(clk_orphan_list);
  28static LIST_HEAD(clk_notifier_list);
  29
  30/***        debugfs support        ***/
  31
  32#ifdef CONFIG_COMMON_CLK_DEBUG
  33#include <linux/debugfs.h>
  34
  35static struct dentry *rootdir;
  36static struct dentry *orphandir;
  37static int inited = 0;
  38
  39static void clk_summary_show_one(struct seq_file *s, struct clk *c, int level)
  40{
  41        if (!c)
  42                return;
  43
  44        seq_printf(s, "%*s%-*s %-11d %-12d %-10lu",
  45                   level * 3 + 1, "",
  46                   30 - level * 3, c->name,
  47                   c->enable_count, c->prepare_count, c->rate);
  48        seq_printf(s, "\n");
  49}
  50
  51static void clk_summary_show_subtree(struct seq_file *s, struct clk *c,
  52                                     int level)
  53{
  54        struct clk *child;
  55
  56        if (!c)
  57                return;
  58
  59        clk_summary_show_one(s, c, level);
  60
  61        hlist_for_each_entry(child, &c->children, child_node)
  62                clk_summary_show_subtree(s, child, level + 1);
  63}
  64
  65static int clk_summary_show(struct seq_file *s, void *data)
  66{
  67        struct clk *c;
  68
  69        seq_printf(s, "   clock                        enable_cnt  prepare_cnt  rate\n");
  70        seq_printf(s, "---------------------------------------------------------------------\n");
  71
  72        mutex_lock(&prepare_lock);
  73
  74        hlist_for_each_entry(c, &clk_root_list, child_node)
  75                clk_summary_show_subtree(s, c, 0);
  76
  77        hlist_for_each_entry(c, &clk_orphan_list, child_node)
  78                clk_summary_show_subtree(s, c, 0);
  79
  80        mutex_unlock(&prepare_lock);
  81
  82        return 0;
  83}
  84
  85
  86static int clk_summary_open(struct inode *inode, struct file *file)
  87{
  88        return single_open(file, clk_summary_show, inode->i_private);
  89}
  90
  91static const struct file_operations clk_summary_fops = {
  92        .open           = clk_summary_open,
  93        .read           = seq_read,
  94        .llseek         = seq_lseek,
  95        .release        = single_release,
  96};
  97
  98static void clk_dump_one(struct seq_file *s, struct clk *c, int level)
  99{
 100        if (!c)
 101                return;
 102
 103        seq_printf(s, "\"%s\": { ", c->name);
 104        seq_printf(s, "\"enable_count\": %d,", c->enable_count);
 105        seq_printf(s, "\"prepare_count\": %d,", c->prepare_count);
 106        seq_printf(s, "\"rate\": %lu", c->rate);
 107}
 108
 109static void clk_dump_subtree(struct seq_file *s, struct clk *c, int level)
 110{
 111        struct clk *child;
 112
 113        if (!c)
 114                return;
 115
 116        clk_dump_one(s, c, level);
 117
 118        hlist_for_each_entry(child, &c->children, child_node) {
 119                seq_printf(s, ",");
 120                clk_dump_subtree(s, child, level + 1);
 121        }
 122
 123        seq_printf(s, "}");
 124}
 125
 126static int clk_dump(struct seq_file *s, void *data)
 127{
 128        struct clk *c;
 129        bool first_node = true;
 130
 131        seq_printf(s, "{");
 132
 133        mutex_lock(&prepare_lock);
 134
 135        hlist_for_each_entry(c, &clk_root_list, child_node) {
 136                if (!first_node)
 137                        seq_printf(s, ",");
 138                first_node = false;
 139                clk_dump_subtree(s, c, 0);
 140        }
 141
 142        hlist_for_each_entry(c, &clk_orphan_list, child_node) {
 143                seq_printf(s, ",");
 144                clk_dump_subtree(s, c, 0);
 145        }
 146
 147        mutex_unlock(&prepare_lock);
 148
 149        seq_printf(s, "}");
 150        return 0;
 151}
 152
 153
 154static int clk_dump_open(struct inode *inode, struct file *file)
 155{
 156        return single_open(file, clk_dump, inode->i_private);
 157}
 158
 159static const struct file_operations clk_dump_fops = {
 160        .open           = clk_dump_open,
 161        .read           = seq_read,
 162        .llseek         = seq_lseek,
 163        .release        = single_release,
 164};
 165
 166/* caller must hold prepare_lock */
 167static int clk_debug_create_one(struct clk *clk, struct dentry *pdentry)
 168{
 169        struct dentry *d;
 170        int ret = -ENOMEM;
 171
 172        if (!clk || !pdentry) {
 173                ret = -EINVAL;
 174                goto out;
 175        }
 176
 177        d = debugfs_create_dir(clk->name, pdentry);
 178        if (!d)
 179                goto out;
 180
 181        clk->dentry = d;
 182
 183        d = debugfs_create_u32("clk_rate", S_IRUGO, clk->dentry,
 184                        (u32 *)&clk->rate);
 185        if (!d)
 186                goto err_out;
 187
 188        d = debugfs_create_x32("clk_flags", S_IRUGO, clk->dentry,
 189                        (u32 *)&clk->flags);
 190        if (!d)
 191                goto err_out;
 192
 193        d = debugfs_create_u32("clk_prepare_count", S_IRUGO, clk->dentry,
 194                        (u32 *)&clk->prepare_count);
 195        if (!d)
 196                goto err_out;
 197
 198        d = debugfs_create_u32("clk_enable_count", S_IRUGO, clk->dentry,
 199                        (u32 *)&clk->enable_count);
 200        if (!d)
 201                goto err_out;
 202
 203        d = debugfs_create_u32("clk_notifier_count", S_IRUGO, clk->dentry,
 204                        (u32 *)&clk->notifier_count);
 205        if (!d)
 206                goto err_out;
 207
 208        ret = 0;
 209        goto out;
 210
 211err_out:
 212        debugfs_remove(clk->dentry);
 213out:
 214        return ret;
 215}
 216
 217/* caller must hold prepare_lock */
 218static int clk_debug_create_subtree(struct clk *clk, struct dentry *pdentry)
 219{
 220        struct clk *child;
 221        int ret = -EINVAL;;
 222
 223        if (!clk || !pdentry)
 224                goto out;
 225
 226        ret = clk_debug_create_one(clk, pdentry);
 227
 228        if (ret)
 229                goto out;
 230
 231        hlist_for_each_entry(child, &clk->children, child_node)
 232                clk_debug_create_subtree(child, clk->dentry);
 233
 234        ret = 0;
 235out:
 236        return ret;
 237}
 238
 239/**
 240 * clk_debug_register - add a clk node to the debugfs clk tree
 241 * @clk: the clk being added to the debugfs clk tree
 242 *
 243 * Dynamically adds a clk to the debugfs clk tree if debugfs has been
 244 * initialized.  Otherwise it bails out early since the debugfs clk tree
 245 * will be created lazily by clk_debug_init as part of a late_initcall.
 246 *
 247 * Caller must hold prepare_lock.  Only clk_init calls this function (so
 248 * far) so this is taken care.
 249 */
 250static int clk_debug_register(struct clk *clk)
 251{
 252        struct clk *parent;
 253        struct dentry *pdentry;
 254        int ret = 0;
 255
 256        if (!inited)
 257                goto out;
 258
 259        parent = clk->parent;
 260
 261        /*
 262         * Check to see if a clk is a root clk.  Also check that it is
 263         * safe to add this clk to debugfs
 264         */
 265        if (!parent)
 266                if (clk->flags & CLK_IS_ROOT)
 267                        pdentry = rootdir;
 268                else
 269                        pdentry = orphandir;
 270        else
 271                if (parent->dentry)
 272                        pdentry = parent->dentry;
 273                else
 274                        goto out;
 275
 276        ret = clk_debug_create_subtree(clk, pdentry);
 277
 278out:
 279        return ret;
 280}
 281
 282/**
 283 * clk_debug_init - lazily create the debugfs clk tree visualization
 284 *
 285 * clks are often initialized very early during boot before memory can
 286 * be dynamically allocated and well before debugfs is setup.
 287 * clk_debug_init walks the clk tree hierarchy while holding
 288 * prepare_lock and creates the topology as part of a late_initcall,
 289 * thus insuring that clks initialized very early will still be
 290 * represented in the debugfs clk tree.  This function should only be
 291 * called once at boot-time, and all other clks added dynamically will
 292 * be done so with clk_debug_register.
 293 */
 294static int __init clk_debug_init(void)
 295{
 296        struct clk *clk;
 297        struct dentry *d;
 298
 299        rootdir = debugfs_create_dir("clk", NULL);
 300
 301        if (!rootdir)
 302                return -ENOMEM;
 303
 304        d = debugfs_create_file("clk_summary", S_IRUGO, rootdir, NULL,
 305                                &clk_summary_fops);
 306        if (!d)
 307                return -ENOMEM;
 308
 309        d = debugfs_create_file("clk_dump", S_IRUGO, rootdir, NULL,
 310                                &clk_dump_fops);
 311        if (!d)
 312                return -ENOMEM;
 313
 314        orphandir = debugfs_create_dir("orphans", rootdir);
 315
 316        if (!orphandir)
 317                return -ENOMEM;
 318
 319        mutex_lock(&prepare_lock);
 320
 321        hlist_for_each_entry(clk, &clk_root_list, child_node)
 322                clk_debug_create_subtree(clk, rootdir);
 323
 324        hlist_for_each_entry(clk, &clk_orphan_list, child_node)
 325                clk_debug_create_subtree(clk, orphandir);
 326
 327        inited = 1;
 328
 329        mutex_unlock(&prepare_lock);
 330
 331        return 0;
 332}
 333late_initcall(clk_debug_init);
 334#else
 335static inline int clk_debug_register(struct clk *clk) { return 0; }
 336#endif
 337
 338/* caller must hold prepare_lock */
 339static void clk_disable_unused_subtree(struct clk *clk)
 340{
 341        struct clk *child;
 342        unsigned long flags;
 343
 344        if (!clk)
 345                goto out;
 346
 347        hlist_for_each_entry(child, &clk->children, child_node)
 348                clk_disable_unused_subtree(child);
 349
 350        spin_lock_irqsave(&enable_lock, flags);
 351
 352        if (clk->enable_count)
 353                goto unlock_out;
 354
 355        if (clk->flags & CLK_IGNORE_UNUSED)
 356                goto unlock_out;
 357
 358        /*
 359         * some gate clocks have special needs during the disable-unused
 360         * sequence.  call .disable_unused if available, otherwise fall
 361         * back to .disable
 362         */
 363        if (__clk_is_enabled(clk)) {
 364                if (clk->ops->disable_unused)
 365                        clk->ops->disable_unused(clk->hw);
 366                else if (clk->ops->disable)
 367                        clk->ops->disable(clk->hw);
 368        }
 369
 370unlock_out:
 371        spin_unlock_irqrestore(&enable_lock, flags);
 372
 373out:
 374        return;
 375}
 376
 377static int clk_disable_unused(void)
 378{
 379        struct clk *clk;
 380
 381        mutex_lock(&prepare_lock);
 382
 383        hlist_for_each_entry(clk, &clk_root_list, child_node)
 384                clk_disable_unused_subtree(clk);
 385
 386        hlist_for_each_entry(clk, &clk_orphan_list, child_node)
 387                clk_disable_unused_subtree(clk);
 388
 389        mutex_unlock(&prepare_lock);
 390
 391        return 0;
 392}
 393late_initcall(clk_disable_unused);
 394
 395/***    helper functions   ***/
 396
 397const char *__clk_get_name(struct clk *clk)
 398{
 399        return !clk ? NULL : clk->name;
 400}
 401EXPORT_SYMBOL_GPL(__clk_get_name);
 402
 403struct clk_hw *__clk_get_hw(struct clk *clk)
 404{
 405        return !clk ? NULL : clk->hw;
 406}
 407
 408u8 __clk_get_num_parents(struct clk *clk)
 409{
 410        return !clk ? 0 : clk->num_parents;
 411}
 412
 413struct clk *__clk_get_parent(struct clk *clk)
 414{
 415        return !clk ? NULL : clk->parent;
 416}
 417
 418unsigned int __clk_get_enable_count(struct clk *clk)
 419{
 420        return !clk ? 0 : clk->enable_count;
 421}
 422
 423unsigned int __clk_get_prepare_count(struct clk *clk)
 424{
 425        return !clk ? 0 : clk->prepare_count;
 426}
 427
 428unsigned long __clk_get_rate(struct clk *clk)
 429{
 430        unsigned long ret;
 431
 432        if (!clk) {
 433                ret = 0;
 434                goto out;
 435        }
 436
 437        ret = clk->rate;
 438
 439        if (clk->flags & CLK_IS_ROOT)
 440                goto out;
 441
 442        if (!clk->parent)
 443                ret = 0;
 444
 445out:
 446        return ret;
 447}
 448
 449unsigned long __clk_get_flags(struct clk *clk)
 450{
 451        return !clk ? 0 : clk->flags;
 452}
 453
 454bool __clk_is_enabled(struct clk *clk)
 455{
 456        int ret;
 457
 458        if (!clk)
 459                return false;
 460
 461        /*
 462         * .is_enabled is only mandatory for clocks that gate
 463         * fall back to software usage counter if .is_enabled is missing
 464         */
 465        if (!clk->ops->is_enabled) {
 466                ret = clk->enable_count ? 1 : 0;
 467                goto out;
 468        }
 469
 470        ret = clk->ops->is_enabled(clk->hw);
 471out:
 472        return !!ret;
 473}
 474
 475static struct clk *__clk_lookup_subtree(const char *name, struct clk *clk)
 476{
 477        struct clk *child;
 478        struct clk *ret;
 479
 480        if (!strcmp(clk->name, name))
 481                return clk;
 482
 483        hlist_for_each_entry(child, &clk->children, child_node) {
 484                ret = __clk_lookup_subtree(name, child);
 485                if (ret)
 486                        return ret;
 487        }
 488
 489        return NULL;
 490}
 491
 492struct clk *__clk_lookup(const char *name)
 493{
 494        struct clk *root_clk;
 495        struct clk *ret;
 496
 497        if (!name)
 498                return NULL;
 499
 500        /* search the 'proper' clk tree first */
 501        hlist_for_each_entry(root_clk, &clk_root_list, child_node) {
 502                ret = __clk_lookup_subtree(name, root_clk);
 503                if (ret)
 504                        return ret;
 505        }
 506
 507        /* if not found, then search the orphan tree */
 508        hlist_for_each_entry(root_clk, &clk_orphan_list, child_node) {
 509                ret = __clk_lookup_subtree(name, root_clk);
 510                if (ret)
 511                        return ret;
 512        }
 513
 514        return NULL;
 515}
 516
 517/***        clk api        ***/
 518
 519void __clk_unprepare(struct clk *clk)
 520{
 521        if (!clk)
 522                return;
 523
 524        if (WARN_ON(clk->prepare_count == 0))
 525                return;
 526
 527        if (--clk->prepare_count > 0)
 528                return;
 529
 530        WARN_ON(clk->enable_count > 0);
 531
 532        if (clk->ops->unprepare)
 533                clk->ops->unprepare(clk->hw);
 534
 535        __clk_unprepare(clk->parent);
 536}
 537
 538/**
 539 * clk_unprepare - undo preparation of a clock source
 540 * @clk: the clk being unprepare
 541 *
 542 * clk_unprepare may sleep, which differentiates it from clk_disable.  In a
 543 * simple case, clk_unprepare can be used instead of clk_disable to gate a clk
 544 * if the operation may sleep.  One example is a clk which is accessed over
 545 * I2c.  In the complex case a clk gate operation may require a fast and a slow
 546 * part.  It is this reason that clk_unprepare and clk_disable are not mutually
 547 * exclusive.  In fact clk_disable must be called before clk_unprepare.
 548 */
 549void clk_unprepare(struct clk *clk)
 550{
 551        mutex_lock(&prepare_lock);
 552        __clk_unprepare(clk);
 553        mutex_unlock(&prepare_lock);
 554}
 555EXPORT_SYMBOL_GPL(clk_unprepare);
 556
 557int __clk_prepare(struct clk *clk)
 558{
 559        int ret = 0;
 560
 561        if (!clk)
 562                return 0;
 563
 564        if (clk->prepare_count == 0) {
 565                ret = __clk_prepare(clk->parent);
 566                if (ret)
 567                        return ret;
 568
 569                if (clk->ops->prepare) {
 570                        ret = clk->ops->prepare(clk->hw);
 571                        if (ret) {
 572                                __clk_unprepare(clk->parent);
 573                                return ret;
 574                        }
 575                }
 576        }
 577
 578        clk->prepare_count++;
 579
 580        return 0;
 581}
 582
 583/**
 584 * clk_prepare - prepare a clock source
 585 * @clk: the clk being prepared
 586 *
 587 * clk_prepare may sleep, which differentiates it from clk_enable.  In a simple
 588 * case, clk_prepare can be used instead of clk_enable to ungate a clk if the
 589 * operation may sleep.  One example is a clk which is accessed over I2c.  In
 590 * the complex case a clk ungate operation may require a fast and a slow part.
 591 * It is this reason that clk_prepare and clk_enable are not mutually
 592 * exclusive.  In fact clk_prepare must be called before clk_enable.
 593 * Returns 0 on success, -EERROR otherwise.
 594 */
 595int clk_prepare(struct clk *clk)
 596{
 597        int ret;
 598
 599        mutex_lock(&prepare_lock);
 600        ret = __clk_prepare(clk);
 601        mutex_unlock(&prepare_lock);
 602
 603        return ret;
 604}
 605EXPORT_SYMBOL_GPL(clk_prepare);
 606
 607static void __clk_disable(struct clk *clk)
 608{
 609        if (!clk)
 610                return;
 611
 612        if (WARN_ON(IS_ERR(clk)))
 613                return;
 614
 615        if (WARN_ON(clk->enable_count == 0))
 616                return;
 617
 618        if (--clk->enable_count > 0)
 619                return;
 620
 621        if (clk->ops->disable)
 622                clk->ops->disable(clk->hw);
 623
 624        __clk_disable(clk->parent);
 625}
 626
 627/**
 628 * clk_disable - gate a clock
 629 * @clk: the clk being gated
 630 *
 631 * clk_disable must not sleep, which differentiates it from clk_unprepare.  In
 632 * a simple case, clk_disable can be used instead of clk_unprepare to gate a
 633 * clk if the operation is fast and will never sleep.  One example is a
 634 * SoC-internal clk which is controlled via simple register writes.  In the
 635 * complex case a clk gate operation may require a fast and a slow part.  It is
 636 * this reason that clk_unprepare and clk_disable are not mutually exclusive.
 637 * In fact clk_disable must be called before clk_unprepare.
 638 */
 639void clk_disable(struct clk *clk)
 640{
 641        unsigned long flags;
 642
 643        spin_lock_irqsave(&enable_lock, flags);
 644        __clk_disable(clk);
 645        spin_unlock_irqrestore(&enable_lock, flags);
 646}
 647EXPORT_SYMBOL_GPL(clk_disable);
 648
 649static int __clk_enable(struct clk *clk)
 650{
 651        int ret = 0;
 652
 653        if (!clk)
 654                return 0;
 655
 656        if (WARN_ON(clk->prepare_count == 0))
 657                return -ESHUTDOWN;
 658
 659        if (clk->enable_count == 0) {
 660                ret = __clk_enable(clk->parent);
 661
 662                if (ret)
 663                        return ret;
 664
 665                if (clk->ops->enable) {
 666                        ret = clk->ops->enable(clk->hw);
 667                        if (ret) {
 668                                __clk_disable(clk->parent);
 669                                return ret;
 670                        }
 671                }
 672        }
 673
 674        clk->enable_count++;
 675        return 0;
 676}
 677
 678/**
 679 * clk_enable - ungate a clock
 680 * @clk: the clk being ungated
 681 *
 682 * clk_enable must not sleep, which differentiates it from clk_prepare.  In a
 683 * simple case, clk_enable can be used instead of clk_prepare to ungate a clk
 684 * if the operation will never sleep.  One example is a SoC-internal clk which
 685 * is controlled via simple register writes.  In the complex case a clk ungate
 686 * operation may require a fast and a slow part.  It is this reason that
 687 * clk_enable and clk_prepare are not mutually exclusive.  In fact clk_prepare
 688 * must be called before clk_enable.  Returns 0 on success, -EERROR
 689 * otherwise.
 690 */
 691int clk_enable(struct clk *clk)
 692{
 693        unsigned long flags;
 694        int ret;
 695
 696        spin_lock_irqsave(&enable_lock, flags);
 697        ret = __clk_enable(clk);
 698        spin_unlock_irqrestore(&enable_lock, flags);
 699
 700        return ret;
 701}
 702EXPORT_SYMBOL_GPL(clk_enable);
 703
 704/**
 705 * __clk_round_rate - round the given rate for a clk
 706 * @clk: round the rate of this clock
 707 *
 708 * Caller must hold prepare_lock.  Useful for clk_ops such as .set_rate
 709 */
 710unsigned long __clk_round_rate(struct clk *clk, unsigned long rate)
 711{
 712        unsigned long parent_rate = 0;
 713
 714        if (!clk)
 715                return 0;
 716
 717        if (!clk->ops->round_rate) {
 718                if (clk->flags & CLK_SET_RATE_PARENT)
 719                        return __clk_round_rate(clk->parent, rate);
 720                else
 721                        return clk->rate;
 722        }
 723
 724        if (clk->parent)
 725                parent_rate = clk->parent->rate;
 726
 727        return clk->ops->round_rate(clk->hw, rate, &parent_rate);
 728}
 729
 730/**
 731 * clk_round_rate - round the given rate for a clk
 732 * @clk: the clk for which we are rounding a rate
 733 * @rate: the rate which is to be rounded
 734 *
 735 * Takes in a rate as input and rounds it to a rate that the clk can actually
 736 * use which is then returned.  If clk doesn't support round_rate operation
 737 * then the parent rate is returned.
 738 */
 739long clk_round_rate(struct clk *clk, unsigned long rate)
 740{
 741        unsigned long ret;
 742
 743        mutex_lock(&prepare_lock);
 744        ret = __clk_round_rate(clk, rate);
 745        mutex_unlock(&prepare_lock);
 746
 747        return ret;
 748}
 749EXPORT_SYMBOL_GPL(clk_round_rate);
 750
 751/**
 752 * __clk_notify - call clk notifier chain
 753 * @clk: struct clk * that is changing rate
 754 * @msg: clk notifier type (see include/linux/clk.h)
 755 * @old_rate: old clk rate
 756 * @new_rate: new clk rate
 757 *
 758 * Triggers a notifier call chain on the clk rate-change notification
 759 * for 'clk'.  Passes a pointer to the struct clk and the previous
 760 * and current rates to the notifier callback.  Intended to be called by
 761 * internal clock code only.  Returns NOTIFY_DONE from the last driver
 762 * called if all went well, or NOTIFY_STOP or NOTIFY_BAD immediately if
 763 * a driver returns that.
 764 */
 765static int __clk_notify(struct clk *clk, unsigned long msg,
 766                unsigned long old_rate, unsigned long new_rate)
 767{
 768        struct clk_notifier *cn;
 769        struct clk_notifier_data cnd;
 770        int ret = NOTIFY_DONE;
 771
 772        cnd.clk = clk;
 773        cnd.old_rate = old_rate;
 774        cnd.new_rate = new_rate;
 775
 776        list_for_each_entry(cn, &clk_notifier_list, node) {
 777                if (cn->clk == clk) {
 778                        ret = srcu_notifier_call_chain(&cn->notifier_head, msg,
 779                                        &cnd);
 780                        break;
 781                }
 782        }
 783
 784        return ret;
 785}
 786
 787/**
 788 * __clk_recalc_rates
 789 * @clk: first clk in the subtree
 790 * @msg: notification type (see include/linux/clk.h)
 791 *
 792 * Walks the subtree of clks starting with clk and recalculates rates as it
 793 * goes.  Note that if a clk does not implement the .recalc_rate callback then
 794 * it is assumed that the clock will take on the rate of it's parent.
 795 *
 796 * clk_recalc_rates also propagates the POST_RATE_CHANGE notification,
 797 * if necessary.
 798 *
 799 * Caller must hold prepare_lock.
 800 */
 801static void __clk_recalc_rates(struct clk *clk, unsigned long msg)
 802{
 803        unsigned long old_rate;
 804        unsigned long parent_rate = 0;
 805        struct clk *child;
 806
 807        old_rate = clk->rate;
 808
 809        if (clk->parent)
 810                parent_rate = clk->parent->rate;
 811
 812        if (clk->ops->recalc_rate)
 813                clk->rate = clk->ops->recalc_rate(clk->hw, parent_rate);
 814        else
 815                clk->rate = parent_rate;
 816
 817        /*
 818         * ignore NOTIFY_STOP and NOTIFY_BAD return values for POST_RATE_CHANGE
 819         * & ABORT_RATE_CHANGE notifiers
 820         */
 821        if (clk->notifier_count && msg)
 822                __clk_notify(clk, msg, old_rate, clk->rate);
 823
 824        hlist_for_each_entry(child, &clk->children, child_node)
 825                __clk_recalc_rates(child, msg);
 826}
 827
 828/**
 829 * clk_get_rate - return the rate of clk
 830 * @clk: the clk whose rate is being returned
 831 *
 832 * Simply returns the cached rate of the clk, unless CLK_GET_RATE_NOCACHE flag
 833 * is set, which means a recalc_rate will be issued.
 834 * If clk is NULL then returns 0.
 835 */
 836unsigned long clk_get_rate(struct clk *clk)
 837{
 838        unsigned long rate;
 839
 840        mutex_lock(&prepare_lock);
 841
 842        if (clk && (clk->flags & CLK_GET_RATE_NOCACHE))
 843                __clk_recalc_rates(clk, 0);
 844
 845        rate = __clk_get_rate(clk);
 846        mutex_unlock(&prepare_lock);
 847
 848        return rate;
 849}
 850EXPORT_SYMBOL_GPL(clk_get_rate);
 851
 852/**
 853 * __clk_speculate_rates
 854 * @clk: first clk in the subtree
 855 * @parent_rate: the "future" rate of clk's parent
 856 *
 857 * Walks the subtree of clks starting with clk, speculating rates as it
 858 * goes and firing off PRE_RATE_CHANGE notifications as necessary.
 859 *
 860 * Unlike clk_recalc_rates, clk_speculate_rates exists only for sending
 861 * pre-rate change notifications and returns early if no clks in the
 862 * subtree have subscribed to the notifications.  Note that if a clk does not
 863 * implement the .recalc_rate callback then it is assumed that the clock will
 864 * take on the rate of it's parent.
 865 *
 866 * Caller must hold prepare_lock.
 867 */
 868static int __clk_speculate_rates(struct clk *clk, unsigned long parent_rate)
 869{
 870        struct clk *child;
 871        unsigned long new_rate;
 872        int ret = NOTIFY_DONE;
 873
 874        if (clk->ops->recalc_rate)
 875                new_rate = clk->ops->recalc_rate(clk->hw, parent_rate);
 876        else
 877                new_rate = parent_rate;
 878
 879        /* abort the rate change if a driver returns NOTIFY_BAD */
 880        if (clk->notifier_count)
 881                ret = __clk_notify(clk, PRE_RATE_CHANGE, clk->rate, new_rate);
 882
 883        if (ret == NOTIFY_BAD)
 884                goto out;
 885
 886        hlist_for_each_entry(child, &clk->children, child_node) {
 887                ret = __clk_speculate_rates(child, new_rate);
 888                if (ret == NOTIFY_BAD)
 889                        break;
 890        }
 891
 892out:
 893        return ret;
 894}
 895
 896static void clk_calc_subtree(struct clk *clk, unsigned long new_rate)
 897{
 898        struct clk *child;
 899
 900        clk->new_rate = new_rate;
 901
 902        hlist_for_each_entry(child, &clk->children, child_node) {
 903                if (child->ops->recalc_rate)
 904                        child->new_rate = child->ops->recalc_rate(child->hw, new_rate);
 905                else
 906                        child->new_rate = new_rate;
 907                clk_calc_subtree(child, child->new_rate);
 908        }
 909}
 910
 911/*
 912 * calculate the new rates returning the topmost clock that has to be
 913 * changed.
 914 */
 915static struct clk *clk_calc_new_rates(struct clk *clk, unsigned long rate)
 916{
 917        struct clk *top = clk;
 918        unsigned long best_parent_rate = 0;
 919        unsigned long new_rate;
 920
 921        /* sanity */
 922        if (IS_ERR_OR_NULL(clk))
 923                return NULL;
 924
 925        /* save parent rate, if it exists */
 926        if (clk->parent)
 927                best_parent_rate = clk->parent->rate;
 928
 929        /* never propagate up to the parent */
 930        if (!(clk->flags & CLK_SET_RATE_PARENT)) {
 931                if (!clk->ops->round_rate) {
 932                        clk->new_rate = clk->rate;
 933                        return NULL;
 934                }
 935                new_rate = clk->ops->round_rate(clk->hw, rate, &best_parent_rate);
 936                goto out;
 937        }
 938
 939        /* need clk->parent from here on out */
 940        if (!clk->parent) {
 941                pr_debug("%s: %s has NULL parent\n", __func__, clk->name);
 942                return NULL;
 943        }
 944
 945        if (!clk->ops->round_rate) {
 946                top = clk_calc_new_rates(clk->parent, rate);
 947                new_rate = clk->parent->new_rate;
 948
 949                goto out;
 950        }
 951
 952        new_rate = clk->ops->round_rate(clk->hw, rate, &best_parent_rate);
 953
 954        if (best_parent_rate != clk->parent->rate) {
 955                top = clk_calc_new_rates(clk->parent, best_parent_rate);
 956
 957                goto out;
 958        }
 959
 960out:
 961        clk_calc_subtree(clk, new_rate);
 962
 963        return top;
 964}
 965
 966/*
 967 * Notify about rate changes in a subtree. Always walk down the whole tree
 968 * so that in case of an error we can walk down the whole tree again and
 969 * abort the change.
 970 */
 971static struct clk *clk_propagate_rate_change(struct clk *clk, unsigned long event)
 972{
 973        struct clk *child, *fail_clk = NULL;
 974        int ret = NOTIFY_DONE;
 975
 976        if (clk->rate == clk->new_rate)
 977                return 0;
 978
 979        if (clk->notifier_count) {
 980                ret = __clk_notify(clk, event, clk->rate, clk->new_rate);
 981                if (ret == NOTIFY_BAD)
 982                        fail_clk = clk;
 983        }
 984
 985        hlist_for_each_entry(child, &clk->children, child_node) {
 986                clk = clk_propagate_rate_change(child, event);
 987                if (clk)
 988                        fail_clk = clk;
 989        }
 990
 991        return fail_clk;
 992}
 993
 994/*
 995 * walk down a subtree and set the new rates notifying the rate
 996 * change on the way
 997 */
 998static void clk_change_rate(struct clk *clk)
 999{
1000        struct clk *child;
1001        unsigned long old_rate;
1002        unsigned long best_parent_rate = 0;
1003
1004        old_rate = clk->rate;
1005
1006        if (clk->parent)
1007                best_parent_rate = clk->parent->rate;
1008
1009        if (clk->ops->set_rate)
1010                clk->ops->set_rate(clk->hw, clk->new_rate, best_parent_rate);
1011
1012        if (clk->ops->recalc_rate)
1013                clk->rate = clk->ops->recalc_rate(clk->hw, best_parent_rate);
1014        else
1015                clk->rate = best_parent_rate;
1016
1017        if (clk->notifier_count && old_rate != clk->rate)
1018                __clk_notify(clk, POST_RATE_CHANGE, old_rate, clk->rate);
1019
1020        hlist_for_each_entry(child, &clk->children, child_node)
1021                clk_change_rate(child);
1022}
1023
1024/**
1025 * clk_set_rate - specify a new rate for clk
1026 * @clk: the clk whose rate is being changed
1027 * @rate: the new rate for clk
1028 *
1029 * In the simplest case clk_set_rate will only adjust the rate of clk.
1030 *
1031 * Setting the CLK_SET_RATE_PARENT flag allows the rate change operation to
1032 * propagate up to clk's parent; whether or not this happens depends on the
1033 * outcome of clk's .round_rate implementation.  If *parent_rate is unchanged
1034 * after calling .round_rate then upstream parent propagation is ignored.  If
1035 * *parent_rate comes back with a new rate for clk's parent then we propagate
1036 * up to clk's parent and set it's rate.  Upward propagation will continue
1037 * until either a clk does not support the CLK_SET_RATE_PARENT flag or
1038 * .round_rate stops requesting changes to clk's parent_rate.
1039 *
1040 * Rate changes are accomplished via tree traversal that also recalculates the
1041 * rates for the clocks and fires off POST_RATE_CHANGE notifiers.
1042 *
1043 * Returns 0 on success, -EERROR otherwise.
1044 */
1045int clk_set_rate(struct clk *clk, unsigned long rate)
1046{
1047        struct clk *top, *fail_clk;
1048        int ret = 0;
1049
1050        /* prevent racing with updates to the clock topology */
1051        mutex_lock(&prepare_lock);
1052
1053        /* bail early if nothing to do */
1054        if (rate == clk->rate)
1055                goto out;
1056
1057        if ((clk->flags & CLK_SET_RATE_GATE) && clk->prepare_count) {
1058                ret = -EBUSY;
1059                goto out;
1060        }
1061
1062        /* calculate new rates and get the topmost changed clock */
1063        top = clk_calc_new_rates(clk, rate);
1064        if (!top) {
1065                ret = -EINVAL;
1066                goto out;
1067        }
1068
1069        /* notify that we are about to change rates */
1070        fail_clk = clk_propagate_rate_change(top, PRE_RATE_CHANGE);
1071        if (fail_clk) {
1072                pr_warn("%s: failed to set %s rate\n", __func__,
1073                                fail_clk->name);
1074                clk_propagate_rate_change(top, ABORT_RATE_CHANGE);
1075                ret = -EBUSY;
1076                goto out;
1077        }
1078
1079        /* change the rates */
1080        clk_change_rate(top);
1081
1082out:
1083        mutex_unlock(&prepare_lock);
1084
1085        return ret;
1086}
1087EXPORT_SYMBOL_GPL(clk_set_rate);
1088
1089/**
1090 * clk_get_parent - return the parent of a clk
1091 * @clk: the clk whose parent gets returned
1092 *
1093 * Simply returns clk->parent.  Returns NULL if clk is NULL.
1094 */
1095struct clk *clk_get_parent(struct clk *clk)
1096{
1097        struct clk *parent;
1098
1099        mutex_lock(&prepare_lock);
1100        parent = __clk_get_parent(clk);
1101        mutex_unlock(&prepare_lock);
1102
1103        return parent;
1104}
1105EXPORT_SYMBOL_GPL(clk_get_parent);
1106
1107/*
1108 * .get_parent is mandatory for clocks with multiple possible parents.  It is
1109 * optional for single-parent clocks.  Always call .get_parent if it is
1110 * available and WARN if it is missing for multi-parent clocks.
1111 *
1112 * For single-parent clocks without .get_parent, first check to see if the
1113 * .parents array exists, and if so use it to avoid an expensive tree
1114 * traversal.  If .parents does not exist then walk the tree with __clk_lookup.
1115 */
1116static struct clk *__clk_init_parent(struct clk *clk)
1117{
1118        struct clk *ret = NULL;
1119        u8 index;
1120
1121        /* handle the trivial cases */
1122
1123        if (!clk->num_parents)
1124                goto out;
1125
1126        if (clk->num_parents == 1) {
1127                if (IS_ERR_OR_NULL(clk->parent))
1128                        ret = clk->parent = __clk_lookup(clk->parent_names[0]);
1129                ret = clk->parent;
1130                goto out;
1131        }
1132
1133        if (!clk->ops->get_parent) {
1134                WARN(!clk->ops->get_parent,
1135                        "%s: multi-parent clocks must implement .get_parent\n",
1136                        __func__);
1137                goto out;
1138        };
1139
1140        /*
1141         * Do our best to cache parent clocks in clk->parents.  This prevents
1142         * unnecessary and expensive calls to __clk_lookup.  We don't set
1143         * clk->parent here; that is done by the calling function
1144         */
1145
1146        index = clk->ops->get_parent(clk->hw);
1147
1148        if (!clk->parents)
1149                clk->parents =
1150                        kzalloc((sizeof(struct clk*) * clk->num_parents),
1151                                        GFP_KERNEL);
1152
1153        if (!clk->parents)
1154                ret = __clk_lookup(clk->parent_names[index]);
1155        else if (!clk->parents[index])
1156                ret = clk->parents[index] =
1157                        __clk_lookup(clk->parent_names[index]);
1158        else
1159                ret = clk->parents[index];
1160
1161out:
1162        return ret;
1163}
1164
1165void __clk_reparent(struct clk *clk, struct clk *new_parent)
1166{
1167#ifdef CONFIG_COMMON_CLK_DEBUG
1168        struct dentry *d;
1169        struct dentry *new_parent_d;
1170#endif
1171
1172        if (!clk || !new_parent)
1173                return;
1174
1175        hlist_del(&clk->child_node);
1176
1177        if (new_parent)
1178                hlist_add_head(&clk->child_node, &new_parent->children);
1179        else
1180                hlist_add_head(&clk->child_node, &clk_orphan_list);
1181
1182#ifdef CONFIG_COMMON_CLK_DEBUG
1183        if (!inited)
1184                goto out;
1185
1186        if (new_parent)
1187                new_parent_d = new_parent->dentry;
1188        else
1189                new_parent_d = orphandir;
1190
1191        d = debugfs_rename(clk->dentry->d_parent, clk->dentry,
1192                        new_parent_d, clk->name);
1193        if (d)
1194                clk->dentry = d;
1195        else
1196                pr_debug("%s: failed to rename debugfs entry for %s\n",
1197                                __func__, clk->name);
1198out:
1199#endif
1200
1201        clk->parent = new_parent;
1202
1203        __clk_recalc_rates(clk, POST_RATE_CHANGE);
1204}
1205
1206static int __clk_set_parent(struct clk *clk, struct clk *parent)
1207{
1208        struct clk *old_parent;
1209        unsigned long flags;
1210        int ret = -EINVAL;
1211        u8 i;
1212
1213        old_parent = clk->parent;
1214
1215        if (!clk->parents)
1216                clk->parents = kzalloc((sizeof(struct clk*) * clk->num_parents),
1217                                                                GFP_KERNEL);
1218
1219        /*
1220         * find index of new parent clock using cached parent ptrs,
1221         * or if not yet cached, use string name comparison and cache
1222         * them now to avoid future calls to __clk_lookup.
1223         */
1224        for (i = 0; i < clk->num_parents; i++) {
1225                if (clk->parents && clk->parents[i] == parent)
1226                        break;
1227                else if (!strcmp(clk->parent_names[i], parent->name)) {
1228                        if (clk->parents)
1229                                clk->parents[i] = __clk_lookup(parent->name);
1230                        break;
1231                }
1232        }
1233
1234        if (i == clk->num_parents) {
1235                pr_debug("%s: clock %s is not a possible parent of clock %s\n",
1236                                __func__, parent->name, clk->name);
1237                goto out;
1238        }
1239
1240        /* migrate prepare and enable */
1241        if (clk->prepare_count)
1242                __clk_prepare(parent);
1243
1244        /* FIXME replace with clk_is_enabled(clk) someday */
1245        spin_lock_irqsave(&enable_lock, flags);
1246        if (clk->enable_count)
1247                __clk_enable(parent);
1248        spin_unlock_irqrestore(&enable_lock, flags);
1249
1250        /* change clock input source */
1251        ret = clk->ops->set_parent(clk->hw, i);
1252
1253        /* clean up old prepare and enable */
1254        spin_lock_irqsave(&enable_lock, flags);
1255        if (clk->enable_count)
1256                __clk_disable(old_parent);
1257        spin_unlock_irqrestore(&enable_lock, flags);
1258
1259        if (clk->prepare_count)
1260                __clk_unprepare(old_parent);
1261
1262out:
1263        return ret;
1264}
1265
1266/**
1267 * clk_set_parent - switch the parent of a mux clk
1268 * @clk: the mux clk whose input we are switching
1269 * @parent: the new input to clk
1270 *
1271 * Re-parent clk to use parent as it's new input source.  If clk has the
1272 * CLK_SET_PARENT_GATE flag set then clk must be gated for this
1273 * operation to succeed.  After successfully changing clk's parent
1274 * clk_set_parent will update the clk topology, sysfs topology and
1275 * propagate rate recalculation via __clk_recalc_rates.  Returns 0 on
1276 * success, -EERROR otherwise.
1277 */
1278int clk_set_parent(struct clk *clk, struct clk *parent)
1279{
1280        int ret = 0;
1281
1282        if (!clk || !clk->ops)
1283                return -EINVAL;
1284
1285        if (!clk->ops->set_parent)
1286                return -ENOSYS;
1287
1288        /* prevent racing with updates to the clock topology */
1289        mutex_lock(&prepare_lock);
1290
1291        if (clk->parent == parent)
1292                goto out;
1293
1294        /* propagate PRE_RATE_CHANGE notifications */
1295        if (clk->notifier_count)
1296                ret = __clk_speculate_rates(clk, parent->rate);
1297
1298        /* abort if a driver objects */
1299        if (ret == NOTIFY_STOP)
1300                goto out;
1301
1302        /* only re-parent if the clock is not in use */
1303        if ((clk->flags & CLK_SET_PARENT_GATE) && clk->prepare_count)
1304                ret = -EBUSY;
1305        else
1306                ret = __clk_set_parent(clk, parent);
1307
1308        /* propagate ABORT_RATE_CHANGE if .set_parent failed */
1309        if (ret) {
1310                __clk_recalc_rates(clk, ABORT_RATE_CHANGE);
1311                goto out;
1312        }
1313
1314        /* propagate rate recalculation downstream */
1315        __clk_reparent(clk, parent);
1316
1317out:
1318        mutex_unlock(&prepare_lock);
1319
1320        return ret;
1321}
1322EXPORT_SYMBOL_GPL(clk_set_parent);
1323
1324/**
1325 * __clk_init - initialize the data structures in a struct clk
1326 * @dev:        device initializing this clk, placeholder for now
1327 * @clk:        clk being initialized
1328 *
1329 * Initializes the lists in struct clk, queries the hardware for the
1330 * parent and rate and sets them both.
1331 */
1332int __clk_init(struct device *dev, struct clk *clk)
1333{
1334        int i, ret = 0;
1335        struct clk *orphan;
1336        struct hlist_node *tmp2;
1337
1338        if (!clk)
1339                return -EINVAL;
1340
1341        mutex_lock(&prepare_lock);
1342
1343        /* check to see if a clock with this name is already registered */
1344        if (__clk_lookup(clk->name)) {
1345                pr_debug("%s: clk %s already initialized\n",
1346                                __func__, clk->name);
1347                ret = -EEXIST;
1348                goto out;
1349        }
1350
1351        /* check that clk_ops are sane.  See Documentation/clk.txt */
1352        if (clk->ops->set_rate &&
1353                        !(clk->ops->round_rate && clk->ops->recalc_rate)) {
1354                pr_warning("%s: %s must implement .round_rate & .recalc_rate\n",
1355                                __func__, clk->name);
1356                ret = -EINVAL;
1357                goto out;
1358        }
1359
1360        if (clk->ops->set_parent && !clk->ops->get_parent) {
1361                pr_warning("%s: %s must implement .get_parent & .set_parent\n",
1362                                __func__, clk->name);
1363                ret = -EINVAL;
1364                goto out;
1365        }
1366
1367        /* throw a WARN if any entries in parent_names are NULL */
1368        for (i = 0; i < clk->num_parents; i++)
1369                WARN(!clk->parent_names[i],
1370                                "%s: invalid NULL in %s's .parent_names\n",
1371                                __func__, clk->name);
1372
1373        /*
1374         * Allocate an array of struct clk *'s to avoid unnecessary string
1375         * look-ups of clk's possible parents.  This can fail for clocks passed
1376         * in to clk_init during early boot; thus any access to clk->parents[]
1377         * must always check for a NULL pointer and try to populate it if
1378         * necessary.
1379         *
1380         * If clk->parents is not NULL we skip this entire block.  This allows
1381         * for clock drivers to statically initialize clk->parents.
1382         */
1383        if (clk->num_parents > 1 && !clk->parents) {
1384                clk->parents = kzalloc((sizeof(struct clk*) * clk->num_parents),
1385                                GFP_KERNEL);
1386                /*
1387                 * __clk_lookup returns NULL for parents that have not been
1388                 * clk_init'd; thus any access to clk->parents[] must check
1389                 * for a NULL pointer.  We can always perform lazy lookups for
1390                 * missing parents later on.
1391                 */
1392                if (clk->parents)
1393                        for (i = 0; i < clk->num_parents; i++)
1394                                clk->parents[i] =
1395                                        __clk_lookup(clk->parent_names[i]);
1396        }
1397
1398        clk->parent = __clk_init_parent(clk);
1399
1400        /*
1401         * Populate clk->parent if parent has already been __clk_init'd.  If
1402         * parent has not yet been __clk_init'd then place clk in the orphan
1403         * list.  If clk has set the CLK_IS_ROOT flag then place it in the root
1404         * clk list.
1405         *
1406         * Every time a new clk is clk_init'd then we walk the list of orphan
1407         * clocks and re-parent any that are children of the clock currently
1408         * being clk_init'd.
1409         */
1410        if (clk->parent)
1411                hlist_add_head(&clk->child_node,
1412                                &clk->parent->children);
1413        else if (clk->flags & CLK_IS_ROOT)
1414                hlist_add_head(&clk->child_node, &clk_root_list);
1415        else
1416                hlist_add_head(&clk->child_node, &clk_orphan_list);
1417
1418        /*
1419         * Set clk's rate.  The preferred method is to use .recalc_rate.  For
1420         * simple clocks and lazy developers the default fallback is to use the
1421         * parent's rate.  If a clock doesn't have a parent (or is orphaned)
1422         * then rate is set to zero.
1423         */
1424        if (clk->ops->recalc_rate)
1425                clk->rate = clk->ops->recalc_rate(clk->hw,
1426                                __clk_get_rate(clk->parent));
1427        else if (clk->parent)
1428                clk->rate = clk->parent->rate;
1429        else
1430                clk->rate = 0;
1431
1432        /*
1433         * walk the list of orphan clocks and reparent any that are children of
1434         * this clock
1435         */
1436        hlist_for_each_entry_safe(orphan, tmp2, &clk_orphan_list, child_node) {
1437                if (orphan->ops->get_parent) {
1438                        i = orphan->ops->get_parent(orphan->hw);
1439                        if (!strcmp(clk->name, orphan->parent_names[i]))
1440                                __clk_reparent(orphan, clk);
1441                        continue;
1442                }
1443
1444                for (i = 0; i < orphan->num_parents; i++)
1445                        if (!strcmp(clk->name, orphan->parent_names[i])) {
1446                                __clk_reparent(orphan, clk);
1447                                break;
1448                        }
1449         }
1450
1451        /*
1452         * optional platform-specific magic
1453         *
1454         * The .init callback is not used by any of the basic clock types, but
1455         * exists for weird hardware that must perform initialization magic.
1456         * Please consider other ways of solving initialization problems before
1457         * using this callback, as it's use is discouraged.
1458         */
1459        if (clk->ops->init)
1460                clk->ops->init(clk->hw);
1461
1462        clk_debug_register(clk);
1463
1464out:
1465        mutex_unlock(&prepare_lock);
1466
1467        return ret;
1468}
1469
1470/**
1471 * __clk_register - register a clock and return a cookie.
1472 *
1473 * Same as clk_register, except that the .clk field inside hw shall point to a
1474 * preallocated (generally statically allocated) struct clk. None of the fields
1475 * of the struct clk need to be initialized.
1476 *
1477 * The data pointed to by .init and .clk field shall NOT be marked as init
1478 * data.
1479 *
1480 * __clk_register is only exposed via clk-private.h and is intended for use with
1481 * very large numbers of clocks that need to be statically initialized.  It is
1482 * a layering violation to include clk-private.h from any code which implements
1483 * a clock's .ops; as such any statically initialized clock data MUST be in a
1484 * separate C file from the logic that implements it's operations.  Returns 0
1485 * on success, otherwise an error code.
1486 */
1487struct clk *__clk_register(struct device *dev, struct clk_hw *hw)
1488{
1489        int ret;
1490        struct clk *clk;
1491
1492        clk = hw->clk;
1493        clk->name = hw->init->name;
1494        clk->ops = hw->init->ops;
1495        clk->hw = hw;
1496        clk->flags = hw->init->flags;
1497        clk->parent_names = hw->init->parent_names;
1498        clk->num_parents = hw->init->num_parents;
1499
1500        ret = __clk_init(dev, clk);
1501        if (ret)
1502                return ERR_PTR(ret);
1503
1504        return clk;
1505}
1506EXPORT_SYMBOL_GPL(__clk_register);
1507
1508static int _clk_register(struct device *dev, struct clk_hw *hw, struct clk *clk)
1509{
1510        int i, ret;
1511
1512        clk->name = kstrdup(hw->init->name, GFP_KERNEL);
1513        if (!clk->name) {
1514                pr_err("%s: could not allocate clk->name\n", __func__);
1515                ret = -ENOMEM;
1516                goto fail_name;
1517        }
1518        clk->ops = hw->init->ops;
1519        clk->hw = hw;
1520        clk->flags = hw->init->flags;
1521        clk->num_parents = hw->init->num_parents;
1522        hw->clk = clk;
1523
1524        /* allocate local copy in case parent_names is __initdata */
1525        clk->parent_names = kzalloc((sizeof(char*) * clk->num_parents),
1526                        GFP_KERNEL);
1527
1528        if (!clk->parent_names) {
1529                pr_err("%s: could not allocate clk->parent_names\n", __func__);
1530                ret = -ENOMEM;
1531                goto fail_parent_names;
1532        }
1533
1534
1535        /* copy each string name in case parent_names is __initdata */
1536        for (i = 0; i < clk->num_parents; i++) {
1537                clk->parent_names[i] = kstrdup(hw->init->parent_names[i],
1538                                                GFP_KERNEL);
1539                if (!clk->parent_names[i]) {
1540                        pr_err("%s: could not copy parent_names\n", __func__);
1541                        ret = -ENOMEM;
1542                        goto fail_parent_names_copy;
1543                }
1544        }
1545
1546        ret = __clk_init(dev, clk);
1547        if (!ret)
1548                return 0;
1549
1550fail_parent_names_copy:
1551        while (--i >= 0)
1552                kfree(clk->parent_names[i]);
1553        kfree(clk->parent_names);
1554fail_parent_names:
1555        kfree(clk->name);
1556fail_name:
1557        return ret;
1558}
1559
1560/**
1561 * clk_register - allocate a new clock, register it and return an opaque cookie
1562 * @dev: device that is registering this clock
1563 * @hw: link to hardware-specific clock data
1564 *
1565 * clk_register is the primary interface for populating the clock tree with new
1566 * clock nodes.  It returns a pointer to the newly allocated struct clk which
1567 * cannot be dereferenced by driver code but may be used in conjuction with the
1568 * rest of the clock API.  In the event of an error clk_register will return an
1569 * error code; drivers must test for an error code after calling clk_register.
1570 */
1571struct clk *clk_register(struct device *dev, struct clk_hw *hw)
1572{
1573        int ret;
1574        struct clk *clk;
1575
1576        clk = kzalloc(sizeof(*clk), GFP_KERNEL);
1577        if (!clk) {
1578                pr_err("%s: could not allocate clk\n", __func__);
1579                ret = -ENOMEM;
1580                goto fail_out;
1581        }
1582
1583        ret = _clk_register(dev, hw, clk);
1584        if (!ret)
1585                return clk;
1586
1587        kfree(clk);
1588fail_out:
1589        return ERR_PTR(ret);
1590}
1591EXPORT_SYMBOL_GPL(clk_register);
1592
1593/**
1594 * clk_unregister - unregister a currently registered clock
1595 * @clk: clock to unregister
1596 *
1597 * Currently unimplemented.
1598 */
1599void clk_unregister(struct clk *clk) {}
1600EXPORT_SYMBOL_GPL(clk_unregister);
1601
1602static void devm_clk_release(struct device *dev, void *res)
1603{
1604        clk_unregister(res);
1605}
1606
1607/**
1608 * devm_clk_register - resource managed clk_register()
1609 * @dev: device that is registering this clock
1610 * @hw: link to hardware-specific clock data
1611 *
1612 * Managed clk_register(). Clocks returned from this function are
1613 * automatically clk_unregister()ed on driver detach. See clk_register() for
1614 * more information.
1615 */
1616struct clk *devm_clk_register(struct device *dev, struct clk_hw *hw)
1617{
1618        struct clk *clk;
1619        int ret;
1620
1621        clk = devres_alloc(devm_clk_release, sizeof(*clk), GFP_KERNEL);
1622        if (!clk)
1623                return ERR_PTR(-ENOMEM);
1624
1625        ret = _clk_register(dev, hw, clk);
1626        if (!ret) {
1627                devres_add(dev, clk);
1628        } else {
1629                devres_free(clk);
1630                clk = ERR_PTR(ret);
1631        }
1632
1633        return clk;
1634}
1635EXPORT_SYMBOL_GPL(devm_clk_register);
1636
1637static int devm_clk_match(struct device *dev, void *res, void *data)
1638{
1639        struct clk *c = res;
1640        if (WARN_ON(!c))
1641                return 0;
1642        return c == data;
1643}
1644
1645/**
1646 * devm_clk_unregister - resource managed clk_unregister()
1647 * @clk: clock to unregister
1648 *
1649 * Deallocate a clock allocated with devm_clk_register(). Normally
1650 * this function will not need to be called and the resource management
1651 * code will ensure that the resource is freed.
1652 */
1653void devm_clk_unregister(struct device *dev, struct clk *clk)
1654{
1655        WARN_ON(devres_release(dev, devm_clk_release, devm_clk_match, clk));
1656}
1657EXPORT_SYMBOL_GPL(devm_clk_unregister);
1658
1659/***        clk rate change notifiers        ***/
1660
1661/**
1662 * clk_notifier_register - add a clk rate change notifier
1663 * @clk: struct clk * to watch
1664 * @nb: struct notifier_block * with callback info
1665 *
1666 * Request notification when clk's rate changes.  This uses an SRCU
1667 * notifier because we want it to block and notifier unregistrations are
1668 * uncommon.  The callbacks associated with the notifier must not
1669 * re-enter into the clk framework by calling any top-level clk APIs;
1670 * this will cause a nested prepare_lock mutex.
1671 *
1672 * Pre-change notifier callbacks will be passed the current, pre-change
1673 * rate of the clk via struct clk_notifier_data.old_rate.  The new,
1674 * post-change rate of the clk is passed via struct
1675 * clk_notifier_data.new_rate.
1676 *
1677 * Post-change notifiers will pass the now-current, post-change rate of
1678 * the clk in both struct clk_notifier_data.old_rate and struct
1679 * clk_notifier_data.new_rate.
1680 *
1681 * Abort-change notifiers are effectively the opposite of pre-change
1682 * notifiers: the original pre-change clk rate is passed in via struct
1683 * clk_notifier_data.new_rate and the failed post-change rate is passed
1684 * in via struct clk_notifier_data.old_rate.
1685 *
1686 * clk_notifier_register() must be called from non-atomic context.
1687 * Returns -EINVAL if called with null arguments, -ENOMEM upon
1688 * allocation failure; otherwise, passes along the return value of
1689 * srcu_notifier_chain_register().
1690 */
1691int clk_notifier_register(struct clk *clk, struct notifier_block *nb)
1692{
1693        struct clk_notifier *cn;
1694        int ret = -ENOMEM;
1695
1696        if (!clk || !nb)
1697                return -EINVAL;
1698
1699        mutex_lock(&prepare_lock);
1700
1701        /* search the list of notifiers for this clk */
1702        list_for_each_entry(cn, &clk_notifier_list, node)
1703                if (cn->clk == clk)
1704                        break;
1705
1706        /* if clk wasn't in the notifier list, allocate new clk_notifier */
1707        if (cn->clk != clk) {
1708                cn = kzalloc(sizeof(struct clk_notifier), GFP_KERNEL);
1709                if (!cn)
1710                        goto out;
1711
1712                cn->clk = clk;
1713                srcu_init_notifier_head(&cn->notifier_head);
1714
1715                list_add(&cn->node, &clk_notifier_list);
1716        }
1717
1718        ret = srcu_notifier_chain_register(&cn->notifier_head, nb);
1719
1720        clk->notifier_count++;
1721
1722out:
1723        mutex_unlock(&prepare_lock);
1724
1725        return ret;
1726}
1727EXPORT_SYMBOL_GPL(clk_notifier_register);
1728
1729/**
1730 * clk_notifier_unregister - remove a clk rate change notifier
1731 * @clk: struct clk *
1732 * @nb: struct notifier_block * with callback info
1733 *
1734 * Request no further notification for changes to 'clk' and frees memory
1735 * allocated in clk_notifier_register.
1736 *
1737 * Returns -EINVAL if called with null arguments; otherwise, passes
1738 * along the return value of srcu_notifier_chain_unregister().
1739 */
1740int clk_notifier_unregister(struct clk *clk, struct notifier_block *nb)
1741{
1742        struct clk_notifier *cn = NULL;
1743        int ret = -EINVAL;
1744
1745        if (!clk || !nb)
1746                return -EINVAL;
1747
1748        mutex_lock(&prepare_lock);
1749
1750        list_for_each_entry(cn, &clk_notifier_list, node)
1751                if (cn->clk == clk)
1752                        break;
1753
1754        if (cn->clk == clk) {
1755                ret = srcu_notifier_chain_unregister(&cn->notifier_head, nb);
1756
1757                clk->notifier_count--;
1758
1759                /* XXX the notifier code should handle this better */
1760                if (!cn->notifier_head.head) {
1761                        srcu_cleanup_notifier_head(&cn->notifier_head);
1762                        kfree(cn);
1763                }
1764
1765        } else {
1766                ret = -ENOENT;
1767        }
1768
1769        mutex_unlock(&prepare_lock);
1770
1771        return ret;
1772}
1773EXPORT_SYMBOL_GPL(clk_notifier_unregister);
1774
1775#ifdef CONFIG_OF
1776/**
1777 * struct of_clk_provider - Clock provider registration structure
1778 * @link: Entry in global list of clock providers
1779 * @node: Pointer to device tree node of clock provider
1780 * @get: Get clock callback.  Returns NULL or a struct clk for the
1781 *       given clock specifier
1782 * @data: context pointer to be passed into @get callback
1783 */
1784struct of_clk_provider {
1785        struct list_head link;
1786
1787        struct device_node *node;
1788        struct clk *(*get)(struct of_phandle_args *clkspec, void *data);
1789        void *data;
1790};
1791
1792extern struct of_device_id __clk_of_table[];
1793
1794static const struct of_device_id __clk_of_table_sentinel
1795        __used __section(__clk_of_table_end);
1796
1797static LIST_HEAD(of_clk_providers);
1798static DEFINE_MUTEX(of_clk_lock);
1799
1800struct clk *of_clk_src_simple_get(struct of_phandle_args *clkspec,
1801                                     void *data)
1802{
1803        return data;
1804}
1805EXPORT_SYMBOL_GPL(of_clk_src_simple_get);
1806
1807struct clk *of_clk_src_onecell_get(struct of_phandle_args *clkspec, void *data)
1808{
1809        struct clk_onecell_data *clk_data = data;
1810        unsigned int idx = clkspec->args[0];
1811
1812        if (idx >= clk_data->clk_num) {
1813                pr_err("%s: invalid clock index %d\n", __func__, idx);
1814                return ERR_PTR(-EINVAL);
1815        }
1816
1817        return clk_data->clks[idx];
1818}
1819EXPORT_SYMBOL_GPL(of_clk_src_onecell_get);
1820
1821/**
1822 * of_clk_add_provider() - Register a clock provider for a node
1823 * @np: Device node pointer associated with clock provider
1824 * @clk_src_get: callback for decoding clock
1825 * @data: context pointer for @clk_src_get callback.
1826 */
1827int of_clk_add_provider(struct device_node *np,
1828                        struct clk *(*clk_src_get)(struct of_phandle_args *clkspec,
1829                                                   void *data),
1830                        void *data)
1831{
1832        struct of_clk_provider *cp;
1833
1834        cp = kzalloc(sizeof(struct of_clk_provider), GFP_KERNEL);
1835        if (!cp)
1836                return -ENOMEM;
1837
1838        cp->node = of_node_get(np);
1839        cp->data = data;
1840        cp->get = clk_src_get;
1841
1842        mutex_lock(&of_clk_lock);
1843        list_add(&cp->link, &of_clk_providers);
1844        mutex_unlock(&of_clk_lock);
1845        pr_debug("Added clock from %s\n", np->full_name);
1846
1847        return 0;
1848}
1849EXPORT_SYMBOL_GPL(of_clk_add_provider);
1850
1851/**
1852 * of_clk_del_provider() - Remove a previously registered clock provider
1853 * @np: Device node pointer associated with clock provider
1854 */
1855void of_clk_del_provider(struct device_node *np)
1856{
1857        struct of_clk_provider *cp;
1858
1859        mutex_lock(&of_clk_lock);
1860        list_for_each_entry(cp, &of_clk_providers, link) {
1861                if (cp->node == np) {
1862                        list_del(&cp->link);
1863                        of_node_put(cp->node);
1864                        kfree(cp);
1865                        break;
1866                }
1867        }
1868        mutex_unlock(&of_clk_lock);
1869}
1870EXPORT_SYMBOL_GPL(of_clk_del_provider);
1871
1872struct clk *of_clk_get_from_provider(struct of_phandle_args *clkspec)
1873{
1874        struct of_clk_provider *provider;
1875        struct clk *clk = ERR_PTR(-ENOENT);
1876
1877        /* Check if we have such a provider in our array */
1878        mutex_lock(&of_clk_lock);
1879        list_for_each_entry(provider, &of_clk_providers, link) {
1880                if (provider->node == clkspec->np)
1881                        clk = provider->get(clkspec, provider->data);
1882                if (!IS_ERR(clk))
1883                        break;
1884        }
1885        mutex_unlock(&of_clk_lock);
1886
1887        return clk;
1888}
1889
1890const char *of_clk_get_parent_name(struct device_node *np, int index)
1891{
1892        struct of_phandle_args clkspec;
1893        const char *clk_name;
1894        int rc;
1895
1896        if (index < 0)
1897                return NULL;
1898
1899        rc = of_parse_phandle_with_args(np, "clocks", "#clock-cells", index,
1900                                        &clkspec);
1901        if (rc)
1902                return NULL;
1903
1904        if (of_property_read_string_index(clkspec.np, "clock-output-names",
1905                                          clkspec.args_count ? clkspec.args[0] : 0,
1906                                          &clk_name) < 0)
1907                clk_name = clkspec.np->name;
1908
1909        of_node_put(clkspec.np);
1910        return clk_name;
1911}
1912EXPORT_SYMBOL_GPL(of_clk_get_parent_name);
1913
1914/**
1915 * of_clk_init() - Scan and init clock providers from the DT
1916 * @matches: array of compatible values and init functions for providers.
1917 *
1918 * This function scans the device tree for matching clock providers and
1919 * calls their initialization functions
1920 */
1921void __init of_clk_init(const struct of_device_id *matches)
1922{
1923        struct device_node *np;
1924
1925        if (!matches)
1926                matches = __clk_of_table;
1927
1928        for_each_matching_node(np, matches) {
1929                const struct of_device_id *match = of_match_node(matches, np);
1930                of_clk_init_cb_t clk_init_cb = match->data;
1931                clk_init_cb(np);
1932        }
1933}
1934#endif
1935
lxr.linux.no kindly hosted by Redpill Linpro AS, provider of Linux consulting and operations services since 1995.