drivers/net/ethernet/ti/cpts.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * TI Common Platform Time Sync
   4  *
   5  * Copyright (C) 2012 Richard Cochran <richardcochran@gmail.com>
   6  *
   7  */
   8 #include <linux/clk-provider.h>
   9 #include <linux/err.h>
  10 #include <linux/if.h>
  11 #include <linux/hrtimer.h>
  12 #include <linux/module.h>
  13 #include <linux/net_tstamp.h>
  14 #include <linux/ptp_classify.h>
  15 #include <linux/time.h>
  16 #include <linux/uaccess.h>
  17 #include <linux/workqueue.h>
  18 #include <linux/if_ether.h>
  19 #include <linux/if_vlan.h>
  20
  21 #include "cpts.h"
  22
  23 #define CPTS_SKB_TX_WORK_TIMEOUT 1 /* jiffies */
  24
  25 struct cpts_skb_cb_data {
  26         unsigned long tmo;
  27 };
  28
  29 #define cpts_read32(c, r)       readl_relaxed(&c->reg->r)
  30 #define cpts_write32(c, v, r)   writel_relaxed(v, &c->reg->r)
  31
  32 static int cpts_match(struct sk_buff *skb, unsigned int ptp_class,
  33                       u16 ts_seqid, u8 ts_msgtype);
  34
  35 static int event_expired(struct cpts_event *event)
  36 {
  37         return time_after(jiffies, event->tmo);
  38 }
  39
  40 static int event_type(struct cpts_event *event)
  41 {
  42         return (event->high >> EVENT_TYPE_SHIFT) & EVENT_TYPE_MASK;
  43 }
  44
  45 static int cpts_fifo_pop(struct cpts *cpts, u32 *high, u32 *low)
  46 {
  47         u32 r = cpts_read32(cpts, intstat_raw);
  48
  49         if (r & TS_PEND_RAW) {
  50                 *high = cpts_read32(cpts, event_high);
  51                 *low  = cpts_read32(cpts, event_low);
  52                 cpts_write32(cpts, EVENT_POP, event_pop);
  53                 return 0;
  54         }
  55         return -1;
  56 }
  57
  58 static int cpts_purge_events(struct cpts *cpts)
  59 {
  60         struct list_head *this, *next;
  61         struct cpts_event *event;
  62         int removed = 0;
  63
  64         list_for_each_safe(this, next, &cpts->events) {
  65                 event = list_entry(this, struct cpts_event, list);
  66                 if (event_expired(event)) {
  67                         list_del_init(&event->list);
  68                         list_add(&event->list, &cpts->pool);
  69                         ++removed;
  70                 }
  71         }
  72
  73         if (removed)
  74                 pr_debug("cpts: event pool cleaned up %d\n", removed);
  75         return removed ? 0 : -1;
  76 }
  77
  78 static void cpts_purge_txq(struct cpts *cpts)
  79 {
  80         struct cpts_skb_cb_data *skb_cb;
  81         struct sk_buff *skb, *tmp;
  82         int removed = 0;
  83
  84         skb_queue_walk_safe(&cpts->txq, skb, tmp) {
  85                 skb_cb = (struct cpts_skb_cb_data *)skb->cb;
  86                 if (time_after(jiffies, skb_cb->tmo)) {
  87                         __skb_unlink(skb, &cpts->txq);
  88                         dev_consume_skb_any(skb);
  89                         ++removed;
  90                 }
  91         }
  92
  93         if (removed)
  94                 dev_dbg(cpts->dev, "txq cleaned up %d\n", removed);
  95 }
  96
  97 static bool cpts_match_tx_ts(struct cpts *cpts, struct cpts_event *event)
  98 {
  99         struct sk_buff *skb, *tmp;
 100         u16 seqid;
 101         u8 mtype;
 102         bool found = false;
 103
 104         mtype = (event->high >> MESSAGE_TYPE_SHIFT) & MESSAGE_TYPE_MASK;
 105         seqid = (event->high >> SEQUENCE_ID_SHIFT) & SEQUENCE_ID_MASK;
 106
 107         /* no need to grab txq.lock as access is always done under cpts->lock */
 108         skb_queue_walk_safe(&cpts->txq, skb, tmp) {
 109                 struct skb_shared_hwtstamps ssh;
 110                 unsigned int class = ptp_classify_raw(skb);
 111                 struct cpts_skb_cb_data *skb_cb =
 112                                         (struct cpts_skb_cb_data *)skb->cb;
 113
 114                 if (cpts_match(skb, class, seqid, mtype)) {
 115                         u64 ns = timecounter_cyc2time(&cpts->tc, event->low);
 116
 117                         memset(&ssh, 0, sizeof(ssh));
 118                         ssh.hwtstamp = ns_to_ktime(ns);
 119                         skb_tstamp_tx(skb, &ssh);
 120                         found = true;
 121                         __skb_unlink(skb, &cpts->txq);
 122                         dev_consume_skb_any(skb);
 123                         dev_dbg(cpts->dev, "match tx timestamp mtype %u seqid %04x\n",
 124                                 mtype, seqid);
 125                         break;
 126                 }
 127
 128                 if (time_after(jiffies, skb_cb->tmo)) {
 129                         /* timeout any expired skbs over 1s */
 130                         dev_dbg(cpts->dev, "expiring tx timestamp from txq\n");
 131                         __skb_unlink(skb, &cpts->txq);
 132                         dev_consume_skb_any(skb);
 133                 }
 134         }
 135
 136         return found;
 137 }
 138
 139 /*
 140  * Returns zero if matching event type was found.
 141  */
 142 static int cpts_fifo_read(struct cpts *cpts, int match)
 143 {
 144         int i, type = -1;
 145         u32 hi, lo;
 146         struct cpts_event *event;
 147
 148         for (i = 0; i < CPTS_FIFO_DEPTH; i++) {
 149                 if (cpts_fifo_pop(cpts, &hi, &lo))
 150                         break;
 151
 152                 if (list_empty(&cpts->pool) && cpts_purge_events(cpts)) {
 153                         pr_err("cpts: event pool empty\n");
 154                         return -1;
 155                 }
 156
 157                 event = list_first_entry(&cpts->pool, struct cpts_event, list);
 158                 event->tmo = jiffies + 2;
 159                 event->high = hi;
 160                 event->low = lo;
 161                 type = event_type(event);
 162                 switch (type) {
 163                 case CPTS_EV_TX:
 164                         if (cpts_match_tx_ts(cpts, event)) {
 165                                 /* if the new event matches an existing skb,
 166                                  * then don't queue it
 167                                  */
 168                                 break;
 169                         }
 170                         /* fall through */
 171                 case CPTS_EV_PUSH:
 172                 case CPTS_EV_RX:
 173                         list_del_init(&event->list);
 174                         list_add_tail(&event->list, &cpts->events);
 175                         break;
 176                 case CPTS_EV_ROLL:
 177                 case CPTS_EV_HALF:
 178                 case CPTS_EV_HW:
 179                         break;
 180                 default:
 181                         pr_err("cpts: unknown event type\n");
 182                         break;
 183                 }
 184                 if (type == match)
 185                         break;
 186         }
 187         return type == match ? 0 : -1;
 188 }
 189
 190 static u64 cpts_systim_read(const struct cyclecounter *cc)
 191 {
 192         u64 val = 0;
 193         struct cpts_event *event;
 194         struct list_head *this, *next;
 195         struct cpts *cpts = container_of(cc, struct cpts, cc);
 196
 197         cpts_write32(cpts, TS_PUSH, ts_push);
 198         if (cpts_fifo_read(cpts, CPTS_EV_PUSH))
 199                 pr_err("cpts: unable to obtain a time stamp\n");
 200
 201         list_for_each_safe(this, next, &cpts->events) {
 202                 event = list_entry(this, struct cpts_event, list);
 203                 if (event_type(event) == CPTS_EV_PUSH) {
 204                         list_del_init(&event->list);
 205                         list_add(&event->list, &cpts->pool);
 206                         val = event->low;
 207                         break;
 208                 }
 209         }
 210
 211         return val;
 212 }
 213
 214 /* PTP clock operations */
 215
 216 static int cpts_ptp_adjfreq(struct ptp_clock_info *ptp, s32 ppb)
 217 {
 218         u64 adj;
 219         u32 diff, mult;
 220         int neg_adj = 0;
 221         unsigned long flags;
 222         struct cpts *cpts = container_of(ptp, struct cpts, info);
 223
 224         if (ppb < 0) {
 225                 neg_adj = 1;
 226                 ppb = -ppb;
 227         }
 228         mult = cpts->cc_mult;
 229         adj = mult;
 230         adj *= ppb;
 231         diff = div_u64(adj, 1000000000ULL);
 232
 233         spin_lock_irqsave(&cpts->lock, flags);
 234
 235         timecounter_read(&cpts->tc);
 236
 237         cpts->cc.mult = neg_adj ? mult - diff : mult + diff;
 238
 239         spin_unlock_irqrestore(&cpts->lock, flags);
 240
 241         return 0;
 242 }
 243
 244 static int cpts_ptp_adjtime(struct ptp_clock_info *ptp, s64 delta)
 245 {
 246         unsigned long flags;
 247         struct cpts *cpts = container_of(ptp, struct cpts, info);
 248
 249         spin_lock_irqsave(&cpts->lock, flags);
 250         timecounter_adjtime(&cpts->tc, delta);
 251         spin_unlock_irqrestore(&cpts->lock, flags);
 252
 253         return 0;
 254 }
 255
 256 static int cpts_ptp_gettime(struct ptp_clock_info *ptp, struct timespec64 *ts)
 257 {
 258         u64 ns;
 259         unsigned long flags;
 260         struct cpts *cpts = container_of(ptp, struct cpts, info);
 261
 262         spin_lock_irqsave(&cpts->lock, flags);
 263         ns = timecounter_read(&cpts->tc);
 264         spin_unlock_irqrestore(&cpts->lock, flags);
 265
 266         *ts = ns_to_timespec64(ns);
 267
 268         return 0;
 269 }
 270
 271 static int cpts_ptp_settime(struct ptp_clock_info *ptp,
 272                             const struct timespec64 *ts)
 273 {
 274         u64 ns;
 275         unsigned long flags;
 276         struct cpts *cpts = container_of(ptp, struct cpts, info);
 277
 278         ns = timespec64_to_ns(ts);
 279
 280         spin_lock_irqsave(&cpts->lock, flags);
 281         timecounter_init(&cpts->tc, &cpts->cc, ns);
 282         spin_unlock_irqrestore(&cpts->lock, flags);
 283
 284         return 0;
 285 }
 286
 287 static int cpts_ptp_enable(struct ptp_clock_info *ptp,
 288                            struct ptp_clock_request *rq, int on)
 289 {
 290         return -EOPNOTSUPP;
 291 }
 292
 293 static long cpts_overflow_check(struct ptp_clock_info *ptp)
 294 {
 295         struct cpts *cpts = container_of(ptp, struct cpts, info);
 296         unsigned long delay = cpts->ov_check_period;
 297         struct timespec64 ts;
 298         unsigned long flags;
 299
 300         spin_lock_irqsave(&cpts->lock, flags);
 301         ts = ns_to_timespec64(timecounter_read(&cpts->tc));
 302
 303         if (!skb_queue_empty(&cpts->txq)) {
 304                 cpts_purge_txq(cpts);
 305                 if (!skb_queue_empty(&cpts->txq))
 306                         delay = CPTS_SKB_TX_WORK_TIMEOUT;
 307         }
 308         spin_unlock_irqrestore(&cpts->lock, flags);
 309
 310         pr_debug("cpts overflow check at %lld.%09ld\n",
 311                  (long long)ts.tv_sec, ts.tv_nsec);
 312         return (long)delay;
 313 }
 314
 315 static const struct ptp_clock_info cpts_info = {
 316         .owner          = THIS_MODULE,
 317         .name           = "CTPS timer",
 318         .max_adj        = 1000000,
 319         .n_ext_ts       = 0,
 320         .n_pins         = 0,
 321         .pps            = 0,
 322         .adjfreq        = cpts_ptp_adjfreq,
 323         .adjtime        = cpts_ptp_adjtime,
 324         .gettime64      = cpts_ptp_gettime,
 325         .settime64      = cpts_ptp_settime,
 326         .enable         = cpts_ptp_enable,
 327         .do_aux_work    = cpts_overflow_check,
 328 };
 329
 330 static int cpts_match(struct sk_buff *skb, unsigned int ptp_class,
 331                       u16 ts_seqid, u8 ts_msgtype)
 332 {
 333         u16 *seqid;
 334         unsigned int offset = 0;
 335         u8 *msgtype, *data = skb->data;
 336
 337         if (ptp_class & PTP_CLASS_VLAN)
 338                 offset += VLAN_HLEN;
 339
 340         switch (ptp_class & PTP_CLASS_PMASK) {
 341         case PTP_CLASS_IPV4:
 342                 offset += ETH_HLEN + IPV4_HLEN(data + offset) + UDP_HLEN;
 343                 break;
 344         case PTP_CLASS_IPV6:
 345                 offset += ETH_HLEN + IP6_HLEN + UDP_HLEN;
 346                 break;
 347         case PTP_CLASS_L2:
 348                 offset += ETH_HLEN;
 349                 break;
 350         default:
 351                 return 0;
 352         }
 353
 354         if (skb->len + ETH_HLEN < offset + OFF_PTP_SEQUENCE_ID + sizeof(*seqid))
 355                 return 0;
 356
 357         if (unlikely(ptp_class & PTP_CLASS_V1))
 358                 msgtype = data + offset + OFF_PTP_CONTROL;
 359         else
 360                 msgtype = data + offset;
 361
 362         seqid = (u16 *)(data + offset + OFF_PTP_SEQUENCE_ID);
 363
 364         return (ts_msgtype == (*msgtype & 0xf) && ts_seqid == ntohs(*seqid));
 365 }
 366
 367 static u64 cpts_find_ts(struct cpts *cpts, struct sk_buff *skb, int ev_type)
 368 {
 369         u64 ns = 0;
 370         struct cpts_event *event;
 371         struct list_head *this, *next;
 372         unsigned int class = ptp_classify_raw(skb);
 373         unsigned long flags;
 374         u16 seqid;
 375         u8 mtype;
 376
 377         if (class == PTP_CLASS_NONE)
 378                 return 0;
 379
 380         spin_lock_irqsave(&cpts->lock, flags);
 381         cpts_fifo_read(cpts, -1);
 382         list_for_each_safe(this, next, &cpts->events) {
 383                 event = list_entry(this, struct cpts_event, list);
 384                 if (event_expired(event)) {
 385                         list_del_init(&event->list);
 386                         list_add(&event->list, &cpts->pool);
 387                         continue;
 388                 }
 389                 mtype = (event->high >> MESSAGE_TYPE_SHIFT) & MESSAGE_TYPE_MASK;
 390                 seqid = (event->high >> SEQUENCE_ID_SHIFT) & SEQUENCE_ID_MASK;
 391                 if (ev_type == event_type(event) &&
 392                     cpts_match(skb, class, seqid, mtype)) {
 393                         ns = timecounter_cyc2time(&cpts->tc, event->low);
 394                         list_del_init(&event->list);
 395                         list_add(&event->list, &cpts->pool);
 396                         break;
 397                 }
 398         }
 399
 400         if (ev_type == CPTS_EV_TX && !ns) {
 401                 struct cpts_skb_cb_data *skb_cb =
 402                                 (struct cpts_skb_cb_data *)skb->cb;
 403                 /* Not found, add frame to queue for processing later.
 404                  * The periodic FIFO check will handle this.
 405                  */
 406                 skb_get(skb);
 407                 /* get the timestamp for timeouts */
 408                 skb_cb->tmo = jiffies + msecs_to_jiffies(100);
 409                 __skb_queue_tail(&cpts->txq, skb);
 410                 ptp_schedule_worker(cpts->clock, 0);
 411         }
 412         spin_unlock_irqrestore(&cpts->lock, flags);
 413
 414         return ns;
 415 }
 416
 417 void cpts_rx_timestamp(struct cpts *cpts, struct sk_buff *skb)
 418 {
 419         u64 ns;
 420         struct skb_shared_hwtstamps *ssh;
 421
 422         ns = cpts_find_ts(cpts, skb, CPTS_EV_RX);
 423         if (!ns)
 424                 return;
 425         ssh = skb_hwtstamps(skb);
 426         memset(ssh, 0, sizeof(*ssh));
 427         ssh->hwtstamp = ns_to_ktime(ns);
 428 }
 429 EXPORT_SYMBOL_GPL(cpts_rx_timestamp);
 430
 431 void cpts_tx_timestamp(struct cpts *cpts, struct sk_buff *skb)
 432 {
 433         u64 ns;
 434         struct skb_shared_hwtstamps ssh;
 435
 436         if (!(skb_shinfo(skb)->tx_flags & SKBTX_IN_PROGRESS))
 437                 return;
 438         ns = cpts_find_ts(cpts, skb, CPTS_EV_TX);
 439         if (!ns)
 440                 return;
 441         memset(&ssh, 0, sizeof(ssh));
 442         ssh.hwtstamp = ns_to_ktime(ns);
 443         skb_tstamp_tx(skb, &ssh);
 444 }
 445 EXPORT_SYMBOL_GPL(cpts_tx_timestamp);
 446
 447 int cpts_register(struct cpts *cpts)
 448 {
 449         int err, i;
 450
 451         skb_queue_head_init(&cpts->txq);
 452         INIT_LIST_HEAD(&cpts->events);
 453         INIT_LIST_HEAD(&cpts->pool);
 454         for (i = 0; i < CPTS_MAX_EVENTS; i++)
 455                 list_add(&cpts->pool_data[i].list, &cpts->pool);
 456
 457         clk_enable(cpts->refclk);
 458
 459         cpts_write32(cpts, CPTS_EN, control);
 460         cpts_write32(cpts, TS_PEND_EN, int_enable);
 461
 462         timecounter_init(&cpts->tc, &cpts->cc, ktime_to_ns(ktime_get_real()));
 463
 464         cpts->clock = ptp_clock_register(&cpts->info, cpts->dev);
 465         if (IS_ERR(cpts->clock)) {
 466                 err = PTR_ERR(cpts->clock);
 467                 cpts->clock = NULL;
 468                 goto err_ptp;
 469         }
 470         cpts->phc_index = ptp_clock_index(cpts->clock);
 471
 472         ptp_schedule_worker(cpts->clock, cpts->ov_check_period);
 473         return 0;
 474
 475 err_ptp:
 476         clk_disable(cpts->refclk);
 477         return err;
 478 }
 479 EXPORT_SYMBOL_GPL(cpts_register);
 480
 481 void cpts_unregister(struct cpts *cpts)
 482 {
 483         if (WARN_ON(!cpts->clock))
 484                 return;
 485
 486         ptp_clock_unregister(cpts->clock);
 487         cpts->clock = NULL;
 488
 489         cpts_write32(cpts, 0, int_enable);
 490         cpts_write32(cpts, 0, control);
 491
 492         /* Drop all packet */
 493         skb_queue_purge(&cpts->txq);
 494
 495         clk_disable(cpts->refclk);
 496 }
 497 EXPORT_SYMBOL_GPL(cpts_unregister);
 498
 499 static void cpts_calc_mult_shift(struct cpts *cpts)
 500 {
 501         u64 frac, maxsec, ns;
 502         u32 freq;
 503
 504         freq = clk_get_rate(cpts->refclk);
 505
 506         /* Calc the maximum number of seconds which we can run before
 507          * wrapping around.
 508          */
 509         maxsec = cpts->cc.mask;
 510         do_div(maxsec, freq);
 511         /* limit conversation rate to 10 sec as higher values will produce
 512          * too small mult factors and so reduce the conversion accuracy
 513          */
 514         if (maxsec > 10)
 515                 maxsec = 10;
 516
 517         /* Calc overflow check period (maxsec / 2) */
 518         cpts->ov_check_period = (HZ * maxsec) / 2;
 519         dev_info(cpts->dev, "cpts: overflow check period %lu (jiffies)\n",
 520                  cpts->ov_check_period);
 521
 522         if (cpts->cc.mult || cpts->cc.shift)
 523                 return;
 524
 525         clocks_calc_mult_shift(&cpts->cc.mult, &cpts->cc.shift,
 526                                freq, NSEC_PER_SEC, maxsec);
 527
 528         frac = 0;
 529         ns = cyclecounter_cyc2ns(&cpts->cc, freq, cpts->cc.mask, &frac);
 530
 531         dev_info(cpts->dev,
 532                  "CPTS: ref_clk_freq:%u calc_mult:%u calc_shift:%u error:%lld nsec/sec\n",
 533                  freq, cpts->cc.mult, cpts->cc.shift, (ns - NSEC_PER_SEC));
 534 }
 535
 536 static int cpts_of_mux_clk_setup(struct cpts *cpts, struct device_node *node)
 537 {
 538         struct device_node *refclk_np;
 539         const char **parent_names;
 540         unsigned int num_parents;
 541         struct clk_hw *clk_hw;
 542         int ret = -EINVAL;
 543         u32 *mux_table;
 544
 545         refclk_np = of_get_child_by_name(node, "cpts-refclk-mux");
 546         if (!refclk_np)
 547                 /* refclk selection supported not for all SoCs */
 548                 return 0;
 549
 550         num_parents = of_clk_get_parent_count(refclk_np);
 551         if (num_parents < 1) {
 552                 dev_err(cpts->dev, "mux-clock %s must have parents\n",
 553                         refclk_np->name);
 554                 goto mux_fail;
 555         }
 556
 557         parent_names = devm_kzalloc(cpts->dev, (sizeof(char *) * num_parents),
 558                                     GFP_KERNEL);
 559
 560         mux_table = devm_kzalloc(cpts->dev, sizeof(*mux_table) * num_parents,
 561                                  GFP_KERNEL);
 562         if (!mux_table || !parent_names) {
 563                 ret = -ENOMEM;
 564                 goto mux_fail;
 565         }
 566
 567         of_clk_parent_fill(refclk_np, parent_names, num_parents);
 568
 569         ret = of_property_read_variable_u32_array(refclk_np, "ti,mux-tbl",
 570                                                   mux_table,
 571                                                   num_parents, num_parents);
 572         if (ret < 0)
 573                 goto mux_fail;
 574
 575         clk_hw = clk_hw_register_mux_table(cpts->dev, refclk_np->name,
 576                                            parent_names, num_parents,
 577                                            0,
 578                                            &cpts->reg->rftclk_sel, 0, 0x1F,
 579                                            0, mux_table, NULL);
 580         if (IS_ERR(clk_hw)) {
 581                 ret = PTR_ERR(clk_hw);
 582                 goto mux_fail;
 583         }
 584
 585         ret = devm_add_action_or_reset(cpts->dev,
 586                                        (void(*)(void *))clk_hw_unregister_mux,
 587                                        clk_hw);
 588         if (ret) {
 589                 dev_err(cpts->dev, "add clkmux unreg action %d", ret);
 590                 goto mux_fail;
 591         }
 592
 593         ret = of_clk_add_hw_provider(refclk_np, of_clk_hw_simple_get, clk_hw);
 594         if (ret)
 595                 goto mux_fail;
 596
 597         ret = devm_add_action_or_reset(cpts->dev,
 598                                        (void(*)(void *))of_clk_del_provider,
 599                                        refclk_np);
 600         if (ret) {
 601                 dev_err(cpts->dev, "add clkmux provider unreg action %d", ret);
 602                 goto mux_fail;
 603         }
 604
 605         return ret;
 606
 607 mux_fail:
 608         of_node_put(refclk_np);
 609         return ret;
 610 }
 611
 612 static int cpts_of_parse(struct cpts *cpts, struct device_node *node)
 613 {
 614         int ret = -EINVAL;
 615         u32 prop;
 616
 617         if (!of_property_read_u32(node, "cpts_clock_mult", &prop))
 618                 cpts->cc.mult = prop;
 619
 620         if (!of_property_read_u32(node, "cpts_clock_shift", &prop))
 621                 cpts->cc.shift = prop;
 622
 623         if ((cpts->cc.mult && !cpts->cc.shift) ||
 624             (!cpts->cc.mult && cpts->cc.shift))
 625                 goto of_error;
 626
 627         return cpts_of_mux_clk_setup(cpts, node);
 628
 629 of_error:
 630         dev_err(cpts->dev, "CPTS: Missing property in the DT.\n");
 631         return ret;
 632 }
 633
 634 struct cpts *cpts_create(struct device *dev, void __iomem *regs,
 635                          struct device_node *node)
 636 {
 637         struct cpts *cpts;
 638         int ret;
 639
 640         cpts = devm_kzalloc(dev, sizeof(*cpts), GFP_KERNEL);
 641         if (!cpts)
 642                 return ERR_PTR(-ENOMEM);
 643
 644         cpts->dev = dev;
 645         cpts->reg = (struct cpsw_cpts __iomem *)regs;
 646         spin_lock_init(&cpts->lock);
 647
 648         ret = cpts_of_parse(cpts, node);
 649         if (ret)
 650                 return ERR_PTR(ret);
 651
 652         cpts->refclk = devm_get_clk_from_child(dev, node, "cpts");
 653         if (IS_ERR(cpts->refclk))
 654                 /* try get clk from dev node for compatibility */
 655                 cpts->refclk = devm_clk_get(dev, "cpts");
 656
 657         if (IS_ERR(cpts->refclk)) {
 658                 dev_err(dev, "Failed to get cpts refclk %ld\n",
 659                         PTR_ERR(cpts->refclk));
 660                 return ERR_CAST(cpts->refclk);
 661         }
 662
 663         ret = clk_prepare(cpts->refclk);
 664         if (ret)
 665                 return ERR_PTR(ret);
 666
 667         cpts->cc.read = cpts_systim_read;
 668         cpts->cc.mask = CLOCKSOURCE_MASK(32);
 669         cpts->info = cpts_info;
 670
 671         cpts_calc_mult_shift(cpts);
 672         /* save cc.mult original value as it can be modified
 673          * by cpts_ptp_adjfreq().
 674          */
 675         cpts->cc_mult = cpts->cc.mult;
 676
 677         return cpts;
 678 }
 679 EXPORT_SYMBOL_GPL(cpts_create);
 680
 681 void cpts_release(struct cpts *cpts)
 682 {
 683         if (!cpts)
 684                 return;
 685
 686         if (WARN_ON(!cpts->refclk))
 687                 return;
 688
 689         clk_unprepare(cpts->refclk);
 690 }
 691 EXPORT_SYMBOL_GPL(cpts_release);
 692
 693 MODULE_LICENSE("GPL v2");
 694 MODULE_DESCRIPTION("TI CPTS driver");
 695 MODULE_AUTHOR("Richard Cochran <richardcochran@gmail.com>");