drivers/clocksource/sh_cmt.c

   1 /*
   2  * SuperH Timer Support - CMT
   3  *
   4  *  Copyright (C) 2008 Magnus Damm
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; either version 2 of the License
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * along with this program; if not, write to the Free Software
  17  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  18  */
  19
  20 #include <linux/init.h>
  21 #include <linux/platform_device.h>
  22 #include <linux/spinlock.h>
  23 #include <linux/interrupt.h>
  24 #include <linux/ioport.h>
  25 #include <linux/io.h>
  26 #include <linux/clk.h>
  27 #include <linux/irq.h>
  28 #include <linux/err.h>
  29 #include <linux/clocksource.h>
  30 #include <linux/clockchips.h>
  31 #include <linux/sh_timer.h>
  32 #include <linux/slab.h>
  33
  34 struct sh_cmt_priv {
  35         void __iomem *mapbase;
  36         struct clk *clk;
  37         unsigned long width; /* 16 or 32 bit version of hardware block */
  38         unsigned long overflow_bit;
  39         unsigned long clear_bits;
  40         struct irqaction irqaction;
  41         struct platform_device *pdev;
  42
  43         unsigned long flags;
  44         unsigned long match_value;
  45         unsigned long next_match_value;
  46         unsigned long max_match_value;
  47         unsigned long rate;
  48         spinlock_t lock;
  49         struct clock_event_device ced;
  50         struct clocksource cs;
  51         unsigned long total_cycles;
  52 };
  53
  54 static DEFINE_SPINLOCK(sh_cmt_lock);
  55
  56 #define CMSTR -1 /* shared register */
  57 #define CMCSR 0 /* channel register */
  58 #define CMCNT 1 /* channel register */
  59 #define CMCOR 2 /* channel register */
  60
  61 static inline unsigned long sh_cmt_read(struct sh_cmt_priv *p, int reg_nr)
  62 {
  63         struct sh_timer_config *cfg = p->pdev->dev.platform_data;
  64         void __iomem *base = p->mapbase;
  65         unsigned long offs;
  66
  67         if (reg_nr == CMSTR) {
  68                 offs = 0;
  69                 base -= cfg->channel_offset;
  70         } else
  71                 offs = reg_nr;
  72
  73         if (p->width == 16)
  74                 offs <<= 1;
  75         else {
  76                 offs <<= 2;
  77                 if ((reg_nr == CMCNT) || (reg_nr == CMCOR))
  78                         return ioread32(base + offs);
  79         }
  80
  81         return ioread16(base + offs);
  82 }
  83
  84 static inline void sh_cmt_write(struct sh_cmt_priv *p, int reg_nr,
  85                                 unsigned long value)
  86 {
  87         struct sh_timer_config *cfg = p->pdev->dev.platform_data;
  88         void __iomem *base = p->mapbase;
  89         unsigned long offs;
  90
  91         if (reg_nr == CMSTR) {
  92                 offs = 0;
  93                 base -= cfg->channel_offset;
  94         } else
  95                 offs = reg_nr;
  96
  97         if (p->width == 16)
  98                 offs <<= 1;
  99         else {
 100                 offs <<= 2;
 101                 if ((reg_nr == CMCNT) || (reg_nr == CMCOR)) {
 102                         iowrite32(value, base + offs);
 103                         return;
 104                 }
 105         }
 106
 107         iowrite16(value, base + offs);
 108 }
 109
 110 static unsigned long sh_cmt_get_counter(struct sh_cmt_priv *p,
 111                                         int *has_wrapped)
 112 {
 113         unsigned long v1, v2, v3;
 114         int o1, o2;
 115
 116         o1 = sh_cmt_read(p, CMCSR) & p->overflow_bit;
 117
 118         /* Make sure the timer value is stable. Stolen from acpi_pm.c */
 119         do {
 120                 o2 = o1;
 121                 v1 = sh_cmt_read(p, CMCNT);
 122                 v2 = sh_cmt_read(p, CMCNT);
 123                 v3 = sh_cmt_read(p, CMCNT);
 124                 o1 = sh_cmt_read(p, CMCSR) & p->overflow_bit;
 125         } while (unlikely((o1 != o2) || (v1 > v2 && v1 < v3)
 126                           || (v2 > v3 && v2 < v1) || (v3 > v1 && v3 < v2)));
 127
 128         *has_wrapped = o1;
 129         return v2;
 130 }
 131
 132
 133 static void sh_cmt_start_stop_ch(struct sh_cmt_priv *p, int start)
 134 {
 135         struct sh_timer_config *cfg = p->pdev->dev.platform_data;
 136         unsigned long flags, value;
 137
 138         /* start stop register shared by multiple timer channels */
 139         spin_lock_irqsave(&sh_cmt_lock, flags);
 140         value = sh_cmt_read(p, CMSTR);
 141
 142         if (start)
 143                 value |= 1 << cfg->timer_bit;
 144         else
 145                 value &= ~(1 << cfg->timer_bit);
 146
 147         sh_cmt_write(p, CMSTR, value);
 148         spin_unlock_irqrestore(&sh_cmt_lock, flags);
 149 }
 150
 151 static int sh_cmt_enable(struct sh_cmt_priv *p, unsigned long *rate)
 152 {
 153         int ret;
 154
 155         /* enable clock */
 156         ret = clk_enable(p->clk);
 157         if (ret) {
 158                 dev_err(&p->pdev->dev, "cannot enable clock\n");
 159                 return ret;
 160         }
 161
 162         /* make sure channel is disabled */
 163         sh_cmt_start_stop_ch(p, 0);
 164
 165         /* configure channel, periodic mode and maximum timeout */
 166         if (p->width == 16) {
 167                 *rate = clk_get_rate(p->clk) / 512;
 168                 sh_cmt_write(p, CMCSR, 0x43);
 169         } else {
 170                 *rate = clk_get_rate(p->clk) / 8;
 171                 sh_cmt_write(p, CMCSR, 0x01a4);
 172         }
 173
 174         sh_cmt_write(p, CMCOR, 0xffffffff);
 175         sh_cmt_write(p, CMCNT, 0);
 176
 177         /* enable channel */
 178         sh_cmt_start_stop_ch(p, 1);
 179         return 0;
 180 }
 181
 182 static void sh_cmt_disable(struct sh_cmt_priv *p)
 183 {
 184         /* disable channel */
 185         sh_cmt_start_stop_ch(p, 0);
 186
 187         /* disable interrupts in CMT block */
 188         sh_cmt_write(p, CMCSR, 0);
 189
 190         /* stop clock */
 191         clk_disable(p->clk);
 192 }
 193
 194 /* private flags */
 195 #define FLAG_CLOCKEVENT (1 << 0)
 196 #define FLAG_CLOCKSOURCE (1 << 1)
 197 #define FLAG_REPROGRAM (1 << 2)
 198 #define FLAG_SKIPEVENT (1 << 3)
 199 #define FLAG_IRQCONTEXT (1 << 4)
 200
 201 static void sh_cmt_clock_event_program_verify(struct sh_cmt_priv *p,
 202                                               int absolute)
 203 {
 204         unsigned long new_match;
 205         unsigned long value = p->next_match_value;
 206         unsigned long delay = 0;
 207         unsigned long now = 0;
 208         int has_wrapped;
 209
 210         now = sh_cmt_get_counter(p, &has_wrapped);
 211         p->flags |= FLAG_REPROGRAM; /* force reprogram */
 212
 213         if (has_wrapped) {
 214                 /* we're competing with the interrupt handler.
 215                  *  -> let the interrupt handler reprogram the timer.
 216                  *  -> interrupt number two handles the event.
 217                  */
 218                 p->flags |= FLAG_SKIPEVENT;
 219                 return;
 220         }
 221
 222         if (absolute)
 223                 now = 0;
 224
 225         do {
 226                 /* reprogram the timer hardware,
 227                  * but don't save the new match value yet.
 228                  */
 229                 new_match = now + value + delay;
 230                 if (new_match > p->max_match_value)
 231                         new_match = p->max_match_value;
 232
 233                 sh_cmt_write(p, CMCOR, new_match);
 234
 235                 now = sh_cmt_get_counter(p, &has_wrapped);
 236                 if (has_wrapped && (new_match > p->match_value)) {
 237                         /* we are changing to a greater match value,
 238                          * so this wrap must be caused by the counter
 239                          * matching the old value.
 240                          * -> first interrupt reprograms the timer.
 241                          * -> interrupt number two handles the event.
 242                          */
 243                         p->flags |= FLAG_SKIPEVENT;
 244                         break;
 245                 }
 246
 247                 if (has_wrapped) {
 248                         /* we are changing to a smaller match value,
 249                          * so the wrap must be caused by the counter
 250                          * matching the new value.
 251                          * -> save programmed match value.
 252                          * -> let isr handle the event.
 253                          */
 254                         p->match_value = new_match;
 255                         break;
 256                 }
 257
 258                 /* be safe: verify hardware settings */
 259                 if (now < new_match) {
 260                         /* timer value is below match value, all good.
 261                          * this makes sure we won't miss any match events.
 262                          * -> save programmed match value.
 263                          * -> let isr handle the event.
 264                          */
 265                         p->match_value = new_match;
 266                         break;
 267                 }
 268
 269                 /* the counter has reached a value greater
 270                  * than our new match value. and since the
 271                  * has_wrapped flag isn't set we must have
 272                  * programmed a too close event.
 273                  * -> increase delay and retry.
 274                  */
 275                 if (delay)
 276                         delay <<= 1;
 277                 else
 278                         delay = 1;
 279
 280                 if (!delay)
 281                         dev_warn(&p->pdev->dev, "too long delay\n");
 282
 283         } while (delay);
 284 }
 285
 286 static void sh_cmt_set_next(struct sh_cmt_priv *p, unsigned long delta)
 287 {
 288         unsigned long flags;
 289
 290         if (delta > p->max_match_value)
 291                 dev_warn(&p->pdev->dev, "delta out of range\n");
 292
 293         spin_lock_irqsave(&p->lock, flags);
 294         p->next_match_value = delta;
 295         sh_cmt_clock_event_program_verify(p, 0);
 296         spin_unlock_irqrestore(&p->lock, flags);
 297 }
 298
 299 static irqreturn_t sh_cmt_interrupt(int irq, void *dev_id)
 300 {
 301         struct sh_cmt_priv *p = dev_id;
 302
 303         /* clear flags */
 304         sh_cmt_write(p, CMCSR, sh_cmt_read(p, CMCSR) & p->clear_bits);
 305
 306         /* update clock source counter to begin with if enabled
 307          * the wrap flag should be cleared by the timer specific
 308          * isr before we end up here.
 309          */
 310         if (p->flags & FLAG_CLOCKSOURCE)
 311                 p->total_cycles += p->match_value + 1;
 312
 313         if (!(p->flags & FLAG_REPROGRAM))
 314                 p->next_match_value = p->max_match_value;
 315
 316         p->flags |= FLAG_IRQCONTEXT;
 317
 318         if (p->flags & FLAG_CLOCKEVENT) {
 319                 if (!(p->flags & FLAG_SKIPEVENT)) {
 320                         if (p->ced.mode == CLOCK_EVT_MODE_ONESHOT) {
 321                                 p->next_match_value = p->max_match_value;
 322                                 p->flags |= FLAG_REPROGRAM;
 323                         }
 324
 325                         p->ced.event_handler(&p->ced);
 326                 }
 327         }
 328
 329         p->flags &= ~FLAG_SKIPEVENT;
 330
 331         if (p->flags & FLAG_REPROGRAM) {
 332                 p->flags &= ~FLAG_REPROGRAM;
 333                 sh_cmt_clock_event_program_verify(p, 1);
 334
 335                 if (p->flags & FLAG_CLOCKEVENT)
 336                         if ((p->ced.mode == CLOCK_EVT_MODE_SHUTDOWN)
 337                             || (p->match_value == p->next_match_value))
 338                                 p->flags &= ~FLAG_REPROGRAM;
 339         }
 340
 341         p->flags &= ~FLAG_IRQCONTEXT;
 342
 343         return IRQ_HANDLED;
 344 }
 345
 346 static int sh_cmt_start(struct sh_cmt_priv *p, unsigned long flag)
 347 {
 348         int ret = 0;
 349         unsigned long flags;
 350
 351         spin_lock_irqsave(&p->lock, flags);
 352
 353         if (!(p->flags & (FLAG_CLOCKEVENT | FLAG_CLOCKSOURCE)))
 354                 ret = sh_cmt_enable(p, &p->rate);
 355
 356         if (ret)
 357                 goto out;
 358         p->flags |= flag;
 359
 360         /* setup timeout if no clockevent */
 361         if ((flag == FLAG_CLOCKSOURCE) && (!(p->flags & FLAG_CLOCKEVENT)))
 362                 sh_cmt_set_next(p, p->max_match_value);
 363  out:
 364         spin_unlock_irqrestore(&p->lock, flags);
 365
 366         return ret;
 367 }
 368
 369 static void sh_cmt_stop(struct sh_cmt_priv *p, unsigned long flag)
 370 {
 371         unsigned long flags;
 372         unsigned long f;
 373
 374         spin_lock_irqsave(&p->lock, flags);
 375
 376         f = p->flags & (FLAG_CLOCKEVENT | FLAG_CLOCKSOURCE);
 377         p->flags &= ~flag;
 378
 379         if (f && !(p->flags & (FLAG_CLOCKEVENT | FLAG_CLOCKSOURCE)))
 380                 sh_cmt_disable(p);
 381
 382         /* adjust the timeout to maximum if only clocksource left */
 383         if ((flag == FLAG_CLOCKEVENT) && (p->flags & FLAG_CLOCKSOURCE))
 384                 sh_cmt_set_next(p, p->max_match_value);
 385
 386         spin_unlock_irqrestore(&p->lock, flags);
 387 }
 388
 389 static struct sh_cmt_priv *cs_to_sh_cmt(struct clocksource *cs)
 390 {
 391         return container_of(cs, struct sh_cmt_priv, cs);
 392 }
 393
 394 static cycle_t sh_cmt_clocksource_read(struct clocksource *cs)
 395 {
 396         struct sh_cmt_priv *p = cs_to_sh_cmt(cs);
 397         unsigned long flags, raw;
 398         unsigned long value;
 399         int has_wrapped;
 400
 401         spin_lock_irqsave(&p->lock, flags);
 402         value = p->total_cycles;
 403         raw = sh_cmt_get_counter(p, &has_wrapped);
 404
 405         if (unlikely(has_wrapped))
 406                 raw += p->match_value + 1;
 407         spin_unlock_irqrestore(&p->lock, flags);
 408
 409         return value + raw;
 410 }
 411
 412 static int sh_cmt_clocksource_enable(struct clocksource *cs)
 413 {
 414         struct sh_cmt_priv *p = cs_to_sh_cmt(cs);
 415
 416         p->total_cycles = 0;
 417
 418         return sh_cmt_start(p, FLAG_CLOCKSOURCE);
 419 }
 420
 421 static void sh_cmt_clocksource_disable(struct clocksource *cs)
 422 {
 423         sh_cmt_stop(cs_to_sh_cmt(cs), FLAG_CLOCKSOURCE);
 424 }
 425
 426 static void sh_cmt_clocksource_resume(struct clocksource *cs)
 427 {
 428         sh_cmt_start(cs_to_sh_cmt(cs), FLAG_CLOCKSOURCE);
 429 }
 430
 431 static int sh_cmt_register_clocksource(struct sh_cmt_priv *p,
 432                                        char *name, unsigned long rating)
 433 {
 434         struct clocksource *cs = &p->cs;
 435
 436         cs->name = name;
 437         cs->rating = rating;
 438         cs->read = sh_cmt_clocksource_read;
 439         cs->enable = sh_cmt_clocksource_enable;
 440         cs->disable = sh_cmt_clocksource_disable;
 441         cs->suspend = sh_cmt_clocksource_disable;
 442         cs->resume = sh_cmt_clocksource_resume;
 443         cs->mask = CLOCKSOURCE_MASK(sizeof(unsigned long) * 8);
 444         cs->flags = CLOCK_SOURCE_IS_CONTINUOUS;
 445
 446         /* clk_get_rate() needs an enabled clock */
 447         clk_enable(p->clk);
 448         p->rate = clk_get_rate(p->clk) / ((p->width == 16) ? 512 : 8);
 449         clk_disable(p->clk);
 450
 451         /* TODO: calculate good shift from rate and counter bit width */
 452         cs->shift = 0;
 453         cs->mult = clocksource_hz2mult(p->rate, cs->shift);
 454
 455         dev_info(&p->pdev->dev, "used as clock source\n");
 456
 457         clocksource_register(cs);
 458
 459         return 0;
 460 }
 461
 462 static struct sh_cmt_priv *ced_to_sh_cmt(struct clock_event_device *ced)
 463 {
 464         return container_of(ced, struct sh_cmt_priv, ced);
 465 }
 466
 467 static void sh_cmt_clock_event_start(struct sh_cmt_priv *p, int periodic)
 468 {
 469         struct clock_event_device *ced = &p->ced;
 470
 471         sh_cmt_start(p, FLAG_CLOCKEVENT);
 472
 473         /* TODO: calculate good shift from rate and counter bit width */
 474
 475         ced->shift = 32;
 476         ced->mult = div_sc(p->rate, NSEC_PER_SEC, ced->shift);
 477         ced->max_delta_ns = clockevent_delta2ns(p->max_match_value, ced);
 478         ced->min_delta_ns = clockevent_delta2ns(0x1f, ced);
 479
 480         if (periodic)
 481                 sh_cmt_set_next(p, ((p->rate + HZ/2) / HZ) - 1);
 482         else
 483                 sh_cmt_set_next(p, p->max_match_value);
 484 }
 485
 486 static void sh_cmt_clock_event_mode(enum clock_event_mode mode,
 487                                     struct clock_event_device *ced)
 488 {
 489         struct sh_cmt_priv *p = ced_to_sh_cmt(ced);
 490
 491         /* deal with old setting first */
 492         switch (ced->mode) {
 493         case CLOCK_EVT_MODE_PERIODIC:
 494         case CLOCK_EVT_MODE_ONESHOT:
 495                 sh_cmt_stop(p, FLAG_CLOCKEVENT);
 496                 break;
 497         default:
 498                 break;
 499         }
 500
 501         switch (mode) {
 502         case CLOCK_EVT_MODE_PERIODIC:
 503                 dev_info(&p->pdev->dev, "used for periodic clock events\n");
 504                 sh_cmt_clock_event_start(p, 1);
 505                 break;
 506         case CLOCK_EVT_MODE_ONESHOT:
 507                 dev_info(&p->pdev->dev, "used for oneshot clock events\n");
 508                 sh_cmt_clock_event_start(p, 0);
 509                 break;
 510         case CLOCK_EVT_MODE_SHUTDOWN:
 511         case CLOCK_EVT_MODE_UNUSED:
 512                 sh_cmt_stop(p, FLAG_CLOCKEVENT);
 513                 break;
 514         default:
 515                 break;
 516         }
 517 }
 518
 519 static int sh_cmt_clock_event_next(unsigned long delta,
 520                                    struct clock_event_device *ced)
 521 {
 522         struct sh_cmt_priv *p = ced_to_sh_cmt(ced);
 523
 524         BUG_ON(ced->mode != CLOCK_EVT_MODE_ONESHOT);
 525         if (likely(p->flags & FLAG_IRQCONTEXT))
 526                 p->next_match_value = delta - 1;
 527         else
 528                 sh_cmt_set_next(p, delta - 1);
 529
 530         return 0;
 531 }
 532
 533 static void sh_cmt_register_clockevent(struct sh_cmt_priv *p,
 534                                        char *name, unsigned long rating)
 535 {
 536         struct clock_event_device *ced = &p->ced;
 537
 538         memset(ced, 0, sizeof(*ced));
 539
 540         ced->name = name;
 541         ced->features = CLOCK_EVT_FEAT_PERIODIC;
 542         ced->features |= CLOCK_EVT_FEAT_ONESHOT;
 543         ced->rating = rating;
 544         ced->cpumask = cpumask_of(0);
 545         ced->set_next_event = sh_cmt_clock_event_next;
 546         ced->set_mode = sh_cmt_clock_event_mode;
 547
 548         dev_info(&p->pdev->dev, "used for clock events\n");
 549         clockevents_register_device(ced);
 550 }
 551
 552 static int sh_cmt_register(struct sh_cmt_priv *p, char *name,
 553                            unsigned long clockevent_rating,
 554                            unsigned long clocksource_rating)
 555 {
 556         if (p->width == (sizeof(p->max_match_value) * 8))
 557                 p->max_match_value = ~0;
 558         else
 559                 p->max_match_value = (1 << p->width) - 1;
 560
 561         p->match_value = p->max_match_value;
 562         spin_lock_init(&p->lock);
 563
 564         if (clockevent_rating)
 565                 sh_cmt_register_clockevent(p, name, clockevent_rating);
 566
 567         if (clocksource_rating)
 568                 sh_cmt_register_clocksource(p, name, clocksource_rating);
 569
 570         return 0;
 571 }
 572
 573 static int sh_cmt_setup(struct sh_cmt_priv *p, struct platform_device *pdev)
 574 {
 575         struct sh_timer_config *cfg = pdev->dev.platform_data;
 576         struct resource *res;
 577         int irq, ret;
 578         ret = -ENXIO;
 579
 580         memset(p, 0, sizeof(*p));
 581         p->pdev = pdev;
 582
 583         if (!cfg) {
 584                 dev_err(&p->pdev->dev, "missing platform data\n");
 585                 goto err0;
 586         }
 587
 588         platform_set_drvdata(pdev, p);
 589
 590         res = platform_get_resource(p->pdev, IORESOURCE_MEM, 0);
 591         if (!res) {
 592                 dev_err(&p->pdev->dev, "failed to get I/O memory\n");
 593                 goto err0;
 594         }
 595
 596         irq = platform_get_irq(p->pdev, 0);
 597         if (irq < 0) {
 598                 dev_err(&p->pdev->dev, "failed to get irq\n");
 599                 goto err0;
 600         }
 601
 602         /* map memory, let mapbase point to our channel */
 603         p->mapbase = ioremap_nocache(res->start, resource_size(res));
 604         if (p->mapbase == NULL) {
 605                 dev_err(&p->pdev->dev, "failed to remap I/O memory\n");
 606                 goto err0;
 607         }
 608
 609         /* request irq using setup_irq() (too early for request_irq()) */
 610         p->irqaction.name = dev_name(&p->pdev->dev);
 611         p->irqaction.handler = sh_cmt_interrupt;
 612         p->irqaction.dev_id = p;
 613         p->irqaction.flags = IRQF_DISABLED | IRQF_TIMER | \
 614                              IRQF_IRQPOLL  | IRQF_NOBALANCING;
 615
 616         /* get hold of clock */
 617         p->clk = clk_get(&p->pdev->dev, "cmt_fck");
 618         if (IS_ERR(p->clk)) {
 619                 dev_err(&p->pdev->dev, "cannot get clock\n");
 620                 ret = PTR_ERR(p->clk);
 621                 goto err1;
 622         }
 623
 624         if (resource_size(res) == 6) {
 625                 p->width = 16;
 626                 p->overflow_bit = 0x80;
 627                 p->clear_bits = ~0x80;
 628         } else {
 629                 p->width = 32;
 630                 p->overflow_bit = 0x8000;
 631                 p->clear_bits = ~0xc000;
 632         }
 633
 634         ret = sh_cmt_register(p, (char *)dev_name(&p->pdev->dev),
 635                               cfg->clockevent_rating,
 636                               cfg->clocksource_rating);
 637         if (ret) {
 638                 dev_err(&p->pdev->dev, "registration failed\n");
 639                 goto err1;
 640         }
 641
 642         ret = setup_irq(irq, &p->irqaction);
 643         if (ret) {
 644                 dev_err(&p->pdev->dev, "failed to request irq %d\n", irq);
 645                 goto err1;
 646         }
 647
 648         return 0;
 649
 650 err1:
 651         iounmap(p->mapbase);
 652 err0:
 653         return ret;
 654 }
 655
 656 static int __devinit sh_cmt_probe(struct platform_device *pdev)
 657 {
 658         struct sh_cmt_priv *p = platform_get_drvdata(pdev);
 659         int ret;
 660
 661         if (p) {
 662                 dev_info(&pdev->dev, "kept as earlytimer\n");
 663                 return 0;
 664         }
 665
 666         p = kmalloc(sizeof(*p), GFP_KERNEL);
 667         if (p == NULL) {
 668                 dev_err(&pdev->dev, "failed to allocate driver data\n");
 669                 return -ENOMEM;
 670         }
 671
 672         ret = sh_cmt_setup(p, pdev);
 673         if (ret) {
 674                 kfree(p);
 675                 platform_set_drvdata(pdev, NULL);
 676         }
 677         return ret;
 678 }
 679
 680 static int __devexit sh_cmt_remove(struct platform_device *pdev)
 681 {
 682         return -EBUSY; /* cannot unregister clockevent and clocksource */
 683 }
 684
 685 static struct platform_driver sh_cmt_device_driver = {
 686         .probe          = sh_cmt_probe,
 687         .remove         = __devexit_p(sh_cmt_remove),
 688         .driver         = {
 689                 .name   = "sh_cmt",
 690         }
 691 };
 692
 693 static int __init sh_cmt_init(void)
 694 {
 695         return platform_driver_register(&sh_cmt_device_driver);
 696 }
 697
 698 static void __exit sh_cmt_exit(void)
 699 {
 700         platform_driver_unregister(&sh_cmt_device_driver);
 701 }
 702
 703 early_platform_init("earlytimer", &sh_cmt_device_driver);
 704 module_init(sh_cmt_init);
 705 module_exit(sh_cmt_exit);
 706
 707 MODULE_AUTHOR("Magnus Damm");
 708 MODULE_DESCRIPTION("SuperH CMT Timer Driver");
 709 MODULE_LICENSE("GPL v2");