linux/drivers/watchdog/cpwd.c
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   1/* cpwd.c - driver implementation for hardware watchdog
   2 * timers found on Sun Microsystems CP1400 and CP1500 boards.
   3 *
   4 * This device supports both the generic Linux watchdog
   5 * interface and Solaris-compatible ioctls as best it is
   6 * able.
   7 *
   8 * NOTE:        CP1400 systems appear to have a defective intr_mask
   9 *                      register on the PLD, preventing the disabling of
  10 *                      timer interrupts.  We use a timer to periodically
  11 *                      reset 'stopped' watchdogs on affected platforms.
  12 *
  13 * Copyright (c) 2000 Eric Brower (ebrower@usa.net)
  14 * Copyright (C) 2008 David S. Miller <davem@davemloft.net>
  15 */
  16
  17#include <linux/kernel.h>
  18#include <linux/module.h>
  19#include <linux/fs.h>
  20#include <linux/errno.h>
  21#include <linux/major.h>
  22#include <linux/init.h>
  23#include <linux/miscdevice.h>
  24#include <linux/interrupt.h>
  25#include <linux/ioport.h>
  26#include <linux/timer.h>
  27#include <linux/slab.h>
  28#include <linux/mutex.h>
  29#include <linux/io.h>
  30#include <linux/of.h>
  31#include <linux/of_device.h>
  32#include <linux/uaccess.h>
  33
  34#include <asm/irq.h>
  35#include <asm/watchdog.h>
  36
  37#define DRIVER_NAME     "cpwd"
  38#define PFX             DRIVER_NAME ": "
  39
  40#define WD_OBPNAME      "watchdog"
  41#define WD_BADMODEL     "SUNW,501-5336"
  42#define WD_BTIMEOUT     (jiffies + (HZ * 1000))
  43#define WD_BLIMIT       0xFFFF
  44
  45#define WD0_MINOR       212
  46#define WD1_MINOR       213
  47#define WD2_MINOR       214
  48
  49/* Internal driver definitions.  */
  50#define WD0_ID                  0
  51#define WD1_ID                  1
  52#define WD2_ID                  2
  53#define WD_NUMDEVS              3
  54
  55#define WD_INTR_OFF             0
  56#define WD_INTR_ON              1
  57
  58#define WD_STAT_INIT    0x01    /* Watchdog timer is initialized        */
  59#define WD_STAT_BSTOP   0x02    /* Watchdog timer is brokenstopped      */
  60#define WD_STAT_SVCD    0x04    /* Watchdog interrupt occurred          */
  61
  62/* Register value definitions
  63 */
  64#define WD0_INTR_MASK   0x01    /* Watchdog device interrupt masks      */
  65#define WD1_INTR_MASK   0x02
  66#define WD2_INTR_MASK   0x04
  67
  68#define WD_S_RUNNING    0x01    /* Watchdog device status running       */
  69#define WD_S_EXPIRED    0x02    /* Watchdog device status expired       */
  70
  71struct cpwd {
  72        void __iomem    *regs;
  73        spinlock_t      lock;
  74
  75        unsigned int    irq;
  76
  77        unsigned long   timeout;
  78        bool            enabled;
  79        bool            reboot;
  80        bool            broken;
  81        bool            initialized;
  82
  83        struct {
  84                struct miscdevice       misc;
  85                void __iomem            *regs;
  86                u8                      intr_mask;
  87                u8                      runstatus;
  88                u16                     timeout;
  89        } devs[WD_NUMDEVS];
  90};
  91
  92static DEFINE_MUTEX(cpwd_mutex);
  93static struct cpwd *cpwd_device;
  94
  95/* Sun uses Altera PLD EPF8820ATC144-4
  96 * providing three hardware watchdogs:
  97 *
  98 * 1) RIC - sends an interrupt when triggered
  99 * 2) XIR - asserts XIR_B_RESET when triggered, resets CPU
 100 * 3) POR - asserts POR_B_RESET when triggered, resets CPU, backplane, board
 101 *
 102 *** Timer register block definition (struct wd_timer_regblk)
 103 *
 104 * dcntr and limit registers (halfword access):
 105 * -------------------
 106 * | 15 | ...| 1 | 0 |
 107 * -------------------
 108 * |-  counter val  -|
 109 * -------------------
 110 * dcntr -      Current 16-bit downcounter value.
 111 *                      When downcounter reaches '0' watchdog expires.
 112 *                      Reading this register resets downcounter with
 113 *                      'limit' value.
 114 * limit -      16-bit countdown value in 1/10th second increments.
 115 *                      Writing this register begins countdown with input value.
 116 *                      Reading from this register does not affect counter.
 117 * NOTES:       After watchdog reset, dcntr and limit contain '1'
 118 *
 119 * status register (byte access):
 120 * ---------------------------
 121 * | 7 | ... | 2 |  1  |  0  |
 122 * --------------+------------
 123 * |-   UNUSED  -| EXP | RUN |
 124 * ---------------------------
 125 * status-      Bit 0 - Watchdog is running
 126 *                      Bit 1 - Watchdog has expired
 127 *
 128 *** PLD register block definition (struct wd_pld_regblk)
 129 *
 130 * intr_mask register (byte access):
 131 * ---------------------------------
 132 * | 7 | ... | 3 |  2  |  1  |  0  |
 133 * +-------------+------------------
 134 * |-   UNUSED  -| WD3 | WD2 | WD1 |
 135 * ---------------------------------
 136 * WD3 -  1 == Interrupt disabled for watchdog 3
 137 * WD2 -  1 == Interrupt disabled for watchdog 2
 138 * WD1 -  1 == Interrupt disabled for watchdog 1
 139 *
 140 * pld_status register (byte access):
 141 * UNKNOWN, MAGICAL MYSTERY REGISTER
 142 *
 143 */
 144#define WD_TIMER_REGSZ  16
 145#define WD0_OFF         0
 146#define WD1_OFF         (WD_TIMER_REGSZ * 1)
 147#define WD2_OFF         (WD_TIMER_REGSZ * 2)
 148#define PLD_OFF         (WD_TIMER_REGSZ * 3)
 149
 150#define WD_DCNTR        0x00
 151#define WD_LIMIT        0x04
 152#define WD_STATUS       0x08
 153
 154#define PLD_IMASK       (PLD_OFF + 0x00)
 155#define PLD_STATUS      (PLD_OFF + 0x04)
 156
 157static struct timer_list cpwd_timer;
 158
 159static int wd0_timeout;
 160static int wd1_timeout;
 161static int wd2_timeout;
 162
 163module_param(wd0_timeout, int, 0);
 164MODULE_PARM_DESC(wd0_timeout, "Default watchdog0 timeout in 1/10secs");
 165module_param(wd1_timeout, int, 0);
 166MODULE_PARM_DESC(wd1_timeout, "Default watchdog1 timeout in 1/10secs");
 167module_param(wd2_timeout, int, 0);
 168MODULE_PARM_DESC(wd2_timeout, "Default watchdog2 timeout in 1/10secs");
 169
 170MODULE_AUTHOR("Eric Brower <ebrower@usa.net>");
 171MODULE_DESCRIPTION("Hardware watchdog driver for Sun Microsystems CP1400/1500");
 172MODULE_LICENSE("GPL");
 173MODULE_SUPPORTED_DEVICE("watchdog");
 174
 175static void cpwd_writew(u16 val, void __iomem *addr)
 176{
 177        writew(cpu_to_le16(val), addr);
 178}
 179static u16 cpwd_readw(void __iomem *addr)
 180{
 181        u16 val = readw(addr);
 182
 183        return le16_to_cpu(val);
 184}
 185
 186static void cpwd_writeb(u8 val, void __iomem *addr)
 187{
 188        writeb(val, addr);
 189}
 190
 191static u8 cpwd_readb(void __iomem *addr)
 192{
 193        return readb(addr);
 194}
 195
 196/* Enable or disable watchdog interrupts
 197 * Because of the CP1400 defect this should only be
 198 * called during initialzation or by wd_[start|stop]timer()
 199 *
 200 * index        - sub-device index, or -1 for 'all'
 201 * enable       - non-zero to enable interrupts, zero to disable
 202 */
 203static void cpwd_toggleintr(struct cpwd *p, int index, int enable)
 204{
 205        unsigned char curregs = cpwd_readb(p->regs + PLD_IMASK);
 206        unsigned char setregs =
 207                (index == -1) ?
 208                (WD0_INTR_MASK | WD1_INTR_MASK | WD2_INTR_MASK) :
 209                (p->devs[index].intr_mask);
 210
 211        if (enable == WD_INTR_ON)
 212                curregs &= ~setregs;
 213        else
 214                curregs |= setregs;
 215
 216        cpwd_writeb(curregs, p->regs + PLD_IMASK);
 217}
 218
 219/* Restarts timer with maximum limit value and
 220 * does not unset 'brokenstop' value.
 221 */
 222static void cpwd_resetbrokentimer(struct cpwd *p, int index)
 223{
 224        cpwd_toggleintr(p, index, WD_INTR_ON);
 225        cpwd_writew(WD_BLIMIT, p->devs[index].regs + WD_LIMIT);
 226}
 227
 228/* Timer method called to reset stopped watchdogs--
 229 * because of the PLD bug on CP1400, we cannot mask
 230 * interrupts within the PLD so me must continually
 231 * reset the timers ad infinitum.
 232 */
 233static void cpwd_brokentimer(unsigned long data)
 234{
 235        struct cpwd *p = (struct cpwd *) data;
 236        int id, tripped = 0;
 237
 238        /* kill a running timer instance, in case we
 239         * were called directly instead of by kernel timer
 240         */
 241        if (timer_pending(&cpwd_timer))
 242                del_timer(&cpwd_timer);
 243
 244        for (id = 0; id < WD_NUMDEVS; id++) {
 245                if (p->devs[id].runstatus & WD_STAT_BSTOP) {
 246                        ++tripped;
 247                        cpwd_resetbrokentimer(p, id);
 248                }
 249        }
 250
 251        if (tripped) {
 252                /* there is at least one timer brokenstopped-- reschedule */
 253                cpwd_timer.expires = WD_BTIMEOUT;
 254                add_timer(&cpwd_timer);
 255        }
 256}
 257
 258/* Reset countdown timer with 'limit' value and continue countdown.
 259 * This will not start a stopped timer.
 260 */
 261static void cpwd_pingtimer(struct cpwd *p, int index)
 262{
 263        if (cpwd_readb(p->devs[index].regs + WD_STATUS) & WD_S_RUNNING)
 264                cpwd_readw(p->devs[index].regs + WD_DCNTR);
 265}
 266
 267/* Stop a running watchdog timer-- the timer actually keeps
 268 * running, but the interrupt is masked so that no action is
 269 * taken upon expiration.
 270 */
 271static void cpwd_stoptimer(struct cpwd *p, int index)
 272{
 273        if (cpwd_readb(p->devs[index].regs + WD_STATUS) & WD_S_RUNNING) {
 274                cpwd_toggleintr(p, index, WD_INTR_OFF);
 275
 276                if (p->broken) {
 277                        p->devs[index].runstatus |= WD_STAT_BSTOP;
 278                        cpwd_brokentimer((unsigned long) p);
 279                }
 280        }
 281}
 282
 283/* Start a watchdog timer with the specified limit value
 284 * If the watchdog is running, it will be restarted with
 285 * the provided limit value.
 286 *
 287 * This function will enable interrupts on the specified
 288 * watchdog.
 289 */
 290static void cpwd_starttimer(struct cpwd *p, int index)
 291{
 292        if (p->broken)
 293                p->devs[index].runstatus &= ~WD_STAT_BSTOP;
 294
 295        p->devs[index].runstatus &= ~WD_STAT_SVCD;
 296
 297        cpwd_writew(p->devs[index].timeout, p->devs[index].regs + WD_LIMIT);
 298        cpwd_toggleintr(p, index, WD_INTR_ON);
 299}
 300
 301static int cpwd_getstatus(struct cpwd *p, int index)
 302{
 303        unsigned char stat = cpwd_readb(p->devs[index].regs + WD_STATUS);
 304        unsigned char intr = cpwd_readb(p->devs[index].regs + PLD_IMASK);
 305        unsigned char ret  = WD_STOPPED;
 306
 307        /* determine STOPPED */
 308        if (!stat)
 309                return ret;
 310
 311        /* determine EXPIRED vs FREERUN vs RUNNING */
 312        else if (WD_S_EXPIRED & stat) {
 313                ret = WD_EXPIRED;
 314        } else if (WD_S_RUNNING & stat) {
 315                if (intr & p->devs[index].intr_mask) {
 316                        ret = WD_FREERUN;
 317                } else {
 318                        /* Fudge WD_EXPIRED status for defective CP1400--
 319                         * IF timer is running
 320                         *      AND brokenstop is set
 321                         *      AND an interrupt has been serviced
 322                         * we are WD_EXPIRED.
 323                         *
 324                         * IF timer is running
 325                         *      AND brokenstop is set
 326                         *      AND no interrupt has been serviced
 327                         * we are WD_FREERUN.
 328                         */
 329                        if (p->broken &&
 330                            (p->devs[index].runstatus & WD_STAT_BSTOP)) {
 331                                if (p->devs[index].runstatus & WD_STAT_SVCD) {
 332                                        ret = WD_EXPIRED;
 333                                } else {
 334                                        /* we could as well pretend
 335                                         * we are expired */
 336                                        ret = WD_FREERUN;
 337                                }
 338                        } else {
 339                                ret = WD_RUNNING;
 340                        }
 341                }
 342        }
 343
 344        /* determine SERVICED */
 345        if (p->devs[index].runstatus & WD_STAT_SVCD)
 346                ret |= WD_SERVICED;
 347
 348        return ret;
 349}
 350
 351static irqreturn_t cpwd_interrupt(int irq, void *dev_id)
 352{
 353        struct cpwd *p = dev_id;
 354
 355        /* Only WD0 will interrupt-- others are NMI and we won't
 356         * see them here....
 357         */
 358        spin_lock_irq(&p->lock);
 359
 360        cpwd_stoptimer(p, WD0_ID);
 361        p->devs[WD0_ID].runstatus |=  WD_STAT_SVCD;
 362
 363        spin_unlock_irq(&p->lock);
 364
 365        return IRQ_HANDLED;
 366}
 367
 368static int cpwd_open(struct inode *inode, struct file *f)
 369{
 370        struct cpwd *p = cpwd_device;
 371
 372        mutex_lock(&cpwd_mutex);
 373        switch (iminor(inode)) {
 374        case WD0_MINOR:
 375        case WD1_MINOR:
 376        case WD2_MINOR:
 377                break;
 378
 379        default:
 380                mutex_unlock(&cpwd_mutex);
 381                return -ENODEV;
 382        }
 383
 384        /* Register IRQ on first open of device */
 385        if (!p->initialized) {
 386                if (request_irq(p->irq, &cpwd_interrupt,
 387                                IRQF_SHARED, DRIVER_NAME, p)) {
 388                        printk(KERN_ERR PFX "Cannot register IRQ %d\n",
 389                                p->irq);
 390                        mutex_unlock(&cpwd_mutex);
 391                        return -EBUSY;
 392                }
 393                p->initialized = true;
 394        }
 395
 396        mutex_unlock(&cpwd_mutex);
 397
 398        return nonseekable_open(inode, f);
 399}
 400
 401static int cpwd_release(struct inode *inode, struct file *file)
 402{
 403        return 0;
 404}
 405
 406static long cpwd_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 407{
 408        static const struct watchdog_info info = {
 409                .options                = WDIOF_SETTIMEOUT,
 410                .firmware_version       = 1,
 411                .identity               = DRIVER_NAME,
 412        };
 413        void __user *argp = (void __user *)arg;
 414        struct inode *inode = file->f_path.dentry->d_inode;
 415        int index = iminor(inode) - WD0_MINOR;
 416        struct cpwd *p = cpwd_device;
 417        int setopt = 0;
 418
 419        switch (cmd) {
 420        /* Generic Linux IOCTLs */
 421        case WDIOC_GETSUPPORT:
 422                if (copy_to_user(argp, &info, sizeof(struct watchdog_info)))
 423                        return -EFAULT;
 424                break;
 425
 426        case WDIOC_GETSTATUS:
 427        case WDIOC_GETBOOTSTATUS:
 428                if (put_user(0, (int __user *)argp))
 429                        return -EFAULT;
 430                break;
 431
 432        case WDIOC_KEEPALIVE:
 433                cpwd_pingtimer(p, index);
 434                break;
 435
 436        case WDIOC_SETOPTIONS:
 437                if (copy_from_user(&setopt, argp, sizeof(unsigned int)))
 438                        return -EFAULT;
 439
 440                if (setopt & WDIOS_DISABLECARD) {
 441                        if (p->enabled)
 442                                return -EINVAL;
 443                        cpwd_stoptimer(p, index);
 444                } else if (setopt & WDIOS_ENABLECARD) {
 445                        cpwd_starttimer(p, index);
 446                } else {
 447                        return -EINVAL;
 448                }
 449                break;
 450
 451        /* Solaris-compatible IOCTLs */
 452        case WIOCGSTAT:
 453                setopt = cpwd_getstatus(p, index);
 454                if (copy_to_user(argp, &setopt, sizeof(unsigned int)))
 455                        return -EFAULT;
 456                break;
 457
 458        case WIOCSTART:
 459                cpwd_starttimer(p, index);
 460                break;
 461
 462        case WIOCSTOP:
 463                if (p->enabled)
 464                        return -EINVAL;
 465
 466                cpwd_stoptimer(p, index);
 467                break;
 468
 469        default:
 470                return -EINVAL;
 471        }
 472
 473        return 0;
 474}
 475
 476static long cpwd_compat_ioctl(struct file *file, unsigned int cmd,
 477                              unsigned long arg)
 478{
 479        int rval = -ENOIOCTLCMD;
 480
 481        switch (cmd) {
 482        /* solaris ioctls are specific to this driver */
 483        case WIOCSTART:
 484        case WIOCSTOP:
 485        case WIOCGSTAT:
 486                mutex_lock(&cpwd_mutex);
 487                rval = cpwd_ioctl(file, cmd, arg);
 488                mutex_unlock(&cpwd_mutex);
 489                break;
 490
 491        /* everything else is handled by the generic compat layer */
 492        default:
 493                break;
 494        }
 495
 496        return rval;
 497}
 498
 499static ssize_t cpwd_write(struct file *file, const char __user *buf,
 500                          size_t count, loff_t *ppos)
 501{
 502        struct inode *inode = file->f_path.dentry->d_inode;
 503        struct cpwd *p = cpwd_device;
 504        int index = iminor(inode);
 505
 506        if (count) {
 507                cpwd_pingtimer(p, index);
 508                return 1;
 509        }
 510
 511        return 0;
 512}
 513
 514static ssize_t cpwd_read(struct file *file, char __user *buffer,
 515                         size_t count, loff_t *ppos)
 516{
 517        return -EINVAL;
 518}
 519
 520static const struct file_operations cpwd_fops = {
 521        .owner =                THIS_MODULE,
 522        .unlocked_ioctl =       cpwd_ioctl,
 523        .compat_ioctl =         cpwd_compat_ioctl,
 524        .open =                 cpwd_open,
 525        .write =                cpwd_write,
 526        .read =                 cpwd_read,
 527        .release =              cpwd_release,
 528        .llseek =               no_llseek,
 529};
 530
 531static int __devinit cpwd_probe(struct platform_device *op,
 532                                const struct of_device_id *match)
 533{
 534        struct device_node *options;
 535        const char *str_prop;
 536        const void *prop_val;
 537        int i, err = -EINVAL;
 538        struct cpwd *p;
 539
 540        if (cpwd_device)
 541                return -EINVAL;
 542
 543        p = kzalloc(sizeof(*p), GFP_KERNEL);
 544        err = -ENOMEM;
 545        if (!p) {
 546                printk(KERN_ERR PFX "Unable to allocate struct cpwd.\n");
 547                goto out;
 548        }
 549
 550        p->irq = op->archdata.irqs[0];
 551
 552        spin_lock_init(&p->lock);
 553
 554        p->regs = of_ioremap(&op->resource[0], 0,
 555                             4 * WD_TIMER_REGSZ, DRIVER_NAME);
 556        if (!p->regs) {
 557                printk(KERN_ERR PFX "Unable to map registers.\n");
 558                goto out_free;
 559        }
 560
 561        options = of_find_node_by_path("/options");
 562        err = -ENODEV;
 563        if (!options) {
 564                printk(KERN_ERR PFX "Unable to find /options node.\n");
 565                goto out_iounmap;
 566        }
 567
 568        prop_val = of_get_property(options, "watchdog-enable?", NULL);
 569        p->enabled = (prop_val ? true : false);
 570
 571        prop_val = of_get_property(options, "watchdog-reboot?", NULL);
 572        p->reboot = (prop_val ? true : false);
 573
 574        str_prop = of_get_property(options, "watchdog-timeout", NULL);
 575        if (str_prop)
 576                p->timeout = simple_strtoul(str_prop, NULL, 10);
 577
 578        /* CP1400s seem to have broken PLD implementations-- the
 579         * interrupt_mask register cannot be written, so no timer
 580         * interrupts can be masked within the PLD.
 581         */
 582        str_prop = of_get_property(op->dev.of_node, "model", NULL);
 583        p->broken = (str_prop && !strcmp(str_prop, WD_BADMODEL));
 584
 585        if (!p->enabled)
 586                cpwd_toggleintr(p, -1, WD_INTR_OFF);
 587
 588        for (i = 0; i < WD_NUMDEVS; i++) {
 589                static const char *cpwd_names[] = { "RIC", "XIR", "POR" };
 590                static int *parms[] = { &wd0_timeout,
 591                                        &wd1_timeout,
 592                                        &wd2_timeout };
 593                struct miscdevice *mp = &p->devs[i].misc;
 594
 595                mp->minor = WD0_MINOR + i;
 596                mp->name = cpwd_names[i];
 597                mp->fops = &cpwd_fops;
 598
 599                p->devs[i].regs = p->regs + (i * WD_TIMER_REGSZ);
 600                p->devs[i].intr_mask = (WD0_INTR_MASK << i);
 601                p->devs[i].runstatus &= ~WD_STAT_BSTOP;
 602                p->devs[i].runstatus |= WD_STAT_INIT;
 603                p->devs[i].timeout = p->timeout;
 604                if (*parms[i])
 605                        p->devs[i].timeout = *parms[i];
 606
 607                err = misc_register(&p->devs[i].misc);
 608                if (err) {
 609                        printk(KERN_ERR "Could not register misc device for "
 610                               "dev %d\n", i);
 611                        goto out_unregister;
 612                }
 613        }
 614
 615        if (p->broken) {
 616                init_timer(&cpwd_timer);
 617                cpwd_timer.function     = cpwd_brokentimer;
 618                cpwd_timer.data         = (unsigned long) p;
 619                cpwd_timer.expires      = WD_BTIMEOUT;
 620
 621                printk(KERN_INFO PFX "PLD defect workaround enabled for "
 622                       "model " WD_BADMODEL ".\n");
 623        }
 624
 625        dev_set_drvdata(&op->dev, p);
 626        cpwd_device = p;
 627        err = 0;
 628
 629out:
 630        return err;
 631
 632out_unregister:
 633        for (i--; i >= 0; i--)
 634                misc_deregister(&p->devs[i].misc);
 635
 636out_iounmap:
 637        of_iounmap(&op->resource[0], p->regs, 4 * WD_TIMER_REGSZ);
 638
 639out_free:
 640        kfree(p);
 641        goto out;
 642}
 643
 644static int __devexit cpwd_remove(struct platform_device *op)
 645{
 646        struct cpwd *p = dev_get_drvdata(&op->dev);
 647        int i;
 648
 649        for (i = 0; i < 4; i++) {
 650                misc_deregister(&p->devs[i].misc);
 651
 652                if (!p->enabled) {
 653                        cpwd_stoptimer(p, i);
 654                        if (p->devs[i].runstatus & WD_STAT_BSTOP)
 655                                cpwd_resetbrokentimer(p, i);
 656                }
 657        }
 658
 659        if (p->broken)
 660                del_timer_sync(&cpwd_timer);
 661
 662        if (p->initialized)
 663                free_irq(p->irq, p);
 664
 665        of_iounmap(&op->resource[0], p->regs, 4 * WD_TIMER_REGSZ);
 666        kfree(p);
 667
 668        cpwd_device = NULL;
 669
 670        return 0;
 671}
 672
 673static const struct of_device_id cpwd_match[] = {
 674        {
 675                .name = "watchdog",
 676        },
 677        {},
 678};
 679MODULE_DEVICE_TABLE(of, cpwd_match);
 680
 681static struct of_platform_driver cpwd_driver = {
 682        .driver = {
 683                .name = DRIVER_NAME,
 684                .owner = THIS_MODULE,
 685                .of_match_table = cpwd_match,
 686        },
 687        .probe          = cpwd_probe,
 688        .remove         = __devexit_p(cpwd_remove),
 689};
 690
 691static int __init cpwd_init(void)
 692{
 693        return of_register_platform_driver(&cpwd_driver);
 694}
 695
 696static void __exit cpwd_exit(void)
 697{
 698        of_unregister_platform_driver(&cpwd_driver);
 699}
 700
 701module_init(cpwd_init);
 702module_exit(cpwd_exit);
 703