2 * Intel & MS High Precision Event Timer Implementation.
4 * Copyright (C) 2003 Intel Corporation
6 * (c) Copyright 2004 Hewlett-Packard Development Company, L.P.
7 * Bob Picco <robert.picco@hp.com>
9 * This program is free software; you can redistribute it and/or modify
10 * it under the terms of the GNU General Public License version 2 as
11 * published by the Free Software Foundation.
14 #include <linux/config.h>
15 #include <linux/interrupt.h>
16 #include <linux/module.h>
17 #include <linux/kernel.h>
18 #include <linux/types.h>
19 #include <linux/miscdevice.h>
20 #include <linux/major.h>
21 #include <linux/ioport.h>
22 #include <linux/fcntl.h>
23 #include <linux/init.h>
24 #include <linux/poll.h>
25 #include <linux/proc_fs.h>
26 #include <linux/spinlock.h>
27 #include <linux/sysctl.h>
28 #include <linux/wait.h>
29 #include <linux/bcd.h>
30 #include <linux/seq_file.h>
31 #include <linux/bitops.h>
33 #include <asm/current.h>
34 #include <asm/uaccess.h>
35 #include <asm/system.h>
38 #include <asm/div64.h>
40 #include <linux/acpi.h>
41 #include <acpi/acpi_bus.h>
42 #include <linux/hpet.h>
45 * The High Precision Event Timer driver.
46 * This driver is closely modelled after the rtc.c driver.
47 * http://www.intel.com/hardwaredesign/hpetspec.htm
49 #define HPET_USER_FREQ (64)
50 #define HPET_DRIFT (500)
52 static u32 hpet_nhpet, hpet_max_freq = HPET_USER_FREQ;
54 /* A lock for concurrent access by app and isr hpet activity. */
55 static DEFINE_SPINLOCK(hpet_lock);
56 /* A lock for concurrent intermodule access to hpet and isr hpet activity. */
57 static DEFINE_SPINLOCK(hpet_task_lock);
59 #define HPET_DEV_NAME (7)
62 struct hpets *hd_hpets;
63 struct hpet __iomem *hd_hpet;
64 struct hpet_timer __iomem *hd_timer;
65 unsigned long hd_ireqfreq;
66 unsigned long hd_irqdata;
67 wait_queue_head_t hd_waitqueue;
68 struct fasync_struct *hd_async_queue;
69 struct hpet_task *hd_task;
70 unsigned int hd_flags;
72 unsigned int hd_hdwirq;
73 char hd_name[HPET_DEV_NAME];
77 struct hpets *hp_next;
78 struct hpet __iomem *hp_hpet;
79 unsigned long hp_hpet_phys;
80 struct time_interpolator *hp_interpolator;
81 unsigned long long hp_tick_freq;
82 unsigned long hp_delta;
83 unsigned int hp_ntimer;
84 unsigned int hp_which;
85 struct hpet_dev hp_dev[1];
88 static struct hpets *hpets;
90 #define HPET_OPEN 0x0001
91 #define HPET_IE 0x0002 /* interrupt enabled */
92 #define HPET_PERIODIC 0x0004
93 #define HPET_SHARED_IRQ 0x0008
95 #if BITS_PER_LONG == 64
96 #define write_counter(V, MC) writeq(V, MC)
97 #define read_counter(MC) readq(MC)
99 #define write_counter(V, MC) writel(V, MC)
100 #define read_counter(MC) readl(MC)
104 static inline unsigned long long readq(void __iomem *addr)
106 return readl(addr) | (((unsigned long long)readl(addr + 4)) << 32LL);
111 static inline void writeq(unsigned long long v, void __iomem *addr)
113 writel(v & 0xffffffff, addr);
114 writel(v >> 32, addr + 4);
118 static irqreturn_t hpet_interrupt(int irq, void *data, struct pt_regs *regs)
120 struct hpet_dev *devp;
124 isr = 1 << (devp - devp->hd_hpets->hp_dev);
126 if ((devp->hd_flags & HPET_SHARED_IRQ) &&
127 !(isr & readl(&devp->hd_hpet->hpet_isr)))
130 spin_lock(&hpet_lock);
134 * For non-periodic timers, increment the accumulator.
135 * This has the effect of treating non-periodic like periodic.
137 if ((devp->hd_flags & (HPET_IE | HPET_PERIODIC)) == HPET_IE) {
140 t = devp->hd_ireqfreq;
141 m = read_counter(&devp->hd_hpet->hpet_mc);
142 write_counter(t + m + devp->hd_hpets->hp_delta,
143 &devp->hd_timer->hpet_compare);
146 if (devp->hd_flags & HPET_SHARED_IRQ)
147 writel(isr, &devp->hd_hpet->hpet_isr);
148 spin_unlock(&hpet_lock);
150 spin_lock(&hpet_task_lock);
152 devp->hd_task->ht_func(devp->hd_task->ht_data);
153 spin_unlock(&hpet_task_lock);
155 wake_up_interruptible(&devp->hd_waitqueue);
157 kill_fasync(&devp->hd_async_queue, SIGIO, POLL_IN);
162 static int hpet_open(struct inode *inode, struct file *file)
164 struct hpet_dev *devp;
168 if (file->f_mode & FMODE_WRITE)
171 spin_lock_irq(&hpet_lock);
173 for (devp = NULL, hpetp = hpets; hpetp && !devp; hpetp = hpetp->hp_next)
174 for (i = 0; i < hpetp->hp_ntimer; i++)
175 if (hpetp->hp_dev[i].hd_flags & HPET_OPEN
176 || hpetp->hp_dev[i].hd_task)
179 devp = &hpetp->hp_dev[i];
184 spin_unlock_irq(&hpet_lock);
188 file->private_data = devp;
189 devp->hd_irqdata = 0;
190 devp->hd_flags |= HPET_OPEN;
191 spin_unlock_irq(&hpet_lock);
197 hpet_read(struct file *file, char __user *buf, size_t count, loff_t * ppos)
199 DECLARE_WAITQUEUE(wait, current);
202 struct hpet_dev *devp;
204 devp = file->private_data;
205 if (!devp->hd_ireqfreq)
208 if (count < sizeof(unsigned long))
211 add_wait_queue(&devp->hd_waitqueue, &wait);
214 set_current_state(TASK_INTERRUPTIBLE);
216 spin_lock_irq(&hpet_lock);
217 data = devp->hd_irqdata;
218 devp->hd_irqdata = 0;
219 spin_unlock_irq(&hpet_lock);
223 else if (file->f_flags & O_NONBLOCK) {
226 } else if (signal_pending(current)) {
227 retval = -ERESTARTSYS;
233 retval = put_user(data, (unsigned long __user *)buf);
235 retval = sizeof(unsigned long);
237 __set_current_state(TASK_RUNNING);
238 remove_wait_queue(&devp->hd_waitqueue, &wait);
243 static unsigned int hpet_poll(struct file *file, poll_table * wait)
246 struct hpet_dev *devp;
248 devp = file->private_data;
250 if (!devp->hd_ireqfreq)
253 poll_wait(file, &devp->hd_waitqueue, wait);
255 spin_lock_irq(&hpet_lock);
256 v = devp->hd_irqdata;
257 spin_unlock_irq(&hpet_lock);
260 return POLLIN | POLLRDNORM;
265 static int hpet_mmap(struct file *file, struct vm_area_struct *vma)
267 #ifdef CONFIG_HPET_MMAP
268 struct hpet_dev *devp;
271 if (((vma->vm_end - vma->vm_start) != PAGE_SIZE) || vma->vm_pgoff)
274 devp = file->private_data;
275 addr = devp->hd_hpets->hp_hpet_phys;
277 if (addr & (PAGE_SIZE - 1))
280 vma->vm_flags |= VM_IO;
281 vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
283 if (io_remap_pfn_range(vma, vma->vm_start, addr >> PAGE_SHIFT,
284 PAGE_SIZE, vma->vm_page_prot)) {
285 printk(KERN_ERR "remap_pfn_range failed in hpet.c\n");
295 static int hpet_fasync(int fd, struct file *file, int on)
297 struct hpet_dev *devp;
299 devp = file->private_data;
301 if (fasync_helper(fd, file, on, &devp->hd_async_queue) >= 0)
307 static int hpet_release(struct inode *inode, struct file *file)
309 struct hpet_dev *devp;
310 struct hpet_timer __iomem *timer;
313 devp = file->private_data;
314 timer = devp->hd_timer;
316 spin_lock_irq(&hpet_lock);
318 writeq((readq(&timer->hpet_config) & ~Tn_INT_ENB_CNF_MASK),
319 &timer->hpet_config);
324 devp->hd_ireqfreq = 0;
326 if (devp->hd_flags & HPET_PERIODIC
327 && readq(&timer->hpet_config) & Tn_TYPE_CNF_MASK) {
330 v = readq(&timer->hpet_config);
331 v ^= Tn_TYPE_CNF_MASK;
332 writeq(v, &timer->hpet_config);
335 devp->hd_flags &= ~(HPET_OPEN | HPET_IE | HPET_PERIODIC);
336 spin_unlock_irq(&hpet_lock);
341 if (file->f_flags & FASYNC)
342 hpet_fasync(-1, file, 0);
344 file->private_data = NULL;
348 static int hpet_ioctl_common(struct hpet_dev *, int, unsigned long, int);
351 hpet_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
354 struct hpet_dev *devp;
356 devp = file->private_data;
357 return hpet_ioctl_common(devp, cmd, arg, 0);
360 static int hpet_ioctl_ieon(struct hpet_dev *devp)
362 struct hpet_timer __iomem *timer;
363 struct hpet __iomem *hpet;
366 unsigned long g, v, t, m;
367 unsigned long flags, isr;
369 timer = devp->hd_timer;
370 hpet = devp->hd_hpet;
371 hpetp = devp->hd_hpets;
373 if (!devp->hd_ireqfreq)
376 spin_lock_irq(&hpet_lock);
378 if (devp->hd_flags & HPET_IE) {
379 spin_unlock_irq(&hpet_lock);
383 devp->hd_flags |= HPET_IE;
385 if (readl(&timer->hpet_config) & Tn_INT_TYPE_CNF_MASK)
386 devp->hd_flags |= HPET_SHARED_IRQ;
387 spin_unlock_irq(&hpet_lock);
389 irq = devp->hd_hdwirq;
392 unsigned long irq_flags;
394 sprintf(devp->hd_name, "hpet%d", (int)(devp - hpetp->hp_dev));
395 irq_flags = devp->hd_flags & HPET_SHARED_IRQ
396 ? SA_SHIRQ : SA_INTERRUPT;
397 if (request_irq(irq, hpet_interrupt, irq_flags,
398 devp->hd_name, (void *)devp)) {
399 printk(KERN_ERR "hpet: IRQ %d is not free\n", irq);
405 spin_lock_irq(&hpet_lock);
406 devp->hd_flags ^= HPET_IE;
407 spin_unlock_irq(&hpet_lock);
412 t = devp->hd_ireqfreq;
413 v = readq(&timer->hpet_config);
414 g = v | Tn_INT_ENB_CNF_MASK;
416 if (devp->hd_flags & HPET_PERIODIC) {
417 write_counter(t, &timer->hpet_compare);
418 g |= Tn_TYPE_CNF_MASK;
419 v |= Tn_TYPE_CNF_MASK;
420 writeq(v, &timer->hpet_config);
421 v |= Tn_VAL_SET_CNF_MASK;
422 writeq(v, &timer->hpet_config);
423 local_irq_save(flags);
424 m = read_counter(&hpet->hpet_mc);
425 write_counter(t + m + hpetp->hp_delta, &timer->hpet_compare);
427 local_irq_save(flags);
428 m = read_counter(&hpet->hpet_mc);
429 write_counter(t + m + hpetp->hp_delta, &timer->hpet_compare);
432 if (devp->hd_flags & HPET_SHARED_IRQ) {
433 isr = 1 << (devp - devp->hd_hpets->hp_dev);
434 writel(isr, &hpet->hpet_isr);
436 writeq(g, &timer->hpet_config);
437 local_irq_restore(flags);
442 /* converts Hz to number of timer ticks */
443 static inline unsigned long hpet_time_div(struct hpets *hpets,
446 unsigned long long m;
448 m = hpets->hp_tick_freq + (dis >> 1);
450 return (unsigned long)m;
454 hpet_ioctl_common(struct hpet_dev *devp, int cmd, unsigned long arg, int kernel)
456 struct hpet_timer __iomem *timer;
457 struct hpet __iomem *hpet;
468 timer = devp->hd_timer;
469 hpet = devp->hd_hpet;
470 hpetp = devp->hd_hpets;
473 return hpet_ioctl_ieon(devp);
482 if ((devp->hd_flags & HPET_IE) == 0)
484 v = readq(&timer->hpet_config);
485 v &= ~Tn_INT_ENB_CNF_MASK;
486 writeq(v, &timer->hpet_config);
488 free_irq(devp->hd_irq, devp);
491 devp->hd_flags ^= HPET_IE;
495 struct hpet_info info;
497 if (devp->hd_ireqfreq)
499 hpet_time_div(hpetp, devp->hd_ireqfreq);
501 info.hi_ireqfreq = 0;
503 readq(&timer->hpet_config) & Tn_PER_INT_CAP_MASK;
504 info.hi_hpet = hpetp->hp_which;
505 info.hi_timer = devp - hpetp->hp_dev;
507 memcpy((void *)arg, &info, sizeof(info));
509 if (copy_to_user((void __user *)arg, &info,
515 v = readq(&timer->hpet_config);
516 if ((v & Tn_PER_INT_CAP_MASK) == 0) {
520 devp->hd_flags |= HPET_PERIODIC;
523 v = readq(&timer->hpet_config);
524 if ((v & Tn_PER_INT_CAP_MASK) == 0) {
528 if (devp->hd_flags & HPET_PERIODIC &&
529 readq(&timer->hpet_config) & Tn_TYPE_CNF_MASK) {
530 v = readq(&timer->hpet_config);
531 v ^= Tn_TYPE_CNF_MASK;
532 writeq(v, &timer->hpet_config);
534 devp->hd_flags &= ~HPET_PERIODIC;
537 if (!kernel && (arg > hpet_max_freq) &&
538 !capable(CAP_SYS_RESOURCE)) {
548 devp->hd_ireqfreq = hpet_time_div(hpetp, arg);
554 static struct file_operations hpet_fops = {
555 .owner = THIS_MODULE,
561 .release = hpet_release,
562 .fasync = hpet_fasync,
566 EXPORT_SYMBOL(hpet_alloc);
567 EXPORT_SYMBOL(hpet_register);
568 EXPORT_SYMBOL(hpet_unregister);
569 EXPORT_SYMBOL(hpet_control);
571 int hpet_register(struct hpet_task *tp, int periodic)
575 struct hpet_timer __iomem *timer;
576 struct hpet_dev *devp;
581 mask = Tn_PER_INT_CAP_MASK;
590 tp->ht_opaque = NULL;
592 spin_lock_irq(&hpet_task_lock);
593 spin_lock(&hpet_lock);
595 for (devp = NULL, hpetp = hpets; hpetp && !devp; hpetp = hpetp->hp_next)
596 for (timer = hpetp->hp_hpet->hpet_timers, i = 0;
597 i < hpetp->hp_ntimer; i++, timer++) {
598 if ((readq(&timer->hpet_config) & Tn_PER_INT_CAP_MASK)
602 devp = &hpetp->hp_dev[i];
604 if (devp->hd_flags & HPET_OPEN || devp->hd_task) {
609 tp->ht_opaque = devp;
614 spin_unlock(&hpet_lock);
615 spin_unlock_irq(&hpet_task_lock);
623 static inline int hpet_tpcheck(struct hpet_task *tp)
625 struct hpet_dev *devp;
628 devp = tp->ht_opaque;
633 for (hpetp = hpets; hpetp; hpetp = hpetp->hp_next)
634 if (devp >= hpetp->hp_dev
635 && devp < (hpetp->hp_dev + hpetp->hp_ntimer)
636 && devp->hd_hpet == hpetp->hp_hpet)
642 int hpet_unregister(struct hpet_task *tp)
644 struct hpet_dev *devp;
645 struct hpet_timer __iomem *timer;
648 if ((err = hpet_tpcheck(tp)))
651 spin_lock_irq(&hpet_task_lock);
652 spin_lock(&hpet_lock);
654 devp = tp->ht_opaque;
655 if (devp->hd_task != tp) {
656 spin_unlock(&hpet_lock);
657 spin_unlock_irq(&hpet_task_lock);
661 timer = devp->hd_timer;
662 writeq((readq(&timer->hpet_config) & ~Tn_INT_ENB_CNF_MASK),
663 &timer->hpet_config);
664 devp->hd_flags &= ~(HPET_IE | HPET_PERIODIC);
665 devp->hd_task = NULL;
666 spin_unlock(&hpet_lock);
667 spin_unlock_irq(&hpet_task_lock);
672 int hpet_control(struct hpet_task *tp, unsigned int cmd, unsigned long arg)
674 struct hpet_dev *devp;
677 if ((err = hpet_tpcheck(tp)))
680 spin_lock_irq(&hpet_lock);
681 devp = tp->ht_opaque;
682 if (devp->hd_task != tp) {
683 spin_unlock_irq(&hpet_lock);
686 spin_unlock_irq(&hpet_lock);
687 return hpet_ioctl_common(devp, cmd, arg, 1);
690 static ctl_table hpet_table[] = {
693 .procname = "max-user-freq",
694 .data = &hpet_max_freq,
695 .maxlen = sizeof(int),
697 .proc_handler = &proc_dointvec,
702 static ctl_table hpet_root[] = {
713 static ctl_table dev_root[] = {
724 static struct ctl_table_header *sysctl_header;
726 static void hpet_register_interpolator(struct hpets *hpetp)
728 #ifdef CONFIG_TIME_INTERPOLATION
729 struct time_interpolator *ti;
731 ti = kmalloc(sizeof(*ti), GFP_KERNEL);
735 memset(ti, 0, sizeof(*ti));
736 ti->source = TIME_SOURCE_MMIO64;
738 ti->addr = &hpetp->hp_hpet->hpet_mc;
739 ti->frequency = hpetp->hp_tick_freq;
740 ti->drift = HPET_DRIFT;
743 hpetp->hp_interpolator = ti;
744 register_time_interpolator(ti);
749 * Adjustment for when arming the timer with
750 * initial conditions. That is, main counter
751 * ticks expired before interrupts are enabled.
753 #define TICK_CALIBRATE (1000UL)
755 static unsigned long hpet_calibrate(struct hpets *hpetp)
757 struct hpet_timer __iomem *timer = NULL;
758 unsigned long t, m, count, i, flags, start;
759 struct hpet_dev *devp;
761 struct hpet __iomem *hpet;
763 for (j = 0, devp = hpetp->hp_dev; j < hpetp->hp_ntimer; j++, devp++)
764 if ((devp->hd_flags & HPET_OPEN) == 0) {
765 timer = devp->hd_timer;
772 hpet = hpetp->hp_hpet;
773 t = read_counter(&timer->hpet_compare);
776 count = hpet_time_div(hpetp, TICK_CALIBRATE);
778 local_irq_save(flags);
780 start = read_counter(&hpet->hpet_mc);
783 m = read_counter(&hpet->hpet_mc);
784 write_counter(t + m + hpetp->hp_delta, &timer->hpet_compare);
785 } while (i++, (m - start) < count);
787 local_irq_restore(flags);
789 return (m - start) / i;
792 int hpet_alloc(struct hpet_data *hdp)
795 struct hpet_dev *devp;
799 struct hpet __iomem *hpet;
800 static struct hpets *last = (struct hpets *)0;
801 unsigned long period;
802 unsigned long long temp;
805 * hpet_alloc can be called by platform dependent code.
806 * if platform dependent code has allocated the hpet
807 * ACPI also reports hpet, then we catch it here.
809 for (hpetp = hpets; hpetp; hpetp = hpetp->hp_next)
810 if (hpetp->hp_hpet == hdp->hd_address)
813 siz = sizeof(struct hpets) + ((hdp->hd_nirqs - 1) *
814 sizeof(struct hpet_dev));
816 hpetp = kmalloc(siz, GFP_KERNEL);
821 memset(hpetp, 0, siz);
823 hpetp->hp_which = hpet_nhpet++;
824 hpetp->hp_hpet = hdp->hd_address;
825 hpetp->hp_hpet_phys = hdp->hd_phys_address;
827 hpetp->hp_ntimer = hdp->hd_nirqs;
829 for (i = 0; i < hdp->hd_nirqs; i++)
830 hpetp->hp_dev[i].hd_hdwirq = hdp->hd_irq[i];
832 hpet = hpetp->hp_hpet;
834 cap = readq(&hpet->hpet_cap);
836 ntimer = ((cap & HPET_NUM_TIM_CAP_MASK) >> HPET_NUM_TIM_CAP_SHIFT) + 1;
838 if (hpetp->hp_ntimer != ntimer) {
839 printk(KERN_WARNING "hpet: number irqs doesn't agree"
840 " with number of timers\n");
846 last->hp_next = hpetp;
852 period = (cap & HPET_COUNTER_CLK_PERIOD_MASK) >>
853 HPET_COUNTER_CLK_PERIOD_SHIFT; /* fs, 10^-15 */
854 temp = 1000000000000000uLL; /* 10^15 femtoseconds per second */
855 temp += period >> 1; /* round */
856 do_div(temp, period);
857 hpetp->hp_tick_freq = temp; /* ticks per second */
859 printk(KERN_INFO "hpet%d: at MMIO 0x%lx, IRQ%s",
860 hpetp->hp_which, hdp->hd_phys_address,
861 hpetp->hp_ntimer > 1 ? "s" : "");
862 for (i = 0; i < hpetp->hp_ntimer; i++)
863 printk("%s %d", i > 0 ? "," : "", hdp->hd_irq[i]);
866 printk(KERN_INFO "hpet%u: %u %d-bit timers, %Lu Hz\n",
867 hpetp->hp_which, hpetp->hp_ntimer,
868 cap & HPET_COUNTER_SIZE_MASK ? 64 : 32, hpetp->hp_tick_freq);
870 mcfg = readq(&hpet->hpet_config);
871 if ((mcfg & HPET_ENABLE_CNF_MASK) == 0) {
872 write_counter(0L, &hpet->hpet_mc);
873 mcfg |= HPET_ENABLE_CNF_MASK;
874 writeq(mcfg, &hpet->hpet_config);
877 for (i = 0, devp = hpetp->hp_dev; i < hpetp->hp_ntimer; i++, devp++) {
878 struct hpet_timer __iomem *timer;
880 timer = &hpet->hpet_timers[devp - hpetp->hp_dev];
882 devp->hd_hpets = hpetp;
883 devp->hd_hpet = hpet;
884 devp->hd_timer = timer;
887 * If the timer was reserved by platform code,
888 * then make timer unavailable for opens.
890 if (hdp->hd_state & (1 << i)) {
891 devp->hd_flags = HPET_OPEN;
895 init_waitqueue_head(&devp->hd_waitqueue);
898 hpetp->hp_delta = hpet_calibrate(hpetp);
899 hpet_register_interpolator(hpetp);
904 static acpi_status hpet_resources(struct acpi_resource *res, void *data)
906 struct hpet_data *hdp;
908 struct acpi_resource_address64 addr;
913 status = acpi_resource_to_address64(res, &addr);
915 if (ACPI_SUCCESS(status)) {
918 size = addr.max_address_range - addr.min_address_range + 1;
919 hdp->hd_phys_address = addr.min_address_range;
920 hdp->hd_address = ioremap(addr.min_address_range, size);
922 for (hpetp = hpets; hpetp; hpetp = hpetp->hp_next)
923 if (hpetp->hp_hpet == hdp->hd_address)
925 } else if (res->id == ACPI_RSTYPE_EXT_IRQ) {
926 struct acpi_resource_ext_irq *irqp;
929 irqp = &res->data.extended_irq;
931 if (irqp->number_of_interrupts > 0) {
932 hdp->hd_nirqs = irqp->number_of_interrupts;
934 for (i = 0; i < hdp->hd_nirqs; i++) {
936 acpi_register_gsi(irqp->interrupts[i],
938 irqp->active_high_low);
949 static int hpet_acpi_add(struct acpi_device *device)
952 struct hpet_data data;
954 memset(&data, 0, sizeof(data));
957 acpi_walk_resources(device->handle, METHOD_NAME__CRS,
958 hpet_resources, &data);
960 if (ACPI_FAILURE(result))
963 if (!data.hd_address || !data.hd_nirqs) {
964 printk("%s: no address or irqs in _CRS\n", __FUNCTION__);
968 return hpet_alloc(&data);
971 static int hpet_acpi_remove(struct acpi_device *device, int type)
973 /* XXX need to unregister interpolator, dealloc mem, etc */
977 static struct acpi_driver hpet_acpi_driver = {
981 .add = hpet_acpi_add,
982 .remove = hpet_acpi_remove,
986 static struct miscdevice hpet_misc = { HPET_MINOR, "hpet", &hpet_fops };
988 static int __init hpet_init(void)
992 result = misc_register(&hpet_misc);
996 sysctl_header = register_sysctl_table(dev_root, 0);
998 result = acpi_bus_register_driver(&hpet_acpi_driver);
1001 unregister_sysctl_table(sysctl_header);
1002 misc_deregister(&hpet_misc);
1009 static void __exit hpet_exit(void)
1011 acpi_bus_unregister_driver(&hpet_acpi_driver);
1014 unregister_sysctl_table(sysctl_header);
1015 misc_deregister(&hpet_misc);
1020 module_init(hpet_init);
1021 module_exit(hpet_exit);
1022 MODULE_AUTHOR("Bob Picco <Robert.Picco@hp.com>");
1023 MODULE_LICENSE("GPL");