Commit 8a0d4900 authored by Randy Dunlap's avatar Randy Dunlap Committed by Linus Torvalds

[PATCH] Doc/hpet.txt: change to < 80 columns

Put text into < 80 columns.  No other changes.
Signed-off-by: default avatarRandy Dunlap <rdunlap@xenotime.net>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 8f2709b5
High Precision Event Timer Driver for Linux
The High Precision Event Timer (HPET) hardware is the future replacement for the 8254 and Real
Time Clock (RTC) periodic timer functionality. Each HPET can have up two 32 timers. It is possible
to configure the first two timers as legacy replacements for 8254 and RTC periodic. A specification
done by INTEL and Microsoft can be found at http://www.intel.com/labs/platcomp/hpet/hpetspec.htm.
The driver supports detection of HPET driver allocation and initialization of the HPET before the
driver module_init routine is called. This enables platform code which uses timer 0 or 1 as the
main timer to intercept HPET initialization. An example of this initialization can be found in
The High Precision Event Timer (HPET) hardware is the future replacement
for the 8254 and Real Time Clock (RTC) periodic timer functionality.
Each HPET can have up two 32 timers. It is possible to configure the
first two timers as legacy replacements for 8254 and RTC periodic timers.
A specification done by Intel and Microsoft can be found at
<http://www.intel.com/hardwaredesign/hpetspec.htm>.
The driver supports detection of HPET driver allocation and initialization
of the HPET before the driver module_init routine is called. This enables
platform code which uses timer 0 or 1 as the main timer to intercept HPET
initialization. An example of this initialization can be found in
arch/i386/kernel/time_hpet.c.
The driver provides two APIs which are very similar to the API found in the rtc.c driver.
There is a user space API and a kernel space API. An example user space program is provided
below.
The driver provides two APIs which are very similar to the API found in
the rtc.c driver. There is a user space API and a kernel space API.
An example user space program is provided below.
#include <stdio.h>
#include <stdlib.h>
......@@ -290,9 +293,8 @@ The kernel API has three interfaces exported from the driver:
hpet_unregister(struct hpet_task *tp)
hpet_control(struct hpet_task *tp, unsigned int cmd, unsigned long arg)
The kernel module using this interface fills in the ht_func and ht_data members of the
hpet_task structure before calling hpet_register. hpet_control simply vectors to the hpet_ioctl
routine and has the same commands and respective arguments as the user API. hpet_unregister
The kernel module using this interface fills in the ht_func and ht_data
members of the hpet_task structure before calling hpet_register.
hpet_control simply vectors to the hpet_ioctl routine and has the same
commands and respective arguments as the user API. hpet_unregister
is used to terminate usage of the HPET timer reserved by hpet_register.
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