mirror of
https://github.com/AuxXxilium/linux_dsm_epyc7002.git
synced 2024-12-26 19:25:27 +07:00
790a19f18a
RTC_VL_READ and RTC_VL_CLR have been introduced in 2012 with commit
0f20b767e2 ("drivers/rtc/rtc-pcf8563.c: add RTC_VL_READ/RTC_VL_CLR ioctl
feature")
Document them now that they have been unified.
Link: https://lore.kernel.org/r/20191214220259.621996-3-alexandre.belloni@bootlin.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
51 lines
2.0 KiB
Plaintext
51 lines
2.0 KiB
Plaintext
What: /dev/rtcX
|
|
Date: April 2005
|
|
KernelVersion: 2.6.12
|
|
Contact: linux-rtc@vger.kernel.org
|
|
Description:
|
|
The ioctl interface to drivers for real-time clocks (RTCs).
|
|
Following actions are supported:
|
|
|
|
* RTC_RD_TIME, RTC_SET_TIME: Read or set the RTC time. Time
|
|
format is a Gregorian calendar date and 24 hour wall clock
|
|
time.
|
|
|
|
* RTC_AIE_ON, RTC_AIE_OFF: Enable or disable the alarm interrupt
|
|
for RTCs that support alarms
|
|
|
|
* RTC_ALM_READ, RTC_ALM_SET: Read or set the alarm time for
|
|
RTCs that support alarms. Can be set upto 24 hours in the
|
|
future. Requires a separate RTC_AIE_ON call to enable the
|
|
alarm interrupt. (Prefer to use RTC_WKALM_*)
|
|
|
|
* RTC_WKALM_RD, RTC_WKALM_SET: For RTCs that support a more
|
|
powerful interface, which can issue alarms beyond 24 hours and
|
|
enable IRQs in the same request.
|
|
|
|
* RTC_PIE_ON, RTC_PIE_OFF: Enable or disable the periodic
|
|
interrupt for RTCs that support periodic interrupts.
|
|
|
|
* RTC_UIE_ON, RTC_UIE_OFF: Enable or disable the update
|
|
interrupt for RTCs that support it.
|
|
|
|
* RTC_IRQP_READ, RTC_IRQP_SET: Read or set the frequency for
|
|
periodic interrupts for RTCs that support periodic interrupts.
|
|
Requires a separate RTC_PIE_ON call to enable the periodic
|
|
interrupts.
|
|
|
|
* RTC_VL_READ: Read the voltage inputs status of the RTC when
|
|
supported. The value is a bit field of RTC_VL_*, giving the
|
|
status of the main and backup voltages.
|
|
|
|
* RTC_VL_CLEAR: Clear the voltage status of the RTC. Some RTCs
|
|
need user interaction when the backup power provider is
|
|
replaced or charged to be able to clear the status.
|
|
|
|
The ioctl() calls supported by the older /dev/rtc interface are
|
|
also supported by the newer RTC class framework. However,
|
|
because the chips and systems are not standardized, some PC/AT
|
|
functionality might not be provided. And in the same way, some
|
|
newer features -- including those enabled by ACPI -- are exposed
|
|
by the RTC class framework, but can't be supported by the older
|
|
driver.
|