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authorAishwarya Pant <aishpant@gmail.com>2018-01-01 20:31:24 +0300
committerAlexandre Belloni <alexandre.belloni@free-electrons.com>2018-01-12 02:20:41 +0300
commit796c0ad79ee65abb9c891e44ccd6e347a6be486f (patch)
tree50cad654b08258997087d3376b8554bfaa441862 /Documentation/ABI
parentd5bc5cde844ebecbc6fac2d65d23610cfd3affc3 (diff)
downloadlinux-796c0ad79ee65abb9c891e44ccd6e347a6be486f.tar.xz
Documentation: rtc: move iotcl interface documentation to ABI
The ioctl interface should be in Documentation/ABI along with the rest of the interfaces. Signed-off-by: Aishwarya Pant <aishpant@gmail.com> Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Diffstat (limited to 'Documentation/ABI')
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+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.
+
+ 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.