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authorAlexandre Belloni <alexandre.belloni@bootlin.com>2019-12-15 01:02:44 +0300
committerAlexandre Belloni <alexandre.belloni@bootlin.com>2019-12-18 12:37:20 +0300
commit790a19f18a70bf1e30b6b4d00559e1bb8a3f7e23 (patch)
treededdcc9505524cc768693815162fd3305a6e1e93 /Documentation/ABI
parent3431ca4837bf7f2b816e4c439db5bb66e7586746 (diff)
downloadlinux-790a19f18a70bf1e30b6b4d00559e1bb8a3f7e23.tar.xz
rtc: Document RTC_VL_READ and RTC_VL_CLR ioctls
RTC_VL_READ and RTC_VL_CLR have been introduced in 2012 with commit 0f20b767e20a ("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>
Diffstat (limited to 'Documentation/ABI')
-rw-r--r--Documentation/ABI/testing/rtc-cdev8
1 files changed, 8 insertions, 0 deletions
diff --git a/Documentation/ABI/testing/rtc-cdev b/Documentation/ABI/testing/rtc-cdev
index 97447283f13b..25910c3c3d7e 100644
--- a/Documentation/ABI/testing/rtc-cdev
+++ b/Documentation/ABI/testing/rtc-cdev
@@ -33,6 +33,14 @@ Description:
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