docs: document --param-get, --param-set

Signed-off-by: Bastian Krause <bst@pengutronix.de>

diff --git a/sys-utils/hwclock.8.adoc b/sys-utils/hwclock.8.adoc
index 2547a2792a744d69c4021dbf12ffccdcc0644eda..aa9f3337bd5c6c94ee96c0aac4b258ce3963ffa5 100644 (file)
--- a/sys-utils/hwclock.8.adoc
+++ b/sys-utils/hwclock.8.adoc
@@ -48,6 +48,11 @@ The RTC driver attempts to guess the correct epoch value, so setting it may not
 +
 This epoch value is used whenever *hwclock* reads or sets the Hardware Clock on an Alpha machine. For ISA machines the kernel uses the fixed Hardware Clock epoch of 1900.
 
+**--param-get=**__parameter__; **--param-set=**__parameter__=__value__::
+Read and set the RTC's parameter. This is useful, for example, to retrieve the RTC's feature or set the RTC's Backup Switchover Mode.
++
+_parameter_ is either a numeric RTC parameter value (see the Kernel's _include/uapi/linux/rtc.h_) or an alias. See *--help* for a list of valid aliases. _parameter_ and _value_, if prefixed with 0x, are interpreted as hexadecimal, otherwise decimal values.
+
 *--predict*::
 Predict what the Hardware Clock will read in the future based upon the time given by the *--date* option and the information in _{ADJTIME_PATH}_. This is useful, for example, to account for drift when setting a Hardware Clock wakeup (aka alarm). See *rtcwake*(8).
 +