[PATCH] rtc/rtc-opal: Enable alarms only when opal supports tpo

[Stewart Smith]

Vaibhav Jain <vaibhav at linux.vnet.ibm.com> writes:
> rtc-opal driver provides support for rtc alarms via
> timed-power-on(tpo). However some Power platforms like BML use a fake
> rtc clock and don't support tpo. Such platforms are indicated by the
> missing 'has-tpo' property in the device tree.
>
> Current implementation however enables callback for
> rtc_class_ops.read/set alarm irrespective of the tpo support from the
> platform. This results in a failed opal call when kernel tries to read
> an existing alarms via opal_get_tpo_time during rtc device registration.
>
> This patch fixes this issue by setting opal_rtc_ops.read/set_alarm
> callback pointers only when tpo is supported.
>
> Acked-by: Michael Neuling <mikey at neuling.org>
> Acked-by: Neelesh Gupta <neelegup at linux.vnet.ibm.com>
> Signed-off-by: Vaibhav Jain <vaibhav at linux.vnet.ibm.com>

Acked-by: Stewart Smith <stewart at linux.vnet.ibm.com>

FWIW I'm updating OPAL docs with this. The TPO calls aren't actually
documented :(

In future, it'd be great if there was an accompanying skiboot patch
updating the documentation there too.