On Fri, 4 May 2018 20:50:52 +0200 Oleksij Rempel [off-list ref] wrote:

Hallo Andrew,
I need your ACK or NACK for this patch.

This function is used to configure external PMIC to interpret
signal which will be triggered by pm_power_off as power off.
Since same signal can be used for stand by, I linked PMIC configuration
with pm_power_off_prepare to avoid possible conflicts.

...

quoted

--- a/kernel/reboot.c
+++ b/kernel/reboot.c

@@ -49,6 +49,7 @@ int reboot_force;
  */
 
 void (*pm_power_off_prepare)(void);
+EXPORT_SYMBOL(pm_power_off_prepare);
 

OK by me, but it's more of a Rafael thing.