[PATCH v2 2/2] ptp: ptp_s390: Add missing facility check

[Sven Schnelle <svens@linux.ibm.com>]

Only register the physical clock when facility 28 is installed
and PTFF QAF returns that PTFF QPT is available.

Fixes: 2d7de7a3010d ("s390/time: Add PtP driver")
Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
Cc: stable@kernel.org
---
 drivers/ptp/ptp_s390.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/ptp/ptp_s390.c b/drivers/ptp/ptp_s390.c
index 29618eb9bf44..02d624d89a0a 100644
--- a/drivers/ptp/ptp_s390.c
+++ b/drivers/ptp/ptp_s390.c
@@ -107,6 +107,9 @@ static __init int ptp_s390_init(void)
 	if (IS_ERR(ptp_stcke_clock))
 		return PTR_ERR(ptp_stcke_clock);
 
+	if (!test_facility(28) || !ptff_query(PTFF_QPT))
+		return 0;
+
 	ptp_qpt_clock = ptp_clock_register(&ptp_s390_qpt_info, NULL);
 	if (IS_ERR(ptp_qpt_clock)) {
 		ptp_clock_unregister(ptp_stcke_clock);
@@ -117,7 +120,8 @@ static __init int ptp_s390_init(void)
 
 static __exit void ptp_s390_exit(void)
 {
-	ptp_clock_unregister(ptp_qpt_clock);
+	if (ptp_qpt_clock)
+		ptp_clock_unregister(ptp_qpt_clock);
 	ptp_clock_unregister(ptp_stcke_clock);
 }
 
-- 
2.55.0