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From:   Harini Katakam <harini.katakam@xilinx.com>
To:     <nicolas.ferre@microchip.com>, <davem@davemloft.net>
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        <michal.simek@xilinx.com>, <harinikatakamlinux@gmail.com>,
        <harini.katakam@xilinx.com>
Subject: [PATCH] net: macb: Fix ptp time adjustment for large negative delta
Date:   Wed, 20 Jun 2018 17:04:20 +0530
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When delta passed to gem_ptp_adjtime is negative, the sign is
maintained in the ns_to_timespec64 conversion. Hence timespec_add
should be used directly. timespec_sub will just subtract the negative
value thus increasing the time difference.

Signed-off-by: Harini Katakam <harini.katakam@xilinx.com>
---
 drivers/net/ethernet/cadence/macb_ptp.c | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/drivers/net/ethernet/cadence/macb_ptp.c b/drivers/net/ethernet/cadence/macb_ptp.c
index 2220c77..6788351 100644
--- a/drivers/net/ethernet/cadence/macb_ptp.c
+++ b/drivers/net/ethernet/cadence/macb_ptp.c
@@ -170,10 +170,7 @@ static int gem_ptp_adjtime(struct ptp_clock_info *ptp, s64 delta)
 
 	if (delta > TSU_NSEC_MAX_VAL) {
 		gem_tsu_get_time(&bp->ptp_clock_info, &now);
-		if (sign)
-			now = timespec64_sub(now, then);
-		else
-			now = timespec64_add(now, then);
+		now = timespec64_add(now, then);
 
 		gem_tsu_set_time(&bp->ptp_clock_info,
 				 (const struct timespec64 *)&now);
-- 
2.7.4