linux-kernel - [PATCH v3 net-next 3/3] ptp: idt82p33: optimize _idt82p33

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Date:   Wed, 4 Nov 2020 19:22:15 -0500
From:   <min.li.xe@...esas.com>
To:     <richardcochran@...il.com>
CC:     <netdev@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        Min Li <min.li.xe@...esas.com>
Subject: [PATCH v3 net-next 3/3] ptp: idt82p33: optimize _idt82p33_adjfine

From: Min Li <min.li.xe@...esas.com>

Use div_s64 so that the neg_adj is not needed.

Signed-off-by: Min Li <min.li.xe@...esas.com>

Acked-by: Richard Cochran <richardcochran@...il.com>
---
 drivers/ptp/ptp_idt82p33.c | 10 +---------
 1 file changed, 1 insertion(+), 9 deletions(-)

diff --git a/drivers/ptp/ptp_idt82p33.c b/drivers/ptp/ptp_idt82p33.c
index b1528a0..e970379d 100644
--- a/drivers/ptp/ptp_idt82p33.c
+++ b/drivers/ptp/ptp_idt82p33.c
@@ -320,7 +320,6 @@ static int _idt82p33_adjfine(struct idt82p33_channel *channel, long scaled_ppm)
 {
 	struct idt82p33 *idt82p33 = channel->idt82p33;
 	unsigned char buf[5] = {0};
-	int neg_adj = 0;
 	int err, i;
 	s64 fcw;
 
@@ -340,16 +339,9 @@ static int _idt82p33_adjfine(struct idt82p33_channel *channel, long scaled_ppm)
 	 * FCW = -------------
 	 *         168 * 2^4
 	 */
-	if (scaled_ppm < 0) {
-		neg_adj = 1;
-		scaled_ppm = -scaled_ppm;
-	}
 
 	fcw = scaled_ppm * 244140625ULL;
-	fcw = div_u64(fcw, 2688);
-
-	if (neg_adj)
-		fcw = -fcw;
+	fcw = div_s64(fcw, 2688);
 
 	for (i = 0; i < 5; i++) {
 		buf[i] = fcw & 0xff;
-- 
2.7.4