[PATCH v3 net-next 3/3] ptp: idt82p33: optimize _idt82p33_adjfine

From: min.li.xe
Date: Wed Nov 04 2020 - 19:34:33 EST


From: Min Li <min.li.xe@xxxxxxxxxxx>

Use div_s64 so that the neg_adj is not needed.

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

Acked-by: Richard Cochran <richardcochran@xxxxxxxxx>
---
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