ptp: tg3: convert .adjfreq to .adjfine

The tg3 implementation of .adjfreq is implemented in terms of a
straight forward "base * ppb / 1 billion" calculation.

Convert this to the newer .adjfine, using the recently added
diff_by_scaled_ppm helper function to calculate the difference and
direction of the adjustment.
Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
Cc: Siva Reddy Kallam <siva.kallam@broadcom.com>
Cc: Prashant Sreedharan <prashant@broadcom.com>
Cc: Michael Chan <mchan@broadcom.com>
Cc: Richard Cochran <richardcochran@gmail.com>
Reviewed-by: Pavan Chebbi <pavan.chebbi@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/broadcom/tg3.c

@@ -6179,34 +6179,26 @@ static int tg3_get_ts_info(struct net_device *dev, struct ethtool_ts_info *info)
 	return 0;
 }
 
-static int tg3_ptp_adjfreq(struct ptp_clock_info *ptp, s32 ppb)
+static int tg3_ptp_adjfine(struct ptp_clock_info *ptp, long scaled_ppm)
 {
 	struct tg3 *tp = container_of(ptp, struct tg3, ptp_info);
-	bool neg_adj = false;
-	u32 correction = 0;
-
-	if (ppb < 0) {
-		neg_adj = true;
-		ppb = -ppb;
-	}
+	u64 correction;
+	bool neg_adj;
 
 	/* Frequency adjustment is performed using hardware with a 24 bit
 	 * accumulator and a programmable correction value. On each clk, the
 	 * correction value gets added to the accumulator and when it
 	 * overflows, the time counter is incremented/decremented.
-	 *
-	 * So conversion from ppb to correction value is
-	 *		ppb * (1 << 24) / 1000000000
 	 */
-	correction = div_u64((u64)ppb * (1 << 24), 1000000000ULL) &
-		     TG3_EAV_REF_CLK_CORRECT_MASK;
+	neg_adj = diff_by_scaled_ppm(1 << 24, scaled_ppm, &correction);
 
 	tg3_full_lock(tp, 0);
 
 	if (correction)
 		tw32(TG3_EAV_REF_CLK_CORRECT_CTL,
 		     TG3_EAV_REF_CLK_CORRECT_EN |
-		     (neg_adj ? TG3_EAV_REF_CLK_CORRECT_NEG : 0) | correction);
+		     (neg_adj ? TG3_EAV_REF_CLK_CORRECT_NEG : 0) |
+		     ((u32)correction & TG3_EAV_REF_CLK_CORRECT_MASK));
 	else
 		tw32(TG3_EAV_REF_CLK_CORRECT_CTL, 0);
 
@@ -6330,7 +6322,7 @@ static const struct ptp_clock_info tg3_ptp_caps = {
 	.n_per_out	= 1,
 	.n_pins		= 0,
 	.pps		= 0,
-	.adjfreq	= tg3_ptp_adjfreq,
+	.adjfine	= tg3_ptp_adjfine,
 	.adjtime	= tg3_ptp_adjtime,
 	.gettimex64	= tg3_ptp_gettimex,
 	.settime64	= tg3_ptp_settime,