ptp_ixp46x: convert .adjfreq to .adjfine

The ptp_ixp46x 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
adjust_by_scaled_ppm helper function.

Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
Cc: Paolo Abeni <pabeni@redhat.com>
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/xscale/ptp_ixp46x.c

@@ -120,24 +120,13 @@ static irqreturn_t isr(int irq, void *priv)
  * PTP clock operations
  */
 
-static int ptp_ixp_adjfreq(struct ptp_clock_info *ptp, s32 ppb)
+static int ptp_ixp_adjfine(struct ptp_clock_info *ptp, long scaled_ppm)
 {
-	u64 adj;
-	u32 diff, addend;
-	int neg_adj = 0;
+	u32 addend;
 	struct ixp_clock *ixp_clock = container_of(ptp, struct ixp_clock, caps);
 	struct ixp46x_ts_regs *regs = ixp_clock->regs;
 
-	if (ppb < 0) {
-		neg_adj = 1;
-		ppb = -ppb;
-	}
-	addend = DEFAULT_ADDEND;
-	adj = addend;
-	adj *= ppb;
-	diff = div_u64(adj, 1000000000ULL);
-
-	addend = neg_adj ? addend - diff : addend + diff;
+	addend = adjust_by_scaled_ppm(DEFAULT_ADDEND, scaled_ppm);
 
 	__raw_writel(addend, &regs->addend);
 
@@ -230,7 +219,7 @@ static const struct ptp_clock_info ptp_ixp_caps = {
 	.n_ext_ts	= N_EXT_TS,
 	.n_pins		= 0,
 	.pps		= 0,
-	.adjfreq	= ptp_ixp_adjfreq,
+	.adjfine	= ptp_ixp_adjfine,
 	.adjtime	= ptp_ixp_adjtime,
 	.gettime64	= ptp_ixp_gettime,
 	.settime64	= ptp_ixp_settime,