net: stmmac: Move subsecond increment configuration in dedicated helper

In preparation for fine/coarse support, let's move the subsecond increment
and addend configuration in a dedicated helper.

Signed-off-by: Maxime Chevallier <[e-mail]>
Reviewed-by: Russell King (Oracle) <[e-mail]>
Link: https://patch.msgid.link/[e-mail]
Signed-off-by: Paolo Abeni <[e-mail]>

drivers/net/ethernet/stmicro/stmmac/stmmac_main.c

···
 	}
 }
 
+static void stmmac_update_subsecond_increment(struct stmmac_priv *priv)
+{
+	bool xmac = dwmac_is_xmac(priv->plat->core_type);
+	u32 sec_inc = 0;
+	u64 temp = 0;
+
+	stmmac_config_hw_tstamping(priv, priv->ptpaddr, priv->systime_flags);
+
+	/* program Sub Second Increment reg */
+	stmmac_config_sub_second_increment(priv, priv->ptpaddr,
+					   priv->plat->clk_ptp_rate,
+					   xmac, &sec_inc);
+	temp = div_u64(1000000000ULL, sec_inc);
+
+	/* Store sub second increment for later use */
+	priv->sub_second_inc = sec_inc;
+
+	/* calculate default added value:
+	 * formula is :
+	 * addend = (2^32)/freq_div_ratio;
+	 * where, freq_div_ratio = 1e9ns/sec_inc
+	 */
+	temp = (u64)(temp << 32);
+	priv->default_addend = div_u64(temp, priv->plat->clk_ptp_rate);
+	stmmac_config_addend(priv, priv->ptpaddr, priv->default_addend);
+}
+
 /**
  *  stmmac_hwtstamp_set - control hardware timestamping.
  *  @dev: device pointer.
···
 static int stmmac_init_tstamp_counter(struct stmmac_priv *priv,
 				      u32 systime_flags)
 {
-	bool xmac = dwmac_is_xmac(priv->plat->core_type);
 	struct timespec64 now;
-	u32 sec_inc = 0;
-	u64 temp = 0;
 
 	if (!priv->plat->clk_ptp_rate) {
 		netdev_err(priv->dev, "Invalid PTP clock rate");
···
 	stmmac_config_hw_tstamping(priv, priv->ptpaddr, systime_flags);
 	priv->systime_flags = systime_flags;
 
-	/* program Sub Second Increment reg */
-	stmmac_config_sub_second_increment(priv, priv->ptpaddr,
-					   priv->plat->clk_ptp_rate,
-					   xmac, &sec_inc);
-	temp = div_u64(1000000000ULL, sec_inc);
-
-	/* Store sub second increment for later use */
-	priv->sub_second_inc = sec_inc;
-
-	/* calculate default added value:
-	 * formula is :
-	 * addend = (2^32)/freq_div_ratio;
-	 * where, freq_div_ratio = 1e9ns/sec_inc
-	 */
-	temp = (u64)(temp << 32);
-	priv->default_addend = div_u64(temp, priv->plat->clk_ptp_rate);
-	stmmac_config_addend(priv, priv->ptpaddr, priv->default_addend);
+	stmmac_update_subsecond_increment(priv);
 
 	/* initialize system time */
 	ktime_get_real_ts64(&now);