net: stmmac: dwmac-stm32: Extract PMCR configuration

Pull the PMCR clock mux configuration into a separate function. This is
the final change of three, which moves external clock rate validation,
external clock selector decoding, and clock mux configuration into
separate functions. This should make the code easier to understand.
No functional change intended.
Signed-off-by: Marek Vasut <marex@denx.de>
Signed-off-by: Christophe Roullier <christophe.roullier@foss.st.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

drivers/net/ethernet/stmicro/stmmac/dwmac-stm32.c

@@ -219,15 +219,11 @@ static int stm32mp1_validate_ethck_rate(struct plat_stmmacenet_data *plat_dat)
 	return -EINVAL;
 }
 
-static int stm32mp1_set_mode(struct plat_stmmacenet_data *plat_dat)
+static int stm32mp1_configure_pmcr(struct plat_stmmacenet_data *plat_dat)
 {
 	struct stm32_dwmac *dwmac = plat_dat->bsp_priv;
 	u32 reg = dwmac->mode_reg;
-	int val, ret;
-
-	ret = stm32mp1_select_ethck_external(plat_dat);
-	if (ret)
-		return ret;
+	int val;
 
 	switch (plat_dat->mac_interface) {
 	case PHY_INTERFACE_MODE_MII:
@@ -262,10 +258,6 @@ static int stm32mp1_set_mode(struct plat_stmmacenet_data *plat_dat)
 		return -EINVAL;
 	}
 
-	ret = stm32mp1_validate_ethck_rate(plat_dat);
-	if (ret)
-		return ret;
-
 	/* Need to update PMCCLRR (clear register) */
 	regmap_write(dwmac->regmap, reg + SYSCFG_PMCCLRR_OFFSET,
 		     dwmac->ops->syscfg_eth_mask);
@@ -275,6 +267,21 @@ static int stm32mp1_set_mode(struct plat_stmmacenet_data *plat_dat)
 				 dwmac->ops->syscfg_eth_mask, val);
 }
 
+static int stm32mp1_set_mode(struct plat_stmmacenet_data *plat_dat)
+{
+	int ret;
+
+	ret = stm32mp1_select_ethck_external(plat_dat);
+	if (ret)
+		return ret;
+
+	ret = stm32mp1_validate_ethck_rate(plat_dat);
+	if (ret)
+		return ret;
+
+	return stm32mp1_configure_pmcr(plat_dat);
+}
+
 static int stm32mcu_set_mode(struct plat_stmmacenet_data *plat_dat)
 {
 	struct stm32_dwmac *dwmac = plat_dat->bsp_priv;