net: stmmac: dwmac-meson8b: Make the clock enabling code re-usable

The timing adjustment clock will need similar logic as the RGMII clock:
It has to be enabled in the driver conditionally and when the driver is
unloaded it should be disabled again. Extract the existing code for the
RGMII clock into a new function so it can be re-used.
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/stmicro/stmmac/dwmac-meson8b.c

@@ -266,6 +266,22 @@ static int meson_axg_set_phy_mode(struct meson8b_dwmac *dwmac)
 	return 0;
 }
 
+static int meson8b_devm_clk_prepare_enable(struct meson8b_dwmac *dwmac,
+					   struct clk *clk)
+{
+	int ret;
+
+	ret = clk_prepare_enable(clk);
+	if (ret)
+		return ret;
+
+	devm_add_action_or_reset(dwmac->dev,
+				 (void(*)(void *))clk_disable_unprepare,
+				 dwmac->rgmii_tx_clk);
+
+	return 0;
+}
+
 static int meson8b_init_prg_eth(struct meson8b_dwmac *dwmac)
 {
 	int ret;
@@ -299,16 +315,13 @@ static int meson8b_init_prg_eth(struct meson8b_dwmac *dwmac)
 			return ret;
 		}
 
-		ret = clk_prepare_enable(dwmac->rgmii_tx_clk);
+		ret = meson8b_devm_clk_prepare_enable(dwmac,
+						      dwmac->rgmii_tx_clk);
 		if (ret) {
 			dev_err(dwmac->dev,
 				"failed to enable the RGMII TX clock\n");
 			return ret;
 		}
-
-		devm_add_action_or_reset(dwmac->dev,
-					(void(*)(void *))clk_disable_unprepare,
-					dwmac->rgmii_tx_clk);
 		break;
 
 	case PHY_INTERFACE_MODE_RMII: