net: stmmac: dwmac-rk: Use standard devicetree property for phy regulator

Currently, dwmac-rk uses a custom propety "phy_regulator" to get the name of the
right regulator to use to power on or power off the phy. This commit converts the
driver to use phy-supply devicetree property and the corresponding API, it cleans
the code a bit and make it simpler to maintain. This also replaces the property
phy_regulator by the standard property phy-supply in rk3288-evb-rk808.dts.

Signed-off-by: Romain Perier <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

arch/arm/boot/dts/rk3288-evb-rk808.dts

···
 };
 
 &gmac {
-	phy_regulator = "vcc_phy";
+	phy-supply = <&vcc_phy>;
 	phy-mode = "rgmii";
 	clock_in_out = "input";
 	snps,reset-gpio = <&gpio4 7 0>;

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

···
 struct rk_priv_data {
 	struct platform_device *pdev;
 	int phy_iface;
-	char regulator[32];
+	struct regulator *regulator;
 
 	bool clk_enabled;
 	bool clock_input;
···
 
 static int phy_power_on(struct rk_priv_data *bsp_priv, bool enable)
 {
-	struct regulator *ldo;
-	char *ldostr = bsp_priv->regulator;
+	struct regulator *ldo = bsp_priv->regulator;
 	int ret;
 	struct device *dev = &bsp_priv->pdev->dev;
 
-	if (!ldostr) {
-		dev_err(dev, "%s: no ldo found\n", __func__);
+	if (!ldo) {
+		dev_err(dev, "%s: no regulator found\n", __func__);
 		return -1;
 	}
 
-	ldo = regulator_get(NULL, ldostr);
-	if (!ldo) {
-		dev_err(dev, "\n%s get ldo %s failed\n", __func__, ldostr);
+	if (enable) {
+		ret = regulator_enable(ldo);
+		if (ret)
+			dev_err(dev, "%s: fail to enable phy-supply\n",
+				__func__);
 	} else {
-		if (enable) {
-			if (!regulator_is_enabled(ldo)) {
-				ret = regulator_enable(ldo);
-				if (ret != 0)
-					dev_err(dev, "%s: fail to enable %s\n",
-						__func__, ldostr);
-				else
-					dev_info(dev, "turn on ldo done.\n");
-			} else {
-				dev_warn(dev, "%s is enabled before enable",
-					 ldostr);
-			}
-		} else {
-			if (regulator_is_enabled(ldo)) {
-				ret = regulator_disable(ldo);
-				if (ret != 0)
-					dev_err(dev, "%s: fail to disable %s\n",
-						__func__, ldostr);
-				else
-					dev_info(dev, "turn off ldo done.\n");
-			} else {
-				dev_warn(dev, "%s is disabled before disable",
-					 ldostr);
-			}
-		}
-		regulator_put(ldo);
+		ret = regulator_disable(ldo);
+		if (ret)
+			dev_err(dev, "%s: fail to disable phy-supply\n",
+				__func__);
 	}
 
 	return 0;
···
 
 	bsp_priv->phy_iface = of_get_phy_mode(dev->of_node);
 
-	ret = of_property_read_string(dev->of_node, "phy_regulator", &strings);
-	if (ret) {
-		dev_warn(dev, "%s: Can not read property: phy_regulator.\n",
-			 __func__);
-	} else {
-		dev_info(dev, "%s: PHY power controlled by regulator(%s).\n",
-			 __func__, strings);
-		strcpy(bsp_priv->regulator, strings);
+	bsp_priv->regulator = devm_regulator_get_optional(dev, "phy");
+	if (IS_ERR(bsp_priv->regulator)) {
+		if (PTR_ERR(bsp_priv->regulator) == -EPROBE_DEFER) {
+			dev_err(dev, "phy regulator is not available yet, deferred probing\n");
+			return ERR_PTR(-EPROBE_DEFER);
+		}
+		dev_err(dev, "no regulator found\n");
+		bsp_priv->regulator = NULL;
 	}
 
 	ret = of_property_read_string(dev->of_node, "clock_in_out", &strings);