[PATCH] net: mdio-ipq4019: Fix the error for an optional regs resource

[Cai Huoqing <caihuoqing@baidu.com>]

The second resource is optional which is only provided on the chipset
IPQ5018. But the blamed commit ignores that and if the resource is
not there it just fails.

the resource is used like this,
	if (priv->eth_ldo_rdy) {
		val = readl(priv->eth_ldo_rdy);
		val |= BIT(0);
		writel(val, priv->eth_ldo_rdy);
		fsleep(IPQ_PHY_SET_DELAY_US);
	}

This patch reverts that to still allow the second resource to be optional
because other SoC have the some MDIO controller and doesn't need to
second resource.

Fix Commit fa14d03e014a ("net: mdio-ipq4019: Make use of
devm_platform_ioremap_resource()")
Signed-off-by: Cai Huoqing <caihuoqing@baidu.com>
---
 drivers/net/mdio/mdio-ipq4019.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/net/mdio/mdio-ipq4019.c b/drivers/net/mdio/mdio-ipq4019.c
index 0d7d3e15d2f0..5f4cd24a0241 100644
--- a/drivers/net/mdio/mdio-ipq4019.c
+++ b/drivers/net/mdio/mdio-ipq4019.c
@@ -207,6 +207,7 @@ static int ipq4019_mdio_probe(struct platform_device *pdev)
 {
 	struct ipq4019_mdio_data *priv;
 	struct mii_bus *bus;
+	struct resource *res;
 	int ret;
 
 	bus = devm_mdiobus_alloc_size(&pdev->dev, sizeof(*priv));
@@ -224,7 +225,10 @@ static int ipq4019_mdio_probe(struct platform_device *pdev)
 		return PTR_ERR(priv->mdio_clk);
 
 	/* The platform resource is provided on the chipset IPQ5018 */
-	priv->eth_ldo_rdy = devm_platform_ioremap_resource(pdev, 1);
+	/* This resource is optional */
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 1);
+	if (res)
+		priv->eth_ldo_rdy = devm_ioremap_resource(&pdev->dev, res);
 
 	bus->name = "ipq4019_mdio";
 	bus->read = ipq4019_mdio_read;
-- 
2.25.1