From c6995117b60ef3f7afca8fb41f906e9f459d869a Mon Sep 17 00:00:00 2001
From: Horatiu Vultur <horatiu.vultur@microchip.com>
Date: Tue, 28 Sep 2021 09:17:20 +0200
Subject: [PATCH] net: mdio: mscc-miim: Fix the mdio controller

According to the documentation the second resource is optional. But the
blamed commit ignores that and if the resource is not there it just
fails.

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.

Fixes: 672a1c394950 ("net: mdio: mscc-miim: Make use of the helper function devm_platform_ioremap_resource()")
Signed-off-by: Horatiu Vultur <horatiu.vultur@microchip.com>
Reviewed-by: Cai Huoqing <caihuoqing@baidu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
 drivers/net/mdio/mdio-mscc-miim.c | 15 ++++++++++-----
 1 file changed, 10 insertions(+), 5 deletions(-)

diff --git a/drivers/net/mdio/mdio-mscc-miim.c b/drivers/net/mdio/mdio-mscc-miim.c
index 1ee592d3eae46..17f98f609ec82 100644
--- a/drivers/net/mdio/mdio-mscc-miim.c
+++ b/drivers/net/mdio/mdio-mscc-miim.c
@@ -134,8 +134,9 @@ static int mscc_miim_reset(struct mii_bus *bus)
 
 static int mscc_miim_probe(struct platform_device *pdev)
 {
-	struct mii_bus *bus;
 	struct mscc_miim_dev *dev;
+	struct resource *res;
+	struct mii_bus *bus;
 	int ret;
 
 	bus = devm_mdiobus_alloc_size(&pdev->dev, sizeof(*dev));
@@ -156,10 +157,14 @@ static int mscc_miim_probe(struct platform_device *pdev)
 		return PTR_ERR(dev->regs);
 	}
 
-	dev->phy_regs = devm_platform_ioremap_resource(pdev, 1);
-	if (IS_ERR(dev->phy_regs)) {
-		dev_err(&pdev->dev, "Unable to map internal phy registers\n");
-		return PTR_ERR(dev->phy_regs);
+	/* This resource is optional */
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 1);
+	if (res) {
+		dev->phy_regs = devm_ioremap_resource(&pdev->dev, res);
+		if (IS_ERR(dev->phy_regs)) {
+			dev_err(&pdev->dev, "Unable to map internal phy registers\n");
+			return PTR_ERR(dev->phy_regs);
+		}
 	}
 
 	ret = of_mdiobus_register(bus, pdev->dev.of_node);
-- 
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