net: mdio: mscc-miim: Handle the switch reset

The mscc-miim device can be impacted by the switch reset, at least when
this device is part of the LAN966x PCI device.

Handle this newly added (optional) resets property.
Signed-off-by: Herve Codina <herve.codina@bootlin.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/mdio/mdio-mscc-miim.c

@@ -19,6 +19,7 @@
 #include <linux/platform_device.h>
 #include <linux/property.h>
 #include <linux/regmap.h>
+#include <linux/reset.h>
 
 #define MSCC_MIIM_REG_STATUS		0x0
 #define		MSCC_MIIM_STATUS_STAT_PENDING	BIT(2)
@@ -271,10 +272,17 @@ static int mscc_miim_probe(struct platform_device *pdev)
 	struct device_node *np = pdev->dev.of_node;
 	struct regmap *mii_regmap, *phy_regmap;
 	struct device *dev = &pdev->dev;
+	struct reset_control *reset;
 	struct mscc_miim_dev *miim;
 	struct mii_bus *bus;
 	int ret;
 
+	reset = devm_reset_control_get_optional_shared(dev, "switch");
+	if (IS_ERR(reset))
+		return dev_err_probe(dev, PTR_ERR(reset), "Failed to get reset\n");
+
+	reset_control_reset(reset);
+
 	mii_regmap = ocelot_regmap_from_resource(pdev, 0,
 						 &mscc_miim_regmap_config);
 	if (IS_ERR(mii_regmap))