phy: ti: gmii-sel: Do not use syscon helper to build regmap

The syscon helper device_node_to_regmap() is used to fetch a regmap
registered to a device node. It also currently creates this regmap
if the node did not already have a regmap associated with it. This
should only be used on "syscon" nodes. This driver is not such a
device and instead uses device_node_to_regmap() on its own node as
a hacky way to create a regmap for itself.

This will not work going forward and so we should create our regmap
the normal way by defining our regmap_config, fetching our memory
resource, then using the normal regmap_init_mmio() function.

Signed-off-by: Andrew Davis <afd@ti.com>
Tested-by: Nishanth Menon <nm@ti.com>
Link: https://lore.kernel.org/r/20250123182234.597665-1-afd@ti.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

drivers/phy/ti/phy-gmii-sel.c

@@ -424,6 +424,12 @@ static int phy_gmii_sel_init_ports(struct phy_gmii_sel_priv *priv)
 	return 0;
 }
 
+static const struct regmap_config phy_gmii_sel_regmap_cfg = {
+	.reg_bits = 32,
+	.val_bits = 32,
+	.reg_stride = 4,
+};
+
 static int phy_gmii_sel_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
@@ -468,7 +474,14 @@ static int phy_gmii_sel_probe(struct platform_device *pdev)
 
 	priv->regmap = syscon_node_to_regmap(node->parent);
 	if (IS_ERR(priv->regmap)) {
-		priv->regmap = device_node_to_regmap(node);
+		void __iomem *base;
+
+		base = devm_platform_ioremap_resource(pdev, 0);
+		if (IS_ERR(base))
+			return dev_err_probe(dev, PTR_ERR(base),
+					     "failed to get base memory resource\n");
+
+		priv->regmap = regmap_init_mmio(dev, base, &phy_gmii_sel_regmap_cfg);
 		if (IS_ERR(priv->regmap))
 			return dev_err_probe(dev, PTR_ERR(priv->regmap),
 					     "Failed to get syscon\n");