[PATCH 2/2] net: mdio-mt7531-mmio: improve parsing of switch register on probe

[Christian Marangi <ansuelsmth@gmail.com>]

The MDIO node is ALWAYS a parent of the MT7531 switch node and the MDIO
registers are in the MT7531 register space (in the context of MT7988
it's all memory-mapped)

With these assumption, we can simplify and permit better usage of PHY OF
automatic probing by binding the mt7531-mdio-mmio driver with the MDIO
node instead of the switch node.

For OF PHY to be correctly autoprobed, the MDIO driver needs to attached
to the MDIO node (the parent of the PHY nodes).

The driver will reach the parent node (the switch node) and will parse
the register address from there.

Signed-off-by: Christian Marangi <ansuelsmth@gmail.com>
---
 drivers/net/mdio-mt7531-mmio.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/net/mdio-mt7531-mmio.c b/drivers/net/mdio-mt7531-mmio.c
index 58cb6e503b8..930454a9b0e 100644
--- a/drivers/net/mdio-mt7531-mmio.c
+++ b/drivers/net/mdio-mt7531-mmio.c
@@ -149,8 +149,13 @@ static const struct mdio_ops mt7531_mdio_ops = {
 static int mt7531_mdio_probe(struct udevice *dev)
 {
 	struct mt7531_mdio_mmio_priv *priv = dev_get_priv(dev);
+	ofnode switch_node;
 
-	priv->switch_regs = dev_read_addr(dev);
+	switch_node = ofnode_get_parent(dev_ofnode(dev));
+	if (!ofnode_valid(switch_node))
+		return -EINVAL;
+
+	priv->switch_regs = ofnode_get_addr(switch_node);
 	if (priv->switch_regs == FDT_ADDR_T_NONE)
 		return -EINVAL;
 
-- 
2.51.0