net: mvmdio: defer probe of orion-mdio if a clock is not ready

Defer probing of the orion-mdio interface when getting a clock returns
EPROBE_DEFER. This avoids locking up the Armada 8k SoC when mdio is used
before all clocks have been enabled.

Signed-off-by: Josua Mayer <josua@solid-run.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/marvell/mvmdio.c

@@ -321,6 +321,10 @@ static int orion_mdio_probe(struct platform_device *pdev)
 
 	for (i = 0; i < ARRAY_SIZE(dev->clk); i++) {
 		dev->clk[i] = of_clk_get(pdev->dev.of_node, i);
+		if (PTR_ERR(dev->clk[i]) == -EPROBE_DEFER) {
+			ret = -EPROBE_DEFER;
+			goto out_clk;
+		}
 		if (IS_ERR(dev->clk[i]))
 			break;
 		clk_prepare_enable(dev->clk[i]);
@@ -366,6 +370,7 @@ static int orion_mdio_probe(struct platform_device *pdev)
 	if (dev->err_interrupt > 0)
 		writel(0, dev->regs + MVMDIO_ERR_INT_MASK);
 
+out_clk:
 	for (i = 0; i < ARRAY_SIZE(dev->clk); i++) {
 		if (IS_ERR(dev->clk[i]))
 			break;