net: phy: sfp: make the i2c-bus dt property mandatory

This patch makes the i2c-bus property mandatory when using a device
tree. If the sfp i2c bus isn't described it's impossible to guess the
protocol to use for a given module, and the sfp module would then not
work in most cases.
Signed-off-by: NAntoine Tenart <antoine.tenart@bootlin.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/phy/sfp.c

@@ -976,6 +976,7 @@ static int sfp_probe(struct platform_device *pdev)
 	if (pdev->dev.of_node) {
 		struct device_node *node = pdev->dev.of_node;
 		const struct of_device_id *id;
+		struct i2c_adapter *i2c;
 		struct device_node *np;
 
 		id = of_match_node(sfp_of_match, node);
@@ -985,8 +986,10 @@ static int sfp_probe(struct platform_device *pdev)
 		sff = sfp->type = id->data;
 
 		np = of_parse_phandle(node, "i2c-bus", 0);
-		if (np) {
-			struct i2c_adapter *i2c;
+		if (!np) {
+			dev_err(sfp->dev, "missing 'i2c-bus' property\n");
+			return -ENODEV;
+		}
 
 		i2c = of_find_i2c_adapter_by_node(np);
 		of_node_put(np);
@@ -999,7 +1002,6 @@ static int sfp_probe(struct platform_device *pdev)
 			return err;
 		}
 	}
-	}
 
 	for (i = 0; i < GPIO_MAX; i++)
 		if (sff->gpios & BIT(i)) {