net: sfp: clean up i2c-bus property parsing

We currently have some complicated code in sfp_probe() which gets the
I2C bus depending on whether the sfp node is DT or ACPI, and we use
completely separate lookup functions.

This could do with being in a separate function to make the code more
readable, so move it to a new function, sfp_i2c_get(). We can also use
fwnode_find_reference() to lookup the I2C bus fwnode before then
decending into fwnode-type specific parsing.

A future cleanup would be to move the fwnode-type specific parsing into
the i2c layer, which is where it really should be.
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Link: https://lore.kernel.org/r/E1p1WGJ-0098wS-4w@rmk-PC.armlinux.org.ukSigned-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/phy/sfp.c

@@ -2642,10 +2642,46 @@ static void sfp_cleanup(void *data)
 	kfree(sfp);
 }
 
+static int sfp_i2c_get(struct sfp *sfp)
+{
+	struct acpi_handle *acpi_handle;
+	struct fwnode_handle *h;
+	struct i2c_adapter *i2c;
+	struct device_node *np;
+	int err;
+
+	h = fwnode_find_reference(dev_fwnode(sfp->dev), "i2c-bus", 0);
+	if (IS_ERR(h)) {
+		dev_err(sfp->dev, "missing 'i2c-bus' property\n");
+		return -ENODEV;
+	}
+
+	if (is_acpi_device_node(h)) {
+		acpi_handle = ACPI_HANDLE_FWNODE(h);
+		i2c = i2c_acpi_find_adapter_by_handle(acpi_handle);
+	} else if ((np = to_of_node(h)) != NULL) {
+		i2c = of_find_i2c_adapter_by_node(np);
+	} else {
+		err = -EINVAL;
+		goto put;
+	}
+
+	if (!i2c) {
+		err = -EPROBE_DEFER;
+		goto put;
+	}
+
+	err = sfp_i2c_configure(sfp, i2c);
+	if (err)
+		i2c_put_adapter(i2c);
+put:
+	fwnode_handle_put(h);
+	return err;
+}
+
 static int sfp_probe(struct platform_device *pdev)
 {
 	const struct sff_data *sff;
-	struct i2c_adapter *i2c;
 	char *sfp_irq_name;
 	struct sfp *sfp;
 	int err, i;
@@ -2663,51 +2699,20 @@ static int sfp_probe(struct platform_device *pdev)
 	sff = sfp->type = &sfp_data;
 
 	if (pdev->dev.of_node) {
-		struct device_node *node = pdev->dev.of_node;
 		const struct of_device_id *id;
-		struct device_node *np;
 
-		id = of_match_node(sfp_of_match, node);
+		id = of_match_node(sfp_of_match, pdev->dev.of_node);
 		if (WARN_ON(!id))
 			return -EINVAL;
 
 		sff = sfp->type = id->data;
-
-		np = of_parse_phandle(node, "i2c-bus", 0);
-		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);
-	} else if (has_acpi_companion(&pdev->dev)) {
-		struct acpi_device *adev = ACPI_COMPANION(&pdev->dev);
-		struct fwnode_handle *fw = acpi_fwnode_handle(adev);
-		struct fwnode_reference_args args;
-		struct acpi_handle *acpi_handle;
-		int ret;
-
-		ret = acpi_node_get_property_reference(fw, "i2c-bus", 0, &args);
-		if (ret || !is_acpi_device_node(args.fwnode)) {
-			dev_err(&pdev->dev, "missing 'i2c-bus' property\n");
-			return -ENODEV;
-		}
-
-		acpi_handle = ACPI_HANDLE_FWNODE(args.fwnode);
-		i2c = i2c_acpi_find_adapter_by_handle(acpi_handle);
-	} else {
+	} else if (!has_acpi_companion(&pdev->dev)) {
 		return -EINVAL;
 	}
 
-	if (!i2c)
-		return -EPROBE_DEFER;
-
-	err = sfp_i2c_configure(sfp, i2c);
-	if (err < 0) {
-		i2c_put_adapter(i2c);
+	err = sfp_i2c_get(sfp);
+	if (err)
 		return err;
-	}
 
 	for (i = 0; i < GPIO_MAX; i++)
 		if (sff->gpios & BIT(i)) {