net: pcs: xpcs: Split up xpcs_create() body to sub-functions

As an initial preparation before adding the fwnode-based DW XPCS device
support let's split the xpcs_create() function code up to a set of the
small sub-functions. Thus the xpcs_create() implementation will get to
look simpler and turn to be more coherent. Further updates will just touch
the new sub-functions a bit: add platform-specific device info, add the
reference clock getting and enabling.

The xpcs_create() method will now contain the next static methods calls:

xpcs_create_data() - create the DW XPCS device descriptor, pre-initialize
it' fields and increase the mdio device refcount-er;

xpcs_init_id() - find XPCS ID instance and save it in the device
descriptor;

xpcs_init_iface() - find MAC/PCS interface descriptor and perform
basic initialization specific to it: soft-reset, disable polling.

The update doesn't imply any semantic change but merely makes the code
looking simpler and more ready for adding new features support.

Note the xpcs_destroy() has been moved to being defined below the
xpcs_create_mdiodev() function as the driver now implies having the
protagonist-then-antagonist functions definition order.
Signed-off-by: Serge Semin <fancer.lancer@gmail.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/pcs/pcs-xpcs.c

@@ -1365,12 +1365,9 @@ static const struct phylink_pcs_ops xpcs_phylink_ops = {
 	.pcs_link_up = xpcs_link_up,
 };
 
-static struct dw_xpcs *xpcs_create(struct mdio_device *mdiodev,
-				   phy_interface_t interface)
+static struct dw_xpcs *xpcs_create_data(struct mdio_device *mdiodev)
 {
 	struct dw_xpcs *xpcs;
-	u32 xpcs_id;
-	int i, ret;
 
 	xpcs = kzalloc(sizeof(*xpcs), GFP_KERNEL);
 	if (!xpcs)
@@ -1378,59 +1375,89 @@ static struct dw_xpcs *xpcs_create(struct mdio_device *mdiodev,
 
 	mdio_device_get(mdiodev);
 	xpcs->mdiodev = mdiodev;
+	xpcs->pcs.ops = &xpcs_phylink_ops;
+	xpcs->pcs.neg_mode = true;
+	xpcs->pcs.poll = true;
+
+	return xpcs;
+}
+
+static void xpcs_free_data(struct dw_xpcs *xpcs)
+{
+	mdio_device_put(xpcs->mdiodev);
+	kfree(xpcs);
+}
+
+static int xpcs_init_id(struct dw_xpcs *xpcs)
+{
+	u32 xpcs_id;
+	int i, ret;
 
 	xpcs_id = xpcs_get_id(xpcs);
 
 	for (i = 0; i < ARRAY_SIZE(xpcs_id_list); i++) {
 		const struct xpcs_id *entry = &xpcs_id_list[i];
-		const struct xpcs_compat *compat;
 
 		if ((xpcs_id & entry->mask) != entry->id)
 			continue;
 
 		xpcs->id = entry;
 
-		compat = xpcs_find_compat(entry, interface);
-		if (!compat) {
-			ret = -ENODEV;
-			goto out;
-		}
+		break;
+	}
 
-		ret = xpcs_dev_flag(xpcs);
-		if (ret)
-			goto out;
+	if (!xpcs->id)
+		return -ENODEV;
 
-		xpcs->pcs.ops = &xpcs_phylink_ops;
-		xpcs->pcs.neg_mode = true;
+	ret = xpcs_dev_flag(xpcs);
+	if (ret < 0)
+		return ret;
 
-		if (xpcs->dev_flag != DW_DEV_TXGBE) {
-			xpcs->pcs.poll = true;
+	return 0;
+}
 
-			ret = xpcs_soft_reset(xpcs, compat);
-			if (ret)
-				goto out;
-		}
+static int xpcs_init_iface(struct dw_xpcs *xpcs, phy_interface_t interface)
+{
+	const struct xpcs_compat *compat;
 
-		return xpcs;
+	compat = xpcs_find_compat(xpcs->id, interface);
+	if (!compat)
+		return -EINVAL;
+
+	if (xpcs->dev_flag == DW_DEV_TXGBE) {
+		xpcs->pcs.poll = false;
+		return 0;
 	}
 
-	ret = -ENODEV;
+	return xpcs_soft_reset(xpcs, compat);
+}
+
+static struct dw_xpcs *xpcs_create(struct mdio_device *mdiodev,
+				   phy_interface_t interface)
+{
+	struct dw_xpcs *xpcs;
+	int ret;
+
+	xpcs = xpcs_create_data(mdiodev);
+	if (IS_ERR(xpcs))
+		return xpcs;
+
+	ret = xpcs_init_id(xpcs);
+	if (ret)
+		goto out;
+
+	ret = xpcs_init_iface(xpcs, interface);
+	if (ret)
+		goto out;
+
+	return xpcs;
 
 out:
-	mdio_device_put(mdiodev);
-	kfree(xpcs);
+	xpcs_free_data(xpcs);
 
 	return ERR_PTR(ret);
 }
 
-void xpcs_destroy(struct dw_xpcs *xpcs)
-{
-	if (xpcs)
-		mdio_device_put(xpcs->mdiodev);
-	kfree(xpcs);
-}
-EXPORT_SYMBOL_GPL(xpcs_destroy);
-
 struct dw_xpcs *xpcs_create_mdiodev(struct mii_bus *bus, int addr,
 				    phy_interface_t interface)
 {
@@ -1455,5 +1482,14 @@ struct dw_xpcs *xpcs_create_mdiodev(struct mii_bus *bus, int addr,
 }
 EXPORT_SYMBOL_GPL(xpcs_create_mdiodev);
 
+void xpcs_destroy(struct dw_xpcs *xpcs)
+{
+	if (!xpcs)
+		return;
+
+	xpcs_free_data(xpcs);
+}
+EXPORT_SYMBOL_GPL(xpcs_destroy);
+
 MODULE_DESCRIPTION("Synopsys DesignWare XPCS library");
 MODULE_LICENSE("GPL v2");