net: of_get_phy_mode: Change API to solve int/unit warnings

Before this change of_get_phy_mode() returned an enum,
phy_interface_t. On error, -ENODEV etc, is returned. If the result of
the function is stored in a variable of type phy_interface_t, and the
compiler has decided to represent this as an unsigned int, comparision
with -ENODEV etc, is a signed vs unsigned comparision.

Fix this problem by changing the API. Make the function return an
error, or 0 on success, and pass a pointer, of type phy_interface_t,
where the phy mode should be stored.

v2:
Return with *interface set to PHY_INTERFACE_MODE_NA on error.
Add error checks to all users of of_get_phy_mode()
Fixup a few reverse christmas tree errors
Fixup a few slightly malformed reverse christmas trees

v3:
Fix 0-day reported errors.

Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/dsa/bcm_sf2.c

@@ -381,8 +381,9 @@ static void bcm_sf2_identify_ports(struct bcm_sf2_priv *priv,
 				   struct device_node *dn)
 {
 	struct device_node *port;
-	int mode;
 	unsigned int port_num;
+	phy_interface_t mode;
+	int err;
 
 	priv->moca_port = -1;
 
@@ -395,8 +396,8 @@ static void bcm_sf2_identify_ports(struct bcm_sf2_priv *priv,
 		 * has completed, since they might be turned off at that
 		 * time
 		 */
-		mode = of_get_phy_mode(port);
-		if (mode < 0)
+		err = of_get_phy_mode(port, &mode);
+		if (err)
 			continue;
 
 		if (mode == PHY_INTERFACE_MODE_INTERNAL)

drivers/net/dsa/microchip/ksz_common.c

@@ -422,6 +422,7 @@ EXPORT_SYMBOL(ksz_switch_alloc);
 int ksz_switch_register(struct ksz_device *dev,
 			const struct ksz_dev_ops *ops)
 {
+	phy_interface_t interface;
 	int ret;
 
 	if (dev->pdata)
@@ -456,9 +457,9 @@ int ksz_switch_register(struct ksz_device *dev,
 	 * device tree.
 	 */
 	if (dev->dev->of_node) {
-		ret = of_get_phy_mode(dev->dev->of_node);
-		if (ret >= 0)
-			dev->interface = ret;
+		ret = of_get_phy_mode(dev->dev->of_node, &interface);
+		if (ret == 0)
+			dev->interface = interface;
 		dev->synclko_125 = of_property_read_bool(dev->dev->of_node,
 							 "microchip,synclko-125");
 	}

drivers/net/dsa/mt7530.c

@@ -1340,7 +1340,9 @@ mt7530_setup(struct dsa_switch *ds)
 
 	if (!dsa_is_unused_port(ds, 5)) {
 		priv->p5_intf_sel = P5_INTF_SEL_GMAC5;
-		interface = of_get_phy_mode(dsa_to_port(ds, 5)->dn);
+		ret = of_get_phy_mode(dsa_to_port(ds, 5)->dn, &interface);
+		if (ret && ret != -ENODEV)
+			return ret;
 	} else {
 		/* Scan the ethernet nodes. look for GMAC1, lookup used phy */
 		for_each_child_of_node(dn, mac_np) {
@@ -1354,7 +1356,9 @@ mt7530_setup(struct dsa_switch *ds)
 
 			phy_node = of_parse_phandle(mac_np, "phy-handle", 0);
 			if (phy_node->parent == priv->dev->of_node->parent) {
-				interface = of_get_phy_mode(mac_np);
+				ret = of_get_phy_mode(mac_np, &interface);
+				if (ret && ret != -ENODEV)
+					return ret;
 				id = of_mdio_parse_addr(ds->dev, phy_node);
 				if (id == 0)
 					priv->p5_intf_sel = P5_INTF_SEL_PHY_P0;

drivers/net/dsa/qca8k.c

@@ -639,7 +639,8 @@ static int
 qca8k_setup(struct dsa_switch *ds)
 {
 	struct qca8k_priv *priv = (struct qca8k_priv *)ds->priv;
-	int ret, i, phy_mode = -1;
+	phy_interface_t phy_mode = PHY_INTERFACE_MODE_NA;
+	int ret, i;
 	u32 mask;
 
 	/* Make sure that port 0 is the cpu port */
@@ -661,10 +662,10 @@ qca8k_setup(struct dsa_switch *ds)
 		return ret;
 
 	/* Initialize CPU port pad mode (xMII type, delays...) */
-	phy_mode = of_get_phy_mode(dsa_to_port(ds, QCA8K_CPU_PORT)->dn);
-	if (phy_mode < 0) {
+	ret = of_get_phy_mode(dsa_to_port(ds, QCA8K_CPU_PORT)->dn, &phy_mode);
+	if (ret) {
 		pr_err("Can't find phy-mode for master device\n");
-		return phy_mode;
+		return ret;
 	}
 	ret = qca8k_set_pad_ctrl(priv, QCA8K_CPU_PORT, phy_mode);
 	if (ret < 0)

drivers/net/dsa/sja1105/sja1105_main.c

@@ -584,8 +584,9 @@ static int sja1105_parse_ports_node(struct sja1105_private *priv,
 
 	for_each_child_of_node(ports_node, child) {
 		struct device_node *phy_node;
-		int phy_mode;
+		phy_interface_t phy_mode;
 		u32 index;
+		int err;
 
 		/* Get switch port number from DT */
 		if (of_property_read_u32(child, "reg", &index) < 0) {
@@ -596,8 +597,8 @@ static int sja1105_parse_ports_node(struct sja1105_private *priv,
 		}
 
 		/* Get PHY mode from DT */
-		phy_mode = of_get_phy_mode(child);
-		if (phy_mode < 0) {
+		err = of_get_phy_mode(child, &phy_mode);
+		if (err) {
 			dev_err(dev, "Failed to read phy-mode or "
 				"phy-interface-type property for port %d\n",
 				index);