[openwrt/openwrt] realtek: mdio: harden mdio probing

[LEDE Commits]

robimarko pushed a commit to openwrt/openwrt.git, branch main:
https://git.openwrt.org/45fa6e317506b72236ff7583e0bde37077337cda

commit 45fa6e317506b72236ff7583e0bde37077337cda
Author: Markus Stockhausen <markus.stockhausen at gmx.de>
AuthorDate: Tue Feb 10 17:16:48 2026 +0100

    realtek: mdio: harden mdio probing
    
    Do better error checks during bus probing. Give meaningful return codes
    in case of invalid DTS data (EINVAL instead of ENODEV). Decrease node
    reference in case of errors.
    
    Signed-off-by: Markus Stockhausen <markus.stockhausen at gmx.de>
    Link: https://github.com/openwrt/openwrt/pull/21968
    Signed-off-by: Robert Marko <robimarko at gmail.com>
---
 .../files-6.12/drivers/net/mdio/mdio-realtek-otto.c        | 14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)

diff --git a/target/linux/realtek/files-6.12/drivers/net/mdio/mdio-realtek-otto.c b/target/linux/realtek/files-6.12/drivers/net/mdio/mdio-realtek-otto.c
index bb61b9d48c..628de4790a 100644
--- a/target/linux/realtek/files-6.12/drivers/net/mdio/mdio-realtek-otto.c
+++ b/target/linux/realtek/files-6.12/drivers/net/mdio/mdio-realtek-otto.c
@@ -913,18 +913,20 @@ static int rtmdio_probe(struct platform_device *pdev)
 		if (of_property_read_u32(dn, "reg", &addr))
 			continue;
 
-		if (addr >= ctrl->cfg->cpu_port) {
-			pr_err("%s: illegal port number %d\n", __func__, addr);
-			return -ENODEV;
+		if (addr < 0 || addr >= ctrl->cfg->cpu_port) {
+			dev_err(dev, "illegal port number %d\n", addr);
+			of_node_put(dn);
+			return -EINVAL;
 		}
 
 		of_property_read_u32(dn->parent, "reg", &ctrl->smi_bus[addr]);
 		if (of_property_read_u32(dn, "realtek,smi-address", &ctrl->smi_addr[addr]))
 			ctrl->smi_addr[addr] = addr;
 		
-		if (ctrl->smi_bus[addr] >= RTMDIO_MAX_SMI_BUS) {
-			pr_err("%s: illegal SMI bus number %d\n", __func__, ctrl->smi_bus[addr]);
-			return -ENODEV;
+		if (ctrl->smi_bus[addr] < 0 || ctrl->smi_bus[addr] >= RTMDIO_MAX_SMI_BUS) {
+			dev_err(dev, "illegal SMI bus number %d\n", ctrl->smi_bus[addr]);
+			of_node_put(dn);
+			return -EINVAL;
 		}
 
 		if (of_device_is_compatible(dn, "ethernet-phy-ieee802.3-c45"))