[openwrt/openwrt] realtek: mdio: rtl838x: re-enable phy control via SoC

[LEDE Commits]

robimarko pushed a commit to openwrt/openwrt.git, branch main:
https://git.openwrt.org/054785b161cd410365c307a44579bfe545e981a1

commit 054785b161cd410365c307a44579bfe545e981a1
Author: Bjørn Mork <bjorn at mork.no>
AuthorDate: Wed Feb 4 12:23:24 2026 +0100

    realtek: mdio: rtl838x: re-enable phy control via SoC
    
    Commit 17f12695d083 ("realtek: mdio: rtl838x: activate combo PHY media detection")
    dropped setting bit 15 of the SMI_GLB_CTRL register without any explanation.  This
    broke the Netgear GS108Tv3, causing phy patching to fail:
    
     Firmware loaded. Size 1184, magic: 83808380
     Realtek RTL8218B (internal) 1b000000.switchcore:mdio-controller-mii:08: patch
     Realtek RTL8218B (internal) 1b000000.switchcore:mdio-controller-mii:08: package not ready for patch.
     Realtek RTL8218B (internal) 1b000000.switchcore:mdio-controller-mii:0f: probe with driver Realtek RTL8218B (internal) failed with error -5
    
    None of the internal phys was able to detect a link after this error.
    
    Some rtl8380 devices, like the Zyxel GS1900-10HP A1, were not affected by the bug
    because their boot loader always sets bit 15. The bug could also be worked around
    on affected devices by running "rtk network on" before booting OpenWrt, setting
    bit 15 as a side effect.
    
    Cc: Markus Stockhausen <markus.stockhausen at gmx.de>
    Cc: Robert Marko <robimarko at gmail.com>
    Fixes: 17f12695d083 ("realtek: mdio: rtl838x: activate combo PHY media detection")
    Signed-off-by: Bjørn Mork <bjorn at mork.no>
    Link: https://github.com/openwrt/openwrt/pull/21868
    Signed-off-by: Robert Marko <robimarko at gmail.com>
---
 target/linux/realtek/files-6.12/drivers/net/mdio/mdio-realtek-otto.c | 5 +++++
 1 file changed, 5 insertions(+)

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 76a61f6f23..e4a7ef49a3 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
@@ -666,6 +666,11 @@ static int rtmdio_838x_reset(struct mii_bus *bus)
 	combo_phy = ctrl->smi_bus[24] < 0 ? 0 : BIT(7);
 	regmap_update_bits(ctrl->map, RTMDIO_838X_SMI_GLB_CTRL, BIT(7), combo_phy);
 
+	/*
+	 * Bit 15, PHY_PATCH_DONE, enables phy control via SoC. This is required for phy
+	 * access, including patching. Must always be set before the phys are probed.
+	 */
+	regmap_update_bits(ctrl->map, RTMDIO_838X_SMI_GLB_CTRL, BIT(15), BIT(15));
 	return 0;
 }