netdev - [PATCH v2] net: phy: realtek: convert RTL8226-CG to c45 only

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Message-ID: <20250731054445.580474-1-markus.stockhausen@gmx.de>
Date: Thu, 31 Jul 2025 01:44:45 -0400
From: Markus Stockhausen <markus.stockhausen@....de>
To: andrew@...n.ch,
	hkallweit1@...il.com,
	linux@...linux.org.uk,
	davem@...emloft.net,
	edumazet@...gle.com,
	kuba@...nel.org,
	pabeni@...hat.com,
	michael@...sekall.de,
	daniel@...rotopia.org,
	netdev@...r.kernel.org,
	jan@....eu
Cc: Markus Stockhausen <markus.stockhausen@....de>
Subject: [PATCH v2] net: phy: realtek: convert RTL8226-CG to c45 only

The RTL8226-CG can be found on devices like the Zyxel XGS1210-12. These
are driven by a Realtek RTL9302B SoC that has phy hardware polling
in the background. One must decide if a port is polled via c22 or c45.
Additionally the hardware disables MMD access in c22 mode. For reference
see mdio-realtek-rtl9300 driver. As this PHY is mostly used in Realtek
switches Convert the phy to a c45-only function set.

Because of these limitations the RTL8226 is not working at all in the
current switches. A "hacked" bus that toggles the mode for each c22/c45
access was used to get a "before status". But that is slow and producec
wrong results in the MAC polling status registers.

The RTL8226 seems to support proper MDIO_PMA_EXTABLE flags. So
genphy_c45_pma_read_abilities() can conveniently call
genphy_c45_pma_read_ext_abilities() and 10/100/1000 is populated right.

Outputs before:

Settings for lan9:
        Supported ports: [ TP MII ]
        Supported link modes:   10baseT/Half 10baseT/Full
                                100baseT/Half 100baseT/Full
                                1000baseT/Full
                                2500baseT/Full
        Supported pause frame use: Symmetric Receive-only
        Supports auto-negotiation: Yes
        Supported FEC modes: Not reported
        Advertised link modes:  10baseT/Half 10baseT/Full
                                100baseT/Half 100baseT/Full
                                1000baseT/Full
                                2500baseT/Full
        Advertised pause frame use: Symmetric Receive-only
        Advertised auto-negotiation: Yes
        Advertised FEC modes: Not reported
        Speed: Unknown!
        Duplex: Unknown! (255)
        Port: Twisted Pair
        PHYAD: 24
        Transceiver: external
        Auto-negotiation: on
        MDI-X: Unknown
        Supports Wake-on: d
        Wake-on: d
        Link detected: no

Outputs with this commit:

Settings for lan9:
        Supported ports: [ TP ]
        Supported link modes:   10baseT/Half 10baseT/Full
                                100baseT/Half 100baseT/Full
                                1000baseT/Full
                                2500baseT/Full
        Supported pause frame use: Symmetric Receive-only
        Supports auto-negotiation: Yes
        Supported FEC modes: Not reported
        Advertised link modes:  10baseT/Half 10baseT/Full
                                100baseT/Half 100baseT/Full
                                1000baseT/Full
                                2500baseT/Full
        Advertised pause frame use: Symmetric Receive-only
        Advertised auto-negotiation: Yes
        Advertised FEC modes: Not reported
        Speed: Unknown!
        Duplex: Unknown! (255)
        Port: Twisted Pair
        PHYAD: 24
        Transceiver: external
        Auto-negotiation: on
        MDI-X: Unknown
        Supports Wake-on: d
        Wake-on: d
        Link detected: no

Signed-off-by: Markus Stockhausen <markus.stockhausen@....de>
---
Changes in v2:
- Added before/after status in commit message

---
 drivers/net/phy/realtek/realtek_main.c | 26 +++++++++++++++++++++-----
 1 file changed, 21 insertions(+), 5 deletions(-)

diff --git a/drivers/net/phy/realtek/realtek_main.c b/drivers/net/phy/realtek/realtek_main.c
index dd0d675149ad..8bc68b31cd31 100644
--- a/drivers/net/phy/realtek/realtek_main.c
+++ b/drivers/net/phy/realtek/realtek_main.c
@@ -1280,6 +1280,21 @@ static int rtl822x_c45_read_status(struct phy_device *phydev)
 	return 0;
 }
 
+static int rtl822x_c45_soft_reset(struct phy_device *phydev)
+{
+	int ret, val;
+
+	ret = phy_modify_mmd(phydev, MDIO_MMD_PMAPMD, MDIO_CTRL1,
+			     MDIO_CTRL1_RESET, MDIO_CTRL1_RESET);
+	if (ret < 0)
+		return ret;
+
+	return phy_read_mmd_poll_timeout(phydev, MDIO_MMD_PMAPMD,
+					 MDIO_CTRL1, val,
+					 !(val & MDIO_CTRL1_RESET),
+					 5000, 100000, true);
+}
+
 static int rtl822xb_c45_read_status(struct phy_device *phydev)
 {
 	int ret;
@@ -1675,11 +1690,12 @@ static struct phy_driver realtek_drvs[] = {
 	}, {
 		PHY_ID_MATCH_EXACT(0x001cc838),
 		.name           = "RTL8226-CG 2.5Gbps PHY",
-		.get_features   = rtl822x_get_features,
-		.config_aneg    = rtl822x_config_aneg,
-		.read_status    = rtl822x_read_status,
-		.suspend        = genphy_suspend,
-		.resume         = rtlgen_resume,
+		.soft_reset     = rtl822x_c45_soft_reset,
+		.get_features   = rtl822x_c45_get_features,
+		.config_aneg    = rtl822x_c45_config_aneg,
+		.read_status    = rtl822x_c45_read_status,
+		.suspend        = genphy_c45_pma_suspend,
+		.resume         = rtlgen_c45_resume,
 		.read_page      = rtl821x_read_page,
 		.write_page     = rtl821x_write_page,
 	}, {
-- 
2.47.0