net: phy: mscc: report and configure in-band auto-negotiation for SGMII/QSGMII

The following Vitesse/Microsemi/Microchip PHYs, among those supported by
this driver, have the host interface configurable as SGMII or QSGMII:
- VSC8504
- VSC8514
- VSC8552
- VSC8562
- VSC8572
- VSC8574
- VSC8575
- VSC8582
- VSC8584

All these PHYs are documented to have bit 7 of "MAC SerDes PCS Control"
as "MAC SerDes ANEG enable".

Out of these, I could test the VSC8514 quad PHY in QSGMII. This works
both with the in-band autoneg on and off, on the NXP LS1028A-RDB and
T1040-RDB boards.

Notably, the bit is sticky (survives soft resets), so giving Linux the
tools to read and modify this settings makes it robust to changes made
to it by previous boot layers (U-Boot).

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Link: https://patch.msgid.link/20250813074454.63224-1-vladimir.oltean@nxp.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/drivers/net/phy/mscc/mscc.h b/drivers/net/phy/mscc/mscc.h
index 6a3d8a754eb8de6dfc1740208744f625fe328384..138355f1ab0bcf27e22c3ffcbd0b272fa594f7c8 100644 (file)
--- a/drivers/net/phy/mscc/mscc.h
+++ b/drivers/net/phy/mscc/mscc.h
@@ -196,6 +196,9 @@ enum rgmii_clock_delay {
 #define MSCC_PHY_EXTENDED_INT_MS_EGR     BIT(9)
 
 /* Extended Page 3 Registers */
+#define MSCC_PHY_SERDES_PCS_CTRL         16
+#define MSCC_PHY_SERDES_ANEG             BIT(7)
+
 #define MSCC_PHY_SERDES_TX_VALID_CNT     21
 #define MSCC_PHY_SERDES_TX_CRC_ERR_CNT   22
 #define MSCC_PHY_SERDES_RX_VALID_CNT     28

diff --git a/drivers/net/phy/mscc/mscc_main.c b/drivers/net/phy/mscc/mscc_main.c
index 7ed6522fb0ef7474762f2a9d417362a6974646c9..3bcf48febb1f9d8c49f2312787df8b8dc0a41b73 100644 (file)
--- a/drivers/net/phy/mscc/mscc_main.c
+++ b/drivers/net/phy/mscc/mscc_main.c
@@ -2202,6 +2202,28 @@ static int vsc85xx_read_status(struct phy_device *phydev)
        return genphy_read_status(phydev);
 }
 
+static unsigned int vsc85xx_inband_caps(struct phy_device *phydev,
+                                       phy_interface_t interface)
+{
+       if (interface != PHY_INTERFACE_MODE_SGMII &&
+           interface != PHY_INTERFACE_MODE_QSGMII)
+               return 0;
+
+       return LINK_INBAND_DISABLE | LINK_INBAND_ENABLE;
+}
+
+static int vsc85xx_config_inband(struct phy_device *phydev, unsigned int modes)
+{
+       u16 reg_val = 0;
+
+       if (modes == LINK_INBAND_ENABLE)
+               reg_val = MSCC_PHY_SERDES_ANEG;
+
+       return phy_modify_paged(phydev, MSCC_PHY_PAGE_EXTENDED_3,
+                               MSCC_PHY_SERDES_PCS_CTRL, MSCC_PHY_SERDES_ANEG,
+                               reg_val);
+}
+
 static int vsc8514_probe(struct phy_device *phydev)
 {
        struct vsc8531_private *vsc8531;
@@ -2409,6 +2431,8 @@ static struct phy_driver vsc85xx_driver[] = {
        .get_sset_count = &vsc85xx_get_sset_count,
        .get_strings    = &vsc85xx_get_strings,
        .get_stats      = &vsc85xx_get_stats,
+       .inband_caps    = vsc85xx_inband_caps,
+       .config_inband  = vsc85xx_config_inband,
 },
 {
        .phy_id         = PHY_ID_VSC8514,
@@ -2432,6 +2456,8 @@ static struct phy_driver vsc85xx_driver[] = {
        .get_sset_count = &vsc85xx_get_sset_count,
        .get_strings    = &vsc85xx_get_strings,
        .get_stats      = &vsc85xx_get_stats,
+       .inband_caps    = vsc85xx_inband_caps,
+       .config_inband  = vsc85xx_config_inband,
 },
 {
        .phy_id         = PHY_ID_VSC8530,
@@ -2552,6 +2578,8 @@ static struct phy_driver vsc85xx_driver[] = {
        .get_sset_count = &vsc85xx_get_sset_count,
        .get_strings    = &vsc85xx_get_strings,
        .get_stats      = &vsc85xx_get_stats,
+       .inband_caps    = vsc85xx_inband_caps,
+       .config_inband  = vsc85xx_config_inband,
 },
 {
        .phy_id         = PHY_ID_VSC856X,
@@ -2574,6 +2602,8 @@ static struct phy_driver vsc85xx_driver[] = {
        .get_sset_count = &vsc85xx_get_sset_count,
        .get_strings    = &vsc85xx_get_strings,
        .get_stats      = &vsc85xx_get_stats,
+       .inband_caps    = vsc85xx_inband_caps,
+       .config_inband  = vsc85xx_config_inband,
 },
 {
        .phy_id         = PHY_ID_VSC8572,
@@ -2599,6 +2629,8 @@ static struct phy_driver vsc85xx_driver[] = {
        .get_sset_count = &vsc85xx_get_sset_count,
        .get_strings    = &vsc85xx_get_strings,
        .get_stats      = &vsc85xx_get_stats,
+       .inband_caps    = vsc85xx_inband_caps,
+       .config_inband  = vsc85xx_config_inband,
 },
 {
        .phy_id         = PHY_ID_VSC8574,
@@ -2624,6 +2656,8 @@ static struct phy_driver vsc85xx_driver[] = {
        .get_sset_count = &vsc85xx_get_sset_count,
        .get_strings    = &vsc85xx_get_strings,
        .get_stats      = &vsc85xx_get_stats,
+       .inband_caps    = vsc85xx_inband_caps,
+       .config_inband  = vsc85xx_config_inband,
 },
 {
        .phy_id         = PHY_ID_VSC8575,
@@ -2647,6 +2681,8 @@ static struct phy_driver vsc85xx_driver[] = {
        .get_sset_count = &vsc85xx_get_sset_count,
        .get_strings    = &vsc85xx_get_strings,
        .get_stats      = &vsc85xx_get_stats,
+       .inband_caps    = vsc85xx_inband_caps,
+       .config_inband  = vsc85xx_config_inband,
 },
 {
        .phy_id         = PHY_ID_VSC8582,
@@ -2670,6 +2706,8 @@ static struct phy_driver vsc85xx_driver[] = {
        .get_sset_count = &vsc85xx_get_sset_count,
        .get_strings    = &vsc85xx_get_strings,
        .get_stats      = &vsc85xx_get_stats,
+       .inband_caps    = vsc85xx_inband_caps,
+       .config_inband  = vsc85xx_config_inband,
 },
 {
        .phy_id         = PHY_ID_VSC8584,
@@ -2694,6 +2732,8 @@ static struct phy_driver vsc85xx_driver[] = {
        .get_strings    = &vsc85xx_get_strings,
        .get_stats      = &vsc85xx_get_stats,
        .link_change_notify = &vsc85xx_link_change_notify,
+       .inband_caps    = vsc85xx_inband_caps,
+       .config_inband  = vsc85xx_config_inband,
 }
 
 };