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

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

[Vladimir Oltean]

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>
---
 drivers/net/phy/mscc/mscc.h      |  3 +++
 drivers/net/phy/mscc/mscc_main.c | 40 ++++++++++++++++++++++++++++++++
 2 files changed, 43 insertions(+)

diff --git a/drivers/net/phy/mscc/mscc.h b/drivers/net/phy/mscc/mscc.h
index 6a3d8a754eb8..138355f1ab0b 100644
--- 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 7ed6522fb0ef..3bcf48febb1f 100644
--- 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,
 }
 
 };
-- 
2.34.1

Re: [PATCH net-next] net: phy: mscc: report and configure in-band auto-negotiation for SGMII/QSGMII

[Russell King (Oracle)]

On Wed, Aug 13, 2025 at 10:44:54AM +0300, Vladimir Oltean wrote:
> 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>

Looks sensible.

Reviewed-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>

Thanks!

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Re: [PATCH net-next] net: phy: mscc: report and configure in-band auto-negotiation for SGMII/QSGMII

[patchwork-bot+netdevbpf]

Hello:

This patch was applied to netdev/net-next.git (main)
by Jakub Kicinski <kuba@kernel.org>:

On Wed, 13 Aug 2025 10:44:54 +0300 you wrote:
> 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
> 
> [...]

Here is the summary with links:
  - [net-next] net: phy: mscc: report and configure in-band auto-negotiation for SGMII/QSGMII
    https://git.kernel.org/netdev/net-next/c/df979273bd71

You are awesome, thank you!
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