The "reverse SGMII" protocol name is an invention derived from
"reverse MII" and "reverse RMII", this means: "behave like an SGMII
PHY".

Signed-off-by: David Yang <mmyangfl@gmail.com>
Reviewed-by: Maxime Chevallier <maxime.chevallier@bootlin.com>
---
 drivers/net/phy/phy-core.c | 1 +
 drivers/net/phy/phy_caps.c | 1 +
 drivers/net/phy/phylink.c  | 1 +
 include/linux/phy.h        | 4 ++++
 4 files changed, 7 insertions(+)

diff --git a/drivers/net/phy/phy-core.c b/drivers/net/phy/phy-core.c
index 605ca20ae192..074645840cd5 100644
--- a/drivers/net/phy/phy-core.c
+++ b/drivers/net/phy/phy-core.c
@@ -132,6 +132,7 @@ int phy_interface_num_ports(phy_interface_t interface)
 	case PHY_INTERFACE_MODE_TRGMII:
 	case PHY_INTERFACE_MODE_USXGMII:
 	case PHY_INTERFACE_MODE_SGMII:
+	case PHY_INTERFACE_MODE_REVSGMII:
 	case PHY_INTERFACE_MODE_SMII:
 	case PHY_INTERFACE_MODE_1000BASEX:
 	case PHY_INTERFACE_MODE_2500BASEX:
diff --git a/drivers/net/phy/phy_caps.c b/drivers/net/phy/phy_caps.c
index 2cc9ee97e867..9a9a8afc056f 100644
--- a/drivers/net/phy/phy_caps.c
+++ b/drivers/net/phy/phy_caps.c
@@ -299,6 +299,7 @@ unsigned long phy_caps_from_interface(phy_interface_t interface)
 	case PHY_INTERFACE_MODE_PSGMII:
 	case PHY_INTERFACE_MODE_QSGMII:
 	case PHY_INTERFACE_MODE_QUSGMII:
+	case PHY_INTERFACE_MODE_REVSGMII:
 	case PHY_INTERFACE_MODE_SGMII:
 	case PHY_INTERFACE_MODE_GMII:
 		link_caps |= BIT(LINK_CAPA_1000HD) | BIT(LINK_CAPA_1000FD);
diff --git a/drivers/net/phy/phylink.c b/drivers/net/phy/phylink.c
index 9d7799ea1c17..910e93d2a324 100644
--- a/drivers/net/phy/phylink.c
+++ b/drivers/net/phy/phylink.c
@@ -255,6 +255,7 @@ static int phylink_interface_max_speed(phy_interface_t interface)
 	case PHY_INTERFACE_MODE_PSGMII:
 	case PHY_INTERFACE_MODE_QSGMII:
 	case PHY_INTERFACE_MODE_QUSGMII:
+	case PHY_INTERFACE_MODE_REVSGMII:
 	case PHY_INTERFACE_MODE_SGMII:
 	case PHY_INTERFACE_MODE_GMII:
 		return SPEED_1000;
diff --git a/include/linux/phy.h b/include/linux/phy.h
index d09fc42e61f3..7390014fccb5 100644
--- a/include/linux/phy.h
+++ b/include/linux/phy.h
@@ -107,6 +107,7 @@ extern const int phy_basic_ports_array[3];
  * @PHY_INTERFACE_MODE_LAUI: 50 Gigabit Attachment Unit Interface
  * @PHY_INTERFACE_MODE_100GBASEP: 100GBase-P - with Clause 134 FEC
  * @PHY_INTERFACE_MODE_MIILITE: MII-Lite - MII without RXER TXER CRS COL
+ * @PHY_INTERFACE_MODE_REVSGMII: Serial gigabit media-independent interface in PHY role
  * @PHY_INTERFACE_MODE_MAX: Book keeping
  *
  * Describes the interface between the MAC and PHY.
@@ -152,6 +153,7 @@ typedef enum {
 	PHY_INTERFACE_MODE_LAUI,
 	PHY_INTERFACE_MODE_100GBASEP,
 	PHY_INTERFACE_MODE_MIILITE,
+	PHY_INTERFACE_MODE_REVSGMII,
 	PHY_INTERFACE_MODE_MAX,
 } phy_interface_t;
 
@@ -286,6 +288,8 @@ static inline const char *phy_modes(phy_interface_t interface)
 		return "100gbase-p";
 	case PHY_INTERFACE_MODE_MIILITE:
 		return "mii-lite";
+	case PHY_INTERFACE_MODE_REVSGMII:
+		return "rev-sgmii";
 	default:
 		return "unknown";
 	}
-- 
2.51.0

On 9/26/25 3:50 PM, David Yang wrote:
> The "reverse SGMII" protocol name is an invention derived from
> "reverse MII" and "reverse RMII", this means: "behave like an SGMII
> PHY".
> 
> Signed-off-by: David Yang <mmyangfl@gmail.com>
> Reviewed-by: Maxime Chevallier <maxime.chevallier@bootlin.com>

My understanding is that Russell question on v11 is still pending:

https://lore.kernel.org/netdev/aNbWEdabqXIaoo2T@shell.armlinux.org.uk/

and the net-next PR for 6.18 is upcoming. Deferring to next cycle.

Cheers,

Paolo