[PATCH] net: ethernet: mvneta: add support for 2.5G DRSGMII mode

[Sascha Hauer]

The Marvell MVNETA Ethernet controller supports a 2.5 Gbps SGMII mode
called DRSGMII.

This patch adds a corresponding phy-mode string 'drsgmii' and parses it
from DT. The MVNETA then configures the SERDES protocol value
accordingly.

It was successfully tested on a MV78460 connected to a FPGA.

Signed-off-by: Sascha Hauer <s.hauer@xxxxxxxxxxxxxx>
---
 .../devicetree/bindings/net/ethernet-controller.yaml       | 1 +
 drivers/net/ethernet/marvell/mvneta.c                      | 7 ++++++-
 include/linux/phy.h                                        | 3 +++
 3 files changed, 10 insertions(+), 1 deletion(-)

This patch has already been sent 3 years ago here:
https://patchwork.ozlabs.org/project/devicetree-bindings/patch/20170123142206.5390-1-jlu@xxxxxxxxxxxxxx/
Since then the driver has evolved a lot. 2.5Gbps is properly configured in the
MAC now.

diff --git a/Documentation/devicetree/bindings/net/ethernet-controller.yaml b/Documentation/devicetree/bindings/net/ethernet-controller.yaml
index ac471b60ed6ae..4eead3c89bd3e 100644
--- a/Documentation/devicetree/bindings/net/ethernet-controller.yaml
+++ b/Documentation/devicetree/bindings/net/ethernet-controller.yaml
@@ -66,6 +66,7 @@ properties:
       - gmii
       - sgmii
       - qsgmii
+      - drsgmii
       - tbi
       - rev-mii
       - rmii
diff --git a/drivers/net/ethernet/marvell/mvneta.c b/drivers/net/ethernet/marvell/mvneta.c
index 51889770958d8..807c698576c74 100644
--- a/drivers/net/ethernet/marvell/mvneta.c
+++ b/drivers/net/ethernet/marvell/mvneta.c
@@ -109,6 +109,7 @@
 #define MVNETA_SERDES_CFG			 0x24A0
 #define      MVNETA_SGMII_SERDES_PROTO		 0x0cc7
 #define      MVNETA_QSGMII_SERDES_PROTO		 0x0667
+#define      MVNETA_DRSGMII_SERDES_PROTO	 0x1107
 #define MVNETA_TYPE_PRIO                         0x24bc
 #define      MVNETA_FORCE_UNI                    BIT(21)
 #define MVNETA_TXQ_CMD_1                         0x24e4
@@ -3734,10 +3735,11 @@ static void mvneta_validate(struct phylink_config *config,
 	struct mvneta_port *pp = netdev_priv(ndev);
 	__ETHTOOL_DECLARE_LINK_MODE_MASK(mask) = { 0, };
 
-	/* We only support QSGMII, SGMII, 802.3z and RGMII modes */
+	/* We only support QSGMII, SGMII, DRSGMII, 802.3z and RGMII modes */
 	if (state->interface != PHY_INTERFACE_MODE_NA &&
 	    state->interface != PHY_INTERFACE_MODE_QSGMII &&
 	    state->interface != PHY_INTERFACE_MODE_SGMII &&
+	    state->interface != PHY_INTERFACE_MODE_DRSGMII &&
 	    !phy_interface_mode_is_8023z(state->interface) &&
 	    !phy_interface_mode_is_rgmii(state->interface)) {
 		bitmap_zero(supported, __ETHTOOL_LINK_MODE_MASK_NBITS);
@@ -3851,6 +3853,7 @@ static void mvneta_mac_config(struct phylink_config *config, unsigned int mode,
 
 	if (state->interface == PHY_INTERFACE_MODE_QSGMII ||
 	    state->interface == PHY_INTERFACE_MODE_SGMII ||
+	    state->interface == PHY_INTERFACE_MODE_DRSGMII ||
 	    phy_interface_mode_is_8023z(state->interface))
 		new_ctrl2 |= MVNETA_GMAC2_PCS_ENABLE;
 
@@ -4968,6 +4971,8 @@ static int mvneta_port_power_up(struct mvneta_port *pp, int phy_mode)
 	else if (phy_mode == PHY_INTERFACE_MODE_SGMII ||
 		 phy_interface_mode_is_8023z(phy_mode))
 		mvreg_write(pp, MVNETA_SERDES_CFG, MVNETA_SGMII_SERDES_PROTO);
+	else if (phy_mode == PHY_INTERFACE_MODE_DRSGMII)
+		mvreg_write(pp, MVNETA_SERDES_CFG, MVNETA_DRSGMII_SERDES_PROTO);
 	else if (!phy_interface_mode_is_rgmii(phy_mode))
 		return -EINVAL;
 
diff --git a/include/linux/phy.h b/include/linux/phy.h
index 2432ca463ddc0..bf3276b330f9e 100644
--- a/include/linux/phy.h
+++ b/include/linux/phy.h
@@ -109,6 +109,7 @@ typedef enum {
 	PHY_INTERFACE_MODE_USXGMII,
 	/* 10GBASE-KR - with Clause 73 AN */
 	PHY_INTERFACE_MODE_10GKR,
+	PHY_INTERFACE_MODE_DRSGMII,
 	PHY_INTERFACE_MODE_MAX,
 } phy_interface_t;
 
@@ -190,6 +191,8 @@ static inline const char *phy_modes(phy_interface_t interface)
 		return "usxgmii";
 	case PHY_INTERFACE_MODE_10GKR:
 		return "10gbase-kr";
+	case PHY_INTERFACE_MODE_DRSGMII:
+		return "drsgmii";
 	default:
 		return "unknown";
 	}
-- 
2.27.0