On Thu, Jun 26, 2025 at 03:10:50PM +0530, Siddharth Vadapalli wrote:

On Tue, Jun 24, 2025 at 12:53:33PM +0200, Matthias Schiffer wrote:

Hello Matthias,

quoted

All am65-cpsw controllers have a fixed TX delay, so the PHY interface
mode must be fixed up to account for this.

Modes that claim to a delay on the PCB can't actually work. Warn people
to update their Device Trees if one of the unsupported modes is specified.

Signed-off-by: Matthias Schiffer <redacted>
Reviewed-by: Maxime Chevallier <maxime.chevallier@bootlin.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
---
 drivers/net/ethernet/ti/am65-cpsw-nuss.c | 27 ++++++++++++++++++++++--
 1 file changed, 25 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/ti/am65-cpsw-nuss.c b/drivers/net/ethernet/ti/am65-cpsw-nuss.c
index f20d1ff192efe..519757e618ad0 100644
--- a/drivers/net/ethernet/ti/am65-cpsw-nuss.c
+++ b/drivers/net/ethernet/ti/am65-cpsw-nuss.c

@@ -2602,6 +2602,7 @@ static int am65_cpsw_nuss_init_slave_ports(struct am65_cpsw_common *common)
 		return -ENOENT;
 
 	for_each_child_of_node(node, port_np) {
+		phy_interface_t phy_if;
 		struct am65_cpsw_port *port;
 		u32 port_id;
 

@@ -2667,14 +2668,36 @@ static int am65_cpsw_nuss_init_slave_ports(struct am65_cpsw_common *common)
 
 		/* get phy/link info */
 		port->slave.port_np = of_node_get(port_np);
-		ret = of_get_phy_mode(port_np, &port->slave.phy_if);
+		ret = of_get_phy_mode(port_np, &phy_if);
 		if (ret) {
 			dev_err(dev, "%pOF read phy-mode err %d\n",
 				port_np, ret);
 			goto of_node_put;
 		}
 
-		ret = phy_set_mode_ext(port->slave.ifphy, PHY_MODE_ETHERNET, port->slave.phy_if);
+		/* CPSW controllers supported by this driver have a fixed
+		 * internal TX delay in RGMII mode. Fix up PHY mode to account
+		 * for this and warn about Device Trees that claim to have a TX
+		 * delay on the PCB.
+		 */
+		switch (phy_if) {
+		case PHY_INTERFACE_MODE_RGMII_ID:
+			phy_if = PHY_INTERFACE_MODE_RGMII_RXID;
+			break;
+		case PHY_INTERFACE_MODE_RGMII_TXID:
+			phy_if = PHY_INTERFACE_MODE_RGMII;
+			break;
+		case PHY_INTERFACE_MODE_RGMII:
+		case PHY_INTERFACE_MODE_RGMII_RXID:
+			dev_warn(dev,
+				 "RGMII mode without internal TX delay unsupported; please fix your Device Tree\n");

Existing users designed boards and enabled Ethernet functionality using
"rgmii-rxid" in the device-tree and implementing the PCB traces in a
way that they interpret "rgmii-rxid". So their (mis)interpretation of
it is being challenged by the series. While it is true that we are updating
the bindings and driver to move towards the correct definition, I believe that
the above message would cause confusion. Would it be alright to update it to
something similar to:

"Interpretation of RGMII delays has been corrected; no functional impact; please fix your Device Tree"

It is dev_warn() not dev_err(), so it should be read as a warning. And
the device will continue to probe and work. So I think the message is
O.K. What we don't want is DT developers thinking they can just ignore
it. So i would keep it reasonably strongly worded.

	Andrew