From: Thanh Quan <[email protected]>
According to the TI DP83869HM datasheet Revision D (June 2025), section
7.6.1.41 STRAP_STS Register, the STRAP_OPMODE bitmask is bit [11:9].
Fix this.
In case the PHY is auto-detected via PHY ID registers, or not described
in DT, or, in case the PHY is described in DT but the optional DT property
"ti,op-mode" is not present, then the driver reads out the PHY functional
mode (RGMII, SGMII, ...) from hardware straps.
Currently, all upstream users of this PHY specify both DT compatible string
"ethernet-phy-id2000.a0f1" and ti,op-mode = <DP83869_RGMII_COPPER_ETHERNET>
property, therefore it seems no upstream users are affected by this bug.
The driver currently interprets bits [2:0] of STRAP_STS register as PHY
functional mode. Those bits are controlled by ANEG_DIS, ANEGSEL_0 straps
and an always-zero reserved bit. Systems that use RGMII-to-Copper functional
mode are unlikely to disable auto-negotiation via ANEG_DIS strap, or change
auto-negotiation behavior via ANEGSEL_0 strap. Therefore, even with this bug
in place, the STRAP_STS register content is likely going to be interpreted
by the driver as RGMII-to-Copper mode.
However, for a system with PHY functional mode strapping set to other mode
than RGMII-to-Copper, the driver is likely to misinterpret the strapping
as RGMII-to-Copper and misconfigure the PHY.
For example, on a system with SGMII-to-Copper strapping, the STRAP_STS
register reads as 0x0c20, but the PHY ends up being configured for
incompatible RGMII-to-Copper mode.
Fixes: f3e22eea815d ("net: phy: add TI DP83869HM ethernet driver")
Signed-off-by: Thanh Quan <[email protected]>
Signed-off-by: Hai Pham <[email protected]>
Signed-off-by: Marek Vasut <[email protected]> # Use FIELD_GET()
---
Cc: Dominic Rath <[email protected]>
Cc: Hai Pham <[email protected]>
Cc: Jerome Forissier <[email protected]>
Cc: Joe Hershberger <[email protected]>
Cc: Ramon Fried <[email protected]>
Cc: Thanh Quan <[email protected]>
Cc: Tom Rini <[email protected]>
Cc: [email protected]
---
V2: Update commit message to match Linux
---
drivers/net/phy/dp83869.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/drivers/net/phy/dp83869.c b/drivers/net/phy/dp83869.c
index b6fb5adae1f..c60fbf26a03 100644
--- a/drivers/net/phy/dp83869.c
+++ b/drivers/net/phy/dp83869.c
@@ -5,6 +5,7 @@
*/
#include <phy.h>
+#include <linux/bitfield.h>
#include <linux/compat.h>
#include <malloc.h>
@@ -64,7 +65,7 @@
#define DP83869_RGMII_RX_CLK_DELAY_EN BIT(0)
/* STRAP_STS1 bits */
-#define DP83869_STRAP_OP_MODE_MASK GENMASK(2, 0)
+#define DP83869_STRAP_OP_MODE_MASK GENMASK(11, 9)
#define DP83869_STRAP_STS1_RESERVED BIT(11)
#define DP83869_STRAP_MIRROR_ENABLED BIT(12)
@@ -168,7 +169,7 @@ static int dp83869_set_strapped_mode(struct phy_device
*phydev)
if (val < 0)
return val;
- dp83869->mode = val & DP83869_STRAP_OP_MODE_MASK;
+ dp83869->mode = FIELD_GET(DP83869_STRAP_OP_MODE_MASK, val);
return 0;
}
--
2.51.0
