[PATCH v3] net: mdio: mux-meson-gxl: set reversed bit when using internal phy

[Da Xue <da@libre.computer>]

This bit is necessary to receive packets from the internal PHY.
Without this bit set, no activity occurs on the interface.

Normally u-boot sets this bit, but if u-boot is compiled without
net support, the interface will be up but without any activity.

The vendor SDK sets this bit along with the PHY_ID bits.

Fixes: 9a24e1ff4326 ("net: mdio: add amlogic gxl mdio mux support");
Signed-off-by: Da Xue <da@libre.computer>
---
Changes since v2:
* Rename REG2_RESERVED_28 to REG2_REVERSED

Link to v2:
https://patchwork.kernel.org/project/linux-amlogic/patch/20250331074420.3443748-1-christianshewitt@gmail.com/
---
 drivers/net/mdio/mdio-mux-meson-gxl.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/net/mdio/mdio-mux-meson-gxl.c b/drivers/net/mdio/mdio-mux-meson-gxl.c
index 00c66240136b..3dd12a8c8b03 100644
--- a/drivers/net/mdio/mdio-mux-meson-gxl.c
+++ b/drivers/net/mdio/mdio-mux-meson-gxl.c
@@ -17,6 +17,7 @@
 #define  REG2_LEDACT		GENMASK(23, 22)
 #define  REG2_LEDLINK		GENMASK(25, 24)
 #define  REG2_DIV4SEL		BIT(27)
+#define  REG2_REVERSED		BIT(28)
 #define  REG2_ADCBYPASS		BIT(30)
 #define  REG2_CLKINSEL		BIT(31)
 #define ETH_REG3		0x4
@@ -65,7 +66,7 @@ static void gxl_enable_internal_mdio(struct gxl_mdio_mux *priv)
 	 * The only constraint is that it must match the one in
 	 * drivers/net/phy/meson-gxl.c to properly match the PHY.
 	 */
-	writel(FIELD_PREP(REG2_PHYID, EPHY_GXL_ID),
+	writel(REG2_REVERSED | FIELD_PREP(REG2_PHYID, EPHY_GXL_ID),
 	       priv->regs + ETH_REG2);
 
 	/* Enable the internal phy */
-- 
2.39.5