Fix missing configuration required for LAN865x silicon revisions B0 and B1,
as documented in Microchip Application Note AN1760 (Revision F, June 2024).

According to the guidance in the application note, register 0x10077 must be
programmed with the value 0x0028 to ensure correct operation on Rev.B0/B1
devices. Without this fixup, the device may not function correctly or may
fail to initialize.

Reference:
https://www.microchip.com/en-us/application-notes/an1760

Fixes: 5cd2340cb6a3 ("microchip: lan865x: add driver support for Microchip's LAN865X MAC-PHY")
Signed-off-by: Parthiban Veerasooran <parthiban.veerasooran@microchip.com>
---
 drivers/net/ethernet/microchip/lan865x/lan865x.c | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/drivers/net/ethernet/microchip/lan865x/lan865x.c b/drivers/net/ethernet/microchip/lan865x/lan865x.c
index d03f5a8de58d..a55ca485062f 100644
--- a/drivers/net/ethernet/microchip/lan865x/lan865x.c
+++ b/drivers/net/ethernet/microchip/lan865x/lan865x.c
@@ -32,6 +32,14 @@
 /* MAC Specific Addr 1 Top Reg */
 #define LAN865X_REG_MAC_H_SADDR1	0x00010023
 
+/* LAN865x Rev.B0/B1 configuration parameters from AN1760
+ * As per the Configuration Application Note AN1760 published in the below link,
+ * https://www.microchip.com/en-us/application-notes/an1760
+ * Revision F (DS60001760G - June 2024)
+ */
+#define LAN865X_REG_FIXUP		0x00010077
+#define LAN865X_FIXUP_VALUE		0x0028
+
 struct lan865x_priv {
 	struct work_struct multicast_work;
 	struct net_device *netdev;
@@ -346,6 +354,14 @@ static int lan865x_probe(struct spi_device *spi)
 		goto free_netdev;
 	}
 
+	/* LAN8650/1 configuration fixup from AN1760 */
+	ret = oa_tc6_write_register(priv->tc6, LAN865X_REG_FIXUP,
+				    LAN865X_FIXUP_VALUE);
+	if (ret) {
+		dev_err(&spi->dev, "Failed to configure fixup: %d\n", ret);
+		goto oa_tc6_exit;
+	}
+
 	/* As per the point s3 in the below errata, SPI receive Ethernet frame
 	 * transfer may halt when starting the next frame in the same data block
 	 * (chunk) as the end of a previous frame. The RFA field should be
-- 
2.34.1

On Wed, 13 Aug 2025 16:03:55 +0530 Parthiban Veerasooran wrote:
> +#define LAN865X_REG_FIXUP		0x00010077
> +#define LAN865X_FIXUP_VALUE		0x0028

Looks like the application note explains what this register is and what
is the meaning of the bits in it. Please break this up and name
properly. "FIXUP_REGISTER" and "FIXUP_VALUE" is about as useful
as naming it "REGSITER_AT_10077" and "VALUE_28" :/
-- 
pw-bot: cr

Hi Kakub,

Thank you for reviewing the patches.

On 16/08/25 7:10 am, Jakub Kicinski wrote:
> EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe
> 
> On Wed, 13 Aug 2025 16:03:55 +0530 Parthiban Veerasooran wrote:
>> +#define LAN865X_REG_FIXUP            0x00010077
>> +#define LAN865X_FIXUP_VALUE          0x0028
> 
> Looks like the application note explains what this register is and what
> is the meaning of the bits in it. Please break this up and name
> properly. "FIXUP_REGISTER" and "FIXUP_VALUE" is about as useful
> as naming it "REGSITER_AT_10077" and "VALUE_28" :/
Yes, sure. I will update the correct details in the next version.

Since this falls under the initial settings, I initially kept this 
configuration as a "fixup," similar to what we did in the PHY driver. In 
that case, the PHY initial settings didn’t have valid register names or 
details, so the "fixup" approach was appropriate.

However, in this case, we do have the register names and details 
available in the configuration application note. So, I will update the 
configuration accordingly.

Best regards,
Parthiban V
> --
> pw-bot: cr