[PATCH net-next v6 6/6] net: dsa: microchip: Disable PTP function of KSZ8463

Tristram.Ha@microchip.com posted 6 patches 2 months, 1 week ago
[PATCH net-next v6 6/6] net: dsa: microchip: Disable PTP function of KSZ8463
Posted by Tristram.Ha@microchip.com 2 months, 1 week ago
From: Tristram Ha <tristram.ha@microchip.com>

The PTP function of KSZ8463 is on by default.  However, its proprietary
way of storing timestamp directly in a reserved field inside the PTP
message header is not suitable for use with the current Linux PTP stack
implementation.  It is necessary to disable the PTP function to not
interfere the normal operation of the MAC.

Note the PTP driver for KSZ switches does not work for KSZ8463 and is not
activated for it.

Signed-off-by: Tristram Ha <tristram.ha@microchip.com>
---
 drivers/net/dsa/microchip/ksz8.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/drivers/net/dsa/microchip/ksz8.c b/drivers/net/dsa/microchip/ksz8.c
index 62224426a9bd..c400e1c0369e 100644
--- a/drivers/net/dsa/microchip/ksz8.c
+++ b/drivers/net/dsa/microchip/ksz8.c
@@ -1760,6 +1760,17 @@ void ksz8_config_cpu_port(struct dsa_switch *ds)
 					   KSZ8463_REG_DSP_CTRL_6,
 					   COPPER_RECEIVE_ADJUSTMENT, 0);
 		}
+
+		/* Turn off PTP function as the switch's proprietary way of
+		 * handling timestamp is not supported in current Linux PTP
+		 * stack implementation.
+		 */
+		regmap_update_bits(ksz_regmap_16(dev),
+				   KSZ8463_PTP_MSG_CONF1,
+				   PTP_ENABLE, 0);
+		regmap_update_bits(ksz_regmap_16(dev),
+				   KSZ8463_PTP_CLK_CTRL,
+				   PTP_CLK_ENABLE, 0);
 	}
 }
 
-- 
2.34.1
Re: [PATCH net-next v6 6/6] net: dsa: microchip: Disable PTP function of KSZ8463
Posted by Andrew Lunn 2 months, 1 week ago
On Thu, Jul 24, 2025 at 05:17:53PM -0700, Tristram.Ha@microchip.com wrote:
> From: Tristram Ha <tristram.ha@microchip.com>
> 
> The PTP function of KSZ8463 is on by default.  However, its proprietary
> way of storing timestamp directly in a reserved field inside the PTP
> message header is not suitable for use with the current Linux PTP stack
> implementation.  It is necessary to disable the PTP function to not
> interfere the normal operation of the MAC.
> 
> Note the PTP driver for KSZ switches does not work for KSZ8463 and is not
> activated for it.
> 
> Signed-off-by: Tristram Ha <tristram.ha@microchip.com>

Reviewed-by: Andrew Lunn <andrew@lunn.ch>

    Andrew