diff mbox series

[net-next,2/6] ARM: dts: ls1021a-tsn: update RGMII delays for sja1105 switch

Message ID 20211013222313.3767605-3-vladimir.oltean@nxp.com (mailing list archive)
State New, archived
Headers show
Series New RGMII delay DT bindings for the SJA1105 DSA driver | expand

Commit Message

Vladimir Oltean Oct. 13, 2021, 10:23 p.m. UTC 
In the new behavior, the sja1105 driver expects there to be explicit
RGMII delays present on the fixed-link ports, otherwise it will complain
that it falls back to legacy behavior, which is to apply RGMII delays
incorrectly derived from the phy-mode string.

In this case, the legacy behavior of the driver is to not apply delays
in any direction (mostly because the SJA1105T can't do that, so this
board uses PCB traces). To preserve that but also silence the driver,
use explicit delays of 0 ns. The delay information from the phy-mode is
ignored by new kernels (it's still RGMII as long as it's "rgmii*"
something), and the explicit {rx,tx}-internal-delay-ps properties are
ignored by old kernels, so the change works both ways.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
---
 arch/arm/boot/dts/ls1021a-tsn.dts | 2 ++
 1 file changed, 2 insertions(+)

Comments

Florian Fainelli Oct. 15, 2021, 5:16 p.m. UTC | #1 
On 10/13/21 3:23 PM, Vladimir Oltean wrote:
> In the new behavior, the sja1105 driver expects there to be explicit
> RGMII delays present on the fixed-link ports, otherwise it will complain
> that it falls back to legacy behavior, which is to apply RGMII delays
> incorrectly derived from the phy-mode string.
> 
> In this case, the legacy behavior of the driver is to not apply delays
> in any direction (mostly because the SJA1105T can't do that, so this
> board uses PCB traces). To preserve that but also silence the driver,
> use explicit delays of 0 ns. The delay information from the phy-mode is
> ignored by new kernels (it's still RGMII as long as it's "rgmii*"
> something), and the explicit {rx,tx}-internal-delay-ps properties are
> ignored by old kernels, so the change works both ways.
> 
> Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>

Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
diff mbox series

Patch

diff --git a/arch/arm/boot/dts/ls1021a-tsn.dts b/arch/arm/boot/dts/ls1021a-tsn.dts
index 9d8f0c2a8aba..517286073451 100644
--- a/arch/arm/boot/dts/ls1021a-tsn.dts
+++ b/arch/arm/boot/dts/ls1021a-tsn.dts
@@ -90,6 +90,8 @@  port@4 {
 				/* Internal port connected to eth2 */
 				ethernet = <&enet2>;
 				phy-mode = "rgmii";
+				rx-internal-delay-ps = <0>;
+				tx-internal-delay-ps = <0>;
 				reg = <4>;
 
 				fixed-link {