* [PATCH] ARM: dts: stm32: lxa-tac: reduce RGMII interface drive strength
@ 2024-01-29 11:46 Uwe Kleine-König
2024-02-14 13:04 ` Alexandre TORGUE
0 siblings, 1 reply; 2+ messages in thread
From: Uwe Kleine-König @ 2024-01-29 11:46 UTC (permalink / raw)
To: Rob Herring, Krzysztof Kozlowski, Conor Dooley, Maxime Coquelin,
Alexandre Torgue
Cc: Leonard Göhrs, devicetree, linux-stm32, linux-arm-kernel,
kernel
From: Leonard Göhrs <l.goehrs@pengutronix.de>
This results in an improvement of EMI performance by reducing the
125MHz emission and its harmonics caused by the RGMII clock line.
Signed-off-by: Leonard Göhrs <l.goehrs@pengutronix.de>
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
---
arch/arm/boot/dts/st/stm32mp15xc-lxa-tac.dtsi | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/arch/arm/boot/dts/st/stm32mp15xc-lxa-tac.dtsi b/arch/arm/boot/dts/st/stm32mp15xc-lxa-tac.dtsi
index 7e835a7cf64a..cfaf8adde319 100644
--- a/arch/arm/boot/dts/st/stm32mp15xc-lxa-tac.dtsi
+++ b/arch/arm/boot/dts/st/stm32mp15xc-lxa-tac.dtsi
@@ -471,6 +471,10 @@ switch: switch@0 {
interrupt-parent = <&gpioa>;
interrupts = <6 IRQ_TYPE_EDGE_RISING>;
+ /* Reduce RGMII EMI emissions by reducing drive strength */
+ microchip,hi-drive-strength-microamp = <2000>;
+ microchip,lo-drive-strength-microamp = <8000>;
+
ports {
#address-cells = <1>;
#size-cells = <0>;
--
2.43.0
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] ARM: dts: stm32: lxa-tac: reduce RGMII interface drive strength
2024-01-29 11:46 [PATCH] ARM: dts: stm32: lxa-tac: reduce RGMII interface drive strength Uwe Kleine-König
@ 2024-02-14 13:04 ` Alexandre TORGUE
0 siblings, 0 replies; 2+ messages in thread
From: Alexandre TORGUE @ 2024-02-14 13:04 UTC (permalink / raw)
To: Uwe Kleine-König, Rob Herring, Krzysztof Kozlowski,
Conor Dooley, Maxime Coquelin
Cc: Leonard Göhrs, devicetree, linux-stm32, linux-arm-kernel,
kernel
Hi
On 1/29/24 12:46, Uwe Kleine-König wrote:
> From: Leonard Göhrs <l.goehrs@pengutronix.de>
>
> This results in an improvement of EMI performance by reducing the
> 125MHz emission and its harmonics caused by the RGMII clock line.
>
> Signed-off-by: Leonard Göhrs <l.goehrs@pengutronix.de>
> Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
> ---
> arch/arm/boot/dts/st/stm32mp15xc-lxa-tac.dtsi | 4 ++++
> 1 file changed, 4 insertions(+)
>
> diff --git a/arch/arm/boot/dts/st/stm32mp15xc-lxa-tac.dtsi b/arch/arm/boot/dts/st/stm32mp15xc-lxa-tac.dtsi
> index 7e835a7cf64a..cfaf8adde319 100644
> --- a/arch/arm/boot/dts/st/stm32mp15xc-lxa-tac.dtsi
> +++ b/arch/arm/boot/dts/st/stm32mp15xc-lxa-tac.dtsi
> @@ -471,6 +471,10 @@ switch: switch@0 {
> interrupt-parent = <&gpioa>;
> interrupts = <6 IRQ_TYPE_EDGE_RISING>;
>
> + /* Reduce RGMII EMI emissions by reducing drive strength */
> + microchip,hi-drive-strength-microamp = <2000>;
> + microchip,lo-drive-strength-microamp = <8000>;
> +
> ports {
> #address-cells = <1>;
> #size-cells = <0>;
Applied on stm32-next.
Thanks
Alex
^ permalink raw reply [flat|nested] 2+ messages in thread
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