The LeMans EVK board routes the RX lines of CAN controllers 2, 4, and 6
(part of the RTSS subsystem) through a signal multiplexer controlled by
GPIO 4 of the I2C GPIO expander at address 0x3b. The remaining CAN
controllers, out of 8 total on RTSS, are wired directly to their
transceivers.

The multiplexer select pin defaults low on reset, disconnecting CAN 2,
4, and 6 RX lines from their respective transceivers, which results in
no data being received on these interfaces.

Configure GPIO 4 as output-high to assert the mux select line at boot,
connecting the RX signals of CAN 2, 4, and 6 to their transceivers as
required by the EVK board wiring.

Signed-off-by: Anup Kulkarni <anup.kulkarni@oss.qualcomm.com>
---
v1->v2
- Fixed commit text to include platform name.

v2->v3
- Updated commit text.
---
 arch/arm64/boot/dts/qcom/lemans-evk.dts | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/arch/arm64/boot/dts/qcom/lemans-evk.dts b/arch/arm64/boot/dts/qcom/lemans-evk.dts
index c665db6a4595..34dfc8d22b6a 100644
--- a/arch/arm64/boot/dts/qcom/lemans-evk.dts
+++ b/arch/arm64/boot/dts/qcom/lemans-evk.dts
@@ -616,6 +616,13 @@ expander3: gpio@3b {
 		interrupts-extended = <&tlmm 39 IRQ_TYPE_LEVEL_LOW>;
 		pinctrl-0 = <&expander3_int>;
 		pinctrl-names = "default";
+
+		rtss-can-sel-hog {
+			gpio-hog;
+			gpios = <4 GPIO_ACTIVE_HIGH>;
+			output-high;
+			line-name = "rtss-can-sel";
+		};
 	};
 
 	eeprom@50 {
-- 
2.34.1

On Tue, 19 May 2026 12:19:54 +0530, Anup Kulkarni wrote:
> The LeMans EVK board routes the RX lines of CAN controllers 2, 4, and 6
> (part of the RTSS subsystem) through a signal multiplexer controlled by
> GPIO 4 of the I2C GPIO expander at address 0x3b. The remaining CAN
> controllers, out of 8 total on RTSS, are wired directly to their
> transceivers.
> 
> The multiplexer select pin defaults low on reset, disconnecting CAN 2,
> 4, and 6 RX lines from their respective transceivers, which results in
> no data being received on these interfaces.
> 
> [...]

Applied, thanks!

[1/1] arm64: dts: qcom: lemans-evk: Enable CAN RX via I2C GPIO expander
      commit: 89e77275b55eac3d3b8027c9806eb32b24b05023

Best regards,
-- 
Bjorn Andersson <andersson@kernel.org>

On Tue, May 19, 2026 at 12:19:54PM +0530, Anup Kulkarni wrote:
> The LeMans EVK board routes the RX lines of CAN controllers 2, 4, and 6
> (part of the RTSS subsystem) through a signal multiplexer controlled by
> GPIO 4 of the I2C GPIO expander at address 0x3b. The remaining CAN
> controllers, out of 8 total on RTSS, are wired directly to their
> transceivers.
> 
> The multiplexer select pin defaults low on reset, disconnecting CAN 2,
> 4, and 6 RX lines from their respective transceivers, which results in
> no data being received on these interfaces.
> 
> Configure GPIO 4 as output-high to assert the mux select line at boot,
> connecting the RX signals of CAN 2, 4, and 6 to their transceivers as
> required by the EVK board wiring.
> 
> Signed-off-by: Anup Kulkarni <anup.kulkarni@oss.qualcomm.com>
> ---
> v1->v2
> - Fixed commit text to include platform name.
> 
> v2->v3
> - Updated commit text.
> ---
>  arch/arm64/boot/dts/qcom/lemans-evk.dts | 7 +++++++
>  1 file changed, 7 insertions(+)
> 

Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>


-- 
With best wishes
Dmitry