Re: [PATCH v1] arm64: dts: qcom: Enable CAN RX via GPIO expander

[Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>]

On 4/14/26 6:08 PM, Dmitry Baryshkov wrote:
> On Thu, Apr 02, 2026 at 04:22:53PM +0530, Anup Kulkarni wrote:
>> Few CAN controllers, part of RTSS sub-system on LeMans, route
>> their RX signal through a I2C GPIO expander at address 0x3b.
>> RTSS subsystem is an MCU like sub-system on LeMans with independent
>> booting capability through OSPI interface and supports peripherals like
>> RGMII, CAN-FD, UART, I2C, SPI etc.
>>
>> Describe this hardware wiring by configuring the expander GPIO 4 pin as
>> hog with output-high, asserting the selected line during boot.
> 
> Missing platform name in the subject.
> 
>>
>> Signed-off-by: Anup Kulkarni <anup.kulkarni@oss.qualcomm.com>
>> ---
>>  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 a1ef4eba2a20..b8371bdf9933 100644
>> --- a/arch/arm64/boot/dts/qcom/lemans-evk.dts
>> +++ b/arch/arm64/boot/dts/qcom/lemans-evk.dts
>> @@ -615,6 +615,13 @@ expander3: gpio@3b {
>>  		interrupts-extended = <&tlmm 39 IRQ_TYPE_LEVEL_LOW>;
>>  		pinctrl-0 = <&expander3_int>;
>>  		pinctrl-names = "default";
>> +
>> +		rtss-can-sel-hog {
> 
> Why is it being described as a hog rather than a pinctrl used by the
> CAN device?

My understanding is that the CAN bus is managed by SAIL ("RTSS")

Konrad