Re: [PATCH 1/2] arm: dts: Add override for RB1

[Caleb Connolly <caleb.connolly@linaro.org>]

On 4/8/25 15:46, Sumit Garg wrote:
> On Tue, Apr 08, 2025 at 02:17:29PM +0200, Caleb Connolly wrote:
>>
>>
>> On 4/7/25 15:28, Sumit Garg wrote:
>>> From: Sumit Garg <sumit.garg@oss.qualcomm.com>
>>>
>>> Add U-Boot override for RB1 to for USB in host mode as OTG mode isn't
>>> supported. Also, disable sdhc_2 as it's currently not supported, sdhc_1
>>> works fine though.
>>>
>>> Signed-off-by: Sumit Garg <sumit.garg@oss.qualcomm.com>
>>> ---
>>>    arch/arm/dts/qrb2210-rb1-u-boot.dtsi | 11 +++++++++++
>>>    1 file changed, 11 insertions(+)
>>>    create mode 100644 arch/arm/dts/qrb2210-rb1-u-boot.dtsi
>>>
>>> diff --git a/arch/arm/dts/qrb2210-rb1-u-boot.dtsi b/arch/arm/dts/qrb2210-rb1-u-boot.dtsi
>>> new file mode 100644
>>> index 00000000000..1e136ee405a
>>> --- /dev/null
>>> +++ b/arch/arm/dts/qrb2210-rb1-u-boot.dtsi
>>> @@ -0,0 +1,11 @@
>>> +// SPDX-License-Identifier: GPL-2.0
>>> +
>>> +/* This is usually OTG but U-Boot doesn't support that properly */
>>> +&usb_dwc3 {
>>> +	dr_mode = "host";
>>> +};
>>> +
>>> +/* SDHC_2 isn't supported in U-Boot as of now */
>>
>> I'd rather avoid disabling this here, I guess it's just missing clocks and
>> regulators which doesn't justify modifying DT. An error that mmc1 couldn't
>> be enabled seems fine to me?
> 
> I totally echo with your thinking that we should avoid modifying DT but
> at the same point we shouldn't enable peripherals in U-Boot which throws
> errors. It's also possible that U-Boot misconfiguring mmc1 which might

I disagree, DT isn't enabling or disabling peripherals, it's describing 
hardware. U-Boot lacking proper support for that hardware isn't a good 
justification to disable it. Especially since you might boot Linux with 
the same DT and now have no working sdcard for seemingly no reason.

An error in U-Boot is exactly the behaviour we want to see, masking it 
only created confusion.> turn as a problem for later stages.
> 
> I have been totally working with a remote lab to fix issues on RB1. I
> will soon get one on my desk then I will be able to fix mmc1 too.

In that case we can surely land the proper fixes for 2025.07 anyway, so 
I'd just keep the errors until then.

Kind regards,>
> -Sumit
> 
>>> +&sdhc_2 {
>>> +	status = "disabled";
>>> +};
>> -- 
>> Caleb (they/them)
>>

-- 
Caleb (they/them)