[PATCH 0/3] ARM: dts: stm32: lxa: change stdout-path baud rate from 9600 to 115200

[Ahmad Fatoum]

Hi David,

On 6/11/26 21:43, David Laight wrote:
> On Thu, 11 Jun 2026 20:12:32 +0200
> Ahmad Fatoum <a.fatoum at pengutronix.de> wrote:
> 
>> The LXA boards are the only STM32 boards that set stdout-path = &uart*
>> instead of explicitly specifying a baud rate.
>>
>> This would mean the default of 9600 is used, but it goes unnoticed when
>> booting normally as barebox fixes up a console= line that includes a
>> baud rate.
>>
>> When EFI booting GRUB however, GRUB will not pass along the console=
>> line and thus the board ends up with a 9600 baud Linux console,
>> confusing users.
> 
> Is it possible to determine the current baud rate (by reading the hardware
> register) and default to that value.
> Then if grub has initialised the uart the kernel will use the same
> baud rate.

I think so, yes. In addition to the register divider configuration, one
would need the input clock rate as well, but that's not a problem.

Do you know if any drivers already do this?

Nevertheless, I would like the LXA device trees changed, even if only
to align them with all other existing STM32 device trees.

Cheers,
Ahmad


> 
> 	David
> 
>>
>> This series fixes this. As the device trees were added at different
>> times, they are fixed each in a separate commit with its own Fixes: tag.
>>
>> ---
>> Ahmad Fatoum (3):
>>       ARM: dts: stm32: lxa-mc1: change stdout-path baud rate from 9600 to 115200
>>       ARM: dts: stm32: lxa-tac: change stdout-path baud rate from 9600 to 115200
>>       ARM: dts: stm32: fairytux2: change stdout-path baud rate from 9600 to 115200
>>
>>  arch/arm/boot/dts/st/stm32mp153c-lxa-fairytux2.dtsi | 2 +-
>>  arch/arm/boot/dts/st/stm32mp157c-lxa-mc1.dts        | 2 +-
>>  arch/arm/boot/dts/st/stm32mp15xc-lxa-tac.dtsi       | 2 +-
>>  3 files changed, 3 insertions(+), 3 deletions(-)
>> ---
>> base-commit: 4549871118cf616eecdd2d939f78e3b9e1dddc48
>> change-id: 20260611-lxa-stdout-path-baudrate-7cf454cdae07
>>
>> Best regards,
>> --  
>> Ahmad Fatoum <a.fatoum at pengutronix.de>
>>
>>
> 
> 


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