Re: [PATCH 4/8] clocksource: stm32-lptimer: add stm32mp25 support

[Fabrice Gasnier <fabrice.gasnier@foss.st.com>]

On 2/25/25 15:57, Fabrice Gasnier wrote:
> On 2/25/25 13:02, Krzysztof Kozlowski wrote:
>> On Mon, Feb 24, 2025 at 07:01:46PM +0100, Fabrice Gasnier wrote:
>>> From: Patrick Delaunay <patrick.delaunay@foss.st.com>
>>>
>>> Add the support of the new compatible for STM32MP25 SoC in driver, as
>>> described in Documentation/devicetree/bindings/mfd/st,stm32-lptimer.yaml
>>> and used in arch/arm64/boot/dts/st/stm32mp251.dtsi.
>>>
>>> Signed-off-by: Patrick Delaunay <patrick.delaunay@foss.st.com>
>>> Signed-off-by: Fabrice Gasnier <fabrice.gasnier@foss.st.com>
>>> ---
>>>  drivers/clocksource/timer-stm32-lp.c | 1 +
>>>  1 file changed, 1 insertion(+)
>>>
>>> diff --git a/drivers/clocksource/timer-stm32-lp.c b/drivers/clocksource/timer-stm32-lp.c
>>> index a4c95161cb22..db055348e2cc 100644
>>> --- a/drivers/clocksource/timer-stm32-lp.c
>>> +++ b/drivers/clocksource/timer-stm32-lp.c
>>> @@ -197,6 +197,7 @@ static int stm32_clkevent_lp_probe(struct platform_device *pdev)
>>>  
>>>  static const struct of_device_id stm32_clkevent_lp_of_match[] = {
>>>  	{ .compatible = "st,stm32-lptimer-timer", },
>>> +	{ .compatible = "st,stm32mp25-lptimer-timer", },
>>>  	{},
>>
>> Same question.
> 
> Oops, I just figured out I have missed a change to this driver, to
> enable interrupts, in order to comply with the LPTimer spec, starting
> with STM32MP25.
> 
> E.g. with earlier STM32MP13, STM32MP15 or even STM32H7:
> * The LPTIM_IER register must only be modified when the LPTIM is
> disabled (ENABLE bit reset to ‘0’)
> 
> On STM32MP25:
> * The LPTIMx_DIER register must only be modified when the LPTIM is
> enabled (ENABLE bit set to 1)
> 
> I'll add this as compatible data in next revision.

This is specific behavior, to the new revision of the LPTimer hardware.
It can be read from revision/identification registers. So this new
compatible can be dropped.

I'll remove "st,stm32mp25-lptimer-timer" compatible string in next revision.

Thanks for reviewing,
BR,
Fabrice

> 
> Best regards,
> Fabrice
> 
>>
>> Best regards,
>> Krzysztof
>>