Re: [PATCH v3 3/3] PCI: apple: Fix #PERST polarity

Luca Ceresoli
2021-11-24T09:16:41Z

Hi,

On 24/11/21 10:02, Marc Zyngier wrote:
> On Tue, 23 Nov 2021 21:36:11 +0000,
> Luca Ceresoli <luca@lucaceresoli.net> wrote:
>>
>> Hi Mark,
>>
>> On 23/11/21 19:06, Marc Zyngier wrote:
>>> Now that #PERST is properly defined as active-low in the device tree,
>>> fix the driver to correctly drive the line indemendently of the
>>> implied polarity.
>>>
>>> Fixes: 1e33888fbe44 ("PCI: apple: Add initial hardware bring-up")
>>> Suggested-by: Pali Rohár <pali@kernel.org>
>>> Signed-off-by: Marc Zyngier <maz@kernel.org>
>>
>> Thanks for quickly addressing this!
>>
>> Do we need a transition path for backward compatibility with old DTs
>> already around? Something like this [0]. You said [1] the DT actually
>> used is not even the one in the kernel, thus how do we guarantee DT and
>> driver switch to the new polarity all at once?
>
> No. As it turns out, neither u-boot nor OpenBSD (the only two other
> payloads that can boot on M1) are upstreamed yet. So we're still in
> that stage where we don't need to maintain backward compatibility. If
> we don't get this patches merged by the end of this cycle, we will
> have to revisit this though.

Good news!

Reviewed-by: Luca Ceresoli <luca@lucaceresoli.net>

--
Luca