Re: [PATCH v4 2/2] PCI: mediatek-gen3: Add power and reset control feature for downstream component

[Krzysztof Kozlowski <krzk@kernel.org>]

On 06/11/2023 09:36, AngeloGioacchino Del Regno wrote:
> Il 06/11/23 08:53, Krzysztof Kozlowski ha scritto:
>> On 06/11/2023 07:12, Jian Yang wrote:
>>> From: "jian.yang" <jian.yang@mediatek.com>
>>>
>>> Make MediaTek's controller driver capable of controlling power
>>> supplies and reset pin of a downstream component in power-on and
>>> power-off process.
>>>
>>> Some downstream components (e.g., a WIFI chip) may need an extra
>>> reset other than PERST# and their power supplies, depending on
>>> the requirements of platform, may need to controlled by their
>>> parent's driver. To meet the requirements described above, I add this
>>> feature to MediaTek's PCIe controller driver as an optional feature.
>>
>> NAK, strong NAK. This should be done in a generic way because nothing
>> here is specific to Mediatek.
>>
>> You just implement power sequencing of devices through quirks specific
>> to one controller.
>>
>> Work with others to provide common solution.
>> https://lpc.events/event/17/contributions/1507/
>>
> 
> I agree that working with everyone else by adding pwrseq is a must, but other
> other PCIe controllers are doing the exact same as this patch: if the supply
> and gpio names are aligned with the others, why shouldn't we let this in and
> then convert this driver, along with the others, to the new pwrseq subsystem
> when it's ready?

Because you already push to the PCI controller bindings new properties
which are not properties of the PCI controller.

> 
> That, because I expect the pwrseq to require a bit more time before being
> ready to get upstream.
> 
> P.S.: Check Tegra, Broadcom, RockChip DW, IMX6Q-pcie.

Every new hack will not make it faster. :( At some point one have to say
- enough of hacks, start doing it properly with upstream.

Best regards,
Krzysztof