Re: [PATCH 8/8] PCI: qcom: Add support to PCIe slot power supplies

[Qiang Yu]

On 9/12/2024 10:49 PM, Dmitry Baryshkov wrote:
> On Thu, 12 Sept 2024 at 17:45, Manivannan Sadhasivam
> <manivannan.sadhasivam@xxxxxxxxxx> wrote:
> > On Thu, Sep 12, 2024 at 04:15:56PM +0200, Konrad Dybcio wrote:
> > > On 12.09.2024 3:39 PM, Qiang Yu wrote:
> > > > On 9/11/2024 11:32 PM, Manivannan Sadhasivam wrote:
> > > > > On Wed, Sep 11, 2024 at 04:17:41PM +0800, Qiang Yu wrote:
> > > > > > On 8/28/2024 12:58 AM, Manivannan Sadhasivam wrote:
> > > > > > > On Tue, Aug 27, 2024 at 02:44:09PM +0300, Dmitry Baryshkov wrote:
> > > > > > > > On Tue, 27 Aug 2024 at 09:36, Qiang Yu <quic_qianyu@xxxxxxxxxxx> wrote:
> > > > > > > > > On platform x1e80100 QCP, PCIe3 is a standard x8 form factor. Hence, add
> > > > > > > > > support to use 3.3v, 3.3v aux and 12v regulators.
> > > > > > > > First of all, I don't see corresponding bindings change.
> > > > > > > >
> > > > > > > > Second, these supplies power up the slot, not the host controller
> > > > > > > > itself. As such these supplies do not belong to the host controller
> > > > > > > > entry. Please consider using the pwrseq framework instead.
> > > > > > > Indeed. For legacy reasons, slot power supplies were populated in the host
> > > > > > > bridge node itself until recently Rob started objecting it [1]. And it makes
> > > > > > > real sense to put these supplies in the root port node and handle them in the
> > > > > > > relevant driver.
> > > > > > >
> > > > > > > I'm still evaluating whether the handling should be done in the portdrv or
> > > > > > > pwrctl driver, but haven't reached the conclusion. Pwrctl seems to be the ideal
> > > > > > > choice, but I see a few issues related to handling the OF node for the root
> > > > > > > port.
> > > > > > >
> > > > > > > Hope I'll come to a conclusion in the next few days and will update this thread.
> > > > > > >
> > > > > > > - Mani
> > > > > > >
> > > > > > > [1] https://lore.kernel.org/lkml/20240604235806.GA1903493-robh@xxxxxxxxxx/
> > > > > > Hi Mani, do you have any updates?
> > > > > I'm working with Bartosz to add a new pwrctl driver for rootports. And we are
> > > > > debugging an issue currently. Unfortunately, the progress is very slow as I'm on
> > > > > vacation still.
> > > > >
> > > > > Will post the patches once it got resolved.
> > > > >
> > > > > - Mani
> > > > OK, thanks for your update.
> > > Qiang, you can still resubmit the rest of the patches without having
> > > to wait on that to be resolved
> > In that case, the slot supplies should be described in the PCIe bridge.
> Patches 1-6 don't seem to depend on slot supplies, so they can be
> submitted separately.
OK, let me send v2 patch. Hi Mani, if you need any supports, please let 
me know.

Thanks,
Qiang
> > - Mani
> >
> > > Konrad
> > --
> > மணிவண்ணன் சதாசிவம்