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SubjectRe: [PATCH v2 3/5] pcie-qcom: provide a way to power up qca6390 chip on RB5 platform
On Sat, 30 Jan 2021 at 11:04, Yassine Oudjana <> wrote:
> On Thu, Jan 28, 2021 at 11:52 AM Dmitry Baryshkov
> <> wrote:
> >
> > Some Qualcomm platforms require to power up an external device before
> > probing the PCI bus. E.g. on RB5 platform the QCA6390 WiFi/BT chip needs
> > to be powered up before PCIe0 bus is probed. Add a quirk to the
> > respective PCIe root bridge to attach to the power domain if one is
> > required, so that the QCA chip is started before scanning the PCIe bus.
> I'm lead to believe that this is also needed for QCA6174. I tried taking
> the driver you wrote and changing regulators to match the ones used by QCA6174,
> but I found that it gets probed after PCIe, which makes it get -EPROBE_DEFER
> when it tries to attach to the power domain, which it doesn't handle it and
> just proceeds to scan the bus and not find the chip as usual.

As a quick hack, you can try using this power domain for the pci_phy
(see my v1). Rob declined this approach, but it is useful to check if
QCA6174 wakes up properly and deferring PCIe probing till the chip is
powered up.

With best wishes

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