Re: [PATCH] arm64: dts: qcom: sc7280-herobrine: Fix PCIe regulator glitch at bootup

[Stephen Boyd]

Quoting Douglas Anderson (2022-03-10 13:04:34)
> While scoping signals, we found that the PCIe signals weren't
> compliant at bootup. Specifically, the bootloader was setting up PCIe
> and leaving it configured, then jumping to the kernel. The kernel was
> turning off the regulator while leaving the PCIe clock running, which
> was a violation.
>
> In the regulator bindings (and the Linux kernel driver that uses
> them), there's currently no way to specify that a GPIO-controlled
> regulator should keep its state at bootup. You've got to pick either
> "on" or "off". Let's switch it so that the PCIe regulator defaults to
> "on" instead of "off". This should be a much safer way to go and
> avoids the timing violation. The regulator will still be turned off
> later if there are no users.
>
> Signed-off-by: Douglas Anderson <dianders@xxxxxxxxxxxx>
> ---

Reviewed-by: Stephen Boyd <swboyd@xxxxxxxxxxxx>