Re: [PATCH 2/2] arm64: dts: qcom: monaco-evk: Describe the PCIe M.2 Key E connector

[Loic Poulain]

Hi Folks,

On Mon, Sep 21, 2026 at 2:38 PM Konrad Dybcio
<konrad.dybcio@xxxxxxxxxxxxxxxx> wrote:
>
> On 9/2/26 3:48 PM, Manivannan Sadhasivam wrote:
> > On Tue, Aug 25, 2026 at 02:57:15PM +0530, Wei Deng wrote:
> >> Hi Konrad,
> >>
> >> On Wed, 19 Aug 2026 16:24:35 +0200, Konrad Dybcio wrote:
> >>> On 8/19/26 4:13 PM, Wei Deng wrote:
> >>>> On Wed, 29 Jul 2026 08:06:54 +0530, Wei Deng wrote:
> >>>>> Fair point. I will move the port/endpoint anchors to monaco.dtsi in v2.
> >>>>
> >>>> After testing v2 on qcs8300-ride-sx, BT init broke. qcs8300-ride-sx has a
> >>>> soldered WCN6855 and no M.2 Key E connector, but the pending series [1]
> >>>> uses of_graph_is_present() to detect whether an M.2 connector is present.
> >>>> Since of_graph_is_present() only checks for a 'port' child node, the empty
> >>>> anchors in monaco.dtsi caused hci_qca to incorrectly enter the M.2 pwrseq
> >>>> path on all monaco boards.
> >>>>
> >>>> v3 moves the port/endpoint nodes back to monaco-evk.dts. Please review.
> >>>>
> >>>> [1] https://lore.kernel.org/all/20260720-monza-wireless-v5-1-69ec6743543c@xxxxxxxxxxxxxxxx/
> >>>
> >>> The series should test of_graph_get_remote_endpoint() instead
> >>>
> >>> Konrad
> >>
> >> Hi Konrad,
> >>
> >> Tested: replacing of_graph_is_present() with of_graph_get_remote_endpoint()
> >> in hci_qca.c works correctly. The M.2 pwrseq path is only entered when a
> >> remote-endpoint is actually populated, so boards like qcs8300-ride (soldered
> >> WCN6855, no M.2 connector) are no longer affected.
> >>
> >> Hi Mani, Loic,
> >>
> >> We are adding M.2 Key E connector support for monaco-evk [2]. Konrad
> >> suggested moving the port/endpoint anchor nodes to the SoC DTSI
> >> (monaco.dtsi) for clean DTS layering, so that board files only need to
> >> fill in remote-endpoint for boards that actually have an M.2 connector.
> >>
> >
> > This means, the dummy port/endpoint node will always be present even when the
> > M.2 connector is not used. I don't see a compelling reason to do so.
>
> I don't really see a compelling reason to defer re-defining them to each
> device DT either..

Adding an empty port/endpoint at the SoC level is problematic for
uart, port is not always expected, this depends if the uart is exposed
through a connector or to an onboard device. So we may end with an
unconnected endpoint but still have a bluetooth subnode, which can be
a bit confusing... Also why adding a port/endpoint only for a specific
uart in the dts, and not for the others? This is a board/SoC level
choice to use a specific uart for M2 or not.

Regards,
Loic