Re: [PATCH v7 0/8] Add support for handling PCIe M.2 Key E connectors in devicetree

[Bartosz Golaszewski]

On Thu, 26 Mar 2026 09:06:28 +0100, Manivannan Sadhasivam via B4 Relay
<devnull+manivannan.sadhasivam.oss.qualcomm.com@xxxxxxxxxx> said:
> Hi,
>
> This series is the continuation of the series [1] that added the initial support
> for the PCIe M.2 connectors. This series extends it by adding support for Key E
> connectors. These connectors are used to connect the Wireless Connectivity
> devices such as WiFi, BT, NFC and GNSS devices to the host machine over
> interfaces such as PCIe/SDIO, USB/UART and NFC. This series adds support for
> connectors that expose PCIe interface for WiFi and UART interface for BT. Other
> interfaces are left for future improvements.
>
> Serdev device support for BT
> ============================
>
> Adding support for the PCIe interface was mostly straightforward and a lot
> similar to the previous Key M connector. But adding UART interface has proved to
> be tricky. This is mostly because of the fact UART is a non-discoverable bus,
> unlike PCIe which is discoverable. So this series relied on the PCI notifier to
> create the serdev device for UART/BT. This means the PCIe interface will be
> brought up first and after the PCIe device enumeration, the serdev device will
> be created by the pwrseq driver. This logic is necessary since the connector
> driver and DT node don't describe the device, but just the connector. So to make
> the connector interface Plug and Play, the connector driver uses the PCIe device
> ID to identify the card and creates the serdev device. This logic could be
> extended in the future to support more M.2 cards. Even if the M.2 card uses SDIO
> interface for connecting WLAN, a SDIO notifier could be added to create the
> serdev device.
>
> Testing
> =======
>
> This series, together with the devicetree changes [2] was tested on the
> Qualcomm X1e based Lenovo Thinkpad T14s Laptop which has the WCN7850 WLAN/BT
> 1620 LGA card connected over PCIe and UART.
>
> Merge Strategy
> ==============
>
> Due to the API dependency, both the serdev and pwrseq patches need to go through
> a single tree, maybe through pwrseq tree. So the serdev patches need Ack from
> Greg. But Bluetooth patch can be merged separately.

I think Rob Herring is the man in charge here. The power sequencing parts look
good to me now so with an Ack on the serdev changes I can queue them for v7.1.
I can also put it on an immutable branch if needed.

Bart