Re: [PATCH 0/5] Rework M.2 Bluetooth instantiation using the auxiliary bus

[Sherry Sun]

On Tue, Sep 15, 2026 at 04:24:01PM +0200, Manivannan Sadhasivam wrote:
> Hi,
>
> This series reworks the PCIe M.2 Bluetooth instantiation using the auxiliary
> bus.
>
> The Bluetooth interface of the QCA2066, WCN6855, WCN7850 and NXP 88W8987
> M.2 modules is accessed over UART, but the modules show up at runtime over
> PCIe and are not described in firmware like devicetree. To make the serdev
> bus match the Bluetooth driver, the power sequencing driver was creating a
> devicetree node at runtime using an of_changeset. But, creating a node just for
> driver matching is not recommended as per Krzysztof [1].
>
> So this series reworks the instantiation to use the auxiliary bus instead. The
> power sequencing driver still allocates the UART serdev, but now hands it over
> through an auxiliary device along with the power sequencing target. So this
> series adds auxiliary driver support to hci_qca and btnxpuart drivers binding to
> this device and brings up the controller over the existing UART transport.
> Finally, it drops the serdev based M.2 code from both BT drivers.
>
> Dependency
> ==========
>
> This series depends on Monza series from Loic [2] and reuses its
> pwrseq_is_controllable() API.
>
> [1] https://lore.kernel.org/linux-pci/768142f0-2638-41f3-a34f-dc80bb99eb7f@xxxxxxxxxx
> [2] https://lore.kernel.org/all/20260904-monza-wireless-v6-0-d8c5042b3efd@xxxxxxxxxxxxxxxx

For the NXP 88W8987 M.2 module related changes:
Tested-by: Sherry Sun <sherry.sun@xxxxxxx>

Best Regards
Sherry Sun

> Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@xxxxxxxxxxxxxxxx>
> ---
> Manivannan Sadhasivam (5):
>      Bluetooth: hci_qca: Add auxiliary driver for PCIe M.2 modules
>      Bluetooth: btnxpuart: Add auxiliary driver for PCIe M.2 modules
>      power: sequencing: pcie-m2: Create auxiliary device for the M.2 BT interface
>      Bluetooth: hci_qca: Drop serdev based M.2 power sequencing code
>      Bluetooth: btnxpuart: Drop serdev based M.2 power sequencing code
>
> MAINTAINERS                               |   1 +
> drivers/bluetooth/Kconfig                 |   2 +
> drivers/bluetooth/btnxpuart.c             | 193 +++++++++++++++++++-----------
> drivers/bluetooth/hci_qca.c               | 138 +++++++++++++++------
> drivers/power/sequencing/Kconfig          |   2 +-
> drivers/power/sequencing/pwrseq-pcie-m2.c | 137 +++++++++++----------
> include/linux/pwrseq/pcie-m2-bt.h         |  38 ++++++
> 7 files changed, 343 insertions(+), 168 deletions(-)
> ---
> base-commit: e5e04726cdd043e309677071ab1b65a4b18f422b
> change-id: 20260806-pci-m2-bt-rework-78dc2c926f00
> prerequisite-message-id: 20260904-monza-wireless-v6-0-d8c5042b3efd@xxxxxxxxxxxxxxxx
> prerequisite-patch-id: c4e777757ca9358cc4dd35e23738cd7dc1ead1a0
> prerequisite-patch-id: 09600595c2e80b12eda3aae39af192847d0f03d0
> prerequisite-patch-id: afe88432c4d459e9094c0e6dd31ebeab6c9f2f08
> prerequisite-patch-id: 60fd7b13447ccad7546fa8e5b5609d8f133f788f
> prerequisite-patch-id: 61dcbe55fdb6f33a3229c197f16a678785aa16d8
> prerequisite-patch-id: 14099e5c573d7c41b899c3f9bb9126aa23f1553e
> prerequisite-patch-id: 647ee15b77671054b4bb012afa9ba8694b6c86c5
> prerequisite-patch-id: c3a774cae81a6fad287731a38f1b76c7e8babc4c
> prerequisite-patch-id: 18b0fa62060a1a2c96e76051944d692699035572
> prerequisite-patch-id: df02ab167976ac1f0d5a38c78e559a7372b16c1f
> prerequisite-patch-id: 3f2dddd108677252a539cdb1eb661912836289ca
>
> Best regards,
> --
> மணிவண்ணன் சதாசிவம்