From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id C48561DFE22; Tue, 24 Feb 2026 05:30:52 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1771911052; cv=none; b=IEif6uezSn054op/9Bl4qhDDEJi3tSgmpw/eyGrB33YqY40QQFi4WBZAC6vgyKRPl3lo5/6dxCEgh55KnXodx+17EPZhSIpQPxpe/nuCsLZ8xR0SUJf4N0/vAl2qKTCBS2PG3eNo5cgV+OXD2Ue4HPgTmAXVoRsKt6bD65zehZI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1771911052; c=relaxed/simple; bh=SnZaSMf2cA5Gwe7vWZar/n+eIHqWH+U1vFZSUccO7B8=; h=From:Subject:Date:Message-Id:MIME-Version:Content-Type:To:Cc; b=Rd5wTeZQE79XxexrC4J/DHEgs3C09QgPTowfTireN3aBqo8d0KXxhZRVlsR0JJyVQ+ZmzFDJdC1dHWPtkeURw+H0tAMkCQTdQrUaECJT9hrUy94folDr9sRaPvtwyw9QECJodCsdfFczsAXLDLYNEtgsT+8wXNZls0T0ovoRCjo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=K/yW2hnT; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="K/yW2hnT" Received: by smtp.kernel.org (Postfix) with ESMTPS id 568ADC116D0; Tue, 24 Feb 2026 05:30:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1771911052; bh=SnZaSMf2cA5Gwe7vWZar/n+eIHqWH+U1vFZSUccO7B8=; h=From:Subject:Date:To:Cc:Reply-To:From; b=K/yW2hnTgjuW+OV4W32r3GuyvCMu1qKhVgDsYCyoGo7rXQ5mDiTZZeM/vxqgWj272 K4qf1SgeNqlrtZdCQdbnR+gYHUoWP91OnkgP944GS8IdPPlIb/ALGqrWh2wB23ahBE 3za6z9CA/8NACBfNVoTfGOd676VLvcbIcBs7BEqwCCy6TcpHxmucIDPwqtQ7ZGYpOk +h81h1aVmcBmeC/3MMw5L/MtkWit1Q884Ca9hFZThgqbZJSv/Asb/8bWHPd23UfMd8 YgJINR27NU3khLdaYSUCze0d5Tuebkn9uGBGBnmh86uBMTD36hzH8BTt2brp8ThZpA ZMR1zfex5zKpw== Received: from aws-us-west-2-korg-lkml-1.web.codeaurora.org (localhost.localdomain [127.0.0.1]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3BA05EFB7F9; Tue, 24 Feb 2026 05:30:52 +0000 (UTC) From: Manivannan Sadhasivam via B4 Relay Subject: [PATCH v5 0/9] Add support for handling PCIe M.2 Key E connectors in devicetree Date: Tue, 24 Feb 2026 11:00:46 +0530 Message-Id: <20260224-pci-m2-e-v5-0-dd9b9501d33c@oss.qualcomm.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit X-B4-Tracking: v=1; b=H4sIAIY3nWkC/3XQTW7DIBAF4KtYrIsFY37srHqPqgsCQ4NUxwk4q FWUu3ecqBKLZIM06H1Po7mygjlhYbvuyjLWVNJypEG/dcwf3PELeQo0MxCgpZTATz7xGTjySZl JOz8Foy2j+CljTD/3qo9Pmg+prEv+vTdXuf0+KamSCz5ZJYdg9nEE9b6U0p8v7tsv89zTw7auC o0H3XggP8AIJqCw3usXfvj3RkgpGj+QV9Eh2iCCdvjCq9a3+yvyGOOoAngTwDzxt8dxMp4vdN7 1cSG2dwX5Fkrrrqu2Fzx7SeHbH931VIiTAQAA X-Change-ID: 20251112-pci-m2-e-94695ac9d657 To: Rob Herring , Greg Kroah-Hartman , Jiri Slaby , Nathan Chancellor , Nicolas Schier , Hans de Goede , =?utf-8?q?Ilpo_J=C3=A4rvinen?= , Mark Pearson , "Derek J. Clark" , Manivannan Sadhasivam , Krzysztof Kozlowski , Conor Dooley , Marcel Holtmann , Luiz Augusto von Dentz , Bartosz Golaszewski , Andy Shevchenko , Bartosz Golaszewski Cc: linux-serial@vger.kernel.org, linux-kernel@vger.kernel.org, linux-kbuild@vger.kernel.org, platform-driver-x86@vger.kernel.org, linux-pci@vger.kernel.org, devicetree@vger.kernel.org, linux-arm-msm@vger.kernel.org, linux-bluetooth@vger.kernel.org, linux-pm@vger.kernel.org, Stephan Gerhold , Dmitry Baryshkov , linux-acpi@vger.kernel.org, Manivannan Sadhasivam , Hans de Goede , Bartosz Golaszewski , Bartosz Golaszewski X-Mailer: b4 0.14.3 X-Developer-Signature: v=1; a=openpgp-sha256; l=7106; i=manivannan.sadhasivam@oss.qualcomm.com; h=from:subject:message-id; bh=SnZaSMf2cA5Gwe7vWZar/n+eIHqWH+U1vFZSUccO7B8=; b=owEBbQGS/pANAwAKAVWfEeb+kc71AcsmYgBpnTeHc38+CBV++wJV7Ph9fzZscIthcHTpquo3C 7qv2DEbNnaJATMEAAEKAB0WIQRnpUMqgUjL2KRYJ5dVnxHm/pHO9QUCaZ03hwAKCRBVnxHm/pHO 9RbuB/92igV75YDs1agNrzI2uKiZVuENfGsyJBJWJHvrh8O9dZTBfeVXJU+ePQoP50g7f2K4eSw etn6zHUocr8MCzv73IE5fFWHefi/fNQT4CfzonA/vtJH4mPWiQN3AeuE5hXfsBNzc3NAipZ+opi +xARb09n8puTbPugIE/4utoJg1vIvAceo/cACSMof5s5zjO0zpu1eBrqE8uFphSDgqeNE6u4k9n J2t1NyTLaJAprIhEUkAsssghZ6BFwT7PfT9l9LdnT05ZXNuIrPhIg4gURB9UaNhFOnZjLp/ujSY 2oPFEHO2uJJshvi6qM4SLCaf73SlDWWUXN0gml66DtFurq43 X-Developer-Key: i=manivannan.sadhasivam@oss.qualcomm.com; a=openpgp; fpr=C668AEC3C3188E4C611465E7488550E901166008 X-Endpoint-Received: by B4 Relay for manivannan.sadhasivam@oss.qualcomm.com/default with auth_id=461 X-Original-From: Manivannan Sadhasivam Reply-To: manivannan.sadhasivam@oss.qualcomm.com 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. Open questions ============== Though this series adds the relevant functionality for handling the M.2 Key M connectors, there are still a few open questions exists on the design. 1. Created a dynamic 'bluetooth' node with the compatible property matching the WCN7850 device and attached it to the serdev device. This allowed reusing the existing OF based BT driver without much modifications. 2. PCIe client drivers of some M.2 WLAN cards like the Qcom QCA6390, rely on the PCIe device DT node to extract properties such as 'qcom,calibration-variant', 'firmware-name', etc... For those drivers, should we add the PCIe DT node in the Root Port in conjunction with the Port node as below? pcie@0 { wifi@0 { compatible = "pci17cb,1103"; ... qcom,calibration-variant = "LE_X13S"; }; port { pcie4_port0_ep: endpoint { remote-endpoint = <&m2_e_pcie_ep>; }; }; }; This will also require marking the PMU supplies optional in the relevant ath bindings for M.2 cards. 3. Some M.2 cards require specific power up sequence like delays between regulator/GPIO and such. For instance, the WCN7850 card supported in this series requires 50ms delay between powering up an interface and driving it. I've just hardcoded the delay in the driver, but it is a pure hack. Since the pwrseq driver doesn't know anything about the device it is dealing with before powering it ON, how should it handle the device specific power requirements? Should we hardcode the device specific property in the connector node? But then, it will no longer become a generic M.2 connector and sort of defeats the purpose of the connector binding. I hope to address these questions with the help of the relevant subsystem maintainers and the community. 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. Dependency ========== This series is dependent on the M.2 Key M series [1] on top of v6.19-rc1. [1] https://lore.kernel.org/linux-pci/20260107-pci-m2-v5-0-8173d8a72641@oss.qualcomm.com [2] https://github.com/Mani-Sadhasivam/linux/commit/b50f8386900990eed3dce8d91c3b643fb0e8739d Signed-off-by: Manivannan Sadhasivam --- Changes in v5: - Incorporated comments in the binding patch by using single endpoint per port, reordering port nodes, adding missing properties and using a complete example. - Incorporated comments in the pwrseq patch (nothing major) - Fixed the build issue in patch 2 - Collected tags - Rebased on top of 7.0-rc1 - Link to v4: https://lore.kernel.org/r/20260112-pci-m2-e-v4-0-eff84d2c6d26@oss.qualcomm.com Changes in v4: - Switched to dynamic OF node for serdev instead of swnode and dropped all swnode related patches - Link to v3: https://lore.kernel.org/r/20260110-pci-m2-e-v3-0-4faee7d0d5ae@oss.qualcomm.com Changes in v3: - Switched to swnode for the serdev device and dropped the custom serdev_device_id related patches - Added new swnode APIs to match the swnode with existing of_device_id - Incorporated comments in the bindings patch - Dropped the UIM interface from binding since it is not clear how it should get wired - Incorporated comments in the pwrseq driver patch - Splitted the pwrseq patch into two - Added the 1620 LGA compatible with Key E fallback based on Stephan's finding - Link to v2: https://lore.kernel.org/r/20251125-pci-m2-e-v2-0-32826de07cc5@oss.qualcomm.com Changes in v2: - Used '-' for GPIO names in the binding and removed led*-gpios properties - Described the endpoint nodes for port@0 and port@1 nodes - Added the OF graph port to the serial binding - Fixed the hci_qca driver to return err if devm_pwrseq_get() fails - Incorporated various review comments in pwrseq driver - Collected Ack - Link to v1: https://lore.kernel.org/r/20251112-pci-m2-e-v1-0-97413d6bf824@oss.qualcomm.com --- Manivannan Sadhasivam (9): serdev: Convert to_serdev_*() helpers to macros and use container_of_const() serdev: Add an API to find the serdev controller associated with the devicetree node serdev: Do not return -ENODEV from of_serdev_register_devices() if external connector is used dt-bindings: serial: Document the graph port dt-bindings: connector: Add PCIe M.2 Mechanical Key E connector dt-bindings: connector: m2: Add M.2 1620 LGA soldered down connector Bluetooth: hci_qca: Add M.2 Bluetooth device support using pwrseq power: sequencing: pcie-m2: Add support for PCIe M.2 Key E connectors power: sequencing: pcie-m2: Create serdev device for WCN7850 bluetooth .../bindings/connector/pcie-m2-e-connector.yaml | 191 ++++++++++++++ .../devicetree/bindings/serial/serial.yaml | 3 + MAINTAINERS | 1 + drivers/bluetooth/hci_qca.c | 9 + drivers/power/sequencing/Kconfig | 3 +- drivers/power/sequencing/pwrseq-pcie-m2.c | 278 ++++++++++++++++++++- drivers/tty/serdev/core.c | 28 ++- include/linux/serdev.h | 24 +- 8 files changed, 514 insertions(+), 23 deletions(-) --- base-commit: 559f264e403e4d58d56a17595c60a1de011c5e20 change-id: 20251112-pci-m2-e-94695ac9d657 Best regards, -- Manivannan Sadhasivam