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 86719324B2E; Tue, 25 Nov 2025 14:45:11 +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=1764081911; cv=none; b=rxWNtK9JKNGYChyhtknrZSVU5hM4x7extJtt09FX/d4B73d6AODF/WqE/lOfP3AtM362Dn+bCGW0/ZALHW3ohx9slEClqFCNdU5A/T5R76mjOHXwno3KVATjK6HEiQ7Y/6/bOpig6wEU41w7mkFTT2G4xFgqKwJzeNgnmVl2yr0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764081911; c=relaxed/simple; bh=uTECYDxx3v1bGzayL89lryGm1s4nv9vi4GpwLXVtnRY=; h=From:Subject:Date:Message-Id:MIME-Version:Content-Type:To:Cc; b=SRv3yF9fD350BLnmnQX7BoZMBMGU7DiVGiXqmTrawn7LiRnSKBI5ttEHQYZdQyiicER/NHsTKFGTie3/2t6fZKqTNWPoRmwB8MuiSm32m4k5hOWjAZj86w9EpGdf25QbdD92sXHCaAdaWh0vd0w+sygy6DYmvlA/dxcQkZ5mX78= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=dL4O+H3y; 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="dL4O+H3y" Received: by smtp.kernel.org (Postfix) with ESMTPS id EF823C4CEF1; Tue, 25 Nov 2025 14:45:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1764081911; bh=uTECYDxx3v1bGzayL89lryGm1s4nv9vi4GpwLXVtnRY=; h=From:Subject:Date:To:Cc:Reply-To:From; b=dL4O+H3ykDcy2uUZ6vMaf+aASZpinT///lkx7BvJsJGjHJFGlCFNSziI7vYYtoTKs xyop0BHzyCBVG6AD99UcjYGU5Dob2fi/5X0VLgsWadAamhh7cDdg5YhAGV83jQjeqZ 9WC6TfdmnO3x4Oj+SBVQykg3a8sEB/mDgGJupSkxAdyjrz0ORbnwKBhvrvNSCrn5TJ QROP18q5ZwbfMpWmU8xTHv6sa3BaPVs/hXZ3H41RygiJDIO4MlUDlmb+ZYWtuH5D3q /vi2xevwO4VTUOvcTnGClv0jXT/K5QvXDl4ij8rkpO5YDbPFmTnVnzK6r34FXfsAp7 jwoSNm+h4mVkg== 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 D51CAD0E6C6; Tue, 25 Nov 2025 14:45:10 +0000 (UTC) From: Manivannan Sadhasivam via B4 Relay Subject: [PATCH v2 00/10] Add support for handling PCIe M.2 Key E connectors in devicetree Date: Tue, 25 Nov 2025 20:15:04 +0530 Message-Id: <20251125-pci-m2-e-v2-0-32826de07cc5@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=H4sIAPDAJWkC/23OzwrCMAwG8FcZPZuxxnZ/PPkeskPtohacm80sy vDdjRNPegl8IfzyzYopBmK1yWYVKQUOw0UCrjLlT+5yJAidZIUFWq01wugD9AgEjSkb63zTlbZ Scj5GOoT7Qu1ayafA0xAfi5z0e/sHSRoKaCqj1125P9RotgNzfr25sx/6Ppeh2ucHj3S9Sb3p8 0H1xOyWetJ2cdF+3bQW1VusC4OOnKl+VTH3jgneizBtslTmuobotfx7vgCNIuqzFgEAAA== 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 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 , Manivannan Sadhasivam X-Mailer: b4 0.14.3 X-Developer-Signature: v=1; a=openpgp-sha256; l=6676; i=manivannan.sadhasivam@oss.qualcomm.com; h=from:subject:message-id; bh=uTECYDxx3v1bGzayL89lryGm1s4nv9vi4GpwLXVtnRY=; b=owEBbQGS/pANAwAKAVWfEeb+kc71AcsmYgBpJcDxM2Jy7w/KJCb/fDPfjtzVC0c80RYMWpVsy RvZgIAfyuaJATMEAAEKAB0WIQRnpUMqgUjL2KRYJ5dVnxHm/pHO9QUCaSXA8QAKCRBVnxHm/pHO 9SCLB/9+huQ91JOYLD8k5L9pr5D9iwA3Gzsmtnb/InTVHyMNpl1ZcaLZLnG0TfekdU7Uucs3bqW lbQhzehgnPRjA1ZceIAMl8GWm6e4bFtKBsCXDGgaczsr02Z+dmjkbvo2IbHr0fpFf//0cQM/yTm 2kUEK1Q/uPAI1FdE/BuLRfuOWqsyVGWuhROsSF/+1S7nHFXNJi0e26wWBsEbh+WzTOVIgbKCDnW kSweB+UBaV2L30XXTlVr0SEXmDsKu/UJpM8/2K6Vyd5k1TI99JeUuCH1j13tHLRdIWEM/JNu2L6 WNSTvfD68P+VA7dWeawbyXi9P2Q4dauUHpyBYI/3kRcYeRWD 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. I've used the M.2 card model name as the serdev device name. This is found out by comparing the PCIe VID:PID in the notifier. Is this approach acceptable? I did not use the PID as the serdev name since it will vary if the SDIO interface is used in the future. 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 M.2 card connected over PCIe and UART. Dependency ========== This series is dependent on the M.2 Key M series [1] on top of v6.18-rc1. [1] https://lore.kernel.org/linux-pci/20251125-pci-m2-v3-0-c528042aea47@oss.qualcomm.com [2] https://github.com/Mani-Sadhasivam/linux/commit/acbee74a5c90fc8839bb7b6f326c677ee1c0d89c Signed-off-by: Manivannan Sadhasivam --- 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 (10): serdev: Convert to_serdev_*() helpers to macros and use container_of_const() serdev: Add serdev device based driver match support serdev: Allow passing the serdev device name to serdev_device_add() serdev: Add an API to find the serdev controller associated with the devicetree node serdev: Add modalias support for serdev client devices dt-bindings: serial: Document the graph port serdev: Do not return -ENODEV from of_serdev_register_devices() if external connector is used dt-bindings: connector: Add PCIe M.2 Mechanical Key E connector Bluetooth: hci_qca: Add support for WCN7850 PCIe M.2 card power: sequencing: pcie-m2: Add support for PCIe M.2 Key E connectors .../bindings/connector/pcie-m2-e-connector.yaml | 178 ++++++++++++++++++ .../devicetree/bindings/serial/serial.yaml | 3 + MAINTAINERS | 1 + drivers/bluetooth/hci_qca.c | 19 ++ drivers/platform/x86/dell/dell-uart-backlight.c | 2 +- .../x86/lenovo/yoga-tab2-pro-1380-fastcharger.c | 2 +- drivers/platform/x86/x86-android-tablets/core.c | 2 +- drivers/power/sequencing/Kconfig | 1 + drivers/power/sequencing/pwrseq-pcie-m2.c | 205 ++++++++++++++++++++- drivers/tty/serdev/core.c | 76 +++++++- include/linux/mod_devicetable.h | 8 + include/linux/serdev.h | 30 +-- scripts/mod/devicetable-offsets.c | 3 + scripts/mod/file2alias.c | 8 + 14 files changed, 505 insertions(+), 33 deletions(-) --- base-commit: cb6649f6217c0331b885cf787f1d175963e2a1d2 change-id: 20251112-pci-m2-e-94695ac9d657 prerequisite-message-id: 20251125-pci-m2-v3-0-c528042aea47@oss.qualcomm.com prerequisite-patch-id: 58778d8eb97ab86008cd48fb5d28ed6cc0bbbc1b prerequisite-patch-id: 2dd7d793a67f59ef6e6b5137e69436896198b965 prerequisite-patch-id: 8ccaa5fdd95e64e69cd942f93c26e89b827d0453 prerequisite-patch-id: 3d3e1bb7959ab1e140c5024acdd8655e7a7e99ef Best regards, -- Manivannan Sadhasivam