[PATCH v6 0/9] Add support for handling PCIe M.2 Key E connectors in devicetree

[PATCH v6 0/9] Add support for handling PCIe M.2 Key E connectors in devicetree

[Manivannan Sadhasivam via B4 Relay]

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.

[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 <manivannan.sadhasivam@oss.qualcomm.com>
---
Changes in v6:
- Added a check to bail out if the serdev device was already added during notifier.
- Collected tags
- Link to v5: https://lore.kernel.org/r/20260224-pci-m2-e-v5-0-dd9b9501d33c@oss.qualcomm.com

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          | 285 ++++++++++++++++++++-
 drivers/tty/serdev/core.c                          |  28 +-
 include/linux/serdev.h                             |  24 +-
 8 files changed, 521 insertions(+), 23 deletions(-)
---
base-commit: 559f264e403e4d58d56a17595c60a1de011c5e20
change-id: 20251112-pci-m2-e-94695ac9d657

Best regards,
-- 
Manivannan Sadhasivam <manivannan.sadhasivam@oss.qualcomm.com>

[PATCH v6 1/9] serdev: Convert to_serdev_*() helpers to macros and use container_of_const()

[Manivannan Sadhasivam via B4 Relay]

From: Manivannan Sadhasivam <manivannan.sadhasivam@oss.qualcomm.com>

If these helpers receive the 'const struct device' pointer, then the const
qualifier will get dropped, leading to below warning:

warning: passing argument 1 of ‘to_serdev_device_driver’ discards 'const'
qualifier from pointer target type [-Wdiscarded-qualifiers]

This is not an issue as of now, but with the future commits adding serdev
device based driver matching, this warning will get triggered. Hence,
convert these helpers to macros so that the qualifier get preserved and
also use container_of_const() as container_of() is deprecated.

Tested-by: Hans de Goede <johannes.goede@oss.qualcomm.com> # ThinkPad T14s gen6 (arm64)
Reviewed-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@oss.qualcomm.com>
---
 include/linux/serdev.h | 15 +++------------
 1 file changed, 3 insertions(+), 12 deletions(-)

diff --git a/include/linux/serdev.h b/include/linux/serdev.h
index 5654c58eb73c..0c7d3c27d1f8 100644
--- a/include/linux/serdev.h
+++ b/include/linux/serdev.h
@@ -49,10 +49,7 @@ struct serdev_device {
 	struct mutex write_lock;
 };
 
-static inline struct serdev_device *to_serdev_device(struct device *d)
-{
-	return container_of(d, struct serdev_device, dev);
-}
+#define to_serdev_device(d) container_of_const(d, struct serdev_device, dev)
 
 /**
  * struct serdev_device_driver - serdev slave device driver
@@ -68,10 +65,7 @@ struct serdev_device_driver {
 	void	(*shutdown)(struct serdev_device *);
 };
 
-static inline struct serdev_device_driver *to_serdev_device_driver(struct device_driver *d)
-{
-	return container_of(d, struct serdev_device_driver, driver);
-}
+#define to_serdev_device_driver(d) container_of_const(d, struct serdev_device_driver, driver)
 
 enum serdev_parity {
 	SERDEV_PARITY_NONE,
@@ -112,10 +106,7 @@ struct serdev_controller {
 	const struct serdev_controller_ops *ops;
 };
 
-static inline struct serdev_controller *to_serdev_controller(struct device *d)
-{
-	return container_of(d, struct serdev_controller, dev);
-}
+#define to_serdev_controller(d) container_of_const(d, struct serdev_controller, dev)
 
 static inline void *serdev_device_get_drvdata(const struct serdev_device *serdev)
 {

-- 
2.51.0

[PATCH v6 2/9] serdev: Add an API to find the serdev controller associated with the devicetree node

[Manivannan Sadhasivam via B4 Relay]

From: Manivannan Sadhasivam <manivannan.sadhasivam@oss.qualcomm.com>

Add of_find_serdev_controller_by_node() API to find the serdev controller
device associated with the devicetree node.

Tested-by: Hans de Goede <johannes.goede@oss.qualcomm.com> # ThinkPad T14s gen6 (arm64)
Reviewed-by: Bartosz Golaszewski <bartosz.golaszewski@oss.qualcomm.com>
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@oss.qualcomm.com>
---
 drivers/tty/serdev/core.c | 19 +++++++++++++++++++
 include/linux/serdev.h    |  9 +++++++++
 2 files changed, 28 insertions(+)

diff --git a/drivers/tty/serdev/core.c b/drivers/tty/serdev/core.c
index 8f25510f89b6..bf88b95f7458 100644
--- a/drivers/tty/serdev/core.c
+++ b/drivers/tty/serdev/core.c
@@ -514,6 +514,25 @@ struct serdev_controller *serdev_controller_alloc(struct device *host,
 }
 EXPORT_SYMBOL_GPL(serdev_controller_alloc);
 
+#ifdef CONFIG_OF
+/**
+ * of_find_serdev_controller_by_node() - Find the serdev controller associated
+ *					 with the devicetree node
+ * @node:	Devicetree node
+ *
+ * Return: Pointer to the serdev controller associated with the node. NULL if
+ * the controller is not found. Caller is responsible for calling
+ * serdev_controller_put() to drop the reference.
+ */
+struct serdev_controller *of_find_serdev_controller_by_node(struct device_node *node)
+{
+	struct device *dev = bus_find_device_by_of_node(&serdev_bus_type, node);
+
+	return (dev && dev->type == &serdev_ctrl_type) ? to_serdev_controller(dev) : NULL;
+}
+EXPORT_SYMBOL_GPL(of_find_serdev_controller_by_node);
+#endif
+
 static int of_serdev_register_devices(struct serdev_controller *ctrl)
 {
 	struct device_node *node;
diff --git a/include/linux/serdev.h b/include/linux/serdev.h
index 0c7d3c27d1f8..188c0ba62d50 100644
--- a/include/linux/serdev.h
+++ b/include/linux/serdev.h
@@ -334,4 +334,13 @@ static inline bool serdev_acpi_get_uart_resource(struct acpi_resource *ares,
 }
 #endif /* CONFIG_ACPI */
 
+#ifdef CONFIG_OF
+struct serdev_controller *of_find_serdev_controller_by_node(struct device_node *node);
+#else
+static inline struct serdev_controller *of_find_serdev_controller_by_node(struct device_node *node)
+{
+	return NULL;
+}
+#endif /* CONFIG_OF */
+
 #endif /*_LINUX_SERDEV_H */

-- 
2.51.0

[PATCH v6 3/9] serdev: Do not return -ENODEV from of_serdev_register_devices() if external connector is used

[Manivannan Sadhasivam via B4 Relay]

From: Manivannan Sadhasivam <manivannan.sadhasivam@oss.qualcomm.com>

If an external connector like M.2 is connected to the serdev controller
in DT, then the serdev devices may be created dynamically by the connector
driver. So do not return -ENODEV from of_serdev_register_devices() if the
static nodes are not found and the graph node is used.

Tested-by: Hans de Goede <johannes.goede@oss.qualcomm.com> # ThinkPad T14s gen6 (arm64)
Reviewed-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@oss.qualcomm.com>
---
 drivers/tty/serdev/core.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/drivers/tty/serdev/core.c b/drivers/tty/serdev/core.c
index bf88b95f7458..e9d044a331b0 100644
--- a/drivers/tty/serdev/core.c
+++ b/drivers/tty/serdev/core.c
@@ -12,6 +12,7 @@
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/of.h>
+#include <linux/of_graph.h>
 #include <linux/of_device.h>
 #include <linux/pm_domain.h>
 #include <linux/pm_runtime.h>
@@ -561,7 +562,13 @@ static int of_serdev_register_devices(struct serdev_controller *ctrl)
 		} else
 			found = true;
 	}
-	if (!found)
+
+	/*
+	 * When the serdev controller is connected to an external connector like
+	 * M.2 in DT, then the serdev devices may be created dynamically by the
+	 * connector driver.
+	 */
+	if (!found && !of_graph_is_present(dev_of_node(&ctrl->dev)))
 		return -ENODEV;
 
 	return 0;

-- 
2.51.0

[PATCH v6 4/9] dt-bindings: serial: Document the graph port

[Manivannan Sadhasivam via B4 Relay]

From: Manivannan Sadhasivam <manivannan.sadhasivam@oss.qualcomm.com>

A serial controller could be connected to an external connector like PCIe
M.2 for controlling the serial interface of the card. Hence, document the
OF graph port.

Reviewed-by: Rob Herring (Arm) <robh@kernel.org>
Reviewed-by: Bartosz Golaszewski <bartosz.golaszewski@oss.qualcomm.com>
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@oss.qualcomm.com>
---
 Documentation/devicetree/bindings/serial/serial.yaml | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/Documentation/devicetree/bindings/serial/serial.yaml b/Documentation/devicetree/bindings/serial/serial.yaml
index 6aa9cfae417b..96eb1de8771e 100644
--- a/Documentation/devicetree/bindings/serial/serial.yaml
+++ b/Documentation/devicetree/bindings/serial/serial.yaml
@@ -87,6 +87,9 @@ properties:
     description:
       TX FIFO threshold configuration (in bytes).
 
+  port:
+    $ref: /schemas/graph.yaml#/properties/port
+
 patternProperties:
   "^(bluetooth|bluetooth-gnss|embedded-controller|gnss|gps|mcu|onewire)$":
     if:

-- 
2.51.0

[PATCH v6 5/9] dt-bindings: connector: Add PCIe M.2 Mechanical Key E connector

[Manivannan Sadhasivam via B4 Relay]

From: Manivannan Sadhasivam <manivannan.sadhasivam@oss.qualcomm.com>

Add the devicetree binding for PCIe M.2 Mechanical Key E connector defined
in the PCI Express M.2 Specification, r4.0, sec 5.1.2. This connector
provides interfaces like PCIe or SDIO to attach the WiFi devices to the
host machine, USB or UART+PCM interfaces to attach the Bluetooth (BT)
devices. Spec also provides an optional interface to connect the UIM card,
but that is not covered in this binding.

The connector provides a primary power supply of 3.3v, along with an
optional 1.8v VIO supply for the Adapter I/O buffer circuitry operating at
1.8v sideband signaling.

The connector also supplies optional signals in the form of GPIOs for fine
grained power management.

Reviewed-by: Rob Herring (Arm) <robh@kernel.org>
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@oss.qualcomm.com>
---
 .../bindings/connector/pcie-m2-e-connector.yaml    | 184 +++++++++++++++++++++
 MAINTAINERS                                        |   1 +
 2 files changed, 185 insertions(+)

diff --git a/Documentation/devicetree/bindings/connector/pcie-m2-e-connector.yaml b/Documentation/devicetree/bindings/connector/pcie-m2-e-connector.yaml
new file mode 100644
index 000000000000..f7859aa9b634
--- /dev/null
+++ b/Documentation/devicetree/bindings/connector/pcie-m2-e-connector.yaml
@@ -0,0 +1,184 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/connector/pcie-m2-e-connector.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: PCIe M.2 Mechanical Key E Connector
+
+maintainers:
+  - Manivannan Sadhasivam <manivannan.sadhasivam@oss.qualcomm.com>
+
+description:
+  A PCIe M.2 E connector node represents a physical PCIe M.2 Mechanical Key E
+  connector. Mechanical Key E connectors are used to connect Wireless
+  Connectivity devices including combinations of Wi-Fi, BT, NFC to the host
+  machine over interfaces like PCIe/SDIO, USB/UART+PCM, and I2C.
+
+properties:
+  compatible:
+    const: pcie-m2-e-connector
+
+  vpcie3v3-supply:
+    description: A phandle to the regulator for 3.3v supply.
+
+  vpcie1v8-supply:
+    description: A phandle to the regulator for VIO 1.8v supply.
+
+  i2c-parent:
+    $ref: /schemas/types.yaml#/definitions/phandle
+    description: I2C interface
+
+  clocks:
+    description: 32.768 KHz Suspend Clock (SUSCLK) input from the host system to
+      the M.2 card. Refer, PCI Express M.2 Specification r4.0, sec 3.1.12.1 for
+      more details.
+    maxItems: 1
+
+  w-disable1-gpios:
+    description: GPIO output to W_DISABLE1# signal. This signal is used by the
+      host system to disable WiFi radio in the M.2 card. Refer, PCI Express M.2
+      Specification r4.0, sec 3.1.12.3 for more details.
+    maxItems: 1
+
+  w-disable2-gpios:
+    description: GPIO output to W_DISABLE2# signal. This signal is used by the
+      host system to disable BT radio in the M.2 card. Refer, PCI Express M.2
+      Specification r4.0, sec 3.1.12.3 for more details.
+    maxItems: 1
+
+  viocfg-gpios:
+    description: GPIO input to IO voltage configuration (VIO_CFG) signal. The
+      card drives this signal to indicate to the host system whether the card
+      supports an independent IO voltage domain for sideband signals. Refer,
+      PCI Express M.2 Specification r4.0, sec 3.1.15.1 for more details.
+    maxItems: 1
+
+  uart-wake-gpios:
+    description: GPIO input to UART_WAKE# signal. The card asserts this signal
+      to wake the host system and initiate UART interface communication. Refer,
+      PCI Express M.2 Specification r4.0, sec 3.1.8.1 for more details.
+    maxItems: 1
+
+  sdio-wake-gpios:
+    description: GPIO input to SDIO_WAKE# signal. The card asserts this signal
+      to wake the host system and initiate SDIO interface communication. Refer,
+      PCI Express M.2 Specification r4.0, sec 3.1.7 for more details.
+    maxItems: 1
+
+  sdio-reset-gpios:
+    description: GPIO output to SDIO_RESET# signal. This signal is used by the
+      host system to reset SDIO interface of the M.2 card. Refer, PCI Express
+      M.2 Specification r4.0, sec 3.1.7 for more details.
+    maxItems: 1
+
+  vendor-porta-gpios:
+    description: GPIO for the first vendor specific signal (VENDOR_PORTA). This
+      signal's functionality is defined by the card manufacturer and may be
+      used for proprietary features. Refer the card vendor's documentation for
+      details.
+    maxItems: 1
+
+  vendor-portb-gpios:
+    description: GPIO for the second vendor specific signal (VENDOR_PORTB). This
+      signal's functionality is defined by the card manufacturer and may be
+      used for proprietary features. Refer the card vendor's documentation for
+      details.
+    maxItems: 1
+
+  vendor-portc-gpios:
+    description: GPIO for the third vendor specific signal (VENDOR_PORTC). This
+      signal's functionality is defined by the card manufacturer and may be
+      used for proprietary features. Refer the card vendor's documentation for
+      details.
+    maxItems: 1
+
+  ports:
+    $ref: /schemas/graph.yaml#/properties/ports
+    description: OF graph bindings modeling the interfaces exposed on the
+      connector. Since a single connector can have multiple interfaces, every
+      interface has an assigned OF graph port number as described below.
+
+    properties:
+      port@0:
+        $ref: /schemas/graph.yaml#/properties/port
+        description: PCIe interface for Wi-Fi
+
+      port@1:
+        $ref: /schemas/graph.yaml#/properties/port
+        description: SDIO interface for Wi-Fi
+
+      port@2:
+        $ref: /schemas/graph.yaml#/properties/port
+        description: USB 2.0 interface for BT
+
+      port@3:
+        $ref: /schemas/graph.yaml#/properties/port
+        description: UART interface for BT
+
+      port@4:
+        $ref: /schemas/graph.yaml#/properties/port
+        description: PCM/I2S interface
+
+    anyOf:
+      - anyOf:
+          - required:
+              - port@0
+          - required:
+              - port@1
+      - anyOf:
+          - required:
+              - port@2
+          - required:
+              - port@3
+
+required:
+  - compatible
+  - vpcie3v3-supply
+
+additionalProperties: false
+
+examples:
+  # PCI M.2 Key E connector for Wi-Fi/BT with PCIe/UART interfaces
+  - |
+    #include <dt-bindings/gpio/gpio.h>
+
+    connector {
+        compatible = "pcie-m2-e-connector";
+        vpcie3v3-supply = <&vreg_wcn_3p3>;
+        vpcie1v8-supply = <&vreg_l15b_1p8>;
+        i2c-parent = <&i2c0>;
+        w-disable1-gpios = <&tlmm 115 GPIO_ACTIVE_LOW>;
+        w-disable2-gpios = <&tlmm 116 GPIO_ACTIVE_LOW>;
+        viocfg-gpios = <&tlmm 117 GPIO_ACTIVE_HIGH>;
+        uart-wake-gpios = <&tlmm 118 GPIO_ACTIVE_LOW>;
+        sdio-wake-gpios = <&tlmm 119 GPIO_ACTIVE_LOW>;
+        sdio-reset-gpios = <&tlmm 120 GPIO_ACTIVE_LOW>;
+
+        ports {
+            #address-cells = <1>;
+            #size-cells = <0>;
+
+            port@0 {
+                reg = <0>;
+                #address-cells = <1>;
+                #size-cells = <0>;
+
+                endpoint@0 {
+                    reg = <0>;
+                    remote-endpoint = <&pcie4_port0_ep>;
+                };
+            };
+
+            port@3 {
+                reg = <3>;
+                #address-cells = <1>;
+                #size-cells = <0>;
+
+                endpoint@0 {
+                    reg = <0>;
+                    remote-endpoint = <&uart14_ep>;
+                };
+            };
+        };
+    };
diff --git a/MAINTAINERS b/MAINTAINERS
index 55af015174a5..565198d3b500 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -21044,6 +21044,7 @@ PCIE M.2 POWER SEQUENCING
 M:	Manivannan Sadhasivam <mani@kernel.org>
 L:	linux-pci@vger.kernel.org
 S:	Maintained
+F:	Documentation/devicetree/bindings/connector/pcie-m2-e-connector.yaml
 F:	Documentation/devicetree/bindings/connector/pcie-m2-m-connector.yaml
 F:	drivers/power/sequencing/pwrseq-pcie-m2.c
 

-- 
2.51.0

[PATCH v6 6/9] dt-bindings: connector: m2: Add M.2 1620 LGA soldered down connector

[Manivannan Sadhasivam via B4 Relay]

From: Manivannan Sadhasivam <manivannan.sadhasivam@oss.qualcomm.com>

Lenovo Thinkpad T14s is found to have a soldered down version of M.2 1620
LGA connector. Though, there is no 1620 LGA form factor defined in the M.2
spec, it looks very similar to the M.2 Key E connector. So add the
"pcie-m2-1620-lga-connector" compatible with "pcie-m2-e-connector" fallback
to reuse the Key E binding.

Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@oss.qualcomm.com>
---
 .../devicetree/bindings/connector/pcie-m2-e-connector.yaml       | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/Documentation/devicetree/bindings/connector/pcie-m2-e-connector.yaml b/Documentation/devicetree/bindings/connector/pcie-m2-e-connector.yaml
index f7859aa9b634..d8cf9a9ec7d0 100644
--- a/Documentation/devicetree/bindings/connector/pcie-m2-e-connector.yaml
+++ b/Documentation/devicetree/bindings/connector/pcie-m2-e-connector.yaml
@@ -17,7 +17,14 @@ description:
 
 properties:
   compatible:
-    const: pcie-m2-e-connector
+    oneOf:
+      - items:
+          - enum:
+              - pcie-m2-1620-lga-connector
+          - const: pcie-m2-e-connector
+      - items:
+          - enum:
+              - pcie-m2-e-connector
 
   vpcie3v3-supply:
     description: A phandle to the regulator for 3.3v supply.

-- 
2.51.0

[PATCH v6 7/9] Bluetooth: hci_qca: Add M.2 Bluetooth device support using pwrseq

[Manivannan Sadhasivam via B4 Relay]

From: Manivannan Sadhasivam <manivannan.sadhasivam@oss.qualcomm.com>

Power supply to the M.2 Bluetooth device attached to the host using M.2
connector is controlled using the 'uart' pwrseq device. So add support for
getting the pwrseq device if the OF graph link is present. Once obtained,
the existing pwrseq APIs can be used to control the power supplies of the
M.2 card.

Tested-by: Hans de Goede <johannes.goede@oss.qualcomm.com> # ThinkPad T14s gen6 (arm64)
Reviewed-by: Bartosz Golaszewski <bartosz.golaszewski@oss.qualcomm.com>
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@oss.qualcomm.com>
---
 drivers/bluetooth/hci_qca.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/drivers/bluetooth/hci_qca.c b/drivers/bluetooth/hci_qca.c
index 5b02e7c3f56d..0454c2318461 100644
--- a/drivers/bluetooth/hci_qca.c
+++ b/drivers/bluetooth/hci_qca.c
@@ -26,6 +26,7 @@
 #include <linux/mod_devicetable.h>
 #include <linux/module.h>
 #include <linux/of.h>
+#include <linux/of_graph.h>
 #include <linux/acpi.h>
 #include <linux/platform_device.h>
 #include <linux/pwrseq/consumer.h>
@@ -2421,6 +2422,14 @@ static int qca_serdev_probe(struct serdev_device *serdev)
 	case QCA_WCN6855:
 	case QCA_WCN7850:
 	case QCA_WCN6750:
+		if (of_graph_is_present(dev_of_node(&serdev->ctrl->dev))) {
+			qcadev->bt_power->pwrseq = devm_pwrseq_get(&serdev->ctrl->dev,
+								   "uart");
+			if (IS_ERR(qcadev->bt_power->pwrseq))
+				return PTR_ERR(qcadev->bt_power->pwrseq);
+			break;
+		}
+
 		if (!device_property_present(&serdev->dev, "enable-gpios")) {
 			/*
 			 * Backward compatibility with old DT sources. If the

-- 
2.51.0

[PATCH v6 8/9] power: sequencing: pcie-m2: Add support for PCIe M.2 Key E connectors

[Manivannan Sadhasivam via B4 Relay]

From: Manivannan Sadhasivam <manivannan.sadhasivam@oss.qualcomm.com>

Add support for handling the power sequence of the PCIe M.2 Key E
connectors. These connectors are used to attach the Wireless Connectivity
devices to the host machine including combinations of WiFi, BT, NFC using
interfaces such as PCIe/SDIO for WiFi, USB/UART for BT and I2C for NFC.

Currently, this driver supports only the PCIe interface for WiFi and UART
interface for BT. The driver also only supports driving the 3.3v/1.8v power
supplies and W_DISABLE{1/2}# GPIOs. The optional signals of the Key E
connectors are not currently supported.

Tested-by: Hans de Goede <johannes.goede@oss.qualcomm.com> # ThinkPad T14s gen6 (arm64)
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@oss.qualcomm.com>
---
 drivers/power/sequencing/pwrseq-pcie-m2.c | 107 ++++++++++++++++++++++++++++--
 1 file changed, 101 insertions(+), 6 deletions(-)

diff --git a/drivers/power/sequencing/pwrseq-pcie-m2.c b/drivers/power/sequencing/pwrseq-pcie-m2.c
index d31a7dd8b35c..3507cdcb1e7b 100644
--- a/drivers/power/sequencing/pwrseq-pcie-m2.c
+++ b/drivers/power/sequencing/pwrseq-pcie-m2.c
@@ -5,10 +5,13 @@
  */
 
 #include <linux/device.h>
+#include <linux/delay.h>
+#include <linux/gpio/consumer.h>
 #include <linux/mod_devicetable.h>
 #include <linux/module.h>
 #include <linux/of.h>
 #include <linux/of_graph.h>
+#include <linux/of_platform.h>
 #include <linux/platform_device.h>
 #include <linux/pwrseq/provider.h>
 #include <linux/regulator/consumer.h>
@@ -25,16 +28,18 @@ struct pwrseq_pcie_m2_ctx {
 	struct regulator_bulk_data *regs;
 	size_t num_vregs;
 	struct notifier_block nb;
+	struct gpio_desc *w_disable1_gpio;
+	struct gpio_desc *w_disable2_gpio;
 };
 
-static int pwrseq_pcie_m2_m_vregs_enable(struct pwrseq_device *pwrseq)
+static int pwrseq_pcie_m2_vregs_enable(struct pwrseq_device *pwrseq)
 {
 	struct pwrseq_pcie_m2_ctx *ctx = pwrseq_device_get_drvdata(pwrseq);
 
 	return regulator_bulk_enable(ctx->num_vregs, ctx->regs);
 }
 
-static int pwrseq_pcie_m2_m_vregs_disable(struct pwrseq_device *pwrseq)
+static int pwrseq_pcie_m2_vregs_disable(struct pwrseq_device *pwrseq)
 {
 	struct pwrseq_pcie_m2_ctx *ctx = pwrseq_device_get_drvdata(pwrseq);
 
@@ -43,18 +48,84 @@ static int pwrseq_pcie_m2_m_vregs_disable(struct pwrseq_device *pwrseq)
 
 static const struct pwrseq_unit_data pwrseq_pcie_m2_vregs_unit_data = {
 	.name = "regulators-enable",
-	.enable = pwrseq_pcie_m2_m_vregs_enable,
-	.disable = pwrseq_pcie_m2_m_vregs_disable,
+	.enable = pwrseq_pcie_m2_vregs_enable,
+	.disable = pwrseq_pcie_m2_vregs_disable,
 };
 
-static const struct pwrseq_unit_data *pwrseq_pcie_m2_m_unit_deps[] = {
+static const struct pwrseq_unit_data *pwrseq_pcie_m2_unit_deps[] = {
 	&pwrseq_pcie_m2_vregs_unit_data,
 	NULL
 };
 
+static int pwrseq_pci_m2_e_uart_enable(struct pwrseq_device *pwrseq)
+{
+	struct pwrseq_pcie_m2_ctx *ctx = pwrseq_device_get_drvdata(pwrseq);
+
+	return gpiod_set_value_cansleep(ctx->w_disable2_gpio, 0);
+}
+
+static int pwrseq_pci_m2_e_uart_disable(struct pwrseq_device *pwrseq)
+{
+	struct pwrseq_pcie_m2_ctx *ctx = pwrseq_device_get_drvdata(pwrseq);
+
+	return gpiod_set_value_cansleep(ctx->w_disable2_gpio, 1);
+}
+
+static const struct pwrseq_unit_data pwrseq_pcie_m2_e_uart_unit_data = {
+	.name = "uart-enable",
+	.deps = pwrseq_pcie_m2_unit_deps,
+	.enable = pwrseq_pci_m2_e_uart_enable,
+	.disable = pwrseq_pci_m2_e_uart_disable,
+};
+
+static int pwrseq_pci_m2_e_pcie_enable(struct pwrseq_device *pwrseq)
+{
+	struct pwrseq_pcie_m2_ctx *ctx = pwrseq_device_get_drvdata(pwrseq);
+
+	return gpiod_set_value_cansleep(ctx->w_disable1_gpio, 0);
+}
+
+static int pwrseq_pci_m2_e_pcie_disable(struct pwrseq_device *pwrseq)
+{
+	struct pwrseq_pcie_m2_ctx *ctx = pwrseq_device_get_drvdata(pwrseq);
+
+	return gpiod_set_value_cansleep(ctx->w_disable1_gpio, 1);
+}
+
+static const struct pwrseq_unit_data pwrseq_pcie_m2_e_pcie_unit_data = {
+	.name = "pcie-enable",
+	.deps = pwrseq_pcie_m2_unit_deps,
+	.enable = pwrseq_pci_m2_e_pcie_enable,
+	.disable = pwrseq_pci_m2_e_pcie_disable,
+};
+
 static const struct pwrseq_unit_data pwrseq_pcie_m2_m_pcie_unit_data = {
 	.name = "pcie-enable",
-	.deps = pwrseq_pcie_m2_m_unit_deps,
+	.deps = pwrseq_pcie_m2_unit_deps,
+};
+
+static int pwrseq_pcie_m2_e_pwup_delay(struct pwrseq_device *pwrseq)
+{
+	/*
+	 * FIXME: This delay is only required for some Qcom WLAN/BT cards like
+	 * WCN7850 and not for all devices. But currently, there is no way to
+	 * identify the device model before enumeration.
+	 */
+	msleep(50);
+
+	return 0;
+}
+
+static const struct pwrseq_target_data pwrseq_pcie_m2_e_uart_target_data = {
+	.name = "uart",
+	.unit = &pwrseq_pcie_m2_e_uart_unit_data,
+	.post_enable = pwrseq_pcie_m2_e_pwup_delay,
+};
+
+static const struct pwrseq_target_data pwrseq_pcie_m2_e_pcie_target_data = {
+	.name = "pcie",
+	.unit = &pwrseq_pcie_m2_e_pcie_unit_data,
+	.post_enable = pwrseq_pcie_m2_e_pwup_delay,
 };
 
 static const struct pwrseq_target_data pwrseq_pcie_m2_m_pcie_target_data = {
@@ -62,11 +133,21 @@ static const struct pwrseq_target_data pwrseq_pcie_m2_m_pcie_target_data = {
 	.unit = &pwrseq_pcie_m2_m_pcie_unit_data,
 };
 
+static const struct pwrseq_target_data *pwrseq_pcie_m2_e_targets[] = {
+	&pwrseq_pcie_m2_e_pcie_target_data,
+	&pwrseq_pcie_m2_e_uart_target_data,
+	NULL
+};
+
 static const struct pwrseq_target_data *pwrseq_pcie_m2_m_targets[] = {
 	&pwrseq_pcie_m2_m_pcie_target_data,
 	NULL
 };
 
+static const struct pwrseq_pcie_m2_pdata pwrseq_pcie_m2_e_of_data = {
+	.targets = pwrseq_pcie_m2_e_targets,
+};
+
 static const struct pwrseq_pcie_m2_pdata pwrseq_pcie_m2_m_of_data = {
 	.targets = pwrseq_pcie_m2_m_targets,
 };
@@ -125,6 +206,16 @@ static int pwrseq_pcie_m2_probe(struct platform_device *pdev)
 		return dev_err_probe(dev, ret,
 				     "Failed to get all regulators\n");
 
+	ctx->w_disable1_gpio = devm_gpiod_get_optional(dev, "w-disable1", GPIOD_OUT_HIGH);
+	if (IS_ERR(ctx->w_disable1_gpio))
+		return dev_err_probe(dev, PTR_ERR(ctx->w_disable1_gpio),
+				     "Failed to get the W_DISABLE_1# GPIO\n");
+
+	ctx->w_disable2_gpio = devm_gpiod_get_optional(dev, "w-disable2", GPIOD_OUT_HIGH);
+	if (IS_ERR(ctx->w_disable2_gpio))
+		return dev_err_probe(dev, PTR_ERR(ctx->w_disable2_gpio),
+				     "Failed to get the W_DISABLE_2# GPIO\n");
+
 	ctx->num_vregs = ret;
 
 	ret = devm_add_action_or_reset(dev, pwrseq_pcie_m2_free_regulators, ctx);
@@ -150,6 +241,10 @@ static const struct of_device_id pwrseq_pcie_m2_of_match[] = {
 		.compatible = "pcie-m2-m-connector",
 		.data = &pwrseq_pcie_m2_m_of_data,
 	},
+	{
+		.compatible = "pcie-m2-e-connector",
+		.data = &pwrseq_pcie_m2_e_of_data,
+	},
 	{ }
 };
 MODULE_DEVICE_TABLE(of, pwrseq_pcie_m2_of_match);

-- 
2.51.0

[PATCH v6 9/9] power: sequencing: pcie-m2: Create serdev device for WCN7850 bluetooth

[Manivannan Sadhasivam via B4 Relay]

From: Manivannan Sadhasivam <manivannan.sadhasivam@oss.qualcomm.com>

For supporting bluetooth over the non-discoverable UART interface of
WCN7850, create the serdev device after enumerating the PCIe interface.
This is mandatory since the device ID is only known after the PCIe
enumeration and the ID is used for creating the serdev device.

Since by default there is no OF or ACPI node for the created serdev,
create a dynamic OF 'bluetooth' node with the 'compatible' property and
attach it to the serdev device. This will allow the serdev device to bind
to the existing bluetooth driver.

Tested-by: Hans de Goede <johannes.goede@oss.qualcomm.com> # ThinkPad T14s gen6 (arm64)
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@oss.qualcomm.com>
---
 drivers/power/sequencing/Kconfig          |   3 +-
 drivers/power/sequencing/pwrseq-pcie-m2.c | 178 +++++++++++++++++++++++++++++-
 2 files changed, 177 insertions(+), 4 deletions(-)

diff --git a/drivers/power/sequencing/Kconfig b/drivers/power/sequencing/Kconfig
index f5fff84566ba..55aeef125e6f 100644
--- a/drivers/power/sequencing/Kconfig
+++ b/drivers/power/sequencing/Kconfig
@@ -37,7 +37,8 @@ config POWER_SEQUENCING_TH1520_GPU
 
 config POWER_SEQUENCING_PCIE_M2
 	tristate "PCIe M.2 connector power sequencing driver"
-	depends on OF || COMPILE_TEST
+	depends on (PCI && OF) || COMPILE_TEST
+	select OF_DYNAMIC
 	help
 	  Say Y here to enable the power sequencing driver for PCIe M.2
 	  connectors. This driver handles the power sequencing for the M.2
diff --git a/drivers/power/sequencing/pwrseq-pcie-m2.c b/drivers/power/sequencing/pwrseq-pcie-m2.c
index 3507cdcb1e7b..77357439ba81 100644
--- a/drivers/power/sequencing/pwrseq-pcie-m2.c
+++ b/drivers/power/sequencing/pwrseq-pcie-m2.c
@@ -12,9 +12,11 @@
 #include <linux/of.h>
 #include <linux/of_graph.h>
 #include <linux/of_platform.h>
+#include <linux/pci.h>
 #include <linux/platform_device.h>
 #include <linux/pwrseq/provider.h>
 #include <linux/regulator/consumer.h>
+#include <linux/serdev.h>
 #include <linux/slab.h>
 
 struct pwrseq_pcie_m2_pdata {
@@ -30,6 +32,9 @@ struct pwrseq_pcie_m2_ctx {
 	struct notifier_block nb;
 	struct gpio_desc *w_disable1_gpio;
 	struct gpio_desc *w_disable2_gpio;
+	struct serdev_device *serdev;
+	struct of_changeset *ocs;
+	struct device *dev;
 };
 
 static int pwrseq_pcie_m2_vregs_enable(struct pwrseq_device *pwrseq)
@@ -172,13 +177,176 @@ static int pwrseq_pcie_m2_match(struct pwrseq_device *pwrseq,
 	return PWRSEQ_NO_MATCH;
 }
 
-static void pwrseq_pcie_m2_free_regulators(void *data)
+static void pwrseq_pcie_m2_free_resources(void *data)
 {
 	struct pwrseq_pcie_m2_ctx *ctx = data;
 
+	serdev_device_remove(ctx->serdev);
+	bus_unregister_notifier(&pci_bus_type, &ctx->nb);
+	of_changeset_revert(ctx->ocs);
+	of_changeset_destroy(ctx->ocs);
 	regulator_bulk_free(ctx->num_vregs, ctx->regs);
 }
 
+static int pwrseq_m2_pcie_create_bt_node(struct pwrseq_pcie_m2_ctx *ctx,
+					struct device_node *parent)
+{
+	struct device *dev = ctx->dev;
+	struct device_node *np;
+	int ret;
+
+	ctx->ocs = devm_kzalloc(dev, sizeof(*ctx->ocs), GFP_KERNEL);
+	if (!ctx->ocs)
+		return -ENOMEM;
+
+	of_changeset_init(ctx->ocs);
+
+	np = of_changeset_create_node(ctx->ocs, parent, "bluetooth");
+	if (!np) {
+		dev_err(dev, "Failed to create bluetooth node\n");
+		ret = -ENODEV;
+		goto err_destroy_changeset;
+	}
+
+	ret = of_changeset_add_prop_string(ctx->ocs, np, "compatible", "qcom,wcn7850-bt");
+	if (ret) {
+		dev_err(dev, "Failed to add bluetooth compatible: %d\n", ret);
+		goto err_destroy_changeset;
+	}
+
+	ret = of_changeset_apply(ctx->ocs);
+	if (ret) {
+		dev_err(dev, "Failed to apply changeset: %d\n", ret);
+		goto err_destroy_changeset;
+	}
+
+	ret = device_add_of_node(&ctx->serdev->dev, np);
+	if (ret) {
+		dev_err(dev, "Failed to add OF node: %d\n", ret);
+		goto err_revert_changeset;
+	}
+
+	return 0;
+
+err_revert_changeset:
+	of_changeset_revert(ctx->ocs);
+err_destroy_changeset:
+	of_changeset_destroy(ctx->ocs);
+
+	return ret;
+}
+
+static int pwrseq_m2_pcie_notify(struct notifier_block *nb, unsigned long action,
+			      void *data)
+{
+	struct pwrseq_pcie_m2_ctx *ctx = container_of(nb, struct pwrseq_pcie_m2_ctx, nb);
+	struct pci_dev *pdev = to_pci_dev(data);
+	struct serdev_controller *serdev_ctrl;
+	struct device *dev = ctx->dev;
+	int ret;
+
+	/*
+	 * Check whether the PCI device is associated with this M.2 connector or
+	 * not, by comparing the OF node of the PCI device parent and the Port 0
+	 * (PCIe) remote node parent OF node.
+	 */
+	struct device_node *pci_parent __free(device_node) =
+			of_graph_get_remote_node(dev_of_node(ctx->dev), 0, 0);
+	if (!pci_parent || (pci_parent != pdev->dev.parent->of_node))
+		return NOTIFY_DONE;
+
+	switch (action) {
+	case BUS_NOTIFY_ADD_DEVICE:
+		/* Create serdev device for WCN7850 */
+		if (pdev->vendor == PCI_VENDOR_ID_QCOM && pdev->device == 0x1107) {
+			struct device_node *serdev_parent __free(device_node) =
+				of_graph_get_remote_node(dev_of_node(ctx->dev), 1, 1);
+			if (!serdev_parent)
+				return NOTIFY_DONE;
+
+			serdev_ctrl = of_find_serdev_controller_by_node(serdev_parent);
+			if (!serdev_ctrl)
+				return NOTIFY_DONE;
+
+			/*
+			 * Bail out if the device was already attached to this
+			 * controller.
+			 */
+			if (serdev_ctrl->serdev)
+				return NOTIFY_DONE;
+
+			ctx->serdev = serdev_device_alloc(serdev_ctrl);
+			if (!ctx->serdev)
+				return NOTIFY_BAD;
+
+			ret = pwrseq_m2_pcie_create_bt_node(ctx, serdev_parent);
+			if (ret) {
+				serdev_device_put(ctx->serdev);
+				return notifier_from_errno(ret);
+			}
+
+			ret = serdev_device_add(ctx->serdev);
+			if (ret) {
+				dev_err(dev, "Failed to add serdev for WCN7850: %d\n", ret);
+				of_changeset_revert(ctx->ocs);
+				of_changeset_destroy(ctx->ocs);
+				serdev_device_put(ctx->serdev);
+				return notifier_from_errno(ret);
+			}
+		}
+		break;
+	case BUS_NOTIFY_REMOVED_DEVICE:
+		/* Destroy serdev device for WCN7850 */
+		if (pdev->vendor == PCI_VENDOR_ID_QCOM && pdev->device == 0x1107) {
+			serdev_device_remove(ctx->serdev);
+			of_changeset_revert(ctx->ocs);
+			of_changeset_destroy(ctx->ocs);
+		}
+		break;
+	}
+
+	return NOTIFY_OK;
+}
+
+static bool pwrseq_pcie_m2_check_remote_node(struct device *dev, u8 port, u8 endpoint,
+					     const char *node)
+{
+	struct device_node *remote __free(device_node) =
+			of_graph_get_remote_node(dev_of_node(dev), port, endpoint);
+
+	if (remote && of_node_name_eq(remote, node))
+		return true;
+
+	return false;
+}
+
+/*
+ * If the connector exposes a non-discoverable bus like UART, the respective
+ * protocol device needs to be created manually with the help of the notifier
+ * of the discoverable bus like PCIe.
+ */
+static int pwrseq_pcie_m2_register_notifier(struct pwrseq_pcie_m2_ctx *ctx, struct device *dev)
+{
+	int ret;
+
+	/*
+	 * Register a PCI notifier for Key E connector that has PCIe as Port
+	 * 0/Endpoint 0 interface and Serial as Port 3/Endpoint 0 interface.
+	 */
+	if (pwrseq_pcie_m2_check_remote_node(dev, 3, 0, "serial")) {
+		if (pwrseq_pcie_m2_check_remote_node(dev, 0, 0, "pcie")) {
+			ctx->dev = dev;
+			ctx->nb.notifier_call = pwrseq_m2_pcie_notify;
+			ret = bus_register_notifier(&pci_bus_type, &ctx->nb);
+			if (ret)
+				return dev_err_probe(dev, ret,
+						     "Failed to register notifier for serdev\n");
+		}
+	}
+
+	return 0;
+}
+
 static int pwrseq_pcie_m2_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
@@ -218,7 +386,7 @@ static int pwrseq_pcie_m2_probe(struct platform_device *pdev)
 
 	ctx->num_vregs = ret;
 
-	ret = devm_add_action_or_reset(dev, pwrseq_pcie_m2_free_regulators, ctx);
+	ret = devm_add_action_or_reset(dev, pwrseq_pcie_m2_free_resources, ctx);
 	if (ret)
 		return ret;
 
@@ -233,7 +401,11 @@ static int pwrseq_pcie_m2_probe(struct platform_device *pdev)
 		return dev_err_probe(dev, PTR_ERR(ctx->pwrseq),
 				     "Failed to register the power sequencer\n");
 
-	return 0;
+	/*
+	 * Register a notifier for creating protocol devices for
+	 * non-discoverable busses like UART.
+	 */
+	return pwrseq_pcie_m2_register_notifier(ctx, dev);
 }
 
 static const struct of_device_id pwrseq_pcie_m2_of_match[] = {

-- 
2.51.0

Re: [PATCH v6 9/9] power: sequencing: pcie-m2: Create serdev device for WCN7850 bluetooth

[Manivannan Sadhasivam]

On Tue, Mar 17, 2026 at 09:59:59AM +0530, Manivannan Sadhasivam via B4 Relay wrote:
> From: Manivannan Sadhasivam <manivannan.sadhasivam@oss.qualcomm.com>
> 
> For supporting bluetooth over the non-discoverable UART interface of
> WCN7850, create the serdev device after enumerating the PCIe interface.
> This is mandatory since the device ID is only known after the PCIe
> enumeration and the ID is used for creating the serdev device.
> 
> Since by default there is no OF or ACPI node for the created serdev,
> create a dynamic OF 'bluetooth' node with the 'compatible' property and
> attach it to the serdev device. This will allow the serdev device to bind
> to the existing bluetooth driver.
> 
> Tested-by: Hans de Goede <johannes.goede@oss.qualcomm.com> # ThinkPad T14s gen6 (arm64)
> Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@oss.qualcomm.com>
> ---
>  drivers/power/sequencing/Kconfig          |   3 +-
>  drivers/power/sequencing/pwrseq-pcie-m2.c | 178 +++++++++++++++++++++++++++++-
>  2 files changed, 177 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/power/sequencing/Kconfig b/drivers/power/sequencing/Kconfig
> index f5fff84566ba..55aeef125e6f 100644
> --- a/drivers/power/sequencing/Kconfig
> +++ b/drivers/power/sequencing/Kconfig
> @@ -37,7 +37,8 @@ config POWER_SEQUENCING_TH1520_GPU
>  
>  config POWER_SEQUENCING_PCIE_M2
>  	tristate "PCIe M.2 connector power sequencing driver"
> -	depends on OF || COMPILE_TEST
> +	depends on (PCI && OF) || COMPILE_TEST
> +	select OF_DYNAMIC
>  	help
>  	  Say Y here to enable the power sequencing driver for PCIe M.2
>  	  connectors. This driver handles the power sequencing for the M.2
> diff --git a/drivers/power/sequencing/pwrseq-pcie-m2.c b/drivers/power/sequencing/pwrseq-pcie-m2.c
> index 3507cdcb1e7b..77357439ba81 100644
> --- a/drivers/power/sequencing/pwrseq-pcie-m2.c
> +++ b/drivers/power/sequencing/pwrseq-pcie-m2.c
> @@ -12,9 +12,11 @@
>  #include <linux/of.h>
>  #include <linux/of_graph.h>
>  #include <linux/of_platform.h>
> +#include <linux/pci.h>
>  #include <linux/platform_device.h>
>  #include <linux/pwrseq/provider.h>
>  #include <linux/regulator/consumer.h>
> +#include <linux/serdev.h>
>  #include <linux/slab.h>
>  
>  struct pwrseq_pcie_m2_pdata {
> @@ -30,6 +32,9 @@ struct pwrseq_pcie_m2_ctx {
>  	struct notifier_block nb;
>  	struct gpio_desc *w_disable1_gpio;
>  	struct gpio_desc *w_disable2_gpio;
> +	struct serdev_device *serdev;
> +	struct of_changeset *ocs;
> +	struct device *dev;
>  };
>  
>  static int pwrseq_pcie_m2_vregs_enable(struct pwrseq_device *pwrseq)
> @@ -172,13 +177,176 @@ static int pwrseq_pcie_m2_match(struct pwrseq_device *pwrseq,
>  	return PWRSEQ_NO_MATCH;
>  }
>  
> -static void pwrseq_pcie_m2_free_regulators(void *data)
> +static void pwrseq_pcie_m2_free_resources(void *data)
>  {
>  	struct pwrseq_pcie_m2_ctx *ctx = data;
>  
> +	serdev_device_remove(ctx->serdev);
> +	bus_unregister_notifier(&pci_bus_type, &ctx->nb);
> +	of_changeset_revert(ctx->ocs);
> +	of_changeset_destroy(ctx->ocs);
>  	regulator_bulk_free(ctx->num_vregs, ctx->regs);
>  }
>  
> +static int pwrseq_m2_pcie_create_bt_node(struct pwrseq_pcie_m2_ctx *ctx,
> +					struct device_node *parent)
> +{
> +	struct device *dev = ctx->dev;
> +	struct device_node *np;
> +	int ret;
> +
> +	ctx->ocs = devm_kzalloc(dev, sizeof(*ctx->ocs), GFP_KERNEL);
> +	if (!ctx->ocs)
> +		return -ENOMEM;
> +
> +	of_changeset_init(ctx->ocs);
> +
> +	np = of_changeset_create_node(ctx->ocs, parent, "bluetooth");
> +	if (!np) {
> +		dev_err(dev, "Failed to create bluetooth node\n");
> +		ret = -ENODEV;
> +		goto err_destroy_changeset;
> +	}
> +
> +	ret = of_changeset_add_prop_string(ctx->ocs, np, "compatible", "qcom,wcn7850-bt");
> +	if (ret) {
> +		dev_err(dev, "Failed to add bluetooth compatible: %d\n", ret);
> +		goto err_destroy_changeset;
> +	}
> +
> +	ret = of_changeset_apply(ctx->ocs);
> +	if (ret) {
> +		dev_err(dev, "Failed to apply changeset: %d\n", ret);
> +		goto err_destroy_changeset;
> +	}
> +
> +	ret = device_add_of_node(&ctx->serdev->dev, np);
> +	if (ret) {
> +		dev_err(dev, "Failed to add OF node: %d\n", ret);
> +		goto err_revert_changeset;
> +	}
> +
> +	return 0;
> +
> +err_revert_changeset:
> +	of_changeset_revert(ctx->ocs);
> +err_destroy_changeset:
> +	of_changeset_destroy(ctx->ocs);
> +
> +	return ret;
> +}
> +
> +static int pwrseq_m2_pcie_notify(struct notifier_block *nb, unsigned long action,
> +			      void *data)
> +{
> +	struct pwrseq_pcie_m2_ctx *ctx = container_of(nb, struct pwrseq_pcie_m2_ctx, nb);
> +	struct pci_dev *pdev = to_pci_dev(data);
> +	struct serdev_controller *serdev_ctrl;
> +	struct device *dev = ctx->dev;
> +	int ret;
> +
> +	/*
> +	 * Check whether the PCI device is associated with this M.2 connector or
> +	 * not, by comparing the OF node of the PCI device parent and the Port 0
> +	 * (PCIe) remote node parent OF node.
> +	 */
> +	struct device_node *pci_parent __free(device_node) =
> +			of_graph_get_remote_node(dev_of_node(ctx->dev), 0, 0);
> +	if (!pci_parent || (pci_parent != pdev->dev.parent->of_node))
> +		return NOTIFY_DONE;
> +
> +	switch (action) {
> +	case BUS_NOTIFY_ADD_DEVICE:
> +		/* Create serdev device for WCN7850 */
> +		if (pdev->vendor == PCI_VENDOR_ID_QCOM && pdev->device == 0x1107) {
> +			struct device_node *serdev_parent __free(device_node) =
> +				of_graph_get_remote_node(dev_of_node(ctx->dev), 1, 1);

Typo. This should be:

	of_graph_get_remote_node(dev_of_node(ctx->dev), 3, 0);

Bartosz, could you please fix it while applying?

- Mani

-- 
மணிவண்ணன் சதாசிவம்

Re: [PATCH v6 9/9] power: sequencing: pcie-m2: Create serdev device for WCN7850 bluetooth

[Bartosz Golaszewski]

On Tue, 17 Mar 2026 05:29:59 +0100, Manivannan Sadhasivam via B4 Relay
<devnull+manivannan.sadhasivam.oss.qualcomm.com@kernel.org> said:
> From: Manivannan Sadhasivam <manivannan.sadhasivam@oss.qualcomm.com>
>
> For supporting bluetooth over the non-discoverable UART interface of
> WCN7850, create the serdev device after enumerating the PCIe interface.
> This is mandatory since the device ID is only known after the PCIe
> enumeration and the ID is used for creating the serdev device.
>
> Since by default there is no OF or ACPI node for the created serdev,
> create a dynamic OF 'bluetooth' node with the 'compatible' property and
> attach it to the serdev device. This will allow the serdev device to bind
> to the existing bluetooth driver.
>
> Tested-by: Hans de Goede <johannes.goede@oss.qualcomm.com> # ThinkPad T14s gen6 (arm64)
> Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@oss.qualcomm.com>
> ---
>  drivers/power/sequencing/Kconfig          |   3 +-
>  drivers/power/sequencing/pwrseq-pcie-m2.c | 178 +++++++++++++++++++++++++++++-
>  2 files changed, 177 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/power/sequencing/Kconfig b/drivers/power/sequencing/Kconfig
> index f5fff84566ba..55aeef125e6f 100644
> --- a/drivers/power/sequencing/Kconfig
> +++ b/drivers/power/sequencing/Kconfig
> @@ -37,7 +37,8 @@ config POWER_SEQUENCING_TH1520_GPU
>
>  config POWER_SEQUENCING_PCIE_M2
>  	tristate "PCIe M.2 connector power sequencing driver"
> -	depends on OF || COMPILE_TEST
> +	depends on (PCI && OF) || COMPILE_TEST
> +	select OF_DYNAMIC
>  	help
>  	  Say Y here to enable the power sequencing driver for PCIe M.2
>  	  connectors. This driver handles the power sequencing for the M.2
> diff --git a/drivers/power/sequencing/pwrseq-pcie-m2.c b/drivers/power/sequencing/pwrseq-pcie-m2.c
> index 3507cdcb1e7b..77357439ba81 100644
> --- a/drivers/power/sequencing/pwrseq-pcie-m2.c
> +++ b/drivers/power/sequencing/pwrseq-pcie-m2.c
> @@ -12,9 +12,11 @@
>  #include <linux/of.h>
>  #include <linux/of_graph.h>
>  #include <linux/of_platform.h>
> +#include <linux/pci.h>
>  #include <linux/platform_device.h>
>  #include <linux/pwrseq/provider.h>
>  #include <linux/regulator/consumer.h>
> +#include <linux/serdev.h>
>  #include <linux/slab.h>
>
>  struct pwrseq_pcie_m2_pdata {
> @@ -30,6 +32,9 @@ struct pwrseq_pcie_m2_ctx {
>  	struct notifier_block nb;
>  	struct gpio_desc *w_disable1_gpio;
>  	struct gpio_desc *w_disable2_gpio;
> +	struct serdev_device *serdev;
> +	struct of_changeset *ocs;
> +	struct device *dev;
>  };
>
>  static int pwrseq_pcie_m2_vregs_enable(struct pwrseq_device *pwrseq)
> @@ -172,13 +177,176 @@ static int pwrseq_pcie_m2_match(struct pwrseq_device *pwrseq,
>  	return PWRSEQ_NO_MATCH;
>  }
>
> -static void pwrseq_pcie_m2_free_regulators(void *data)
> +static void pwrseq_pcie_m2_free_resources(void *data)
>  {
>  	struct pwrseq_pcie_m2_ctx *ctx = data;
>
> +	serdev_device_remove(ctx->serdev);
> +	bus_unregister_notifier(&pci_bus_type, &ctx->nb);
> +	of_changeset_revert(ctx->ocs);
> +	of_changeset_destroy(ctx->ocs);
>  	regulator_bulk_free(ctx->num_vregs, ctx->regs);
>  }
>
> +static int pwrseq_m2_pcie_create_bt_node(struct pwrseq_pcie_m2_ctx *ctx,
> +					struct device_node *parent)
> +{
> +	struct device *dev = ctx->dev;
> +	struct device_node *np;
> +	int ret;
> +
> +	ctx->ocs = devm_kzalloc(dev, sizeof(*ctx->ocs), GFP_KERNEL);
> +	if (!ctx->ocs)
> +		return -ENOMEM;
> +
> +	of_changeset_init(ctx->ocs);
> +
> +	np = of_changeset_create_node(ctx->ocs, parent, "bluetooth");
> +	if (!np) {
> +		dev_err(dev, "Failed to create bluetooth node\n");
> +		ret = -ENODEV;
> +		goto err_destroy_changeset;
> +	}
> +
> +	ret = of_changeset_add_prop_string(ctx->ocs, np, "compatible", "qcom,wcn7850-bt");
> +	if (ret) {
> +		dev_err(dev, "Failed to add bluetooth compatible: %d\n", ret);
> +		goto err_destroy_changeset;
> +	}
> +
> +	ret = of_changeset_apply(ctx->ocs);
> +	if (ret) {
> +		dev_err(dev, "Failed to apply changeset: %d\n", ret);
> +		goto err_destroy_changeset;
> +	}
> +
> +	ret = device_add_of_node(&ctx->serdev->dev, np);
> +	if (ret) {
> +		dev_err(dev, "Failed to add OF node: %d\n", ret);
> +		goto err_revert_changeset;
> +	}
> +
> +	return 0;
> +
> +err_revert_changeset:
> +	of_changeset_revert(ctx->ocs);
> +err_destroy_changeset:
> +	of_changeset_destroy(ctx->ocs);
> +
> +	return ret;
> +}
> +
> +static int pwrseq_m2_pcie_notify(struct notifier_block *nb, unsigned long action,
> +			      void *data)
> +{
> +	struct pwrseq_pcie_m2_ctx *ctx = container_of(nb, struct pwrseq_pcie_m2_ctx, nb);
> +	struct pci_dev *pdev = to_pci_dev(data);
> +	struct serdev_controller *serdev_ctrl;
> +	struct device *dev = ctx->dev;
> +	int ret;
> +
> +	/*
> +	 * Check whether the PCI device is associated with this M.2 connector or
> +	 * not, by comparing the OF node of the PCI device parent and the Port 0
> +	 * (PCIe) remote node parent OF node.
> +	 */
> +	struct device_node *pci_parent __free(device_node) =
> +			of_graph_get_remote_node(dev_of_node(ctx->dev), 0, 0);
> +	if (!pci_parent || (pci_parent != pdev->dev.parent->of_node))
> +		return NOTIFY_DONE;
> +
> +	switch (action) {
> +	case BUS_NOTIFY_ADD_DEVICE:
> +		/* Create serdev device for WCN7850 */
> +		if (pdev->vendor == PCI_VENDOR_ID_QCOM && pdev->device == 0x1107) {
> +			struct device_node *serdev_parent __free(device_node) =
> +				of_graph_get_remote_node(dev_of_node(ctx->dev), 1, 1);
> +			if (!serdev_parent)
> +				return NOTIFY_DONE;
> +
> +			serdev_ctrl = of_find_serdev_controller_by_node(serdev_parent);
> +			if (!serdev_ctrl)
> +				return NOTIFY_DONE;
> +
> +			/*
> +			 * Bail out if the device was already attached to this
> +			 * controller.
> +			 */
> +			if (serdev_ctrl->serdev)
> +				return NOTIFY_DONE;
> +
> +			ctx->serdev = serdev_device_alloc(serdev_ctrl);
> +			if (!ctx->serdev)
> +				return NOTIFY_BAD;

If you bail out here, on driver unbind you'll call serdev_device_remove() which
uncoditionally dereferences the serdev pointer.

> +
> +			ret = pwrseq_m2_pcie_create_bt_node(ctx, serdev_parent);

If this doesn't succeed, ctx->ocs remains set to NULL (correct me if I'm wrong)
and you end up calling of_changeset_revert() which will unconditionally
dereference the of_changeset pointer in __of_changeset_entry_invert().

> +			if (ret) {
> +				serdev_device_put(ctx->serdev);
> +				return notifier_from_errno(ret);
> +			}
> +
> +			ret = serdev_device_add(ctx->serdev);
> +			if (ret) {
> +				dev_err(dev, "Failed to add serdev for WCN7850: %d\n", ret);
> +				of_changeset_revert(ctx->ocs);
> +				of_changeset_destroy(ctx->ocs);
> +				serdev_device_put(ctx->serdev);
> +				return notifier_from_errno(ret);
> +			}
> +		}
> +		break;
> +	case BUS_NOTIFY_REMOVED_DEVICE:
> +		/* Destroy serdev device for WCN7850 */
> +		if (pdev->vendor == PCI_VENDOR_ID_QCOM && pdev->device == 0x1107) {
> +			serdev_device_remove(ctx->serdev);
> +			of_changeset_revert(ctx->ocs);
> +			of_changeset_destroy(ctx->ocs);
> +		}
> +		break;
> +	}
> +
> +	return NOTIFY_OK;
> +}
> +
> +static bool pwrseq_pcie_m2_check_remote_node(struct device *dev, u8 port, u8 endpoint,
> +					     const char *node)
> +{
> +	struct device_node *remote __free(device_node) =
> +			of_graph_get_remote_node(dev_of_node(dev), port, endpoint);
> +
> +	if (remote && of_node_name_eq(remote, node))
> +		return true;
> +
> +	return false;
> +}
> +
> +/*
> + * If the connector exposes a non-discoverable bus like UART, the respective
> + * protocol device needs to be created manually with the help of the notifier
> + * of the discoverable bus like PCIe.
> + */
> +static int pwrseq_pcie_m2_register_notifier(struct pwrseq_pcie_m2_ctx *ctx, struct device *dev)
> +{
> +	int ret;
> +
> +	/*
> +	 * Register a PCI notifier for Key E connector that has PCIe as Port
> +	 * 0/Endpoint 0 interface and Serial as Port 3/Endpoint 0 interface.
> +	 */
> +	if (pwrseq_pcie_m2_check_remote_node(dev, 3, 0, "serial")) {
> +		if (pwrseq_pcie_m2_check_remote_node(dev, 0, 0, "pcie")) {
> +			ctx->dev = dev;
> +			ctx->nb.notifier_call = pwrseq_m2_pcie_notify;
> +			ret = bus_register_notifier(&pci_bus_type, &ctx->nb);
> +			if (ret)
> +				return dev_err_probe(dev, ret,
> +						     "Failed to register notifier for serdev\n");
> +		}
> +	}
> +
> +	return 0;
> +}
> +
>  static int pwrseq_pcie_m2_probe(struct platform_device *pdev)
>  {
>  	struct device *dev = &pdev->dev;
> @@ -218,7 +386,7 @@ static int pwrseq_pcie_m2_probe(struct platform_device *pdev)
>
>  	ctx->num_vregs = ret;
>
> -	ret = devm_add_action_or_reset(dev, pwrseq_pcie_m2_free_regulators, ctx);
> +	ret = devm_add_action_or_reset(dev, pwrseq_pcie_m2_free_resources, ctx);
>  	if (ret)
>  		return ret;
>
> @@ -233,7 +401,11 @@ static int pwrseq_pcie_m2_probe(struct platform_device *pdev)
>  		return dev_err_probe(dev, PTR_ERR(ctx->pwrseq),
>  				     "Failed to register the power sequencer\n");

If you bail out here, you will call bus_unregister_notifier() before your
registered it. Kernel docs are not clear on whether that's a bug but it still
looks fishy to me.

Am I not seeing something or is the error path broken? I'm doubting myself
here. :)

This is why I advised to split pwrseq_pcie_m2_free_resources() and only schedule
individual devres actions after their allocation succeeds.

As it is now, you're better off providing a remove() callback with NULL checks.

Bart

>
> -	return 0;
> +	/*
> +	 * Register a notifier for creating protocol devices for
> +	 * non-discoverable busses like UART.
> +	 */
> +	return pwrseq_pcie_m2_register_notifier(ctx, dev);
>  }
>
>  static const struct of_device_id pwrseq_pcie_m2_of_match[] = {
>
> --
> 2.51.0
>
>
>

Re: [PATCH v6 9/9] power: sequencing: pcie-m2: Create serdev device for WCN7850 bluetooth

[kernel test robot]

Hi Manivannan,

kernel test robot noticed the following build errors:

[auto build test ERROR on 559f264e403e4d58d56a17595c60a1de011c5e20]

url:    https://github.com/intel-lab-lkp/linux/commits/Manivannan-Sadhasivam-via-B4-Relay/serdev-Convert-to_serdev_-helpers-to-macros-and-use-container_of_const/20260317-123910
base:   559f264e403e4d58d56a17595c60a1de011c5e20
patch link:    https://lore.kernel.org/r/20260317-pci-m2-e-v6-9-9c898f108d3d%40oss.qualcomm.com
patch subject: [PATCH v6 9/9] power: sequencing: pcie-m2: Create serdev device for WCN7850 bluetooth
config: nios2-allmodconfig (https://download.01.org/0day-ci/archive/20260318/202603180609.ucspJefN-lkp@intel.com/config)
compiler: nios2-linux-gcc (GCC) 11.5.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260318/202603180609.ucspJefN-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202603180609.ucspJefN-lkp@intel.com/

All errors (new ones prefixed by >>):

   drivers/power/sequencing/pwrseq-pcie-m2.c: In function 'pwrseq_pcie_m2_free_resources':
>> drivers/power/sequencing/pwrseq-pcie-m2.c:185:34: error: 'pci_bus_type' undeclared (first use in this function); did you mean 'pci_pcie_type'?
     185 |         bus_unregister_notifier(&pci_bus_type, &ctx->nb);
         |                                  ^~~~~~~~~~~~
         |                                  pci_pcie_type
   drivers/power/sequencing/pwrseq-pcie-m2.c:185:34: note: each undeclared identifier is reported only once for each function it appears in
   drivers/power/sequencing/pwrseq-pcie-m2.c: In function 'pwrseq_pcie_m2_register_notifier':
   drivers/power/sequencing/pwrseq-pcie-m2.c:340:54: error: 'pci_bus_type' undeclared (first use in this function); did you mean 'pci_pcie_type'?
     340 |                         ret = bus_register_notifier(&pci_bus_type, &ctx->nb);
         |                                                      ^~~~~~~~~~~~
         |                                                      pci_pcie_type


vim +185 drivers/power/sequencing/pwrseq-pcie-m2.c

   179	
   180	static void pwrseq_pcie_m2_free_resources(void *data)
   181	{
   182		struct pwrseq_pcie_m2_ctx *ctx = data;
   183	
   184		serdev_device_remove(ctx->serdev);
 > 185		bus_unregister_notifier(&pci_bus_type, &ctx->nb);
   186		of_changeset_revert(ctx->ocs);
   187		of_changeset_destroy(ctx->ocs);
   188		regulator_bulk_free(ctx->num_vregs, ctx->regs);
   189	}
   190	

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki

Re: [PATCH v6 9/9] power: sequencing: pcie-m2: Create serdev device for WCN7850 bluetooth

[kernel test robot]

Hi Manivannan,

kernel test robot noticed the following build errors:

[auto build test ERROR on 559f264e403e4d58d56a17595c60a1de011c5e20]

url:    https://github.com/intel-lab-lkp/linux/commits/Manivannan-Sadhasivam-via-B4-Relay/serdev-Convert-to_serdev_-helpers-to-macros-and-use-container_of_const/20260317-123910
base:   559f264e403e4d58d56a17595c60a1de011c5e20
patch link:    https://lore.kernel.org/r/20260317-pci-m2-e-v6-9-9c898f108d3d%40oss.qualcomm.com
patch subject: [PATCH v6 9/9] power: sequencing: pcie-m2: Create serdev device for WCN7850 bluetooth
config: um-randconfig-002-20260318 (https://download.01.org/0day-ci/archive/20260318/202603180601.E8FFoQ4J-lkp@intel.com/config)
compiler: clang version 23.0.0git (https://github.com/llvm/llvm-project 4abb927bacf37f18f6359a41639a6d1b3bffffb5)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260318/202603180601.E8FFoQ4J-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202603180601.E8FFoQ4J-lkp@intel.com/

All errors (new ones prefixed by >>):

   In file included from kernel/sched/rq-offsets.c:5:
   In file included from kernel/sched/sched.h:28:
   In file included from include/linux/cgroup_api.h:1:
   In file included from include/linux/cgroup.h:27:
   In file included from include/linux/kernel_stat.h:8:
   In file included from include/linux/interrupt.h:11:
   In file included from include/linux/hardirq.h:11:
   In file included from arch/um/include/asm/hardirq.h:24:
   In file included from include/linux/irq.h:20:
   In file included from include/linux/io.h:12:
   In file included from arch/um/include/asm/io.h:24:
   include/asm-generic/io.h:1209:55: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
    1209 |         return (port > MMIO_UPPER_LIMIT) ? NULL : PCI_IOBASE + port;
         |                                                   ~~~~~~~~~~ ^
   In file included from kernel/sched/rq-offsets.c:5:
   In file included from kernel/sched/sched.h:31:
   In file included from include/linux/cpufreq.h:17:
>> include/linux/of.h:1652:34: error: use of undeclared identifier 'OF_RECONFIG_ATTACH_NODE'; did you mean 'OF_RECONFIG_NO_CHANGE'?
    1652 |         return of_changeset_action(ocs, OF_RECONFIG_ATTACH_NODE, np, NULL);
         |                                         ^~~~~~~~~~~~~~~~~~~~~~~
         |                                         OF_RECONFIG_NO_CHANGE
   include/linux/of.h:1627:2: note: 'OF_RECONFIG_NO_CHANGE' declared here
    1627 |         OF_RECONFIG_NO_CHANGE = 0,
         |         ^
>> include/linux/of.h:1658:34: error: use of undeclared identifier 'OF_RECONFIG_DETACH_NODE'; did you mean 'OF_RECONFIG_NO_CHANGE'?
    1658 |         return of_changeset_action(ocs, OF_RECONFIG_DETACH_NODE, np, NULL);
         |                                         ^~~~~~~~~~~~~~~~~~~~~~~
         |                                         OF_RECONFIG_NO_CHANGE
   include/linux/of.h:1627:2: note: 'OF_RECONFIG_NO_CHANGE' declared here
    1627 |         OF_RECONFIG_NO_CHANGE = 0,
         |         ^
>> include/linux/of.h:1664:34: error: use of undeclared identifier 'OF_RECONFIG_ADD_PROPERTY'
    1664 |         return of_changeset_action(ocs, OF_RECONFIG_ADD_PROPERTY, np, prop);
         |                                         ^~~~~~~~~~~~~~~~~~~~~~~~
>> include/linux/of.h:1670:34: error: use of undeclared identifier 'OF_RECONFIG_REMOVE_PROPERTY'
    1670 |         return of_changeset_action(ocs, OF_RECONFIG_REMOVE_PROPERTY, np, prop);
         |                                         ^~~~~~~~~~~~~~~~~~~~~~~~~~~
>> include/linux/of.h:1676:34: error: use of undeclared identifier 'OF_RECONFIG_UPDATE_PROPERTY'
    1676 |         return of_changeset_action(ocs, OF_RECONFIG_UPDATE_PROPERTY, np, prop);
         |                                         ^~~~~~~~~~~~~~~~~~~~~~~~~~~
   1 warning and 5 errors generated.
   make[3]: *** [scripts/Makefile.build:184: kernel/sched/rq-offsets.s] Error 1 shuffle=497447418
   make[3]: Target 'prepare' not remade because of errors.
   make[2]: *** [Makefile:1333: prepare0] Error 2 shuffle=497447418
   make[2]: Target 'prepare' not remade because of errors.
   make[1]: *** [Makefile:248: __sub-make] Error 2 shuffle=497447418
   make[1]: Target 'prepare' not remade because of errors.
   make: *** [Makefile:248: __sub-make] Error 2 shuffle=497447418
   make: Target 'prepare' not remade because of errors.

Kconfig warnings: (for reference only)
   WARNING: unmet direct dependencies detected for OF_DYNAMIC
   Depends on [n]: OF [=n]
   Selected by [y]:
   - POWER_SEQUENCING_PCIE_M2 [=y] && POWER_SEQUENCING [=y] && (PCI [=n] && OF [=n] || COMPILE_TEST [=y])


vim +1652 include/linux/of.h

2e8fff668dc14e Rob Herring       2023-03-29  1633  
201c910bd6898d Pantelis Antoniou 2014-07-04  1634  #ifdef CONFIG_OF_DYNAMIC
f6892d193fb9d6 Grant Likely      2014-11-21  1635  extern int of_reconfig_notifier_register(struct notifier_block *);
f6892d193fb9d6 Grant Likely      2014-11-21  1636  extern int of_reconfig_notifier_unregister(struct notifier_block *);
f5242e5a883bf1 Grant Likely      2014-11-24  1637  extern int of_reconfig_notify(unsigned long, struct of_reconfig_data *rd);
f5242e5a883bf1 Grant Likely      2014-11-24  1638  extern int of_reconfig_get_state_change(unsigned long action,
f5242e5a883bf1 Grant Likely      2014-11-24  1639  					struct of_reconfig_data *arg);
f6892d193fb9d6 Grant Likely      2014-11-21  1640  
201c910bd6898d Pantelis Antoniou 2014-07-04  1641  extern void of_changeset_init(struct of_changeset *ocs);
201c910bd6898d Pantelis Antoniou 2014-07-04  1642  extern void of_changeset_destroy(struct of_changeset *ocs);
201c910bd6898d Pantelis Antoniou 2014-07-04  1643  extern int of_changeset_apply(struct of_changeset *ocs);
201c910bd6898d Pantelis Antoniou 2014-07-04  1644  extern int of_changeset_revert(struct of_changeset *ocs);
201c910bd6898d Pantelis Antoniou 2014-07-04  1645  extern int of_changeset_action(struct of_changeset *ocs,
201c910bd6898d Pantelis Antoniou 2014-07-04  1646  		unsigned long action, struct device_node *np,
201c910bd6898d Pantelis Antoniou 2014-07-04  1647  		struct property *prop);
201c910bd6898d Pantelis Antoniou 2014-07-04  1648  
201c910bd6898d Pantelis Antoniou 2014-07-04  1649  static inline int of_changeset_attach_node(struct of_changeset *ocs,
201c910bd6898d Pantelis Antoniou 2014-07-04  1650  		struct device_node *np)
201c910bd6898d Pantelis Antoniou 2014-07-04  1651  {
201c910bd6898d Pantelis Antoniou 2014-07-04 @1652  	return of_changeset_action(ocs, OF_RECONFIG_ATTACH_NODE, np, NULL);
201c910bd6898d Pantelis Antoniou 2014-07-04  1653  }
201c910bd6898d Pantelis Antoniou 2014-07-04  1654  
201c910bd6898d Pantelis Antoniou 2014-07-04  1655  static inline int of_changeset_detach_node(struct of_changeset *ocs,
201c910bd6898d Pantelis Antoniou 2014-07-04  1656  		struct device_node *np)
201c910bd6898d Pantelis Antoniou 2014-07-04  1657  {
201c910bd6898d Pantelis Antoniou 2014-07-04 @1658  	return of_changeset_action(ocs, OF_RECONFIG_DETACH_NODE, np, NULL);
201c910bd6898d Pantelis Antoniou 2014-07-04  1659  }
201c910bd6898d Pantelis Antoniou 2014-07-04  1660  
201c910bd6898d Pantelis Antoniou 2014-07-04  1661  static inline int of_changeset_add_property(struct of_changeset *ocs,
201c910bd6898d Pantelis Antoniou 2014-07-04  1662  		struct device_node *np, struct property *prop)
201c910bd6898d Pantelis Antoniou 2014-07-04  1663  {
201c910bd6898d Pantelis Antoniou 2014-07-04 @1664  	return of_changeset_action(ocs, OF_RECONFIG_ADD_PROPERTY, np, prop);
201c910bd6898d Pantelis Antoniou 2014-07-04  1665  }
201c910bd6898d Pantelis Antoniou 2014-07-04  1666  
201c910bd6898d Pantelis Antoniou 2014-07-04  1667  static inline int of_changeset_remove_property(struct of_changeset *ocs,
201c910bd6898d Pantelis Antoniou 2014-07-04  1668  		struct device_node *np, struct property *prop)
201c910bd6898d Pantelis Antoniou 2014-07-04  1669  {
201c910bd6898d Pantelis Antoniou 2014-07-04 @1670  	return of_changeset_action(ocs, OF_RECONFIG_REMOVE_PROPERTY, np, prop);
201c910bd6898d Pantelis Antoniou 2014-07-04  1671  }
201c910bd6898d Pantelis Antoniou 2014-07-04  1672  
201c910bd6898d Pantelis Antoniou 2014-07-04  1673  static inline int of_changeset_update_property(struct of_changeset *ocs,
201c910bd6898d Pantelis Antoniou 2014-07-04  1674  		struct device_node *np, struct property *prop)
201c910bd6898d Pantelis Antoniou 2014-07-04  1675  {
201c910bd6898d Pantelis Antoniou 2014-07-04 @1676  	return of_changeset_action(ocs, OF_RECONFIG_UPDATE_PROPERTY, np, prop);
201c910bd6898d Pantelis Antoniou 2014-07-04  1677  }
b544fc2b8606d7 Lizhi Hou         2023-08-15  1678  

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki

Re: [PATCH v6 9/9] power: sequencing: pcie-m2: Create serdev device for WCN7850 bluetooth

[Manivannan Sadhasivam]

On Tue, Mar 17, 2026 at 09:06:20AM -0400, Bartosz Golaszewski wrote:
> On Tue, 17 Mar 2026 05:29:59 +0100, Manivannan Sadhasivam via B4 Relay
> <devnull+manivannan.sadhasivam.oss.qualcomm.com@kernel.org> said:
> > From: Manivannan Sadhasivam <manivannan.sadhasivam@oss.qualcomm.com>
> >
> > For supporting bluetooth over the non-discoverable UART interface of
> > WCN7850, create the serdev device after enumerating the PCIe interface.
> > This is mandatory since the device ID is only known after the PCIe
> > enumeration and the ID is used for creating the serdev device.
> >
> > Since by default there is no OF or ACPI node for the created serdev,
> > create a dynamic OF 'bluetooth' node with the 'compatible' property and
> > attach it to the serdev device. This will allow the serdev device to bind
> > to the existing bluetooth driver.
> >
> > Tested-by: Hans de Goede <johannes.goede@oss.qualcomm.com> # ThinkPad T14s gen6 (arm64)
> > Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@oss.qualcomm.com>
> > ---
> >  drivers/power/sequencing/Kconfig          |   3 +-
> >  drivers/power/sequencing/pwrseq-pcie-m2.c | 178 +++++++++++++++++++++++++++++-
> >  2 files changed, 177 insertions(+), 4 deletions(-)
> >
> > diff --git a/drivers/power/sequencing/Kconfig b/drivers/power/sequencing/Kconfig
> > index f5fff84566ba..55aeef125e6f 100644
> > --- a/drivers/power/sequencing/Kconfig
> > +++ b/drivers/power/sequencing/Kconfig
> > @@ -37,7 +37,8 @@ config POWER_SEQUENCING_TH1520_GPU
> >
> >  config POWER_SEQUENCING_PCIE_M2
> >  	tristate "PCIe M.2 connector power sequencing driver"
> > -	depends on OF || COMPILE_TEST
> > +	depends on (PCI && OF) || COMPILE_TEST
> > +	select OF_DYNAMIC
> >  	help
> >  	  Say Y here to enable the power sequencing driver for PCIe M.2
> >  	  connectors. This driver handles the power sequencing for the M.2
> > diff --git a/drivers/power/sequencing/pwrseq-pcie-m2.c b/drivers/power/sequencing/pwrseq-pcie-m2.c
> > index 3507cdcb1e7b..77357439ba81 100644
> > --- a/drivers/power/sequencing/pwrseq-pcie-m2.c
> > +++ b/drivers/power/sequencing/pwrseq-pcie-m2.c
> > @@ -12,9 +12,11 @@
> >  #include <linux/of.h>
> >  #include <linux/of_graph.h>
> >  #include <linux/of_platform.h>
> > +#include <linux/pci.h>
> >  #include <linux/platform_device.h>
> >  #include <linux/pwrseq/provider.h>
> >  #include <linux/regulator/consumer.h>
> > +#include <linux/serdev.h>
> >  #include <linux/slab.h>
> >
> >  struct pwrseq_pcie_m2_pdata {
> > @@ -30,6 +32,9 @@ struct pwrseq_pcie_m2_ctx {
> >  	struct notifier_block nb;
> >  	struct gpio_desc *w_disable1_gpio;
> >  	struct gpio_desc *w_disable2_gpio;
> > +	struct serdev_device *serdev;
> > +	struct of_changeset *ocs;
> > +	struct device *dev;
> >  };
> >
> >  static int pwrseq_pcie_m2_vregs_enable(struct pwrseq_device *pwrseq)
> > @@ -172,13 +177,176 @@ static int pwrseq_pcie_m2_match(struct pwrseq_device *pwrseq,
> >  	return PWRSEQ_NO_MATCH;
> >  }
> >
> > -static void pwrseq_pcie_m2_free_regulators(void *data)
> > +static void pwrseq_pcie_m2_free_resources(void *data)
> >  {
> >  	struct pwrseq_pcie_m2_ctx *ctx = data;
> >
> > +	serdev_device_remove(ctx->serdev);
> > +	bus_unregister_notifier(&pci_bus_type, &ctx->nb);
> > +	of_changeset_revert(ctx->ocs);
> > +	of_changeset_destroy(ctx->ocs);
> >  	regulator_bulk_free(ctx->num_vregs, ctx->regs);
> >  }
> >
> > +static int pwrseq_m2_pcie_create_bt_node(struct pwrseq_pcie_m2_ctx *ctx,
> > +					struct device_node *parent)
> > +{
> > +	struct device *dev = ctx->dev;
> > +	struct device_node *np;
> > +	int ret;
> > +
> > +	ctx->ocs = devm_kzalloc(dev, sizeof(*ctx->ocs), GFP_KERNEL);
> > +	if (!ctx->ocs)
> > +		return -ENOMEM;
> > +
> > +	of_changeset_init(ctx->ocs);
> > +
> > +	np = of_changeset_create_node(ctx->ocs, parent, "bluetooth");
> > +	if (!np) {
> > +		dev_err(dev, "Failed to create bluetooth node\n");
> > +		ret = -ENODEV;
> > +		goto err_destroy_changeset;
> > +	}
> > +
> > +	ret = of_changeset_add_prop_string(ctx->ocs, np, "compatible", "qcom,wcn7850-bt");
> > +	if (ret) {
> > +		dev_err(dev, "Failed to add bluetooth compatible: %d\n", ret);
> > +		goto err_destroy_changeset;
> > +	}
> > +
> > +	ret = of_changeset_apply(ctx->ocs);
> > +	if (ret) {
> > +		dev_err(dev, "Failed to apply changeset: %d\n", ret);
> > +		goto err_destroy_changeset;
> > +	}
> > +
> > +	ret = device_add_of_node(&ctx->serdev->dev, np);
> > +	if (ret) {
> > +		dev_err(dev, "Failed to add OF node: %d\n", ret);
> > +		goto err_revert_changeset;
> > +	}
> > +
> > +	return 0;
> > +
> > +err_revert_changeset:
> > +	of_changeset_revert(ctx->ocs);
> > +err_destroy_changeset:
> > +	of_changeset_destroy(ctx->ocs);
> > +
> > +	return ret;
> > +}
> > +
> > +static int pwrseq_m2_pcie_notify(struct notifier_block *nb, unsigned long action,
> > +			      void *data)
> > +{
> > +	struct pwrseq_pcie_m2_ctx *ctx = container_of(nb, struct pwrseq_pcie_m2_ctx, nb);
> > +	struct pci_dev *pdev = to_pci_dev(data);
> > +	struct serdev_controller *serdev_ctrl;
> > +	struct device *dev = ctx->dev;
> > +	int ret;
> > +
> > +	/*
> > +	 * Check whether the PCI device is associated with this M.2 connector or
> > +	 * not, by comparing the OF node of the PCI device parent and the Port 0
> > +	 * (PCIe) remote node parent OF node.
> > +	 */
> > +	struct device_node *pci_parent __free(device_node) =
> > +			of_graph_get_remote_node(dev_of_node(ctx->dev), 0, 0);
> > +	if (!pci_parent || (pci_parent != pdev->dev.parent->of_node))
> > +		return NOTIFY_DONE;
> > +
> > +	switch (action) {
> > +	case BUS_NOTIFY_ADD_DEVICE:
> > +		/* Create serdev device for WCN7850 */
> > +		if (pdev->vendor == PCI_VENDOR_ID_QCOM && pdev->device == 0x1107) {
> > +			struct device_node *serdev_parent __free(device_node) =
> > +				of_graph_get_remote_node(dev_of_node(ctx->dev), 1, 1);
> > +			if (!serdev_parent)
> > +				return NOTIFY_DONE;
> > +
> > +			serdev_ctrl = of_find_serdev_controller_by_node(serdev_parent);
> > +			if (!serdev_ctrl)
> > +				return NOTIFY_DONE;
> > +
> > +			/*
> > +			 * Bail out if the device was already attached to this
> > +			 * controller.
> > +			 */
> > +			if (serdev_ctrl->serdev)
> > +				return NOTIFY_DONE;
> > +
> > +			ctx->serdev = serdev_device_alloc(serdev_ctrl);
> > +			if (!ctx->serdev)
> > +				return NOTIFY_BAD;
> 
> If you bail out here, on driver unbind you'll call serdev_device_remove() which
> uncoditionally dereferences the serdev pointer.
> 
> > +
> > +			ret = pwrseq_m2_pcie_create_bt_node(ctx, serdev_parent);
> 
> If this doesn't succeed, ctx->ocs remains set to NULL (correct me if I'm wrong)
> and you end up calling of_changeset_revert() which will unconditionally
> dereference the of_changeset pointer in __of_changeset_entry_invert().
> 
> > +			if (ret) {
> > +				serdev_device_put(ctx->serdev);
> > +				return notifier_from_errno(ret);
> > +			}
> > +
> > +			ret = serdev_device_add(ctx->serdev);
> > +			if (ret) {
> > +				dev_err(dev, "Failed to add serdev for WCN7850: %d\n", ret);
> > +				of_changeset_revert(ctx->ocs);
> > +				of_changeset_destroy(ctx->ocs);
> > +				serdev_device_put(ctx->serdev);
> > +				return notifier_from_errno(ret);
> > +			}
> > +		}
> > +		break;
> > +	case BUS_NOTIFY_REMOVED_DEVICE:
> > +		/* Destroy serdev device for WCN7850 */
> > +		if (pdev->vendor == PCI_VENDOR_ID_QCOM && pdev->device == 0x1107) {
> > +			serdev_device_remove(ctx->serdev);
> > +			of_changeset_revert(ctx->ocs);
> > +			of_changeset_destroy(ctx->ocs);
> > +		}
> > +		break;
> > +	}
> > +
> > +	return NOTIFY_OK;
> > +}
> > +
> > +static bool pwrseq_pcie_m2_check_remote_node(struct device *dev, u8 port, u8 endpoint,
> > +					     const char *node)
> > +{
> > +	struct device_node *remote __free(device_node) =
> > +			of_graph_get_remote_node(dev_of_node(dev), port, endpoint);
> > +
> > +	if (remote && of_node_name_eq(remote, node))
> > +		return true;
> > +
> > +	return false;
> > +}
> > +
> > +/*
> > + * If the connector exposes a non-discoverable bus like UART, the respective
> > + * protocol device needs to be created manually with the help of the notifier
> > + * of the discoverable bus like PCIe.
> > + */
> > +static int pwrseq_pcie_m2_register_notifier(struct pwrseq_pcie_m2_ctx *ctx, struct device *dev)
> > +{
> > +	int ret;
> > +
> > +	/*
> > +	 * Register a PCI notifier for Key E connector that has PCIe as Port
> > +	 * 0/Endpoint 0 interface and Serial as Port 3/Endpoint 0 interface.
> > +	 */
> > +	if (pwrseq_pcie_m2_check_remote_node(dev, 3, 0, "serial")) {
> > +		if (pwrseq_pcie_m2_check_remote_node(dev, 0, 0, "pcie")) {
> > +			ctx->dev = dev;
> > +			ctx->nb.notifier_call = pwrseq_m2_pcie_notify;
> > +			ret = bus_register_notifier(&pci_bus_type, &ctx->nb);
> > +			if (ret)
> > +				return dev_err_probe(dev, ret,
> > +						     "Failed to register notifier for serdev\n");
> > +		}
> > +	}
> > +
> > +	return 0;
> > +}
> > +
> >  static int pwrseq_pcie_m2_probe(struct platform_device *pdev)
> >  {
> >  	struct device *dev = &pdev->dev;
> > @@ -218,7 +386,7 @@ static int pwrseq_pcie_m2_probe(struct platform_device *pdev)
> >
> >  	ctx->num_vregs = ret;
> >
> > -	ret = devm_add_action_or_reset(dev, pwrseq_pcie_m2_free_regulators, ctx);
> > +	ret = devm_add_action_or_reset(dev, pwrseq_pcie_m2_free_resources, ctx);
> >  	if (ret)
> >  		return ret;
> >
> > @@ -233,7 +401,11 @@ static int pwrseq_pcie_m2_probe(struct platform_device *pdev)
> >  		return dev_err_probe(dev, PTR_ERR(ctx->pwrseq),
> >  				     "Failed to register the power sequencer\n");
> 
> If you bail out here, you will call bus_unregister_notifier() before your
> registered it. Kernel docs are not clear on whether that's a bug but it still
> looks fishy to me.
> 
> Am I not seeing something or is the error path broken? I'm doubting myself
> here. :)
> 

No, it was me who has gone bonkers with the error path. I was so delusional to
assume that these APIs handle NULL ptrs :/

> This is why I advised to split pwrseq_pcie_m2_free_resources() and only schedule
> individual devres actions after their allocation succeeds.
> 
> As it is now, you're better off providing a remove() callback with NULL checks.
> 

Makes sense. I'll fix them all in next version.

- Mani

-- 
மணிவண்ணன் சதாசிவம்

Re: [PATCH v6 6/9] dt-bindings: connector: m2: Add M.2 1620 LGA soldered down connector

[Rob Herring]

On Tue, Mar 17, 2026 at 09:59:56AM +0530, Manivannan Sadhasivam wrote:
> Lenovo Thinkpad T14s is found to have a soldered down version of M.2 1620
> LGA connector. Though, there is no 1620 LGA form factor defined in the M.2
> spec, it looks very similar to the M.2 Key E connector. So add the
> "pcie-m2-1620-lga-connector" compatible with "pcie-m2-e-connector" fallback
> to reuse the Key E binding.

What is LGA?

If not in the spec, is it really something generic?

> 
> Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@oss.qualcomm.com>
> ---
>  .../devicetree/bindings/connector/pcie-m2-e-connector.yaml       | 9 ++++++++-
>  1 file changed, 8 insertions(+), 1 deletion(-)
> 
> diff --git a/Documentation/devicetree/bindings/connector/pcie-m2-e-connector.yaml b/Documentation/devicetree/bindings/connector/pcie-m2-e-connector.yaml
> index f7859aa9b634..d8cf9a9ec7d0 100644
> --- a/Documentation/devicetree/bindings/connector/pcie-m2-e-connector.yaml
> +++ b/Documentation/devicetree/bindings/connector/pcie-m2-e-connector.yaml
> @@ -17,7 +17,14 @@ description:
>  
>  properties:
>    compatible:
> -    const: pcie-m2-e-connector
> +    oneOf:
> +      - items:
> +          - enum:
> +              - pcie-m2-1620-lga-connector
> +          - const: pcie-m2-e-connector
> +      - items:
> +          - enum:
> +              - pcie-m2-e-connector
>  
>    vpcie3v3-supply:
>      description: A phandle to the regulator for 3.3v supply.
> 
> -- 
> 2.51.0
> 

Re: [PATCH v6 6/9] dt-bindings: connector: m2: Add M.2 1620 LGA soldered down connector

[Manivannan Sadhasivam]

On Sun, Mar 22, 2026 at 06:37:13PM -0500, Rob Herring wrote:
> On Tue, Mar 17, 2026 at 09:59:56AM +0530, Manivannan Sadhasivam wrote:
> > Lenovo Thinkpad T14s is found to have a soldered down version of M.2 1620
> > LGA connector. Though, there is no 1620 LGA form factor defined in the M.2
> > spec, it looks very similar to the M.2 Key E connector. So add the
> > "pcie-m2-1620-lga-connector" compatible with "pcie-m2-e-connector" fallback
> > to reuse the Key E binding.
> 
> What is LGA?
> 

Land Grid Array

> If not in the spec, is it really something generic?
> 

Good question. Yes and No! LGA is not something that Lenovo only uses. Other
vendors may also use this form factor. PCIe connectors are full of innovation as
the spec gives room for hardware designers to be as innovative as possible to
save the BOM cost.

This is why I do not want to make it Lenovo specific. But if you prefer that, I
can name it as "lenovo,pcie-m2-1620-lga-connector".

- Mani

> > 
> > Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@oss.qualcomm.com>
> > ---
> >  .../devicetree/bindings/connector/pcie-m2-e-connector.yaml       | 9 ++++++++-
> >  1 file changed, 8 insertions(+), 1 deletion(-)
> > 
> > diff --git a/Documentation/devicetree/bindings/connector/pcie-m2-e-connector.yaml b/Documentation/devicetree/bindings/connector/pcie-m2-e-connector.yaml
> > index f7859aa9b634..d8cf9a9ec7d0 100644
> > --- a/Documentation/devicetree/bindings/connector/pcie-m2-e-connector.yaml
> > +++ b/Documentation/devicetree/bindings/connector/pcie-m2-e-connector.yaml
> > @@ -17,7 +17,14 @@ description:
> >  
> >  properties:
> >    compatible:
> > -    const: pcie-m2-e-connector
> > +    oneOf:
> > +      - items:
> > +          - enum:
> > +              - pcie-m2-1620-lga-connector
> > +          - const: pcie-m2-e-connector
> > +      - items:
> > +          - enum:
> > +              - pcie-m2-e-connector
> >  
> >    vpcie3v3-supply:
> >      description: A phandle to the regulator for 3.3v supply.
> > 
> > -- 
> > 2.51.0
> > 

-- 
மணிவண்ணன் சதாசிவம்

Re: [PATCH v6 6/9] dt-bindings: connector: m2: Add M.2 1620 LGA soldered down connector

[Rob Herring]

On Mon, Mar 23, 2026 at 7:16 AM Manivannan Sadhasivam <mani@kernel.org> wrote:
>
> On Sun, Mar 22, 2026 at 06:37:13PM -0500, Rob Herring wrote:
> > On Tue, Mar 17, 2026 at 09:59:56AM +0530, Manivannan Sadhasivam wrote:
> > > Lenovo Thinkpad T14s is found to have a soldered down version of M.2 1620
> > > LGA connector. Though, there is no 1620 LGA form factor defined in the M.2
> > > spec, it looks very similar to the M.2 Key E connector. So add the
> > > "pcie-m2-1620-lga-connector" compatible with "pcie-m2-e-connector" fallback
> > > to reuse the Key E binding.
> >
> > What is LGA?
> >
>
> Land Grid Array
>
> > If not in the spec, is it really something generic?
> >
>
> Good question. Yes and No! LGA is not something that Lenovo only uses. Other
> vendors may also use this form factor. PCIe connectors are full of innovation as
> the spec gives room for hardware designers to be as innovative as possible to
> save the BOM cost.

innovation == incompatible changes

> This is why I do not want to make it Lenovo specific. But if you prefer that, I
> can name it as "lenovo,pcie-m2-1620-lga-connector".

Depends if you think that s/w needs to know the differences. Hard to
say with a sample size of 1.

Rob

Re: [PATCH v6 6/9] dt-bindings: connector: m2: Add M.2 1620 LGA soldered down connector

[Manivannan Sadhasivam]

On Mon, Mar 23, 2026 at 08:39:55AM -0500, Rob Herring wrote:
> On Mon, Mar 23, 2026 at 7:16 AM Manivannan Sadhasivam <mani@kernel.org> wrote:
> >
> > On Sun, Mar 22, 2026 at 06:37:13PM -0500, Rob Herring wrote:
> > > On Tue, Mar 17, 2026 at 09:59:56AM +0530, Manivannan Sadhasivam wrote:
> > > > Lenovo Thinkpad T14s is found to have a soldered down version of M.2 1620
> > > > LGA connector. Though, there is no 1620 LGA form factor defined in the M.2
> > > > spec, it looks very similar to the M.2 Key E connector. So add the
> > > > "pcie-m2-1620-lga-connector" compatible with "pcie-m2-e-connector" fallback
> > > > to reuse the Key E binding.
> > >
> > > What is LGA?
> > >
> >
> > Land Grid Array
> >
> > > If not in the spec, is it really something generic?
> > >
> >
> > Good question. Yes and No! LGA is not something that Lenovo only uses. Other
> > vendors may also use this form factor. PCIe connectors are full of innovation as
> > the spec gives room for hardware designers to be as innovative as possible to
> > save the BOM cost.
> 
> innovation == incompatible changes
> 

Yes, I was trying to sound nice :)

> > This is why I do not want to make it Lenovo specific. But if you prefer that, I
> > can name it as "lenovo,pcie-m2-1620-lga-connector".
> 
> Depends if you think that s/w needs to know the differences. Hard to
> say with a sample size of 1.
> 

Sure. Will add the 'lenovo' prefix then.

- Mani

-- 
மணிவண்ணன் சதாசிவம்

Re: [PATCH v6 6/9] dt-bindings: connector: m2: Add M.2 1620 LGA soldered down connector

[Dmitry Baryshkov]

On Mon, Mar 23, 2026 at 07:14:25PM +0530, Manivannan Sadhasivam wrote:
> On Mon, Mar 23, 2026 at 08:39:55AM -0500, Rob Herring wrote:
> > On Mon, Mar 23, 2026 at 7:16 AM Manivannan Sadhasivam <mani@kernel.org> wrote:
> > >
> > > On Sun, Mar 22, 2026 at 06:37:13PM -0500, Rob Herring wrote:
> > > > On Tue, Mar 17, 2026 at 09:59:56AM +0530, Manivannan Sadhasivam wrote:
> > > > > Lenovo Thinkpad T14s is found to have a soldered down version of M.2 1620
> > > > > LGA connector. Though, there is no 1620 LGA form factor defined in the M.2
> > > > > spec, it looks very similar to the M.2 Key E connector. So add the
> > > > > "pcie-m2-1620-lga-connector" compatible with "pcie-m2-e-connector" fallback
> > > > > to reuse the Key E binding.
> > > >
> > > > What is LGA?
> > > >
> > >
> > > Land Grid Array
> > >
> > > > If not in the spec, is it really something generic?
> > > >
> > >
> > > Good question. Yes and No! LGA is not something that Lenovo only uses. Other
> > > vendors may also use this form factor. PCIe connectors are full of innovation as
> > > the spec gives room for hardware designers to be as innovative as possible to
> > > save the BOM cost.
> > 
> > innovation == incompatible changes
> > 
> 
> Yes, I was trying to sound nice :)
> 
> > > This is why I do not want to make it Lenovo specific. But if you prefer that, I
> > > can name it as "lenovo,pcie-m2-1620-lga-connector".
> > 
> > Depends if you think that s/w needs to know the differences. Hard to
> > say with a sample size of 1.
> > 
> 
> Sure. Will add the 'lenovo' prefix then.

Is it really Lenovo? Or is it some other module vendor, whose LGAs are
being used by Lenovo?

I remember that DB820c also used some kind of a module for the WiFi card
(which might be M.2 compatible or might not, I can't find exact docs at
this point).

-- 
With best wishes
Dmitry

Re: [PATCH v6 6/9] dt-bindings: connector: m2: Add M.2 1620 LGA soldered down connector

[Manivannan Sadhasivam]

On Mon, Mar 23, 2026 at 05:14:30PM +0200, Dmitry Baryshkov wrote:
> On Mon, Mar 23, 2026 at 07:14:25PM +0530, Manivannan Sadhasivam wrote:
> > On Mon, Mar 23, 2026 at 08:39:55AM -0500, Rob Herring wrote:
> > > On Mon, Mar 23, 2026 at 7:16 AM Manivannan Sadhasivam <mani@kernel.org> wrote:
> > > >
> > > > On Sun, Mar 22, 2026 at 06:37:13PM -0500, Rob Herring wrote:
> > > > > On Tue, Mar 17, 2026 at 09:59:56AM +0530, Manivannan Sadhasivam wrote:
> > > > > > Lenovo Thinkpad T14s is found to have a soldered down version of M.2 1620
> > > > > > LGA connector. Though, there is no 1620 LGA form factor defined in the M.2
> > > > > > spec, it looks very similar to the M.2 Key E connector. So add the
> > > > > > "pcie-m2-1620-lga-connector" compatible with "pcie-m2-e-connector" fallback
> > > > > > to reuse the Key E binding.
> > > > >
> > > > > What is LGA?
> > > > >
> > > >
> > > > Land Grid Array
> > > >
> > > > > If not in the spec, is it really something generic?
> > > > >
> > > >
> > > > Good question. Yes and No! LGA is not something that Lenovo only uses. Other
> > > > vendors may also use this form factor. PCIe connectors are full of innovation as
> > > > the spec gives room for hardware designers to be as innovative as possible to
> > > > save the BOM cost.
> > > 
> > > innovation == incompatible changes
> > > 
> > 
> > Yes, I was trying to sound nice :)
> > 
> > > > This is why I do not want to make it Lenovo specific. But if you prefer that, I
> > > > can name it as "lenovo,pcie-m2-1620-lga-connector".
> > > 
> > > Depends if you think that s/w needs to know the differences. Hard to
> > > say with a sample size of 1.
> > > 
> > 
> > Sure. Will add the 'lenovo' prefix then.
> 
> Is it really Lenovo? Or is it some other module vendor, whose LGAs are
> being used by Lenovo?
> 
> I remember that DB820c also used some kind of a module for the WiFi card
> (which might be M.2 compatible or might not, I can't find exact docs at
> this point).
> 

I don't know. These kind of designs might be reused by several vendors. But
considering that we should not make it generic, I'd go with Lenovo as that's
the only vendor we know as of now.

- Mani

-- 
மணிவண்ணன் சதாசிவம்

Re: [PATCH v6 6/9] dt-bindings: connector: m2: Add M.2 1620 LGA soldered down connector

[Dmitry Baryshkov]

On Mon, Mar 23, 2026 at 09:26:04PM +0530, Manivannan Sadhasivam wrote:
> On Mon, Mar 23, 2026 at 05:14:30PM +0200, Dmitry Baryshkov wrote:
> > On Mon, Mar 23, 2026 at 07:14:25PM +0530, Manivannan Sadhasivam wrote:
> > > On Mon, Mar 23, 2026 at 08:39:55AM -0500, Rob Herring wrote:
> > > > On Mon, Mar 23, 2026 at 7:16 AM Manivannan Sadhasivam <mani@kernel.org> wrote:
> > > > >
> > > > > On Sun, Mar 22, 2026 at 06:37:13PM -0500, Rob Herring wrote:
> > > > > > On Tue, Mar 17, 2026 at 09:59:56AM +0530, Manivannan Sadhasivam wrote:
> > > > > > > Lenovo Thinkpad T14s is found to have a soldered down version of M.2 1620
> > > > > > > LGA connector. Though, there is no 1620 LGA form factor defined in the M.2
> > > > > > > spec, it looks very similar to the M.2 Key E connector. So add the
> > > > > > > "pcie-m2-1620-lga-connector" compatible with "pcie-m2-e-connector" fallback
> > > > > > > to reuse the Key E binding.
> > > > > >
> > > > > > What is LGA?
> > > > > >
> > > > >
> > > > > Land Grid Array
> > > > >
> > > > > > If not in the spec, is it really something generic?
> > > > > >
> > > > >
> > > > > Good question. Yes and No! LGA is not something that Lenovo only uses. Other
> > > > > vendors may also use this form factor. PCIe connectors are full of innovation as
> > > > > the spec gives room for hardware designers to be as innovative as possible to
> > > > > save the BOM cost.
> > > > 
> > > > innovation == incompatible changes
> > > > 
> > > 
> > > Yes, I was trying to sound nice :)
> > > 
> > > > > This is why I do not want to make it Lenovo specific. But if you prefer that, I
> > > > > can name it as "lenovo,pcie-m2-1620-lga-connector".
> > > > 
> > > > Depends if you think that s/w needs to know the differences. Hard to
> > > > say with a sample size of 1.
> > > > 
> > > 
> > > Sure. Will add the 'lenovo' prefix then.
> > 
> > Is it really Lenovo? Or is it some other module vendor, whose LGAs are
> > being used by Lenovo?
> > 
> > I remember that DB820c also used some kind of a module for the WiFi card
> > (which might be M.2 compatible or might not, I can't find exact docs at
> > this point).
> > 
> 
> I don't know. These kind of designs might be reused by several vendors. But
> considering that we should not make it generic, I'd go with Lenovo as that's
> the only vendor we know as of now.

... and later we learn that other vendors use the same idea /pinout,
then nothing stops us from still telling that it's a
"lenovo,pcie-m2-something-lga". 

-- 
With best wishes
Dmitry

Re: [PATCH v6 6/9] dt-bindings: connector: m2: Add M.2 1620 LGA soldered down connector

[Manivannan Sadhasivam]

On Mon, Mar 23, 2026 at 06:45:15PM +0200, Dmitry Baryshkov wrote:
> On Mon, Mar 23, 2026 at 09:26:04PM +0530, Manivannan Sadhasivam wrote:
> > On Mon, Mar 23, 2026 at 05:14:30PM +0200, Dmitry Baryshkov wrote:
> > > On Mon, Mar 23, 2026 at 07:14:25PM +0530, Manivannan Sadhasivam wrote:
> > > > On Mon, Mar 23, 2026 at 08:39:55AM -0500, Rob Herring wrote:
> > > > > On Mon, Mar 23, 2026 at 7:16 AM Manivannan Sadhasivam <mani@kernel.org> wrote:
> > > > > >
> > > > > > On Sun, Mar 22, 2026 at 06:37:13PM -0500, Rob Herring wrote:
> > > > > > > On Tue, Mar 17, 2026 at 09:59:56AM +0530, Manivannan Sadhasivam wrote:
> > > > > > > > Lenovo Thinkpad T14s is found to have a soldered down version of M.2 1620
> > > > > > > > LGA connector. Though, there is no 1620 LGA form factor defined in the M.2
> > > > > > > > spec, it looks very similar to the M.2 Key E connector. So add the
> > > > > > > > "pcie-m2-1620-lga-connector" compatible with "pcie-m2-e-connector" fallback
> > > > > > > > to reuse the Key E binding.
> > > > > > >
> > > > > > > What is LGA?
> > > > > > >
> > > > > >
> > > > > > Land Grid Array
> > > > > >
> > > > > > > If not in the spec, is it really something generic?
> > > > > > >
> > > > > >
> > > > > > Good question. Yes and No! LGA is not something that Lenovo only uses. Other
> > > > > > vendors may also use this form factor. PCIe connectors are full of innovation as
> > > > > > the spec gives room for hardware designers to be as innovative as possible to
> > > > > > save the BOM cost.
> > > > > 
> > > > > innovation == incompatible changes
> > > > > 
> > > > 
> > > > Yes, I was trying to sound nice :)
> > > > 
> > > > > > This is why I do not want to make it Lenovo specific. But if you prefer that, I
> > > > > > can name it as "lenovo,pcie-m2-1620-lga-connector".
> > > > > 
> > > > > Depends if you think that s/w needs to know the differences. Hard to
> > > > > say with a sample size of 1.
> > > > > 
> > > > 
> > > > Sure. Will add the 'lenovo' prefix then.
> > > 
> > > Is it really Lenovo? Or is it some other module vendor, whose LGAs are
> > > being used by Lenovo?
> > > 
> > > I remember that DB820c also used some kind of a module for the WiFi card
> > > (which might be M.2 compatible or might not, I can't find exact docs at
> > > this point).
> > > 
> > 
> > I don't know. These kind of designs might be reused by several vendors. But
> > considering that we should not make it generic, I'd go with Lenovo as that's
> > the only vendor we know as of now.
> 
> ... and later we learn that other vendors use the same idea /pinout,
> then nothing stops us from still telling that it's a
> "lenovo,pcie-m2-something-lga". 
> 

How do you possibly know whether a single vendor has introduced this form factor
or reused by multiple ones? Atleast, I don't have access to such a source to
confirm.

- Mani

-- 
மணிவண்ணன் சதாசிவம்

Re: [PATCH v6 6/9] dt-bindings: connector: m2: Add M.2 1620 LGA soldered down connector

[Mark Pearson]

On Mon, Mar 23, 2026, at 12:52 PM, Manivannan Sadhasivam wrote:
> On Mon, Mar 23, 2026 at 06:45:15PM +0200, Dmitry Baryshkov wrote:
>> On Mon, Mar 23, 2026 at 09:26:04PM +0530, Manivannan Sadhasivam wrote:
>> > On Mon, Mar 23, 2026 at 05:14:30PM +0200, Dmitry Baryshkov wrote:
>> > > On Mon, Mar 23, 2026 at 07:14:25PM +0530, Manivannan Sadhasivam wrote:
>> > > > On Mon, Mar 23, 2026 at 08:39:55AM -0500, Rob Herring wrote:
>> > > > > On Mon, Mar 23, 2026 at 7:16 AM Manivannan Sadhasivam <mani@kernel.org> wrote:
>> > > > > >
>> > > > > > On Sun, Mar 22, 2026 at 06:37:13PM -0500, Rob Herring wrote:
>> > > > > > > On Tue, Mar 17, 2026 at 09:59:56AM +0530, Manivannan Sadhasivam wrote:
>> > > > > > > > Lenovo Thinkpad T14s is found to have a soldered down version of M.2 1620
>> > > > > > > > LGA connector. Though, there is no 1620 LGA form factor defined in the M.2
>> > > > > > > > spec, it looks very similar to the M.2 Key E connector. So add the
>> > > > > > > > "pcie-m2-1620-lga-connector" compatible with "pcie-m2-e-connector" fallback
>> > > > > > > > to reuse the Key E binding.
>> > > > > > >
>> > > > > > > What is LGA?
>> > > > > > >
>> > > > > >
>> > > > > > Land Grid Array
>> > > > > >
>> > > > > > > If not in the spec, is it really something generic?
>> > > > > > >
>> > > > > >
>> > > > > > Good question. Yes and No! LGA is not something that Lenovo only uses. Other
>> > > > > > vendors may also use this form factor. PCIe connectors are full of innovation as
>> > > > > > the spec gives room for hardware designers to be as innovative as possible to
>> > > > > > save the BOM cost.
>> > > > > 
>> > > > > innovation == incompatible changes
>> > > > > 
>> > > > 
>> > > > Yes, I was trying to sound nice :)
>> > > > 
>> > > > > > This is why I do not want to make it Lenovo specific. But if you prefer that, I
>> > > > > > can name it as "lenovo,pcie-m2-1620-lga-connector".
>> > > > > 
>> > > > > Depends if you think that s/w needs to know the differences. Hard to
>> > > > > say with a sample size of 1.
>> > > > > 
>> > > > 
>> > > > Sure. Will add the 'lenovo' prefix then.
>> > > 
>> > > Is it really Lenovo? Or is it some other module vendor, whose LGAs are
>> > > being used by Lenovo?
>> > > 
>> > > I remember that DB820c also used some kind of a module for the WiFi card
>> > > (which might be M.2 compatible or might not, I can't find exact docs at
>> > > this point).
>> > > 
>> > 
>> > I don't know. These kind of designs might be reused by several vendors. But
>> > considering that we should not make it generic, I'd go with Lenovo as that's
>> > the only vendor we know as of now.
>> 
>> ... and later we learn that other vendors use the same idea /pinout,
>> then nothing stops us from still telling that it's a
>> "lenovo,pcie-m2-something-lga". 
>> 
>
> How do you possibly know whether a single vendor has introduced this form factor
> or reused by multiple ones? Atleast, I don't have access to such a source to
> confirm.
>
I've not really been following this thread/patchset in detail; but want me to try and check with the T14s platform team if this device is specifically made for us (Lenovo) or not?
I doubt it is - we just don't do that usually, but I can go and ask the question if it will help resolve this (with the caveat that it could hold up the review for a bit and I may not be able to get a straight answer)

My vote (for what little it's worth) would be to make it non-Lenovo specific. Then when the same part causes issues on another vendors platform I won't get asked questions about why Lenovo is breaking <other vendor> :)

Mark

Re: [PATCH v6 6/9] dt-bindings: connector: m2: Add M.2 1620 LGA soldered down connector

[Manivannan Sadhasivam]

On Mon, Mar 23, 2026 at 01:23:07PM -0400, Mark Pearson wrote:
> 
> 
> On Mon, Mar 23, 2026, at 12:52 PM, Manivannan Sadhasivam wrote:
> > On Mon, Mar 23, 2026 at 06:45:15PM +0200, Dmitry Baryshkov wrote:
> >> On Mon, Mar 23, 2026 at 09:26:04PM +0530, Manivannan Sadhasivam wrote:
> >> > On Mon, Mar 23, 2026 at 05:14:30PM +0200, Dmitry Baryshkov wrote:
> >> > > On Mon, Mar 23, 2026 at 07:14:25PM +0530, Manivannan Sadhasivam wrote:
> >> > > > On Mon, Mar 23, 2026 at 08:39:55AM -0500, Rob Herring wrote:
> >> > > > > On Mon, Mar 23, 2026 at 7:16 AM Manivannan Sadhasivam <mani@kernel.org> wrote:
> >> > > > > >
> >> > > > > > On Sun, Mar 22, 2026 at 06:37:13PM -0500, Rob Herring wrote:
> >> > > > > > > On Tue, Mar 17, 2026 at 09:59:56AM +0530, Manivannan Sadhasivam wrote:
> >> > > > > > > > Lenovo Thinkpad T14s is found to have a soldered down version of M.2 1620
> >> > > > > > > > LGA connector. Though, there is no 1620 LGA form factor defined in the M.2
> >> > > > > > > > spec, it looks very similar to the M.2 Key E connector. So add the
> >> > > > > > > > "pcie-m2-1620-lga-connector" compatible with "pcie-m2-e-connector" fallback
> >> > > > > > > > to reuse the Key E binding.
> >> > > > > > >
> >> > > > > > > What is LGA?
> >> > > > > > >
> >> > > > > >
> >> > > > > > Land Grid Array
> >> > > > > >
> >> > > > > > > If not in the spec, is it really something generic?
> >> > > > > > >
> >> > > > > >
> >> > > > > > Good question. Yes and No! LGA is not something that Lenovo only uses. Other
> >> > > > > > vendors may also use this form factor. PCIe connectors are full of innovation as
> >> > > > > > the spec gives room for hardware designers to be as innovative as possible to
> >> > > > > > save the BOM cost.
> >> > > > > 
> >> > > > > innovation == incompatible changes
> >> > > > > 
> >> > > > 
> >> > > > Yes, I was trying to sound nice :)
> >> > > > 
> >> > > > > > This is why I do not want to make it Lenovo specific. But if you prefer that, I
> >> > > > > > can name it as "lenovo,pcie-m2-1620-lga-connector".
> >> > > > > 
> >> > > > > Depends if you think that s/w needs to know the differences. Hard to
> >> > > > > say with a sample size of 1.
> >> > > > > 
> >> > > > 
> >> > > > Sure. Will add the 'lenovo' prefix then.
> >> > > 
> >> > > Is it really Lenovo? Or is it some other module vendor, whose LGAs are
> >> > > being used by Lenovo?
> >> > > 
> >> > > I remember that DB820c also used some kind of a module for the WiFi card
> >> > > (which might be M.2 compatible or might not, I can't find exact docs at
> >> > > this point).
> >> > > 
> >> > 
> >> > I don't know. These kind of designs might be reused by several vendors. But
> >> > considering that we should not make it generic, I'd go with Lenovo as that's
> >> > the only vendor we know as of now.
> >> 
> >> ... and later we learn that other vendors use the same idea /pinout,
> >> then nothing stops us from still telling that it's a
> >> "lenovo,pcie-m2-something-lga". 
> >> 
> >
> > How do you possibly know whether a single vendor has introduced this form factor
> > or reused by multiple ones? Atleast, I don't have access to such a source to
> > confirm.
> >
> I've not really been following this thread/patchset in detail; but want me to try and check with the T14s platform team if this device is specifically made for us (Lenovo) or not?
> I doubt it is - we just don't do that usually, but I can go and ask the question if it will help resolve this (with the caveat that it could hold up the review for a bit and I may not be able to get a straight answer)
> 

I can drop this specific patch in the meantime.

> My vote (for what little it's worth) would be to make it non-Lenovo specific. Then when the same part causes issues on another vendors platform I won't get asked questions about why Lenovo is breaking <other vendor> :)
> 

Even if Lenovo prefix is used, it won't break other vendors. Just that we will
end up adding more compatibles.

Anyhow, I'll wait for your reply and drop this patch for next revision.

- Mani

-- 
மணிவண்ணன் சதாசிவம்