[PATCH v6 0/4] PCI: Add initial support for handling PCIe M.2 connectors in devicetree

[PATCH v6 0/4] PCI: Add initial support for handling PCIe M.2 connectors in devicetree

[Manivannan Sadhasivam via B4 Relay]

Hi,

This series is an initial attempt to support the PCIe M.2 connectors in the
kernel and devicetree binding. The PCIe M.2 connectors as defined in the PCI
Express M.2 Specification are widely used in Notebooks/Tablet form factors (even
in PCs). On the ACPI platforms, power to these connectors are mostly handled by
the firmware/BIOS and the kernel never bothered to directly power manage them as
like other PCIe connectors. But on the devicetree platforms, the kernel needs to
power manage these connectors with the help of the devicetree description. But
so far, there is no proper representation of the M.2 connectors in devicetree
binding. This forced the developers to fake the M.2 connectors as PMU nodes [1]
and fixed regulators in devicetree.

So to properly support the M.2 connectors in devicetree platforms, this series
introduces the devicetree binding for Mechanical Key M connector as an example
and also the corresponding pwrseq driver and PCI changes in kernel to driver the
connector.

The Mechanical Key M connector is used to connect SSDs to the host machine over
PCIe/SATA interfaces. Due to the hardware constraints, this series only adds
support for driving the PCIe interface of the connector in the kernel.

Also, the optional interfaces supported by the Key M connectors are not
supported in the driver and left for the future enhancements.

Testing
=======

This series, together with the devicetree changes [2] [3] were tested on the
Qualcomm X1e based Lenovo Thinkpad T14s Laptop which has the NVMe SSD connected
over PCIe.

[1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/arch/arm64/boot/dts/qcom/x1e80100-qcp.dts?h=v6.18-rc4&id=d09ab685a8f51ba412d37305ea62628a01cbea57
[2] https://github.com/Mani-Sadhasivam/linux/commit/40120d02219f34d2040ffa6328f0d406b1e4c04d
[3] https://github.com/Mani-Sadhasivam/linux/commit/ff6c3075836cc794a3700b0ec6a4a9eb21d14c6f

Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@oss.qualcomm.com>
---
Changes in v6:
- Used 'ports' to describe interfaces instead of endpoints in the binding
- Added GPIOs and USB to the example in binding
- Incorporated minor comments in the pwrseq driver
- Dropped the ata binding patch as it got applied
- Link to v5: https://lore.kernel.org/r/20260107-pci-m2-v5-0-8173d8a72641@oss.qualcomm.com

Changes in v5:
- used of_node_get() and devm_action to free regulators
- Link to v4: https://lore.kernel.org/r/20251228-pci-m2-v4-0-5684868b0d5f@oss.qualcomm.com

Changes in v4:
- Added graph property to SATA in this series and PCI to dtschema:
  https://github.com/devicetree-org/dt-schema/pull/180
- Used 'i2c-parent' instead of SMBus port
- Reworded the -gpios property description
- Rebased on top of v6.19-rc1
- Link to v3: https://lore.kernel.org/r/20251125-pci-m2-v3-0-c528042aea47@oss.qualcomm.com

Changes in v3:
- Changed the VIO supply name as per dtschema
- Added explicit endpoint properties to port 0 node for host I/F
- Used scope based cleanup for OF node in pwrseq driver
- Collected review tags
- Link to v2: https://lore.kernel.org/r/20251108-pci-m2-v2-0-e8bc4d7bf42d@oss.qualcomm.com

Changes in v2:
- Incorporated comments from Bartosz and Frank for pwrseq and dt-binding
  patches, especially adding the pwrseq match() code.
- Link to v1: https://lore.kernel.org/r/20251105-pci-m2-v1-0-84b5f1f1e5e8@oss.qualcomm.com

---
Manivannan Sadhasivam (4):
      dt-bindings: connector: Add PCIe M.2 Mechanical Key M connector
      PCI/pwrctrl: Add support for handling PCIe M.2 connectors
      PCI/pwrctrl: Create pwrctrl device if the graph port is found
      power: sequencing: Add the Power Sequencing driver for the PCIe M.2 connectors

 .../bindings/connector/pcie-m2-m-connector.yaml    | 145 ++++++++++++++++++
 MAINTAINERS                                        |   7 +
 drivers/pci/probe.c                                |   3 +-
 drivers/pci/pwrctrl/Kconfig                        |   1 +
 drivers/pci/pwrctrl/slot.c                         |  35 ++++-
 drivers/power/sequencing/Kconfig                   |   8 +
 drivers/power/sequencing/Makefile                  |   1 +
 drivers/power/sequencing/pwrseq-pcie-m2.c          | 168 +++++++++++++++++++++
 8 files changed, 362 insertions(+), 6 deletions(-)
---
base-commit: 8f0b4cce4481fb22653697cced8d0d04027cb1e8
change-id: 20251103-pci-m2-7633631b6faa

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

[PATCH v6 1/4] dt-bindings: connector: Add PCIe M.2 Mechanical Key M connector

[Manivannan Sadhasivam via B4 Relay]

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

Add the devicetree binding for PCIe M.2 Mechanical Key M connector defined
in the PCI Express M.2 Specification, r4.0, sec 5.3. This connector
provides interfaces like PCIe and SATA to attach the Solid State Drives
(SSDs) to the host machine along with additional interfaces like USB, and
SMBus for debugging and supplementary features.

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: Frank Li <Frank.Li@nxp.com>
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@oss.qualcomm.com>
---
 .../bindings/connector/pcie-m2-m-connector.yaml    | 145 +++++++++++++++++++++
 1 file changed, 145 insertions(+)

diff --git a/Documentation/devicetree/bindings/connector/pcie-m2-m-connector.yaml b/Documentation/devicetree/bindings/connector/pcie-m2-m-connector.yaml
new file mode 100644
index 000000000000..36a99a3b39d7
--- /dev/null
+++ b/Documentation/devicetree/bindings/connector/pcie-m2-m-connector.yaml
@@ -0,0 +1,145 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/connector/pcie-m2-m-connector.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: PCIe M.2 Mechanical Key M Connector
+
+maintainers:
+  - Manivannan Sadhasivam <manivannan.sadhasivam@oss.qualcomm.com>
+
+description:
+  A PCIe M.2 M connector node represents a physical PCIe M.2 Mechanical Key M
+  connector. The Mechanical Key M connectors are used to connect SSDs to the
+  host system over PCIe/SATA interfaces. These connectors also offer optional
+  interfaces like USB, SMBus.
+
+properties:
+  compatible:
+    const: pcie-m2-m-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.
+
+  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
+
+      port@1:
+        $ref: /schemas/graph.yaml#/properties/port
+        description: SATA interface
+
+      port@2:
+        $ref: /schemas/graph.yaml#/properties/port
+        description: USB 2.0 interface
+
+    anyOf:
+      - required:
+          - port@0
+      - required:
+          - port@1
+
+  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
+
+  pedet-gpios:
+    description: GPIO input to PEDET signal. This signal is used by the host
+      systems to determine the communication protocol that the M.2 card uses;
+      SATA signaling (low) or PCIe signaling (high). Refer, PCI Express M.2
+      Specification r4.0, sec 3.3.4.2 for more details.
+    maxItems: 1
+
+  viocfg-gpios:
+    description: GPIO input to IO voltage configuration (VIO_CFG) signal. This
+      signal is used by the host systems to determine whether the card supports
+      an independent IO voltage domain for the sideband signals or not. Refer,
+      PCI Express M.2 Specification r4.0, sec 3.1.15.1 for more details.
+    maxItems: 1
+
+  pwrdis-gpios:
+    description: GPIO output to Power Disable (PWRDIS) signal. This signal is
+      used by the host system to disable power on the M.2 card. Refer, PCI
+      Express M.2 Specification r4.0, sec 3.3.5.2 for more details.
+    maxItems: 1
+
+  pln-gpios:
+    description: GPIO output to Power Loss Notification (PLN#) signal. This
+      signal is used by the host system to notify the M.2 card that the power
+      loss event is about to occur. Refer, PCI Express M.2 Specification r4.0,
+      sec 3.2.17.1 for more details.
+    maxItems: 1
+
+  plas3-gpios:
+    description: GPIO input to Power Loss Acknowledge (PLA_S3#) signal. This
+      signal is used by the host system to receive the acknowledgment of the M.2
+      card's preparation for power loss.
+    maxItems: 1
+
+required:
+  - compatible
+  - vpcie3v3-supply
+
+additionalProperties: false
+
+examples:
+  # PCI M.2 Key M connector for SSDs with PCIe interface
+  - |
+    #include <dt-bindings/gpio/gpio.h>
+
+    connector {
+        compatible = "pcie-m2-m-connector";
+        vpcie3v3-supply = <&vreg_nvme>;
+        i2c-parent = <&i2c0>;
+        pedet-gpios = <&tlmm 95 GPIO_ACTIVE_HIGH>;
+        viocfg-gpios = <&tlmm 96 GPIO_ACTIVE_HIGH>;
+        pwrdis-gpios = <&tlmm 97 GPIO_ACTIVE_HIGH>;
+        pln-gpios = <&tlmm 98 GPIO_ACTIVE_LOW>;
+        plas3-gpios = <&tlmm 99 GPIO_ACTIVE_LOW>;
+
+        ports {
+            #address-cells = <1>;
+            #size-cells = <0>;
+
+            port@0 {
+                #address-cells = <1>;
+                #size-cells = <0>;
+
+                reg = <0>;
+
+                endpoint@0 {
+                    reg = <0>;
+                    remote-endpoint = <&pcie6_port0_ep>;
+                };
+            };
+
+            port@2 {
+                #address-cells = <1>;
+                #size-cells = <0>;
+
+                reg = <2>;
+
+                endpoint@0 {
+                    reg = <0>;
+                    remote-endpoint = <&usb_hs_ep>;
+                };
+            };
+        };
+    };

-- 
2.51.0

[PATCH v6 2/4] PCI/pwrctrl: Add support for handling PCIe M.2 connectors

[Manivannan Sadhasivam via B4 Relay]

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

Add support for handling the PCIe M.2 connectors as Power Sequencing
devices. These connectors are exposed as the Power Sequencing devices
as they often support multiple interfaces like PCIe/SATA, USB/UART to the
host machine and each interfaces could be driven by different client
drivers at the same time.

This driver handles the PCIe interface of these connectors. It first checks
for the presence of the graph port in the Root Port node with the help of
of_graph_is_present() API, if present, it acquires/poweres ON the
corresponding pwrseq device.

Once the pwrseq device is powered ON, the driver will skip parsing the Root
Port/Slot resources and registers with the pwrctrl framework.

Reviewed-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@oss.qualcomm.com>
---
 drivers/pci/pwrctrl/Kconfig |  1 +
 drivers/pci/pwrctrl/slot.c  | 35 ++++++++++++++++++++++++++++++-----
 2 files changed, 31 insertions(+), 5 deletions(-)

diff --git a/drivers/pci/pwrctrl/Kconfig b/drivers/pci/pwrctrl/Kconfig
index e0f999f299bb..cd3aa15bad00 100644
--- a/drivers/pci/pwrctrl/Kconfig
+++ b/drivers/pci/pwrctrl/Kconfig
@@ -13,6 +13,7 @@ config PCI_PWRCTRL_PWRSEQ
 
 config PCI_PWRCTRL_SLOT
 	tristate "PCI Power Control driver for PCI slots"
+	select POWER_SEQUENCING
 	select PCI_PWRCTRL
 	help
 	  Say Y here to enable the PCI Power Control driver to control the power
diff --git a/drivers/pci/pwrctrl/slot.c b/drivers/pci/pwrctrl/slot.c
index 3320494b62d8..d46c2365208a 100644
--- a/drivers/pci/pwrctrl/slot.c
+++ b/drivers/pci/pwrctrl/slot.c
@@ -8,8 +8,10 @@
 #include <linux/device.h>
 #include <linux/mod_devicetable.h>
 #include <linux/module.h>
+#include <linux/of_graph.h>
 #include <linux/pci-pwrctrl.h>
 #include <linux/platform_device.h>
+#include <linux/pwrseq/consumer.h>
 #include <linux/regulator/consumer.h>
 #include <linux/slab.h>
 
@@ -17,12 +19,18 @@ struct pci_pwrctrl_slot_data {
 	struct pci_pwrctrl ctx;
 	struct regulator_bulk_data *supplies;
 	int num_supplies;
+	struct pwrseq_desc *pwrseq;
 };
 
 static void devm_pci_pwrctrl_slot_power_off(void *data)
 {
 	struct pci_pwrctrl_slot_data *slot = data;
 
+	if (slot->pwrseq) {
+		pwrseq_power_off(slot->pwrseq);
+		return;
+	}
+
 	regulator_bulk_disable(slot->num_supplies, slot->supplies);
 	regulator_bulk_free(slot->num_supplies, slot->supplies);
 }
@@ -38,6 +46,20 @@ static int pci_pwrctrl_slot_probe(struct platform_device *pdev)
 	if (!slot)
 		return -ENOMEM;
 
+	if (of_graph_is_present(dev_of_node(dev))) {
+		slot->pwrseq = devm_pwrseq_get(dev, "pcie");
+		if (IS_ERR(slot->pwrseq))
+			return dev_err_probe(dev, PTR_ERR(slot->pwrseq),
+				     "Failed to get the power sequencer\n");
+
+		ret = pwrseq_power_on(slot->pwrseq);
+		if (ret)
+			return dev_err_probe(dev, ret,
+				     "Failed to power-on the device\n");
+
+		goto skip_resources;
+	}
+
 	ret = of_regulator_bulk_get_all(dev, dev_of_node(dev),
 					&slot->supplies);
 	if (ret < 0) {
@@ -53,17 +75,20 @@ static int pci_pwrctrl_slot_probe(struct platform_device *pdev)
 		return ret;
 	}
 
-	ret = devm_add_action_or_reset(dev, devm_pci_pwrctrl_slot_power_off,
-				       slot);
-	if (ret)
-		return ret;
-
 	clk = devm_clk_get_optional_enabled(dev, NULL);
 	if (IS_ERR(clk)) {
+		regulator_bulk_disable(slot->num_supplies, slot->supplies);
+		regulator_bulk_free(slot->num_supplies, slot->supplies);
 		return dev_err_probe(dev, PTR_ERR(clk),
 				     "Failed to enable slot clock\n");
 	}
 
+skip_resources:
+	ret = devm_add_action_or_reset(dev, devm_pci_pwrctrl_slot_power_off,
+				       slot);
+	if (ret)
+		return ret;
+
 	pci_pwrctrl_init(&slot->ctx, dev);
 
 	ret = devm_pci_pwrctrl_device_set_ready(dev, &slot->ctx);

-- 
2.51.0

[PATCH v6 3/4] PCI/pwrctrl: Create pwrctrl device if the graph port is found

[Manivannan Sadhasivam via B4 Relay]

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

The devicetree node of the PCIe Root Port/Slot could have the graph port
to link the PCIe M.2 connector node. Since the M.2 connectors are modelled
as Power Sequencing devices, they need to be controlled by the pwrctrl
driver as like the Root Port/Slot supplies.

Hence, create the pwrctrl device if the graph port is found in the node.

Reviewed-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@oss.qualcomm.com>
---
 drivers/pci/probe.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index 41183aed8f5d..cd7efd20a74a 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -9,6 +9,7 @@
 #include <linux/init.h>
 #include <linux/pci.h>
 #include <linux/msi.h>
+#include <linux/of_graph.h>
 #include <linux/of_pci.h>
 #include <linux/of_platform.h>
 #include <linux/platform_device.h>
@@ -2585,7 +2586,7 @@ static struct platform_device *pci_pwrctrl_create_device(struct pci_bus *bus, in
 	 * not. This is decided based on at least one of the power supplies
 	 * being defined in the devicetree node of the device.
 	 */
-	if (!of_pci_supply_present(np)) {
+	if (!of_pci_supply_present(np) && !of_graph_is_present(np)) {
 		pr_debug("PCI/pwrctrl: Skipping OF node: %s\n", np->name);
 		goto err_put_of_node;
 	}

-- 
2.51.0

[PATCH v6 4/4] power: sequencing: Add the Power Sequencing driver for the PCIe M.2 connectors

[Manivannan Sadhasivam via B4 Relay]

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

This driver is used to control the PCIe M.2 connectors of different
Mechanical Keys attached to the host machines and supporting different
interfaces like PCIe/SATA, USB/UART etc...

Currently, this driver supports only the Mechanical Key M connectors with
PCIe interface. The driver also only supports driving the mandatory 3.3v
and optional 1.8v power supplies. The optional signals of the Key M
connectors are not currently supported.

Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@oss.qualcomm.com>
---
 MAINTAINERS                               |   7 ++
 drivers/power/sequencing/Kconfig          |   8 ++
 drivers/power/sequencing/Makefile         |   1 +
 drivers/power/sequencing/pwrseq-pcie-m2.c | 168 ++++++++++++++++++++++++++++++
 4 files changed, 184 insertions(+)

diff --git a/MAINTAINERS b/MAINTAINERS
index 5b11839cba9d..2eb7b6d26573 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -20791,6 +20791,13 @@ F:	Documentation/driver-api/pwrseq.rst
 F:	drivers/power/sequencing/
 F:	include/linux/pwrseq/
 
+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-m-connector.yaml
+F:	drivers/power/sequencing/pwrseq-pcie-m2.c
+
 POWER STATE COORDINATION INTERFACE (PSCI)
 M:	Mark Rutland <mark.rutland@arm.com>
 M:	Lorenzo Pieralisi <lpieralisi@kernel.org>
diff --git a/drivers/power/sequencing/Kconfig b/drivers/power/sequencing/Kconfig
index 280f92beb5d0..f5fff84566ba 100644
--- a/drivers/power/sequencing/Kconfig
+++ b/drivers/power/sequencing/Kconfig
@@ -35,4 +35,12 @@ config POWER_SEQUENCING_TH1520_GPU
 	  GPU. This driver handles the complex clock and reset sequence
 	  required to power on the Imagination BXM GPU on this platform.
 
+config POWER_SEQUENCING_PCIE_M2
+	tristate "PCIe M.2 connector power sequencing driver"
+	depends on OF || COMPILE_TEST
+	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
+	  connectors exposing multiple interfaces like PCIe, SATA, UART, etc...
+
 endif
diff --git a/drivers/power/sequencing/Makefile b/drivers/power/sequencing/Makefile
index 96c1cf0a98ac..0911d4618298 100644
--- a/drivers/power/sequencing/Makefile
+++ b/drivers/power/sequencing/Makefile
@@ -5,3 +5,4 @@ pwrseq-core-y				:= core.o
 
 obj-$(CONFIG_POWER_SEQUENCING_QCOM_WCN)	+= pwrseq-qcom-wcn.o
 obj-$(CONFIG_POWER_SEQUENCING_TH1520_GPU) += pwrseq-thead-gpu.o
+obj-$(CONFIG_POWER_SEQUENCING_PCIE_M2)	+= pwrseq-pcie-m2.o
diff --git a/drivers/power/sequencing/pwrseq-pcie-m2.c b/drivers/power/sequencing/pwrseq-pcie-m2.c
new file mode 100644
index 000000000000..96ea4adc9d22
--- /dev/null
+++ b/drivers/power/sequencing/pwrseq-pcie-m2.c
@@ -0,0 +1,168 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) Qualcomm Technologies, Inc. and/or its subsidiaries.
+ * Author: Manivannan Sadhasivam <manivannan.sadhasivam@oss.qualcomm.com>
+ */
+
+#include <linux/device.h>
+#include <linux/mod_devicetable.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_graph.h>
+#include <linux/platform_device.h>
+#include <linux/pwrseq/provider.h>
+#include <linux/regulator/consumer.h>
+#include <linux/slab.h>
+
+struct pwrseq_pcie_m2_pdata {
+	const struct pwrseq_target_data **targets;
+};
+
+struct pwrseq_pcie_m2_ctx {
+	struct pwrseq_device *pwrseq;
+	struct device_node *of_node;
+	const struct pwrseq_pcie_m2_pdata *pdata;
+	struct regulator_bulk_data *regs;
+	size_t num_vregs;
+	struct notifier_block nb;
+};
+
+static int pwrseq_pcie_m2_m_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)
+{
+	struct pwrseq_pcie_m2_ctx *ctx = pwrseq_device_get_drvdata(pwrseq);
+
+	return regulator_bulk_disable(ctx->num_vregs, ctx->regs);
+}
+
+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,
+};
+
+static const struct pwrseq_unit_data *pwrseq_pcie_m2_m_unit_deps[] = {
+	&pwrseq_pcie_m2_vregs_unit_data,
+	NULL
+};
+
+static const struct pwrseq_unit_data pwrseq_pcie_m2_m_pcie_unit_data = {
+	.name = "pcie-enable",
+	.deps = pwrseq_pcie_m2_m_unit_deps,
+};
+
+static const struct pwrseq_target_data pwrseq_pcie_m2_m_pcie_target_data = {
+	.name = "pcie",
+	.unit = &pwrseq_pcie_m2_m_pcie_unit_data,
+};
+
+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_m_of_data = {
+	.targets = pwrseq_pcie_m2_m_targets,
+};
+
+static int pwrseq_pcie_m2_match(struct pwrseq_device *pwrseq,
+				 struct device *dev)
+{
+	struct pwrseq_pcie_m2_ctx *ctx = pwrseq_device_get_drvdata(pwrseq);
+	struct device_node *endpoint __free(device_node) = NULL;
+
+	/*
+	 * Traverse the 'remote-endpoint' nodes and check if the remote node's
+	 * parent matches the OF node of 'dev'.
+	 */
+	for_each_endpoint_of_node(ctx->of_node, endpoint) {
+		struct device_node *remote __free(device_node) =
+				of_graph_get_remote_port_parent(endpoint);
+		if (remote && (remote == dev_of_node(dev)))
+			return PWRSEQ_MATCH_OK;
+	}
+
+	return PWRSEQ_NO_MATCH;
+}
+
+static void pwrseq_pcie_m2_free_resources(void *data)
+{
+	struct pwrseq_pcie_m2_ctx *ctx = data;
+
+	regulator_bulk_free(ctx->num_vregs, ctx->regs);
+}
+
+static int pwrseq_pcie_m2_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct pwrseq_pcie_m2_ctx *ctx;
+	struct pwrseq_config config = {};
+	int ret;
+
+	ctx = devm_kzalloc(dev, sizeof(*ctx), GFP_KERNEL);
+	if (!ctx)
+		return -ENOMEM;
+
+	ctx->of_node = of_node_get(dev->of_node);
+	ctx->pdata = device_get_match_data(dev);
+	if (!ctx->pdata)
+		return dev_err_probe(dev, -ENODEV,
+				     "Failed to obtain platform data\n");
+
+	/*
+	 * Currently, of_regulator_bulk_get_all() is the only regulator API that
+	 * allows to get all supplies in the devicetree node without manually
+	 * specifying them.
+	 */
+	ret = of_regulator_bulk_get_all(dev, dev_of_node(dev), &ctx->regs);
+	if (ret < 0)
+		return dev_err_probe(dev, ret,
+				     "Failed to get all regulators\n");
+
+	ctx->num_vregs = ret;
+
+	ret = devm_add_action_or_reset(dev, pwrseq_pcie_m2_free_resources, ctx);
+	if (ret)
+		return ret;
+
+	config.parent = dev;
+	config.owner = THIS_MODULE;
+	config.drvdata = ctx;
+	config.match = pwrseq_pcie_m2_match;
+	config.targets = ctx->pdata->targets;
+
+	ctx->pwrseq = devm_pwrseq_device_register(dev, &config);
+	if (IS_ERR(ctx->pwrseq))
+		return dev_err_probe(dev, PTR_ERR(ctx->pwrseq),
+				     "Failed to register the power sequencer\n");
+
+	return 0;
+}
+
+static const struct of_device_id pwrseq_pcie_m2_of_match[] = {
+	{
+		.compatible = "pcie-m2-m-connector",
+		.data = &pwrseq_pcie_m2_m_of_data,
+	},
+	{ }
+};
+MODULE_DEVICE_TABLE(of, pwrseq_pcie_m2_of_match);
+
+static struct platform_driver pwrseq_pcie_m2_driver = {
+	.driver = {
+		.name = "pwrseq-pcie-m2",
+		.of_match_table = pwrseq_pcie_m2_of_match,
+	},
+	.probe = pwrseq_pcie_m2_probe,
+};
+module_platform_driver(pwrseq_pcie_m2_driver);
+
+MODULE_AUTHOR("Manivannan Sadhasivam <manivannan.sadhasivam@oss.qualcomm.com>");
+MODULE_DESCRIPTION("Power Sequencing driver for PCIe M.2 connector");
+MODULE_LICENSE("GPL");

-- 
2.51.0

Re: [PATCH v6 1/4] dt-bindings: connector: Add PCIe M.2 Mechanical Key M connector

[Rob Herring (Arm)]

On Thu, 22 Jan 2026 22:46:51 +0530, Manivannan Sadhasivam wrote:
> Add the devicetree binding for PCIe M.2 Mechanical Key M connector defined
> in the PCI Express M.2 Specification, r4.0, sec 5.3. This connector
> provides interfaces like PCIe and SATA to attach the Solid State Drives
> (SSDs) to the host machine along with additional interfaces like USB, and
> SMBus for debugging and supplementary features.
> 
> 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: Frank Li <Frank.Li@nxp.com>
> Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@oss.qualcomm.com>
> ---
>  .../bindings/connector/pcie-m2-m-connector.yaml    | 145 +++++++++++++++++++++
>  1 file changed, 145 insertions(+)
> 

Reviewed-by: Rob Herring (Arm) <robh@kernel.org>

Re: (subset) [PATCH v6 0/4] PCI: Add initial support for handling PCIe M.2 connectors in devicetree

[Bartosz Golaszewski]

On Thu, 22 Jan 2026 22:46:50 +0530, Manivannan Sadhasivam wrote:
> This series is an initial attempt to support the PCIe M.2 connectors in the
> kernel and devicetree binding. The PCIe M.2 connectors as defined in the PCI
> Express M.2 Specification are widely used in Notebooks/Tablet form factors (even
> in PCs). On the ACPI platforms, power to these connectors are mostly handled by
> the firmware/BIOS and the kernel never bothered to directly power manage them as
> like other PCIe connectors. But on the devicetree platforms, the kernel needs to
> power manage these connectors with the help of the devicetree description. But
> so far, there is no proper representation of the M.2 connectors in devicetree
> binding. This forced the developers to fake the M.2 connectors as PMU nodes [1]
> and fixed regulators in devicetree.
> 
> [...]

Applied, thanks!

[1/4] dt-bindings: connector: Add PCIe M.2 Mechanical Key M connector
      commit: 926194a6675a9cd5943f85820508648b74669fc6
[4/4] power: sequencing: Add the Power Sequencing driver for the PCIe M.2 connectors
      commit: 52e7b5bd62bab3851f25d8b70ad7eae9e94aba60

Best regards,
-- 
Bartosz Golaszewski <bartosz.golaszewski@oss.qualcomm.com>

Re: [PATCH v6 0/4] PCI: Add initial support for handling PCIe M.2 connectors in devicetree

[Bjorn Helgaas]

On Thu, Jan 22, 2026 at 10:46:50PM +0530, Manivannan Sadhasivam via B4 Relay wrote:
> Hi,
> 
> This series is an initial attempt to support the PCIe M.2 connectors in the
> kernel and devicetree binding. The PCIe M.2 connectors as defined in the PCI
> Express M.2 Specification are widely used in Notebooks/Tablet form factors (even
> in PCs). On the ACPI platforms, power to these connectors are mostly handled by
> the firmware/BIOS and the kernel never bothered to directly power manage them as
> like other PCIe connectors. But on the devicetree platforms, the kernel needs to
> power manage these connectors with the help of the devicetree description. But
> so far, there is no proper representation of the M.2 connectors in devicetree
> binding. This forced the developers to fake the M.2 connectors as PMU nodes [1]
> and fixed regulators in devicetree.

Could you rebase this series on pci/pwrctrl, please?

I'm pretty sure I would mess up the conflict resolutions, and I have
no way to test this.

Re: [PATCH v6 2/4] PCI/pwrctrl: Add support for handling PCIe M.2 connectors

[Bjorn Helgaas]

On Thu, Jan 22, 2026 at 10:46:52PM +0530, Manivannan Sadhasivam via B4 Relay wrote:
> From: Manivannan Sadhasivam <manivannan.sadhasivam@oss.qualcomm.com>
> 
> Add support for handling the PCIe M.2 connectors as Power Sequencing
> devices. These connectors are exposed as the Power Sequencing devices
> as they often support multiple interfaces like PCIe/SATA, USB/UART to the
> host machine and each interfaces could be driven by different client
> drivers at the same time.

s/each interfaces/each interface/

> This driver handles the PCIe interface of these connectors. It first checks
> for the presence of the graph port in the Root Port node with the help of
> of_graph_is_present() API, if present, it acquires/poweres ON the
> corresponding pwrseq device.

s/API, if/API. If/
s/poweres/powers/

> Once the pwrseq device is powered ON, the driver will skip parsing the Root
> Port/Slot resources and registers with the pwrctrl framework.

s/and registers/and register/