On Fri, Jan 02, 2026 at 12:26:21PM +0100, Bartosz Golaszewski wrote:

On Sun, Dec 28, 2025 at 6:01 PM Manivannan Sadhasivam
[off-list ref] wrote:

quoted

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 <redacted>
---
 MAINTAINERS                               |   7 ++
 drivers/power/sequencing/Kconfig          |   8 ++
 drivers/power/sequencing/Makefile         |   1 +
 drivers/power/sequencing/pwrseq-pcie-m2.c | 160 ++++++++++++++++++++++++++++++
 4 files changed, 176 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..4835d099d967
--- /dev/null
+++ b/drivers/power/sequencing/pwrseq-pcie-m2.c

@@ -0,0 +1,160 @@
+// 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/of_platform.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 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 = dev_of_node(dev);

Since you're storing the node address for later, I'd suggest using
of_node_get() to get a real reference.

If CONFIG_OF_DYNAMIC is not enabled, then of_node_get() will just return the
passed pointer. I always prefer using dev_of_node() since it has the CONFIG_OF
and NULL check. Though, the checks won't apply here, I used it for consistency.

quoted

+       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;
+
+       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)) {
+               regulator_bulk_free(ctx->num_vregs, ctx->regs);

You're freeing it on error but not on driver detach? Maybe schedule a
devm action if there's no devres variant?

Ok!

- Mani

-- 
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