power: sequencing: Add the Power Sequencing driver for the PCIe M.2 connectors

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>
Link: https://lore.kernel.org/r/20260122-pci-m2-v6-4-575da9f97239@oss.qualcomm.com
[Bartosz: rename pwrseq_pcie_m2_free_resources() to pwrseq_pcie_m2_free_regulators()]
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@oss.qualcomm.com>

diff --git a/MAINTAINERS b/MAINTAINERS
index 5b11839cba9de1e9e43f63787578edd8c429ca39..2eb7b6d26573947a5f4e0c153dc40d028efac96a 100644 (file)
--- 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 280f92beb5d0ed524e67a28d1c5dd264bbd6c87e..f5fff84566ba463b55d3cd0c07db34c82f9f1e31 100644 (file)
--- 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 96c1cf0a98ac54c9c1d65a4bb4e34289a3550fa1..0911d461829897c5018e26dbe475b28f6fb6914c 100644 (file)
--- 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 (file)
index 0000000..d31a7dd
--- /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_regulators(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_regulators, 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");