4 files changed, 260 insertions, 0 deletions

diff --git a/drivers/pci/pwrctrl/Kconfig b/drivers/pci/pwrctrl/Kconfig
new file mode 100644
index 000000000000..54589bb2403b
--- /dev/null
+++ b/drivers/pci/pwrctrl/Kconfig
@@ -0,0 +1,12 @@
+# SPDX-License-Identifier: GPL-2.0-only
+
+config HAVE_PWRCTL
+	bool
+
+config PCI_PWRCTL
+	tristate
+
+config PCI_PWRCTL_PWRSEQ
+	tristate
+	select POWER_SEQUENCING
+	select PCI_PWRCTL
diff --git a/drivers/pci/pwrctrl/Makefile b/drivers/pci/pwrctrl/Makefile
new file mode 100644
index 000000000000..75c7ce531c7e
--- /dev/null
+++ b/drivers/pci/pwrctrl/Makefile
@@ -0,0 +1,6 @@
+# SPDX-License-Identifier: GPL-2.0-only
+
+obj-$(CONFIG_PCI_PWRCTL)		+= pci-pwrctrl-core.o
+pci-pwrctrl-core-y			:= core.o
+
+obj-$(CONFIG_PCI_PWRCTL_PWRSEQ)		+= pci-pwrctrl-pwrseq.o
diff --git a/drivers/pci/pwrctrl/core.c b/drivers/pci/pwrctrl/core.c
new file mode 100644
index 000000000000..2fb174db91e5
--- /dev/null
+++ b/drivers/pci/pwrctrl/core.c
@@ -0,0 +1,148 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2024 Linaro Ltd.
+ */
+
+#include <linux/device.h>
+#include <linux/export.h>
+#include <linux/kernel.h>
+#include <linux/pci.h>
+#include <linux/pci-pwrctrl.h>
+#include <linux/property.h>
+#include <linux/slab.h>
+
+static int pci_pwrctrl_notify(struct notifier_block *nb, unsigned long action,
+			      void *data)
+{
+	struct pci_pwrctrl *pwrctrl = container_of(nb, struct pci_pwrctrl, nb);
+	struct device *dev = data;
+
+	if (dev_fwnode(dev) != dev_fwnode(pwrctrl->dev))
+		return NOTIFY_DONE;
+
+	switch (action) {
+	case BUS_NOTIFY_ADD_DEVICE:
+		/*
+		 * We will have two struct device objects bound to two different
+		 * drivers on different buses but consuming the same DT node. We
+		 * must not bind the pins twice in this case but only once for
+		 * the first device to be added.
+		 *
+		 * If we got here then the PCI device is the second after the
+		 * power control platform device. Mark its OF node as reused.
+		 */
+		dev->of_node_reused = true;
+		break;
+	}
+
+	return NOTIFY_DONE;
+}
+
+static void rescan_work_func(struct work_struct *work)
+{
+	struct pci_pwrctrl *pwrctrl = container_of(work,
+						   struct pci_pwrctrl, work);
+
+	pci_lock_rescan_remove();
+	pci_rescan_bus(to_pci_dev(pwrctrl->dev->parent)->bus);
+	pci_unlock_rescan_remove();
+}
+
+/**
+ * pci_pwrctrl_init() - Initialize the PCI power control context struct
+ *
+ * @pwrctrl: PCI power control data
+ * @dev: Parent device
+ */
+void pci_pwrctrl_init(struct pci_pwrctrl *pwrctrl, struct device *dev)
+{
+	pwrctrl->dev = dev;
+	INIT_WORK(&pwrctrl->work, rescan_work_func);
+}
+EXPORT_SYMBOL_GPL(pci_pwrctrl_init);
+
+/**
+ * pci_pwrctrl_device_set_ready() - Notify the pwrctrl subsystem that the PCI
+ * device is powered-up and ready to be detected.
+ *
+ * @pwrctrl: PCI power control data.
+ *
+ * Returns:
+ * 0 on success, negative error number on error.
+ *
+ * Note:
+ * This function returning 0 doesn't mean the device was detected. It means,
+ * that the bus rescan was successfully started. The device will get bound to
+ * its PCI driver asynchronously.
+ */
+int pci_pwrctrl_device_set_ready(struct pci_pwrctrl *pwrctrl)
+{
+	int ret;
+
+	if (!pwrctrl->dev)
+		return -ENODEV;
+
+	pwrctrl->nb.notifier_call = pci_pwrctrl_notify;
+	ret = bus_register_notifier(&pci_bus_type, &pwrctrl->nb);
+	if (ret)
+		return ret;
+
+	schedule_work(&pwrctrl->work);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(pci_pwrctrl_device_set_ready);
+
+/**
+ * pci_pwrctrl_device_unset_ready() - Notify the pwrctrl subsystem that the PCI
+ * device is about to be powered-down.
+ *
+ * @pwrctrl: PCI power control data.
+ */
+void pci_pwrctrl_device_unset_ready(struct pci_pwrctrl *pwrctrl)
+{
+	/*
+	 * We don't have to delete the link here. Typically, this function
+	 * is only called when the power control device is being detached. If
+	 * it is being detached then the child PCI device must have already
+	 * been unbound too or the device core wouldn't let us unbind.
+	 */
+	bus_unregister_notifier(&pci_bus_type, &pwrctrl->nb);
+}
+EXPORT_SYMBOL_GPL(pci_pwrctrl_device_unset_ready);
+
+static void devm_pci_pwrctrl_device_unset_ready(void *data)
+{
+	struct pci_pwrctrl *pwrctrl = data;
+
+	pci_pwrctrl_device_unset_ready(pwrctrl);
+}
+
+/**
+ * devm_pci_pwrctrl_device_set_ready - Managed variant of
+ * pci_pwrctrl_device_set_ready().
+ *
+ * @dev: Device managing this pwrctrl provider.
+ * @pwrctrl: PCI power control data.
+ *
+ * Returns:
+ * 0 on success, negative error number on error.
+ */
+int devm_pci_pwrctrl_device_set_ready(struct device *dev,
+				      struct pci_pwrctrl *pwrctrl)
+{
+	int ret;
+
+	ret = pci_pwrctrl_device_set_ready(pwrctrl);
+	if (ret)
+		return ret;
+
+	return devm_add_action_or_reset(dev,
+					devm_pci_pwrctrl_device_unset_ready,
+					pwrctrl);
+}
+EXPORT_SYMBOL_GPL(devm_pci_pwrctrl_device_set_ready);
+
+MODULE_AUTHOR("Bartosz Golaszewski <[email protected]>");
+MODULE_DESCRIPTION("PCI Device Power Control core driver");
+MODULE_LICENSE("GPL");
diff --git a/drivers/pci/pwrctrl/pci-pwrctrl-pwrseq.c b/drivers/pci/pwrctrl/pci-pwrctrl-pwrseq.c
new file mode 100644
index 000000000000..e9f89866b7c2
--- /dev/null
+++ b/drivers/pci/pwrctrl/pci-pwrctrl-pwrseq.c
@@ -0,0 +1,94 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2024 Linaro Ltd.
+ */
+
+#include <linux/device.h>
+#include <linux/mod_devicetable.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/pci-pwrctrl.h>
+#include <linux/platform_device.h>
+#include <linux/pwrseq/consumer.h>
+#include <linux/slab.h>
+#include <linux/types.h>
+
+struct pci_pwrctrl_pwrseq_data {
+	struct pci_pwrctrl ctx;
+	struct pwrseq_desc *pwrseq;
+};
+
+static void devm_pci_pwrctrl_pwrseq_power_off(void *data)
+{
+	struct pwrseq_desc *pwrseq = data;
+
+	pwrseq_power_off(pwrseq);
+}
+
+static int pci_pwrctrl_pwrseq_probe(struct platform_device *pdev)
+{
+	struct pci_pwrctrl_pwrseq_data *data;
+	struct device *dev = &pdev->dev;
+	int ret;
+
+	data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+
+	data->pwrseq = devm_pwrseq_get(dev, of_device_get_match_data(dev));
+	if (IS_ERR(data->pwrseq))
+		return dev_err_probe(dev, PTR_ERR(data->pwrseq),
+				     "Failed to get the power sequencer\n");
+
+	ret = pwrseq_power_on(data->pwrseq);
+	if (ret)
+		return dev_err_probe(dev, ret,
+				     "Failed to power-on the device\n");
+
+	ret = devm_add_action_or_reset(dev, devm_pci_pwrctrl_pwrseq_power_off,
+				       data->pwrseq);
+	if (ret)
+		return ret;
+
+	pci_pwrctrl_init(&data->ctx, dev);
+
+	ret = devm_pci_pwrctrl_device_set_ready(dev, &data->ctx);
+	if (ret)
+		return dev_err_probe(dev, ret,
+				     "Failed to register the pwrctrl wrapper\n");
+
+	return 0;
+}
+
+static const struct of_device_id pci_pwrctrl_pwrseq_of_match[] = {
+	{
+		/* ATH11K in QCA6390 package. */
+		.compatible = "pci17cb,1101",
+		.data = "wlan",
+	},
+	{
+		/* ATH11K in WCN6855 package. */
+		.compatible = "pci17cb,1103",
+		.data = "wlan",
+	},
+	{
+		/* ATH12K in WCN7850 package. */
+		.compatible = "pci17cb,1107",
+		.data = "wlan",
+	},
+	{ }
+};
+MODULE_DEVICE_TABLE(of, pci_pwrctrl_pwrseq_of_match);
+
+static struct platform_driver pci_pwrctrl_pwrseq_driver = {
+	.driver = {
+		.name = "pci-pwrctrl-pwrseq",
+		.of_match_table = pci_pwrctrl_pwrseq_of_match,
+	},
+	.probe = pci_pwrctrl_pwrseq_probe,
+};
+module_platform_driver(pci_pwrctrl_pwrseq_driver);
+
+MODULE_AUTHOR("Bartosz Golaszewski <[email protected]>");
+MODULE_DESCRIPTION("Generic PCI Power Control module for power sequenced devices");
+MODULE_LICENSE("GPL");