Merge branch 'pci/pwrctrl'

- Create pwrctrl devices in pci_scan_device() to make it more symmetric
  with pci_pwrctrl_unregister() and make pwrctrl devices for PCI bridges
  possible (Manivannan Sadhasivam)

- Unregister pwrctrl devices in pci_destroy_dev() so DOE, ASPM, etc. can
  still access devices after pci_stop_dev() (Manivannan Sadhasivam)

- If there's a pwrctrl device for a PCI device, skip scanning it because
  the pwrctrl core will rescan the bus after the device is powered on
  (Manivannan Sadhasivam)

- Add a pwrctrl driver for PCI slots based on voltage regulators described
  via devicetree (Manivannan Sadhasivam)

* pci/pwrctrl:
  PCI/pwrctrl: Add pwrctrl driver for PCI slots
  dt-bindings: vendor-prefixes: Document the 'pciclass' prefix
  PCI/pwrctrl: Skip scanning for the device further if pwrctrl device is created
  PCI/pwrctrl: Move pci_pwrctrl_unregister() to pci_destroy_dev()
  PCI/pwrctrl: Move creation of pwrctrl devices to pci_scan_device()

Author: bjorn-helgaas

Documentation/devicetree/bindings/vendor-prefixes.yaml

@@ -18,7 +18,7 @@ patternProperties:
   # DO NOT ADD NEW PROPERTIES TO THIS LIST
   "^(at25|bm|devbus|dmacap|dsa|exynos|fsi[ab]|gpio-fan|gpio-key|gpio|gpmc|hdmi|i2c-gpio),.*": true
   "^(keypad|m25p|max8952|max8997|max8998|mpmc),.*": true
-  "^(pinctrl-single|#pinctrl-single|PowerPC),.*": true
+  "^(pciclass|pinctrl-single|#pinctrl-single|PowerPC),.*": true
   "^(pl022|pxa-mmc|rcar_sound|rotary-encoder|s5m8767|sdhci),.*": true
   "^(simple-audio-card|st-plgpio|st-spics|ts),.*": true
 

drivers/pci/bus.c

@@ -331,47 +331,6 @@ void __weak pcibios_resource_survey_bus(struct pci_bus *bus) { }
 
 void __weak pcibios_bus_add_device(struct pci_dev *pdev) { }
 
-/*
- * Create pwrctrl devices (if required) for the PCI devices to handle the power
- * state.
- */
-static void pci_pwrctrl_create_devices(struct pci_dev *dev)
-{
-	struct device_node *np = dev_of_node(&dev->dev);
-	struct device *parent = &dev->dev;
-	struct platform_device *pdev;
-
-	/*
-	 * First ensure that we are starting from a PCI bridge and it has a
-	 * corresponding devicetree node.
-	 */
-	if (np && pci_is_bridge(dev)) {
-		/*
-		 * Now look for the child PCI device nodes and create pwrctrl
-		 * devices for them. The pwrctrl device drivers will manage the
-		 * power state of the devices.
-		 */
-		for_each_available_child_of_node_scoped(np, child) {
-			/*
-			 * First check whether the pwrctrl device really
-			 * needs to be created or 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(child)) {
-				pci_dbg(dev, "skipping OF node: %s\n", child->name);
-				return;
-			}
-
-			/* Now create the pwrctrl device */
-			pdev = of_platform_device_create(child, NULL, parent);
-			if (!pdev)
-				pci_err(dev, "failed to create OF node: %s\n", child->name);
-		}
-	}
-}
-
 /**
  * pci_bus_add_device - start driver for a single device
  * @dev: device to add
@@ -396,8 +355,6 @@ void pci_bus_add_device(struct pci_dev *dev)
 	pci_proc_attach_device(dev);
 	pci_bridge_d3_update(dev);
 
-	pci_pwrctrl_create_devices(dev);
-
 	/*
 	 * If the PCI device is associated with a pwrctrl device with a
 	 * power supply, create a device link between the PCI device and

drivers/pci/probe.c

@@ -9,6 +9,8 @@
 #include <linux/pci.h>
 #include <linux/msi.h>
 #include <linux/of_pci.h>
+#include <linux/of_platform.h>
+#include <linux/platform_device.h>
 #include <linux/pci_hotplug.h>
 #include <linux/slab.h>
 #include <linux/module.h>
@@ -2503,6 +2505,36 @@ bool pci_bus_read_dev_vendor_id(struct pci_bus *bus, int devfn, u32 *l,
 }
 EXPORT_SYMBOL(pci_bus_read_dev_vendor_id);
 
+static struct platform_device *pci_pwrctrl_create_device(struct pci_bus *bus, int devfn)
+{
+	struct pci_host_bridge *host = pci_find_host_bridge(bus);
+	struct platform_device *pdev;
+	struct device_node *np;
+
+	np = of_pci_find_child_device(dev_of_node(&bus->dev), devfn);
+	if (!np || of_find_device_by_node(np))
+		return NULL;
+
+	/*
+	 * First check whether the pwrctrl device really needs to be created or
+	 * 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)) {
+		pr_debug("PCI/pwrctrl: Skipping OF node: %s\n", np->name);
+		return NULL;
+	}
+
+	/* Now create the pwrctrl device */
+	pdev = of_platform_device_create(np, NULL, &host->dev);
+	if (!pdev) {
+		pr_err("PCI/pwrctrl: Failed to create pwrctrl device for node: %s\n", np->name);
+		return NULL;
+	}
+
+	return pdev;
+}
+
 /*
  * Read the config data for a PCI device, sanity-check it,
  * and fill in the dev structure.
@@ -2512,6 +2544,15 @@ static struct pci_dev *pci_scan_device(struct pci_bus *bus, int devfn)
 	struct pci_dev *dev;
 	u32 l;
 
+	/*
+	 * Create pwrctrl device (if required) for the PCI device to handle the
+	 * power state. If the pwrctrl device is created, then skip scanning
+	 * further as the pwrctrl core will rescan the bus after powering on
+	 * the device.
+	 */
+	if (pci_pwrctrl_create_device(bus, devfn))
+		return NULL;
+
 	if (!pci_bus_read_dev_vendor_id(bus, devfn, &l, 60*1000))
 		return NULL;
 

drivers/pci/pwrctrl/Kconfig

@@ -10,3 +10,14 @@ config PCI_PWRCTL_PWRSEQ
 	tristate
 	select POWER_SEQUENCING
 	select PCI_PWRCTL
+
+config PCI_PWRCTL_SLOT
+	tristate "PCI Power Control driver for PCI slots"
+	select PCI_PWRCTL
+	help
+	  Say Y here to enable the PCI Power Control driver to control the power
+	  state of PCI slots.
+
+	  This is a generic driver that controls the power state of different
+	  PCI slots. The voltage regulators powering the rails of the PCI slots
+	  are expected to be defined in the devicetree node of the PCI bridge.

drivers/pci/pwrctrl/Makefile

@@ -4,3 +4,6 @@ obj-$(CONFIG_PCI_PWRCTL)		+= pci-pwrctrl-core.o
 pci-pwrctrl-core-y			:= core.o
 
 obj-$(CONFIG_PCI_PWRCTL_PWRSEQ)		+= pci-pwrctrl-pwrseq.o
+
+obj-$(CONFIG_PCI_PWRCTL_SLOT)		+= pci-pwrctl-slot.o
+pci-pwrctl-slot-y			:= slot.o

drivers/pci/pwrctrl/core.c

@@ -44,7 +44,7 @@ static void rescan_work_func(struct work_struct *work)
 						   struct pci_pwrctrl, work);
 
 	pci_lock_rescan_remove();
-	pci_rescan_bus(to_pci_dev(pwrctrl->dev->parent)->bus);
+	pci_rescan_bus(to_pci_host_bridge(pwrctrl->dev->parent)->bus);
 	pci_unlock_rescan_remove();
 }
 

drivers/pci/pwrctrl/slot.c

@@ -0,0 +1,93 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2024 Linaro Ltd.
+ * Author: Manivannan Sadhasivam <[email protected]>
+ */
+
+#include <linux/device.h>
+#include <linux/mod_devicetable.h>
+#include <linux/module.h>
+#include <linux/pci-pwrctrl.h>
+#include <linux/platform_device.h>
+#include <linux/regulator/consumer.h>
+#include <linux/slab.h>
+
+struct pci_pwrctrl_slot_data {
+	struct pci_pwrctrl ctx;
+	struct regulator_bulk_data *supplies;
+	int num_supplies;
+};
+
+static void devm_pci_pwrctrl_slot_power_off(void *data)
+{
+	struct pci_pwrctrl_slot_data *slot = data;
+
+	regulator_bulk_disable(slot->num_supplies, slot->supplies);
+	regulator_bulk_free(slot->num_supplies, slot->supplies);
+}
+
+static int pci_pwrctrl_slot_probe(struct platform_device *pdev)
+{
+	struct pci_pwrctrl_slot_data *slot;
+	struct device *dev = &pdev->dev;
+	int ret;
+
+	slot = devm_kzalloc(dev, sizeof(*slot), GFP_KERNEL);
+	if (!slot)
+		return -ENOMEM;
+
+	ret = of_regulator_bulk_get_all(dev, dev_of_node(dev),
+					&slot->supplies);
+	if (ret < 0) {
+		dev_err_probe(dev, ret, "Failed to get slot regulators\n");
+		return ret;
+	}
+
+	slot->num_supplies = ret;
+	ret = regulator_bulk_enable(slot->num_supplies, slot->supplies);
+	if (ret < 0) {
+		dev_err_probe(dev, ret, "Failed to enable slot regulators\n");
+		goto err_regulator_free;
+	}
+
+	ret = devm_add_action_or_reset(dev, devm_pci_pwrctrl_slot_power_off,
+				       slot);
+	if (ret)
+		goto err_regulator_disable;
+
+	pci_pwrctrl_init(&slot->ctx, dev);
+
+	ret = devm_pci_pwrctrl_device_set_ready(dev, &slot->ctx);
+	if (ret)
+		return dev_err_probe(dev, ret, "Failed to register pwrctrl driver\n");
+
+	return 0;
+
+err_regulator_disable:
+	regulator_bulk_disable(slot->num_supplies, slot->supplies);
+err_regulator_free:
+	regulator_bulk_free(slot->num_supplies, slot->supplies);
+
+	return ret;
+}
+
+static const struct of_device_id pci_pwrctrl_slot_of_match[] = {
+	{
+		.compatible = "pciclass,0604",
+	},
+	{ }
+};
+MODULE_DEVICE_TABLE(of, pci_pwrctrl_slot_of_match);
+
+static struct platform_driver pci_pwrctrl_slot_driver = {
+	.driver = {
+		.name = "pci-pwrctrl-slot",
+		.of_match_table = pci_pwrctrl_slot_of_match,
+	},
+	.probe = pci_pwrctrl_slot_probe,
+};
+module_platform_driver(pci_pwrctrl_slot_driver);
+
+MODULE_AUTHOR("Manivannan Sadhasivam <[email protected]>");
+MODULE_DESCRIPTION("Generic PCI Power Control driver for PCI Slots");
+MODULE_LICENSE("GPL");

drivers/pci/remove.c

@@ -41,7 +41,6 @@ static void pci_stop_dev(struct pci_dev *dev)
 	if (!pci_dev_test_and_clear_added(dev))
 		return;
 
-	pci_pwrctrl_unregister(&dev->dev);
 	device_release_driver(&dev->dev);
 	pci_proc_detach_device(dev);
 	pci_remove_sysfs_dev_files(dev);
@@ -65,6 +64,7 @@ static void pci_destroy_dev(struct pci_dev *dev)
 	pci_doe_destroy(dev);
 	pcie_aspm_exit_link_state(dev);
 	pci_bridge_d3_update(dev);
+	pci_pwrctrl_unregister(&dev->dev);
 	pci_free_resources(dev);
 	put_device(&dev->dev);
 }