[PATCH v9 0/5] PCI/pwrctl: initial implementation and first user

[PATCH v9 0/5] PCI/pwrctl: initial implementation and first user

[Bartosz Golaszewski]

From: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

I'm sending the PCI part separately to keep the history on the list.
Bjorn acked all of them so I'll pick them up later today into the pwrseq
tree.

Changelog:

Since v8:
- split out the PCI patches into their own series
- improved commit messages (added rationale for the PCI pwrctl and the
  powrseq driver for QCOM QCAxyz, start with a capital letter)
- pick up Acks from Bjorn
- Link to v8: https://lore.kernel.org/r/20240528-pwrseq-v8-0-d354d52b763c@linaro.org

Since v7:
- added DTS changes for sm8650-hdk
- added circular dependency detection for pwrseq units
- fixed a KASAN reported use-after-free error in remove path
- improve Kconfig descriptions
- fix typos in bindings and Kconfig
- fixed issues reported by smatch
- fix the unbind path in PCI pwrctl
- lots of minor improvements to the pwrseq core

Since v6:
- kernel doc fixes
- drop myself from the DT bindings maintainers list for ath12k
- wait until the PCI bridge device is fully added before creating the
  PCI pwrctl platform devices for its sub-nodes, otherwise we may see
  sysfs and procfs attribute failures (due to duplication, we're
  basically trying to probe the same device twice at the same time)
- I kept the regulators for QCA6390's ath11k as required as they only
  apply to this specific Qualcomm package

Since v5:
- unify the approach to modelling the WCN WLAN/BT chips by always exposing
  the PMU node on the device tree and making the WLAN and BT nodes become
  consumers of its power outputs; this includes a major rework of the DT
  sources, bindings and driver code; there's no more a separate PCI
  pwrctl driver for WCN7850, instead its power-up sequence was moved
  into the pwrseq driver common for all WCN chips
- don't set load_uA from new regulator consumers
- fix reported kerneldoc issues
- drop voltage ranges for PMU outputs from DT
- many minor tweaks and reworks

v1: Original RFC:

https://lore.kernel.org/lkml/20240104130123.37115-1-brgl@bgdev.pl/T/

v2: First real patch series (should have been PATCH v2) adding what I
    referred to back then as PCI power sequencing:

https://lore.kernel.org/linux-arm-kernel/2024021413-grumbling-unlivable-c145@gregkh/T/

v3: RFC for the DT representation of the PMU supplying the WLAN and BT
    modules inside the QCA6391 package (was largely separate from the
    series but probably should have been called PATCH or RFC v3):

https://lore.kernel.org/all/CAMRc=Mc+GNoi57eTQg71DXkQKjdaoAmCpB=h2ndEpGnmdhVV-Q@mail.gmail.com/T/

v4: Second attempt at the full series with changed scope (introduction of
    the pwrseq subsystem, should have been RFC v4)

https://lore.kernel.org/lkml/20240201155532.49707-1-brgl@bgdev.pl/T/

v5: Two different ways of handling QCA6390 and WCN7850:

https://lore.kernel.org/lkml/20240216203215.40870-1-brgl@bgdev.pl/

Bartosz Golaszewski (5):
  PCI: Hold the rescan mutex when scanning for the first time
  PCI/pwrctl: Reuse the OF node for power controlled devices
  PCI/pwrctl: Create platform devices for child OF nodes of the port
    node
  PCI/pwrctl: Add PCI power control core code
  PCI/pwrctl: Add a PCI power control driver for power sequenced devices

 MAINTAINERS                            |   8 ++
 drivers/pci/Kconfig                    |   1 +
 drivers/pci/Makefile                   |   1 +
 drivers/pci/bus.c                      |   9 ++
 drivers/pci/of.c                       |  14 ++-
 drivers/pci/probe.c                    |   2 +
 drivers/pci/pwrctl/Kconfig             |  17 +++
 drivers/pci/pwrctl/Makefile            |   6 ++
 drivers/pci/pwrctl/core.c              | 137 +++++++++++++++++++++++++
 drivers/pci/pwrctl/pci-pwrctl-pwrseq.c |  89 ++++++++++++++++
 drivers/pci/remove.c                   |   3 +-
 include/linux/pci-pwrctl.h             |  51 +++++++++
 12 files changed, 333 insertions(+), 5 deletions(-)
 create mode 100644 drivers/pci/pwrctl/Kconfig
 create mode 100644 drivers/pci/pwrctl/Makefile
 create mode 100644 drivers/pci/pwrctl/core.c
 create mode 100644 drivers/pci/pwrctl/pci-pwrctl-pwrseq.c
 create mode 100644 include/linux/pci-pwrctl.h

-- 
2.40.1

[PATCH v9 1/5] PCI: Hold the rescan mutex when scanning for the first time

[Bartosz Golaszewski]

From: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

With the introduction of PCI device power control drivers that will be
able to trigger the port rescan when probing, we need to hold the rescan
mutex during the initial pci_host_probe() too or the two could get in
each other's way.

Tested-by: Amit Pundir <amit.pundir@linaro.org>
Tested-by: Neil Armstrong <neil.armstrong@linaro.org> # on SM8550-QRD, SM8650-QRD & SM8650-HDK
Tested-by: Caleb Connolly <caleb.connolly@linaro.org> # OnePlus 8T
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
---
 drivers/pci/probe.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index bfeeaf2d1fa9..b14b9876c030 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -3083,7 +3083,9 @@ int pci_host_probe(struct pci_host_bridge *bridge)
 	struct pci_bus *bus, *child;
 	int ret;
 
+	pci_lock_rescan_remove();
 	ret = pci_scan_root_bus_bridge(bridge);
+	pci_unlock_rescan_remove();
 	if (ret < 0) {
 		dev_err(bridge->dev.parent, "Scanning root bridge failed");
 		return ret;
-- 
2.40.1

[PATCH v9 2/5] PCI/pwrctl: Reuse the OF node for power controlled devices

[Bartosz Golaszewski]

From: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

With PCI power control we deal with two struct device objects bound to
two different drivers but consuming the same OF node. We must not bind
the pinctrl twice. To that end: before setting the OF node of the newly
instantiated PCI device, check if a platform device consuming the same
OF node doesn't already exist on the platform bus and - if so - mark the
PCI device as reusing the OF node.

Tested-by: Amit Pundir <amit.pundir@linaro.org>
Tested-by: Neil Armstrong <neil.armstrong@linaro.org> # on SM8550-QRD, SM8650-QRD & SM8650-HDK
Tested-by: Caleb Connolly <caleb.connolly@linaro.org> # OnePlus 8T
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
---
 drivers/pci/of.c | 14 ++++++++++----
 1 file changed, 10 insertions(+), 4 deletions(-)

diff --git a/drivers/pci/of.c b/drivers/pci/of.c
index 48ba95e4ab05..dacea3fc5128 100644
--- a/drivers/pci/of.c
+++ b/drivers/pci/of.c
@@ -6,6 +6,7 @@
  */
 #define pr_fmt(fmt)	"PCI: OF: " fmt
 
+#include <linux/cleanup.h>
 #include <linux/irqdomain.h>
 #include <linux/kernel.h>
 #include <linux/pci.h>
@@ -13,6 +14,7 @@
 #include <linux/of_irq.h>
 #include <linux/of_address.h>
 #include <linux/of_pci.h>
+#include <linux/platform_device.h>
 #include "pci.h"
 
 #ifdef CONFIG_PCI
@@ -25,16 +27,20 @@
  */
 int pci_set_of_node(struct pci_dev *dev)
 {
-	struct device_node *node;
-
 	if (!dev->bus->dev.of_node)
 		return 0;
 
-	node = of_pci_find_child_device(dev->bus->dev.of_node, dev->devfn);
+	struct device_node *node __free(device_node) =
+		of_pci_find_child_device(dev->bus->dev.of_node, dev->devfn);
 	if (!node)
 		return 0;
 
-	device_set_node(&dev->dev, of_fwnode_handle(node));
+	struct device *pdev __free(put_device) =
+		bus_find_device_by_of_node(&platform_bus_type, node);
+	if (pdev)
+		dev->bus->dev.of_node_reused = true;
+
+	device_set_node(&dev->dev, of_fwnode_handle(no_free_ptr(node)));
 	return 0;
 }
 
-- 
2.40.1

[PATCH v9 3/5] PCI/pwrctl: Create platform devices for child OF nodes of the port node

[Bartosz Golaszewski]

From: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

In preparation for introducing PCI device power control - a set of
library functions that will allow powering-up of PCI devices before
they're detected on the PCI bus - we need to populate the devices
defined on the device-tree.

We are reusing the platform bus as it provides us with all the
infrastructure we need to match the pwrctl drivers against the
compatibles from OF nodes.

These platform devices will be probed by the driver core and bound to
the PCI pwrctl drivers we'll introduce later.

Tested-by: Amit Pundir <amit.pundir@linaro.org>
Tested-by: Neil Armstrong <neil.armstrong@linaro.org> # on SM8550-QRD, SM8650-QRD & SM8650-HDK
Tested-by: Caleb Connolly <caleb.connolly@linaro.org> # OnePlus 8T
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
---
 drivers/pci/bus.c    | 9 +++++++++
 drivers/pci/remove.c | 3 ++-
 2 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/drivers/pci/bus.c b/drivers/pci/bus.c
index dfc99b3cb958..e4735428814d 100644
--- a/drivers/pci/bus.c
+++ b/drivers/pci/bus.c
@@ -12,6 +12,7 @@
 #include <linux/errno.h>
 #include <linux/ioport.h>
 #include <linux/of.h>
+#include <linux/of_platform.h>
 #include <linux/proc_fs.h>
 #include <linux/slab.h>
 
@@ -348,6 +349,14 @@ void pci_bus_add_device(struct pci_dev *dev)
 		pci_warn(dev, "device attach failed (%d)\n", retval);
 
 	pci_dev_assign_added(dev, true);
+
+	if (pci_is_bridge(dev)) {
+		retval = of_platform_populate(dev->dev.of_node, NULL, NULL,
+					      &dev->dev);
+		if (retval)
+			pci_err(dev, "failed to populate child OF nodes (%d)\n",
+				retval);
+	}
 }
 EXPORT_SYMBOL_GPL(pci_bus_add_device);
 
diff --git a/drivers/pci/remove.c b/drivers/pci/remove.c
index d749ea8250d6..910387e5bdbf 100644
--- a/drivers/pci/remove.c
+++ b/drivers/pci/remove.c
@@ -1,6 +1,7 @@
 // SPDX-License-Identifier: GPL-2.0
 #include <linux/pci.h>
 #include <linux/module.h>
+#include <linux/of_platform.h>
 #include "pci.h"
 
 static void pci_free_resources(struct pci_dev *dev)
@@ -18,7 +19,7 @@ static void pci_stop_dev(struct pci_dev *dev)
 	pci_pme_active(dev, false);
 
 	if (pci_dev_is_added(dev)) {
-
+		of_platform_depopulate(&dev->dev);
 		device_release_driver(&dev->dev);
 		pci_proc_detach_device(dev);
 		pci_remove_sysfs_dev_files(dev);
-- 
2.40.1

[PATCH v9 4/5] PCI/pwrctl: Add PCI power control core code

[Bartosz Golaszewski]

From: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

Some PCI devices must be powered-on before they can be detected on the
bus. Introduce a simple framework reusing the existing PCI OF
infrastructure.

The way this works is: a DT node representing a PCI device connected to
the port can be matched against its power control platform driver. If
the match succeeds, the driver is responsible for powering-up the device
and calling pci_pwrctl_device_set_ready() which will trigger a PCI bus
rescan as well as subscribe to PCI bus notifications.

When the device is detected and created, we'll make it consume the same
DT node that the platform device did. When the device is bound, we'll
create a device link between it and the parent power control device.

Tested-by: Amit Pundir <amit.pundir@linaro.org>
Tested-by: Neil Armstrong <neil.armstrong@linaro.org> # on SM8550-QRD, SM8650-QRD & SM8650-HDK
Tested-by: Caleb Connolly <caleb.connolly@linaro.org> # OnePlus 8T
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
---
 MAINTAINERS                 |   8 +++
 drivers/pci/Kconfig         |   1 +
 drivers/pci/Makefile        |   1 +
 drivers/pci/pwrctl/Kconfig  |   8 +++
 drivers/pci/pwrctl/Makefile |   4 ++
 drivers/pci/pwrctl/core.c   | 137 ++++++++++++++++++++++++++++++++++++
 include/linux/pci-pwrctl.h  |  51 ++++++++++++++
 7 files changed, 210 insertions(+)
 create mode 100644 drivers/pci/pwrctl/Kconfig
 create mode 100644 drivers/pci/pwrctl/Makefile
 create mode 100644 drivers/pci/pwrctl/core.c
 create mode 100644 include/linux/pci-pwrctl.h

diff --git a/MAINTAINERS b/MAINTAINERS
index 3ee6e0cbc630..d8350d11a18d 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -17411,6 +17411,14 @@ F:	Documentation/driver-api/pci/p2pdma.rst
 F:	drivers/pci/p2pdma.c
 F:	include/linux/pci-p2pdma.h
 
+PCI POWER CONTROL
+M:	Bartosz Golaszewski <brgl@bgdev.pl>
+L:	linux-pci@vger.kernel.org
+S:	Maintained
+T:	git git://git.kernel.org/pub/scm/linux/kernel/git/pci/pci.git
+F:	drivers/pci/pwrctl/*
+F:	include/linux/pci-pwrctl.h
+
 PCI SUBSYSTEM
 M:	Bjorn Helgaas <bhelgaas@google.com>
 L:	linux-pci@vger.kernel.org
diff --git a/drivers/pci/Kconfig b/drivers/pci/Kconfig
index d35001589d88..aa4d1833f442 100644
--- a/drivers/pci/Kconfig
+++ b/drivers/pci/Kconfig
@@ -296,5 +296,6 @@ source "drivers/pci/hotplug/Kconfig"
 source "drivers/pci/controller/Kconfig"
 source "drivers/pci/endpoint/Kconfig"
 source "drivers/pci/switch/Kconfig"
+source "drivers/pci/pwrctl/Kconfig"
 
 endif
diff --git a/drivers/pci/Makefile b/drivers/pci/Makefile
index 175302036890..8ddad57934a6 100644
--- a/drivers/pci/Makefile
+++ b/drivers/pci/Makefile
@@ -9,6 +9,7 @@ obj-$(CONFIG_PCI)		+= access.o bus.o probe.o host-bridge.o \
 
 obj-$(CONFIG_PCI)		+= msi/
 obj-$(CONFIG_PCI)		+= pcie/
+obj-$(CONFIG_PCI)		+= pwrctl/
 
 ifdef CONFIG_PCI
 obj-$(CONFIG_PROC_FS)		+= proc.o
diff --git a/drivers/pci/pwrctl/Kconfig b/drivers/pci/pwrctl/Kconfig
new file mode 100644
index 000000000000..96195395af69
--- /dev/null
+++ b/drivers/pci/pwrctl/Kconfig
@@ -0,0 +1,8 @@
+# SPDX-License-Identifier: GPL-2.0-only
+
+menu "PCI Power control drivers"
+
+config PCI_PWRCTL
+	tristate
+
+endmenu
diff --git a/drivers/pci/pwrctl/Makefile b/drivers/pci/pwrctl/Makefile
new file mode 100644
index 000000000000..52ae0640ef7b
--- /dev/null
+++ b/drivers/pci/pwrctl/Makefile
@@ -0,0 +1,4 @@
+# SPDX-License-Identifier: GPL-2.0-only
+
+obj-$(CONFIG_PCI_PWRCTL)		+= pci-pwrctl-core.o
+pci-pwrctl-core-y			:= core.o
diff --git a/drivers/pci/pwrctl/core.c b/drivers/pci/pwrctl/core.c
new file mode 100644
index 000000000000..feca26ad2f6a
--- /dev/null
+++ b/drivers/pci/pwrctl/core.c
@@ -0,0 +1,137 @@
+// 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-pwrctl.h>
+#include <linux/property.h>
+#include <linux/slab.h>
+
+static int pci_pwrctl_notify(struct notifier_block *nb, unsigned long action,
+			     void *data)
+{
+	struct pci_pwrctl *pwrctl = container_of(nb, struct pci_pwrctl, nb);
+	struct device *dev = data;
+
+	if (dev_fwnode(dev) != dev_fwnode(pwrctl->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;
+	case BUS_NOTIFY_BOUND_DRIVER:
+		pwrctl->link = device_link_add(dev, pwrctl->dev,
+					       DL_FLAG_AUTOREMOVE_CONSUMER);
+		if (!pwrctl->link)
+			dev_err(pwrctl->dev, "Failed to add device link\n");
+		break;
+	case BUS_NOTIFY_UNBOUND_DRIVER:
+		if (pwrctl->link)
+			device_link_remove(dev, pwrctl->dev);
+		break;
+	}
+
+	return NOTIFY_DONE;
+}
+
+/**
+ * pci_pwrctl_device_set_ready() - Notify the pwrctl subsystem that the PCI
+ * device is powered-up and ready to be detected.
+ *
+ * @pwrctl: 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_pwrctl_device_set_ready(struct pci_pwrctl *pwrctl)
+{
+	int ret;
+
+	if (!pwrctl->dev)
+		return -ENODEV;
+
+	pwrctl->nb.notifier_call = pci_pwrctl_notify;
+	ret = bus_register_notifier(&pci_bus_type, &pwrctl->nb);
+	if (ret)
+		return ret;
+
+	pci_lock_rescan_remove();
+	pci_rescan_bus(to_pci_dev(pwrctl->dev->parent)->bus);
+	pci_unlock_rescan_remove();
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(pci_pwrctl_device_set_ready);
+
+/**
+ * pci_pwrctl_device_unset_ready() - Notify the pwrctl subsystem that the PCI
+ * device is about to be powered-down.
+ *
+ * @pwrctl: PCI power control data.
+ */
+void pci_pwrctl_device_unset_ready(struct pci_pwrctl *pwrctl)
+{
+	/*
+	 * 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, &pwrctl->nb);
+}
+EXPORT_SYMBOL_GPL(pci_pwrctl_device_unset_ready);
+
+static void devm_pci_pwrctl_device_unset_ready(void *data)
+{
+	struct pci_pwrctl *pwrctl = data;
+
+	pci_pwrctl_device_unset_ready(pwrctl);
+}
+
+/**
+ * devm_pci_pwrctl_device_set_ready - Managed variant of
+ * pci_pwrctl_device_set_ready().
+ *
+ * @dev: Device managing this pwrctl provider.
+ * @pwrctl: PCI power control data.
+ *
+ * Returns:
+ * 0 on success, negative error number on error.
+ */
+int devm_pci_pwrctl_device_set_ready(struct device *dev,
+				     struct pci_pwrctl *pwrctl)
+{
+	int ret;
+
+	ret = pci_pwrctl_device_set_ready(pwrctl);
+	if (ret)
+		return ret;
+
+	return devm_add_action_or_reset(dev,
+					devm_pci_pwrctl_device_unset_ready,
+					pwrctl);
+}
+EXPORT_SYMBOL_GPL(devm_pci_pwrctl_device_set_ready);
+
+MODULE_AUTHOR("Bartosz Golaszewski <bartosz.golaszewski@linaro.org>");
+MODULE_DESCRIPTION("PCI Device Power Control core driver");
+MODULE_LICENSE("GPL");
diff --git a/include/linux/pci-pwrctl.h b/include/linux/pci-pwrctl.h
new file mode 100644
index 000000000000..45e9cfe740e4
--- /dev/null
+++ b/include/linux/pci-pwrctl.h
@@ -0,0 +1,51 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (C) 2024 Linaro Ltd.
+ */
+
+#ifndef __PCI_PWRCTL_H__
+#define __PCI_PWRCTL_H__
+
+#include <linux/notifier.h>
+
+struct device;
+struct device_link;
+
+/*
+ * This is a simple framework for solving the issue of PCI devices that require
+ * certain resources (regulators, GPIOs, clocks) to be enabled before the
+ * device can actually be detected on the PCI bus.
+ *
+ * The idea is to reuse the platform bus to populate OF nodes describing the
+ * PCI device and its resources, let these platform devices probe and enable
+ * relevant resources and then trigger a rescan of the PCI bus allowing for the
+ * same device (with a second associated struct device) to be registered with
+ * the PCI subsystem.
+ *
+ * To preserve a correct hierarchy for PCI power management and device reset,
+ * we create a device link between the power control platform device (parent)
+ * and the supplied PCI device (child).
+ */
+
+/**
+ * struct pci_pwrctl - PCI device power control context.
+ * @dev: Address of the power controlling device.
+ *
+ * An object of this type must be allocated by the PCI power control device and
+ * passed to the pwrctl subsystem to trigger a bus rescan and setup a device
+ * link with the device once it's up.
+ */
+struct pci_pwrctl {
+	struct device *dev;
+
+	/* Private: don't use. */
+	struct notifier_block nb;
+	struct device_link *link;
+};
+
+int pci_pwrctl_device_set_ready(struct pci_pwrctl *pwrctl);
+void pci_pwrctl_device_unset_ready(struct pci_pwrctl *pwrctl);
+int devm_pci_pwrctl_device_set_ready(struct device *dev,
+				     struct pci_pwrctl *pwrctl);
+
+#endif /* __PCI_PWRCTL_H__ */
-- 
2.40.1

[PATCH v9 5/5] PCI/pwrctl: Add a PCI power control driver for power sequenced devices

[Bartosz Golaszewski]

From: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

Add a PCI power control driver that's capable of correctly powering up
devices using the power sequencing subsystem. The first users of this
driver are the ath11k module on QCA6390 and ath12k on WCN7850. These
packages require a certain delay between enabling the Bluetooth and WLAN
modules and the power sequencing subsystem takes care of it behind the
scenes.

Tested-by: Amit Pundir <amit.pundir@linaro.org>
Tested-by: Neil Armstrong <neil.armstrong@linaro.org> # on SM8550-QRD, SM8650-QRD & SM8650-HDK
Tested-by: Caleb Connolly <caleb.connolly@linaro.org> # OnePlus 8T
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
---
 drivers/pci/pwrctl/Kconfig             |  9 +++
 drivers/pci/pwrctl/Makefile            |  2 +
 drivers/pci/pwrctl/pci-pwrctl-pwrseq.c | 89 ++++++++++++++++++++++++++
 3 files changed, 100 insertions(+)
 create mode 100644 drivers/pci/pwrctl/pci-pwrctl-pwrseq.c

diff --git a/drivers/pci/pwrctl/Kconfig b/drivers/pci/pwrctl/Kconfig
index 96195395af69..f1b824955d4b 100644
--- a/drivers/pci/pwrctl/Kconfig
+++ b/drivers/pci/pwrctl/Kconfig
@@ -5,4 +5,13 @@ menu "PCI Power control drivers"
 config PCI_PWRCTL
 	tristate
 
+config PCI_PWRCTL_PWRSEQ
+	tristate "PCI Power Control driver using the Power Sequencing subsystem"
+	select POWER_SEQUENCING
+	select PCI_PWRCTL
+	default m if ((ATH11K_PCI || ATH12K) && ARCH_QCOM)
+	help
+	  Enable support for the PCI power control driver for device
+	  drivers using the Power Sequencing subsystem.
+
 endmenu
diff --git a/drivers/pci/pwrctl/Makefile b/drivers/pci/pwrctl/Makefile
index 52ae0640ef7b..d308aae4800c 100644
--- a/drivers/pci/pwrctl/Makefile
+++ b/drivers/pci/pwrctl/Makefile
@@ -2,3 +2,5 @@
 
 obj-$(CONFIG_PCI_PWRCTL)		+= pci-pwrctl-core.o
 pci-pwrctl-core-y			:= core.o
+
+obj-$(CONFIG_PCI_PWRCTL_PWRSEQ)		+= pci-pwrctl-pwrseq.o
diff --git a/drivers/pci/pwrctl/pci-pwrctl-pwrseq.c b/drivers/pci/pwrctl/pci-pwrctl-pwrseq.c
new file mode 100644
index 000000000000..c7a113a76c0c
--- /dev/null
+++ b/drivers/pci/pwrctl/pci-pwrctl-pwrseq.c
@@ -0,0 +1,89 @@
+// 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-pwrctl.h>
+#include <linux/platform_device.h>
+#include <linux/pwrseq/consumer.h>
+#include <linux/slab.h>
+#include <linux/types.h>
+
+struct pci_pwrctl_pwrseq_data {
+	struct pci_pwrctl ctx;
+	struct pwrseq_desc *pwrseq;
+};
+
+static void devm_pci_pwrctl_pwrseq_power_off(void *data)
+{
+	struct pwrseq_desc *pwrseq = data;
+
+	pwrseq_power_off(pwrseq);
+}
+
+static int pci_pwrctl_pwrseq_probe(struct platform_device *pdev)
+{
+	struct pci_pwrctl_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_pwrctl_pwrseq_power_off,
+				       data->pwrseq);
+	if (ret)
+		return ret;
+
+	data->ctx.dev = dev;
+
+	ret = devm_pci_pwrctl_device_set_ready(dev, &data->ctx);
+	if (ret)
+		return dev_err_probe(dev, ret,
+				     "Failed to register the pwrctl wrapper\n");
+
+	return 0;
+}
+
+static const struct of_device_id pci_pwrctl_pwrseq_of_match[] = {
+	{
+		/* ATH11K in QCA6390 package. */
+		.compatible = "pci17cb,1101",
+		.data = "wlan",
+	},
+	{
+		/* ATH12K in WCN7850 package. */
+		.compatible = "pci17cb,1107",
+		.data = "wlan",
+	},
+	{ }
+};
+MODULE_DEVICE_TABLE(of, pci_pwrctl_pwrseq_of_match);
+
+static struct platform_driver pci_pwrctl_pwrseq_driver = {
+	.driver = {
+		.name = "pci-pwrctl-pwrseq",
+		.of_match_table = pci_pwrctl_pwrseq_of_match,
+	},
+	.probe = pci_pwrctl_pwrseq_probe,
+};
+module_platform_driver(pci_pwrctl_pwrseq_driver);
+
+MODULE_AUTHOR("Bartosz Golaszewski <bartosz.golaszewski@linaro.org>");
+MODULE_DESCRIPTION("Generic PCI Power Control module for power sequenced devices");
+MODULE_LICENSE("GPL");
-- 
2.40.1

Re: [PATCH v9 0/5] PCI/pwrctl: initial implementation and first user

[Bartosz Golaszewski]

From: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>


On Wed, 12 Jun 2024 10:20:13 +0200, Bartosz Golaszewski wrote:
> From: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
> 
> I'm sending the PCI part separately to keep the history on the list.
> Bjorn acked all of them so I'll pick them up later today into the pwrseq
> tree.
> 
> Changelog:
> 
> [...]

Applied, thanks!

[1/5] PCI: Hold the rescan mutex when scanning for the first time
      commit: 5799eba8eeabe79a476016f22a7aea57467b7638
[2/5] PCI/pwrctl: Reuse the OF node for power controlled devices
      commit: 62c953f0f4fb0b5f67b0ad3096ab38f5c5712d75
[3/5] PCI/pwrctl: Create platform devices for child OF nodes of the port node
      commit: 8fb18619d9102e8f4f6184cdac482422d9293b48
[4/5] PCI/pwrctl: Add PCI power control core code
      commit: 4565d2652a37e438e4cd729e2a8dfeffe34c958c
[5/5] PCI/pwrctl: Add a PCI power control driver for power sequenced devices
      commit: 6140d185a43daa298d43453929560388d6d49b6e

Best regards,
-- 
Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

Re: [PATCH v9 4/5] PCI/pwrctl: Add PCI power control core code

[Bjorn Helgaas]

On Wed, Jun 12, 2024 at 10:20:17AM +0200, Bartosz Golaszewski wrote:
> From: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
> 
> Some PCI devices must be powered-on before they can be detected on the
> bus. Introduce a simple framework reusing the existing PCI OF
> infrastructure.

> +/**
> + * struct pci_pwrctl - PCI device power control context.
> + * @dev: Address of the power controlling device.
> + *
> + * An object of this type must be allocated by the PCI power control device and
> + * passed to the pwrctl subsystem to trigger a bus rescan and setup a device
> + * link with the device once it's up.
> + */
> +struct pci_pwrctl {
> +	struct device *dev;
> +
> +	/* Private: don't use. */
> +	struct notifier_block nb;
> +	struct device_link *link;
> +};

This is old and I should have noticed before, but we have partial
kernel-doc for this struct:

  $ find include -name \*pci\* | xargs scripts/kernel-doc -none
  Warning: include/linux/pci-pwrctrl.h:45 struct member 'nb' not described in 'pci_pwrctrl'
  Warning: include/linux/pci-pwrctrl.h:45 struct member 'link' not described in 'pci_pwrctrl'
  Warning: include/linux/pci-pwrctrl.h:45 struct member 'work' not described in 'pci_pwrctrl'

Re: [PATCH v9 4/5] PCI/pwrctl: Add PCI power control core code

[Bartosz Golaszewski]

On Wed, Jun 18, 2025 at 1:35 AM Bjorn Helgaas <helgaas@kernel.org> wrote:
>
> On Wed, Jun 12, 2024 at 10:20:17AM +0200, Bartosz Golaszewski wrote:
> > From: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
> >
> > Some PCI devices must be powered-on before they can be detected on the
> > bus. Introduce a simple framework reusing the existing PCI OF
> > infrastructure.
>
> > +/**
> > + * struct pci_pwrctl - PCI device power control context.
> > + * @dev: Address of the power controlling device.
> > + *
> > + * An object of this type must be allocated by the PCI power control device and
> > + * passed to the pwrctl subsystem to trigger a bus rescan and setup a device
> > + * link with the device once it's up.
> > + */
> > +struct pci_pwrctl {
> > +     struct device *dev;
> > +
> > +     /* Private: don't use. */
> > +     struct notifier_block nb;
> > +     struct device_link *link;
> > +};
>
> This is old and I should have noticed before, but we have partial
> kernel-doc for this struct:
>
>   $ find include -name \*pci\* | xargs scripts/kernel-doc -none
>   Warning: include/linux/pci-pwrctrl.h:45 struct member 'nb' not described in 'pci_pwrctrl'
>   Warning: include/linux/pci-pwrctrl.h:45 struct member 'link' not described in 'pci_pwrctrl'
>   Warning: include/linux/pci-pwrctrl.h:45 struct member 'work' not described in 'pci_pwrctrl'
>

I didn't want to document these as they're not part of the API.
Probably should have been "/* private: internal use only */". I will
check and send a patch.

Bart