Merge tag 'gpio-updates-for-v6.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/brgl/linux

Pull gpio updates from Bartosz Golaszewski:
 "The biggest feature is the locking overhaul. Up until now the
  synchronization in the GPIO subsystem was broken. There was a single
  spinlock "protecting" multiple data structures but doing it wrong (as
  evidenced by several places where it would be released when a sleeping
  function was called and then reacquired without checking the protected
  state).

  We tried to use an RW semaphore before but the main issue with GPIO is
  that we have drivers implementing the interfaces in both sleeping and
  non-sleeping ways as well as user-facing interfaces that can be called
  both from process as well as atomic contexts. Both ends converge in
  the same code paths that can use neither spinlocks nor mutexes. The
  only reasonable way out is to use SRCU and go mostly lockless. To that
  end: we add several SRCU structs in relevant places and use them to
  assure consistency between API calls together with atomic reads and
  writes of GPIO descriptor flags where it makes sense.

  This code has spent several weeks in next and has received several
  fixes in the first week or two after which it stabilized nicely. The
  GPIO subsystem is now resilient to providers being suddenly unbound.
  We managed to also remove the existing character device RW semaphore
  and the obsolete global spinlock.

  Other than the locking rework we have one new driver (for Chromebook
  EC), much appreciated documentation improvements from Kent and the
  regular driver improvements, DT-bindings updates and GPIOLIB core
  tweaks.

  Serialization rework:
   - use SRCU to serialize access to the global GPIO device list, to
     GPIO device structs themselves and to GPIO descriptors
   - make the GPIO subsystem resilient to the GPIO providers being
     unbound while the API calls are in progress
   - don't dereference the SRCU-protected chip pointer if the
     information we need can be obtained from the GPIO device structure
   - move some of the information contained in struct gpio_chip to
     struct gpio_device to further reduce the need to dereference the
     former
   - pass the GPIO device struct instead of the GPIO chip to sysfs
     callback to, again, reduce the need for accessing the latter
   - get GPIO descriptors from the GPIO device, not from the chip for
     the same reason
   - allow for mostly lockless operation of the GPIO driver API: assure
     consistency with SRCU and atomic operations
   - remove the global GPIO spinlock
   - remove the character device RW semaphore

  Core GPIOLIB:
   - constify pointers in GPIO API where applicable
   - unify the GPIO counting APIs for ACPI and OF
   - provide a macro for iterating over all GPIOs, not only the ones
     that are requested
   - remove leftover typedefs
   - pass the consumer device to GPIO core in
     devm_fwnode_gpiod_get_index() for improved logging
   - constify the GPIO bus type
   - don't warn about removing GPIO chips with descriptors still held by
     users as we can now handle this situation gracefully
   - remove unused logging helpers
   - unexport functions that are only used internally in the GPIO
     subsystem
   - set the device type (assign the relevant struct device_type) for
     GPIO devices

  New drivers:
   - add the ChromeOS EC GPIO driver

  Driver improvements:
   - allow building gpio-vf610 with COMPILE_TEST as well as disabling it
     in menuconfig (before it was always built for i.MX cofigs)
   - count the number of EICs using the device properties instead of
     hard-coding it in gpio-eic-sprd
   - improve the device naming, extend the debugfs output and add
     lockdep asserts to gpio-sim

  DT bindings:
   - document the 'label' property for gpio-pca9570
   - convert aspeed,ast2400-gpio bindings to DT schema
   - disallow unevaluated properties for gpio-mvebu
   - document a new model in renesas,rcar-gpio

  Documentation:
   - improve the character device kerneldocs in user-space headers
   - add proper documentation for the character device uAPI (both v1 and v2)
   - move the sysfs and gpio-mockup docs into the "obsolete" section
   - improve naming consistency for GPIO terms
   - clarify the line values description for sysfs
   - minor docs improvements
   - improve the driver API contract for setting GPIO direction
   - mark unsafe APIs as deprecated in kerneldocs and suggest
     replacements

  Other:
   - remove an obsolete test from selftests"

* tag 'gpio-updates-for-v6.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/brgl/linux: (79 commits)
  gpio: sysfs: repair export returning -EPERM on 1st attempt
  selftest: gpio: remove obsolete gpio-mockup test
  gpiolib: Deduplicate cleanup for-loop in gpiochip_add_data_with_key()
  dt-bindings: gpio: aspeed,ast2400-gpio: Convert to DT schema
  gpio: acpi: Make acpi_gpio_count() take firmware node as a parameter
  gpio: of: Make of_gpio_get_count() take firmware node as a parameter
  gpiolib: Pass consumer device through to core in devm_fwnode_gpiod_get_index()
  gpio: sim: use for_each_hwgpio()
  gpio: provide for_each_hwgpio()
  gpio: don't warn about removing GPIO chips with active users anymore
  gpio: sim: delimit the fwnode name with a ":" when generating labels
  gpio: sim: add lockdep asserts
  gpio: Add ChromeOS EC GPIO driver
  gpio: constify of_phandle_args in of_find_gpio_device_by_xlate()
  gpio: fix memory leak in gpiod_request_commit()
  gpio: constify opaque pointer "data" in gpio_device_find()
  gpio: cdev: fix a NULL-pointer dereference with DEBUG enabled
  gpio: uapi: clarify default_values being logical
  gpio: sysfs: fix inverted pointer logic
  gpio: don't let lockdep complain about inherently dangerous RCU usage
  ...

1 files changed, 518 insertions, 451 deletions

diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index 75be4a3ca7f8..ce94e37bcbee 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -2,6 +2,7 @@
 
 #include <linux/acpi.h>
 #include <linux/bitmap.h>
+#include <linux/cleanup.h>
 #include <linux/compat.h>
 #include <linux/debugfs.h>
 #include <linux/device.h>
@@ -14,12 +15,14 @@
 #include <linux/irq.h>
 #include <linux/kernel.h>
 #include <linux/list.h>
+#include <linux/lockdep.h>
 #include <linux/module.h>
 #include <linux/of.h>
 #include <linux/pinctrl/consumer.h>
 #include <linux/seq_file.h>
 #include <linux/slab.h>
 #include <linux/spinlock.h>
+#include <linux/srcu.h>
 #include <linux/string.h>
 
 #include <linux/gpio.h>
@@ -63,7 +66,7 @@ static int gpio_bus_match(struct device *dev, struct device_driver *drv)
 	return 1;
 }
 
-static struct bus_type gpio_bus_type = {
+static const struct bus_type gpio_bus_type = {
 	.name = "gpio",
 	.match = gpio_bus_match,
 };
@@ -73,15 +76,14 @@ static struct bus_type gpio_bus_type = {
  */
 #define FASTPATH_NGPIO CONFIG_GPIOLIB_FASTPATH_LIMIT
 
-/* gpio_lock prevents conflicts during gpio_desc[] table updates.
- * While any GPIO is requested, its gpio_chip is not removable;
- * each GPIO's "requested" flag serves as a lock and refcount.
- */
-DEFINE_SPINLOCK(gpio_lock);
-
 static DEFINE_MUTEX(gpio_lookup_lock);
 static LIST_HEAD(gpio_lookup_list);
-LIST_HEAD(gpio_devices);
+
+static LIST_HEAD(gpio_devices);
+/* Protects the GPIO device list against concurrent modifications. */
+static DEFINE_MUTEX(gpio_devices_lock);
+/* Ensures coherence during read-only accesses to the list of GPIO devices. */
+DEFINE_STATIC_SRCU(gpio_devices_srcu);
 
 static DEFINE_MUTEX(gpio_machine_hogs_mutex);
 static LIST_HEAD(gpio_machine_hogs);
@@ -97,9 +99,34 @@ static void gpiochip_irqchip_free_valid_mask(struct gpio_chip *gc);
 
 static bool gpiolib_initialized;
 
-static inline void desc_set_label(struct gpio_desc *d, const char *label)
+const char *gpiod_get_label(struct gpio_desc *desc)
 {
-	d->label = label;
+	unsigned long flags;
+
+	flags = READ_ONCE(desc->flags);
+	if (test_bit(FLAG_USED_AS_IRQ, &flags) &&
+	    !test_bit(FLAG_REQUESTED, &flags))
+		return "interrupt";
+
+	return test_bit(FLAG_REQUESTED, &flags) ?
+			srcu_dereference(desc->label, &desc->srcu) : NULL;
+}
+
+static int desc_set_label(struct gpio_desc *desc, const char *label)
+{
+	const char *new = NULL, *old;
+
+	if (label) {
+		new = kstrdup_const(label, GFP_KERNEL);
+		if (!new)
+			return -ENOMEM;
+	}
+
+	old = rcu_replace_pointer(desc->label, new, 1);
+	synchronize_srcu(&desc->srcu);
+	kfree_const(old);
+
+	return 0;
 }
 
 /**
@@ -113,20 +140,16 @@ static inline void desc_set_label(struct gpio_desc *d, const char *label)
 struct gpio_desc *gpio_to_desc(unsigned gpio)
 {
 	struct gpio_device *gdev;
-	unsigned long flags;
-
-	spin_lock_irqsave(&gpio_lock, flags);
 
-	list_for_each_entry(gdev, &gpio_devices, list) {
-		if (gdev->base <= gpio &&
-		    gdev->base + gdev->ngpio > gpio) {
-			spin_unlock_irqrestore(&gpio_lock, flags);
-			return &gdev->descs[gpio - gdev->base];
+	scoped_guard(srcu, &gpio_devices_srcu) {
+		list_for_each_entry_srcu(gdev, &gpio_devices, list,
+				srcu_read_lock_held(&gpio_devices_srcu)) {
+			if (gdev->base <= gpio &&
+			    gdev->base + gdev->ngpio > gpio)
+				return &gdev->descs[gpio - gdev->base];
 		}
 	}
 
-	spin_unlock_irqrestore(&gpio_lock, flags);
-
 	if (!gpio_is_valid(gpio))
 		pr_warn("invalid GPIO %d\n", gpio);
 
@@ -161,16 +184,6 @@ EXPORT_SYMBOL_GPL(gpiochip_get_desc);
 struct gpio_desc *
 gpio_device_get_desc(struct gpio_device *gdev, unsigned int hwnum)
 {
-	struct gpio_chip *gc;
-
-	/*
-	 * FIXME: This will be locked once we protect gdev->chip everywhere
-	 * with SRCU.
-	 */
-	gc = gdev->chip;
-	if (!gc)
-		return ERR_PTR(-ENODEV);
-
 	if (hwnum >= gdev->ngpio)
 		return ERR_PTR(-EINVAL);
 
@@ -198,12 +211,18 @@ EXPORT_SYMBOL_GPL(desc_to_gpio);
 /**
  * gpiod_to_chip - Return the GPIO chip to which a GPIO descriptor belongs
  * @desc:	descriptor to return the chip of
+ *
+ * *DEPRECATED*
+ * This function is unsafe and should not be used. Using the chip address
+ * without taking the SRCU read lock may result in dereferencing a dangling
+ * pointer.
  */
 struct gpio_chip *gpiod_to_chip(const struct gpio_desc *desc)
 {
-	if (!desc || !desc->gdev)
+	if (!desc)
 		return NULL;
-	return desc->gdev->chip;
+
+	return gpio_device_get_chip(desc->gdev);
 }
 EXPORT_SYMBOL_GPL(gpiod_to_chip);
 
@@ -262,6 +281,7 @@ EXPORT_SYMBOL(gpio_device_get_label);
  * Returns:
  * Address of the GPIO chip backing this device.
  *
+ * *DEPRECATED*
  * Until we can get rid of all non-driver users of struct gpio_chip, we must
  * provide a way of retrieving the pointer to it from struct gpio_device. This
  * is *NOT* safe as the GPIO API is considered to be hot-unpluggable and the
@@ -272,7 +292,7 @@ EXPORT_SYMBOL(gpio_device_get_label);
  */
 struct gpio_chip *gpio_device_get_chip(struct gpio_device *gdev)
 {
-	return gdev->chip;
+	return rcu_dereference_check(gdev->chip, 1);
 }
 EXPORT_SYMBOL_GPL(gpio_device_get_chip);
 
@@ -282,7 +302,8 @@ static int gpiochip_find_base_unlocked(int ngpio)
 	struct gpio_device *gdev;
 	int base = GPIO_DYNAMIC_BASE;
 
-	list_for_each_entry(gdev, &gpio_devices, list) {
+	list_for_each_entry_srcu(gdev, &gpio_devices, list,
+				 lockdep_is_held(&gpio_devices_lock)) {
 		/* found a free space? */
 		if (gdev->base >= base + ngpio)
 			break;
@@ -311,25 +332,36 @@ static int gpiochip_find_base_unlocked(int ngpio)
  */
 int gpiod_get_direction(struct gpio_desc *desc)
 {
-	struct gpio_chip *gc;
+	unsigned long flags;
 	unsigned int offset;
 	int ret;
 
-	gc = gpiod_to_chip(desc);
+	/*
+	 * We cannot use VALIDATE_DESC() as we must not return 0 for a NULL
+	 * descriptor like we usually do.
+	 */
+	if (!desc || IS_ERR(desc))
+		return -EINVAL;
+
+	CLASS(gpio_chip_guard, guard)(desc);
+	if (!guard.gc)
+		return -ENODEV;
+
 	offset = gpio_chip_hwgpio(desc);
+	flags = READ_ONCE(desc->flags);
 
 	/*
 	 * Open drain emulation using input mode may incorrectly report
 	 * input here, fix that up.
 	 */
-	if (test_bit(FLAG_OPEN_DRAIN, &desc->flags) &&
-	    test_bit(FLAG_IS_OUT, &desc->flags))
+	if (test_bit(FLAG_OPEN_DRAIN, &flags) &&
+	    test_bit(FLAG_IS_OUT, &flags))
 		return 0;
 
-	if (!gc->get_direction)
+	if (!guard.gc->get_direction)
 		return -ENOTSUPP;
 
-	ret = gc->get_direction(gc, offset);
+	ret = guard.gc->get_direction(guard.gc, offset);
 	if (ret < 0)
 		return ret;
 
@@ -337,7 +369,8 @@ int gpiod_get_direction(struct gpio_desc *desc)
 	if (ret > 0)
 		ret = 1;
 
-	assign_bit(FLAG_IS_OUT, &desc->flags, !ret);
+	assign_bit(FLAG_IS_OUT, &flags, !ret);
+	WRITE_ONCE(desc->flags, flags);
 
 	return ret;
 }
@@ -354,23 +387,25 @@ static int gpiodev_add_to_list_unlocked(struct gpio_device *gdev)
 {
 	struct gpio_device *prev, *next;
 
+	lockdep_assert_held(&gpio_devices_lock);
+
 	if (list_empty(&gpio_devices)) {
 		/* initial entry in list */
-		list_add_tail(&gdev->list, &gpio_devices);
+		list_add_tail_rcu(&gdev->list, &gpio_devices);
 		return 0;
 	}
 
 	next = list_first_entry(&gpio_devices, struct gpio_device, list);
 	if (gdev->base + gdev->ngpio <= next->base) {
 		/* add before first entry */
-		list_add(&gdev->list, &gpio_devices);
+		list_add_rcu(&gdev->list, &gpio_devices);
 		return 0;
 	}
 
 	prev = list_last_entry(&gpio_devices, struct gpio_device, list);
 	if (prev->base + prev->ngpio <= gdev->base) {
 		/* add behind last entry */
-		list_add_tail(&gdev->list, &gpio_devices);
+		list_add_tail_rcu(&gdev->list, &gpio_devices);
 		return 0;
 	}
 
@@ -382,11 +417,13 @@ static int gpiodev_add_to_list_unlocked(struct gpio_device *gdev)
 		/* add between prev and next */
 		if (prev->base + prev->ngpio <= gdev->base
 				&& gdev->base + gdev->ngpio <= next->base) {
-			list_add(&gdev->list, &prev->list);
+			list_add_rcu(&gdev->list, &prev->list);
 			return 0;
 		}
 	}
 
+	synchronize_srcu(&gpio_devices_srcu);
+
 	return -EBUSY;
 }
 
@@ -399,26 +436,28 @@ static int gpiodev_add_to_list_unlocked(struct gpio_device *gdev)
 static struct gpio_desc *gpio_name_to_desc(const char * const name)
 {
 	struct gpio_device *gdev;
-	unsigned long flags;
+	struct gpio_desc *desc;
+	struct gpio_chip *gc;
 
 	if (!name)
 		return NULL;
 
-	spin_lock_irqsave(&gpio_lock, flags);
+	guard(srcu)(&gpio_devices_srcu);
 
-	list_for_each_entry(gdev, &gpio_devices, list) {
-		struct gpio_desc *desc;
+	list_for_each_entry_srcu(gdev, &gpio_devices, list,
+				 srcu_read_lock_held(&gpio_devices_srcu)) {
+		guard(srcu)(&gdev->srcu);
 
-		for_each_gpio_desc(gdev->chip, desc) {
-			if (desc->name && !strcmp(desc->name, name)) {
-				spin_unlock_irqrestore(&gpio_lock, flags);
+		gc = srcu_dereference(gdev->chip, &gdev->srcu);
+		if (!gc)
+			continue;
+
+		for_each_gpio_desc(gc, desc) {
+			if (desc->name && !strcmp(desc->name, name))
 				return desc;
-			}
 		}
 	}
 
-	spin_unlock_irqrestore(&gpio_lock, flags);
-
 	return NULL;
 }
 
@@ -656,13 +695,23 @@ EXPORT_SYMBOL_GPL(gpiochip_line_is_valid);
 static void gpiodev_release(struct device *dev)
 {
 	struct gpio_device *gdev = to_gpio_device(dev);
+	unsigned int i;
+
+	for (i = 0; i < gdev->ngpio; i++)
+		cleanup_srcu_struct(&gdev->descs[i].srcu);
 
 	ida_free(&gpio_ida, gdev->id);
 	kfree_const(gdev->label);
 	kfree(gdev->descs);
+	cleanup_srcu_struct(&gdev->srcu);
 	kfree(gdev);
 }
 
+static const struct device_type gpio_dev_type = {
+	.name = "gpio_chip",
+	.release = gpiodev_release,
+};
+
 #ifdef CONFIG_GPIO_CDEV
 #define gcdev_register(gdev, devt)	gpiolib_cdev_register((gdev), (devt))
 #define gcdev_unregister(gdev)		gpiolib_cdev_unregister((gdev))
@@ -680,6 +729,8 @@ static int gpiochip_setup_dev(struct gpio_device *gdev)
 	struct fwnode_handle *fwnode = dev_fwnode(&gdev->dev);
 	int ret;
 
+	device_initialize(&gdev->dev);
+
 	/*
 	 * If fwnode doesn't belong to another device, it's safe to clear its
 	 * initialized flag.
@@ -691,15 +742,12 @@ static int gpiochip_setup_dev(struct gpio_device *gdev)
 	if (ret)
 		return ret;
 
-	/* From this point, the .release() function cleans up gpio_device */
-	gdev->dev.release = gpiodev_release;
-
 	ret = gpiochip_sysfs_register(gdev);
 	if (ret)
 		goto err_remove_device;
 
 	dev_dbg(&gdev->dev, "registered GPIOs %d to %d on %s\n", gdev->base,
-		gdev->base + gdev->ngpio - 1, gdev->chip->label ? : "generic");
+		gdev->base + gdev->ngpio - 1, gdev->label);
 
 	return 0;
 
@@ -720,9 +768,6 @@ static void gpiochip_machine_hog(struct gpio_chip *gc, struct gpiod_hog *hog)
 		return;
 	}
 
-	if (test_bit(FLAG_IS_HOGGED, &desc->flags))
-		return;
-
 	rv = gpiod_hog(desc, hog->line_name, hog->lflags, hog->dflags);
 	if (rv)
 		gpiod_err(desc, "%s: unable to hog GPIO line (%s:%u): %d\n",
@@ -748,7 +793,10 @@ static void gpiochip_setup_devs(void)
 	struct gpio_device *gdev;
 	int ret;
 
-	list_for_each_entry(gdev, &gpio_devices, list) {
+	guard(srcu)(&gpio_devices_srcu);
+
+	list_for_each_entry_srcu(gdev, &gpio_devices, list,
+				 srcu_read_lock_held(&gpio_devices_srcu)) {
 		ret = gpiochip_setup_dev(gdev);
 		if (ret)
 			dev_err(&gdev->dev,
@@ -813,8 +861,7 @@ int gpiochip_add_data_with_key(struct gpio_chip *gc, void *data,
 			       struct lock_class_key *request_key)
 {
 	struct gpio_device *gdev;
-	unsigned long flags;
-	unsigned int i;
+	unsigned int desc_index;
 	int base = 0;
 	int ret = 0;
 
@@ -825,9 +872,11 @@ int gpiochip_add_data_with_key(struct gpio_chip *gc, void *data,
 	gdev = kzalloc(sizeof(*gdev), GFP_KERNEL);
 	if (!gdev)
 		return -ENOMEM;
+
+	gdev->dev.type = &gpio_dev_type;
 	gdev->dev.bus = &gpio_bus_type;
 	gdev->dev.parent = gc->parent;
-	gdev->chip = gc;
+	rcu_assign_pointer(gdev->chip, gc);
 
 	gc->gpiodev = gdev;
 	gpiochip_set_data(gc, data);
@@ -851,7 +900,6 @@ int gpiochip_add_data_with_key(struct gpio_chip *gc, void *data,
 	if (ret)
 		goto err_free_ida;
 
-	device_initialize(&gdev->dev);
 	if (gc->parent && gc->parent->driver)
 		gdev->owner = gc->parent->driver->owner;
 	else if (gc->owner)
@@ -877,53 +925,55 @@ int gpiochip_add_data_with_key(struct gpio_chip *gc, void *data,
 	}
 
 	gdev->ngpio = gc->ngpio;
+	gdev->can_sleep = gc->can_sleep;
 
-	spin_lock_irqsave(&gpio_lock, flags);
-
-	/*
-	 * TODO: this allocates a Linux GPIO number base in the global
-	 * GPIO numberspace for this chip. In the long run we want to
-	 * get *rid* of this numberspace and use only descriptors, but
-	 * it may be a pipe dream. It will not happen before we get rid
-	 * of the sysfs interface anyways.
-	 */
-	base = gc->base;
-	if (base < 0) {
-		base = gpiochip_find_base_unlocked(gc->ngpio);
-		if (base < 0) {
-			spin_unlock_irqrestore(&gpio_lock, flags);
-			ret = base;
-			base = 0;
-			goto err_free_label;
-		}
+	scoped_guard(mutex, &gpio_devices_lock) {
 		/*
-		 * TODO: it should not be necessary to reflect the assigned
-		 * base outside of the GPIO subsystem. Go over drivers and
-		 * see if anyone makes use of this, else drop this and assign
-		 * a poison instead.
+		 * TODO: this allocates a Linux GPIO number base in the global
+		 * GPIO numberspace for this chip. In the long run we want to
+		 * get *rid* of this numberspace and use only descriptors, but
+		 * it may be a pipe dream. It will not happen before we get rid
+		 * of the sysfs interface anyways.
 		 */
-		gc->base = base;
-	} else {
-		dev_warn(&gdev->dev,
-			 "Static allocation of GPIO base is deprecated, use dynamic allocation.\n");
-	}
-	gdev->base = base;
+		base = gc->base;
+		if (base < 0) {
+			base = gpiochip_find_base_unlocked(gc->ngpio);
+			if (base < 0) {
+				ret = base;
+				base = 0;
+				goto err_free_label;
+			}
 
-	ret = gpiodev_add_to_list_unlocked(gdev);
-	if (ret) {
-		spin_unlock_irqrestore(&gpio_lock, flags);
-		chip_err(gc, "GPIO integer space overlap, cannot add chip\n");
-		goto err_free_label;
-	}
+			/*
+			 * TODO: it should not be necessary to reflect the
+			 * assigned base outside of the GPIO subsystem. Go over
+			 * drivers and see if anyone makes use of this, else
+			 * drop this and assign a poison instead.
+			 */
+			gc->base = base;
+		} else {
+			dev_warn(&gdev->dev,
+				 "Static allocation of GPIO base is deprecated, use dynamic allocation.\n");
+		}
+
+		gdev->base = base;
 
-	for (i = 0; i < gc->ngpio; i++)
-		gdev->descs[i].gdev = gdev;
+		ret = gpiodev_add_to_list_unlocked(gdev);
+		if (ret) {
+			chip_err(gc, "GPIO integer space overlap, cannot add chip\n");
+			goto err_free_label;
+		}
+	}
 
-	spin_unlock_irqrestore(&gpio_lock, flags);
+	for (desc_index = 0; desc_index < gc->ngpio; desc_index++)
+		gdev->descs[desc_index].gdev = gdev;
 
 	BLOCKING_INIT_NOTIFIER_HEAD(&gdev->line_state_notifier);
 	BLOCKING_INIT_NOTIFIER_HEAD(&gdev->device_notifier);
-	init_rwsem(&gdev->sem);
+
+	ret = init_srcu_struct(&gdev->srcu);
+	if (ret)
+		goto err_remove_from_list;
 
 #ifdef CONFIG_PINCTRL
 	INIT_LIST_HEAD(&gdev->pin_ranges);
@@ -932,32 +982,36 @@ int gpiochip_add_data_with_key(struct gpio_chip *gc, void *data,
 	if (gc->names) {
 		ret = gpiochip_set_desc_names(gc);
 		if (ret)
-			goto err_remove_from_list;
+			goto err_cleanup_gdev_srcu;
 	}
 	ret = gpiochip_set_names(gc);
 	if (ret)
-		goto err_remove_from_list;
+		goto err_cleanup_gdev_srcu;
 
 	ret = gpiochip_init_valid_mask(gc);
 	if (ret)
-		goto err_remove_from_list;
+		goto err_cleanup_gdev_srcu;
 
-	ret = of_gpiochip_add(gc);
-	if (ret)
-		goto err_free_gpiochip_mask;
+	for (desc_index = 0; desc_index < gc->ngpio; desc_index++) {
+		struct gpio_desc *desc = &gdev->descs[desc_index];
 
-	for (i = 0; i < gc->ngpio; i++) {
-		struct gpio_desc *desc = &gdev->descs[i];
+		ret = init_srcu_struct(&desc->srcu);
+		if (ret)
+			goto err_cleanup_desc_srcu;
 
-		if (gc->get_direction && gpiochip_line_is_valid(gc, i)) {
+		if (gc->get_direction && gpiochip_line_is_valid(gc, desc_index)) {
 			assign_bit(FLAG_IS_OUT,
-				   &desc->flags, !gc->get_direction(gc, i));
+				   &desc->flags, !gc->get_direction(gc, desc_index));
 		} else {
 			assign_bit(FLAG_IS_OUT,
 				   &desc->flags, !gc->direction_input);
 		}
 	}
 
+	ret = of_gpiochip_add(gc);
+	if (ret)
+		goto err_cleanup_desc_srcu;
+
 	ret = gpiochip_add_pin_ranges(gc);
 	if (ret)
 		goto err_remove_of_chip;
@@ -1003,12 +1057,16 @@ err_free_hogs:
 	gpiochip_remove_pin_ranges(gc);
 err_remove_of_chip:
 	of_gpiochip_remove(gc);
-err_free_gpiochip_mask:
+err_cleanup_desc_srcu:
+	while (desc_index--)
+		cleanup_srcu_struct(&gdev->descs[desc_index].srcu);
 	gpiochip_free_valid_mask(gc);
+err_cleanup_gdev_srcu:
+	cleanup_srcu_struct(&gdev->srcu);
 err_remove_from_list:
-	spin_lock_irqsave(&gpio_lock, flags);
-	list_del(&gdev->list);
-	spin_unlock_irqrestore(&gpio_lock, flags);
+	scoped_guard(mutex, &gpio_devices_lock)
+		list_del_rcu(&gdev->list);
+	synchronize_srcu(&gpio_devices_srcu);
 	if (gdev->dev.release) {
 		/* release() has been registered by gpiochip_setup_dev() */
 		gpio_device_put(gdev);
@@ -1044,16 +1102,18 @@ EXPORT_SYMBOL_GPL(gpiochip_add_data_with_key);
 void gpiochip_remove(struct gpio_chip *gc)
 {
 	struct gpio_device *gdev = gc->gpiodev;
-	unsigned long flags;
-	unsigned int i;
-
-	down_write(&gdev->sem);
 
 	/* FIXME: should the legacy sysfs handling be moved to gpio_device? */
 	gpiochip_sysfs_unregister(gdev);
 	gpiochip_free_hogs(gc);
+
+	scoped_guard(mutex, &gpio_devices_lock)
+		list_del_rcu(&gdev->list);
+	synchronize_srcu(&gpio_devices_srcu);
+
 	/* Numb the device, cancelling all outstanding operations */
-	gdev->chip = NULL;
+	rcu_assign_pointer(gdev->chip, NULL);
+	synchronize_srcu(&gdev->srcu);
 	gpiochip_irqchip_remove(gc);
 	acpi_gpiochip_remove(gc);
 	of_gpiochip_remove(gc);
@@ -1065,20 +1125,6 @@ void gpiochip_remove(struct gpio_chip *gc)
 	 */
 	gpiochip_set_data(gc, NULL);
 
-	spin_lock_irqsave(&gpio_lock, flags);
-	for (i = 0; i < gdev->ngpio; i++) {
-		if (test_bit(FLAG_REQUESTED, &gdev->descs[i].flags))
-			break;
-	}
-	spin_unlock_irqrestore(&gpio_lock, flags);
-
-	if (i != gdev->ngpio)
-		dev_crit(&gdev->dev,
-			 "REMOVING GPIOCHIP WITH GPIOS STILL REQUESTED\n");
-
-	scoped_guard(spinlock_irqsave, &gpio_lock)
-		list_del(&gdev->list);
-
 	/*
 	 * The gpiochip side puts its use of the device to rest here:
 	 * if there are no userspace clients, the chardev and device will
@@ -1086,7 +1132,6 @@ void gpiochip_remove(struct gpio_chip *gc)
 	 * gone.
 	 */
 	gcdev_unregister(gdev);
-	up_write(&gdev->sem);
 	gpio_device_put(gdev);
 }
 EXPORT_SYMBOL_GPL(gpiochip_remove);
@@ -1112,11 +1157,12 @@ EXPORT_SYMBOL_GPL(gpiochip_remove);
  * If the function returns non-NULL, the returned reference must be freed by
  * the caller using gpio_device_put().
  */
-struct gpio_device *gpio_device_find(void *data,
+struct gpio_device *gpio_device_find(const void *data,
 				     int (*match)(struct gpio_chip *gc,
-						  void *data))
+						  const void *data))
 {
 	struct gpio_device *gdev;
+	struct gpio_chip *gc;
 
 	/*
 	 * Not yet but in the future the spinlock below will become a mutex.
@@ -1125,10 +1171,15 @@ struct gpio_device *gpio_device_find(void *data,
 	 */
 	might_sleep();
 
-	guard(spinlock_irqsave)(&gpio_lock);
+	guard(srcu)(&gpio_devices_srcu);
 
-	list_for_each_entry(gdev, &gpio_devices, list) {
-		if (gdev->chip && match(gdev->chip, data))
+	list_for_each_entry_srcu(gdev, &gpio_devices, list,
+				 srcu_read_lock_held(&gpio_devices_srcu)) {
+		guard(srcu)(&gdev->srcu);
+
+		gc = srcu_dereference(gdev->chip, &gdev->srcu);
+
+		if (gc && match(gc, data))
 			return gpio_device_get(gdev);
 	}
 
@@ -1136,7 +1187,7 @@ struct gpio_device *gpio_device_find(void *data,
 }
 EXPORT_SYMBOL_GPL(gpio_device_find);
 
-static int gpio_chip_match_by_label(struct gpio_chip *gc, void *label)
+static int gpio_chip_match_by_label(struct gpio_chip *gc, const void *label)
 {
 	return gc->label && !strcmp(gc->label, label);
 }
@@ -1156,7 +1207,7 @@ struct gpio_device *gpio_device_find_by_label(const char *label)
 }
 EXPORT_SYMBOL_GPL(gpio_device_find_by_label);
 
-static int gpio_chip_match_by_fwnode(struct gpio_chip *gc, void *fwnode)
+static int gpio_chip_match_by_fwnode(struct gpio_chip *gc, const void *fwnode)
 {
 	return device_match_fwnode(&gc->gpiodev->dev, fwnode);
 }
@@ -1254,8 +1305,8 @@ static void gpiochip_irqchip_free_valid_mask(struct gpio_chip *gc)
 	gpiochip_free_mask(&gc->irq.valid_mask);
 }
 
-bool gpiochip_irqchip_irq_valid(const struct gpio_chip *gc,
-				unsigned int offset)
+static bool gpiochip_irqchip_irq_valid(const struct gpio_chip *gc,
+				       unsigned int offset)
 {
 	if (!gpiochip_line_is_valid(gc, offset))
 		return false;
@@ -1264,7 +1315,6 @@ bool gpiochip_irqchip_irq_valid(const struct gpio_chip *gc,
 		return true;
 	return test_bit(offset, gc->irq.valid_mask);
 }
-EXPORT_SYMBOL_GPL(gpiochip_irqchip_irq_valid);
 
 #ifdef CONFIG_IRQ_DOMAIN_HIERARCHY
 
@@ -1439,6 +1489,43 @@ static unsigned int gpiochip_child_offset_to_irq_noop(struct gpio_chip *gc,
 	return offset;
 }
 
+/**
+ * gpiochip_irq_domain_activate() - Lock a GPIO to be used as an IRQ
+ * @domain: The IRQ domain used by this IRQ chip
+ * @data: Outermost irq_data associated with the IRQ
+ * @reserve: If set, only reserve an interrupt vector instead of assigning one
+ *
+ * This function is a wrapper that calls gpiochip_lock_as_irq() and is to be
+ * used as the activate function for the &struct irq_domain_ops. The host_data
+ * for the IRQ domain must be the &struct gpio_chip.
+ */
+static int gpiochip_irq_domain_activate(struct irq_domain *domain,
+					struct irq_data *data, bool reserve)
+{
+	struct gpio_chip *gc = domain->host_data;
+	unsigned int hwirq = irqd_to_hwirq(data);
+
+	return gpiochip_lock_as_irq(gc, hwirq);
+}
+
+/**
+ * gpiochip_irq_domain_deactivate() - Unlock a GPIO used as an IRQ
+ * @domain: The IRQ domain used by this IRQ chip
+ * @data: Outermost irq_data associated with the IRQ
+ *
+ * This function is a wrapper that will call gpiochip_unlock_as_irq() and is to
+ * be used as the deactivate function for the &struct irq_domain_ops. The
+ * host_data for the IRQ domain must be the &struct gpio_chip.
+ */
+static void gpiochip_irq_domain_deactivate(struct irq_domain *domain,
+					   struct irq_data *data)
+{
+	struct gpio_chip *gc = domain->host_data;
+	unsigned int hwirq = irqd_to_hwirq(data);
+
+	return gpiochip_unlock_as_irq(gc, hwirq);
+}
+
 static void gpiochip_hierarchy_setup_domain_ops(struct irq_domain_ops *ops)
 {
 	ops->activate = gpiochip_irq_domain_activate;
@@ -1556,7 +1643,8 @@ static bool gpiochip_hierarchy_is_hierarchical(struct gpio_chip *gc)
  * gpiochip by assigning the gpiochip as chip data, and using the irqchip
  * stored inside the gpiochip.
  */
-int gpiochip_irq_map(struct irq_domain *d, unsigned int irq, irq_hw_number_t hwirq)
+static int gpiochip_irq_map(struct irq_domain *d, unsigned int irq,
+			    irq_hw_number_t hwirq)
 {
 	struct gpio_chip *gc = d->host_data;
 	int ret = 0;
@@ -1593,9 +1681,8 @@ int gpiochip_irq_map(struct irq_domain *d, unsigned int irq, irq_hw_number_t hwi
 
 	return 0;
 }
-EXPORT_SYMBOL_GPL(gpiochip_irq_map);
 
-void gpiochip_irq_unmap(struct irq_domain *d, unsigned int irq)
+static void gpiochip_irq_unmap(struct irq_domain *d, unsigned int irq)
 {
 	struct gpio_chip *gc = d->host_data;
 
@@ -1604,7 +1691,6 @@ void gpiochip_irq_unmap(struct irq_domain *d, unsigned int irq)
 	irq_set_chip_and_handler(irq, NULL, NULL);
 	irq_set_chip_data(irq, NULL);
 }
-EXPORT_SYMBOL_GPL(gpiochip_irq_unmap);
 
 static const struct irq_domain_ops gpiochip_domain_ops = {
 	.map	= gpiochip_irq_map,
@@ -1626,50 +1712,6 @@ static struct irq_domain *gpiochip_simple_create_domain(struct gpio_chip *gc)
 	return domain;
 }
 
-/*
- * TODO: move these activate/deactivate in under the hierarchicial
- * irqchip implementation as static once SPMI and SSBI (all external
- * users) are phased over.
- */
-/**
- * gpiochip_irq_domain_activate() - Lock a GPIO to be used as an IRQ
- * @domain: The IRQ domain used by this IRQ chip
- * @data: Outermost irq_data associated with the IRQ
- * @reserve: If set, only reserve an interrupt vector instead of assigning one
- *
- * This function is a wrapper that calls gpiochip_lock_as_irq() and is to be
- * used as the activate function for the &struct irq_domain_ops. The host_data
- * for the IRQ domain must be the &struct gpio_chip.
- */
-int gpiochip_irq_domain_activate(struct irq_domain *domain,
-				 struct irq_data *data, bool reserve)
-{
-	struct gpio_chip *gc = domain->host_data;
-	unsigned int hwirq = irqd_to_hwirq(data);
-
-	return gpiochip_lock_as_irq(gc, hwirq);
-}
-EXPORT_SYMBOL_GPL(gpiochip_irq_domain_activate);
-
-/**
- * gpiochip_irq_domain_deactivate() - Unlock a GPIO used as an IRQ
- * @domain: The IRQ domain used by this IRQ chip
- * @data: Outermost irq_data associated with the IRQ
- *
- * This function is a wrapper that will call gpiochip_unlock_as_irq() and is to
- * be used as the deactivate function for the &struct irq_domain_ops. The
- * host_data for the IRQ domain must be the &struct gpio_chip.
- */
-void gpiochip_irq_domain_deactivate(struct irq_domain *domain,
-				    struct irq_data *data)
-{
-	struct gpio_chip *gc = domain->host_data;
-	unsigned int hwirq = irqd_to_hwirq(data);
-
-	return gpiochip_unlock_as_irq(gc, hwirq);
-}
-EXPORT_SYMBOL_GPL(gpiochip_irq_domain_deactivate);
-
 static int gpiochip_to_irq(struct gpio_chip *gc, unsigned int offset)
 {
 	struct irq_domain *domain = gc->irq.domain;
@@ -2189,58 +2231,41 @@ EXPORT_SYMBOL_GPL(gpiochip_remove_pin_ranges);
  */
 static int gpiod_request_commit(struct gpio_desc *desc, const char *label)
 {
-	struct gpio_chip *gc = desc->gdev->chip;
-	unsigned long flags;
 	unsigned int offset;
 	int ret;
 
-	if (label) {
-		label = kstrdup_const(label, GFP_KERNEL);
-		if (!label)
-			return -ENOMEM;
-	}
+	CLASS(gpio_chip_guard, guard)(desc);
+	if (!guard.gc)
+		return -ENODEV;
 
-	spin_lock_irqsave(&gpio_lock, flags);
+	if (test_and_set_bit(FLAG_REQUESTED, &desc->flags))
+		return -EBUSY;
 
 	/* NOTE:  gpio_request() can be called in early boot,
 	 * before IRQs are enabled, for non-sleeping (SOC) GPIOs.
 	 */
 
-	if (test_and_set_bit(FLAG_REQUESTED, &desc->flags) == 0) {
-		desc_set_label(desc, label ? : "?");
-	} else {
-		ret = -EBUSY;
-		goto out_free_unlock;
-	}
-
-	if (gc->request) {
-		/* gc->request may sleep */
-		spin_unlock_irqrestore(&gpio_lock, flags);
+	if (guard.gc->request) {
 		offset = gpio_chip_hwgpio(desc);
-		if (gpiochip_line_is_valid(gc, offset))
-			ret = gc->request(gc, offset);
+		if (gpiochip_line_is_valid(guard.gc, offset))
+			ret = guard.gc->request(guard.gc, offset);
 		else
 			ret = -EINVAL;
-		spin_lock_irqsave(&gpio_lock, flags);
-
-		if (ret) {
-			desc_set_label(desc, NULL);
-			clear_bit(FLAG_REQUESTED, &desc->flags);
-			goto out_free_unlock;
-		}
+		if (ret)
+			goto out_clear_bit;
 	}
-	if (gc->get_direction) {
-		/* gc->get_direction may sleep */
-		spin_unlock_irqrestore(&gpio_lock, flags);
+
+	if (guard.gc->get_direction)
 		gpiod_get_direction(desc);
-		spin_lock_irqsave(&gpio_lock, flags);
-	}
-	spin_unlock_irqrestore(&gpio_lock, flags);
+
+	ret = desc_set_label(desc, label ? : "?");
+	if (ret)
+		goto out_clear_bit;
+
 	return 0;
 
-out_free_unlock:
-	spin_unlock_irqrestore(&gpio_lock, flags);
-	kfree_const(label);
+out_clear_bit:
+	clear_bit(FLAG_REQUESTED, &desc->flags);
 	return ret;
 }
 
@@ -2254,19 +2279,12 @@ static int validate_desc(const struct gpio_desc *desc, const char *func)
 {
 	if (!desc)
 		return 0;
+
 	if (IS_ERR(desc)) {
 		pr_warn("%s: invalid GPIO (errorpointer)\n", func);
 		return PTR_ERR(desc);
 	}
-	if (!desc->gdev) {
-		pr_warn("%s: invalid GPIO (no device)\n", func);
-		return -EINVAL;
-	}
-	if (!desc->gdev->chip) {
-		dev_warn(&desc->gdev->dev,
-			 "%s: backing chip is gone\n", func);
-		return 0;
-	}
+
 	return 1;
 }
 
@@ -2302,60 +2320,45 @@ int gpiod_request(struct gpio_desc *desc, const char *label)
 	return ret;
 }
 
-static bool gpiod_free_commit(struct gpio_desc *desc)
+static void gpiod_free_commit(struct gpio_desc *desc)
 {
-	struct gpio_chip *gc;
 	unsigned long flags;
-	bool ret = false;
 
 	might_sleep();
 
-	spin_lock_irqsave(&gpio_lock, flags);
+	CLASS(gpio_chip_guard, guard)(desc);
 
-	gc = desc->gdev->chip;
-	if (gc && test_bit(FLAG_REQUESTED, &desc->flags)) {
-		if (gc->free) {
-			spin_unlock_irqrestore(&gpio_lock, flags);
-			might_sleep_if(gc->can_sleep);
-			gc->free(gc, gpio_chip_hwgpio(desc));
-			spin_lock_irqsave(&gpio_lock, flags);
-		}
-		kfree_const(desc->label);
-		desc_set_label(desc, NULL);
-		clear_bit(FLAG_ACTIVE_LOW, &desc->flags);
-		clear_bit(FLAG_REQUESTED, &desc->flags);
-		clear_bit(FLAG_OPEN_DRAIN, &desc->flags);
-		clear_bit(FLAG_OPEN_SOURCE, &desc->flags);
-		clear_bit(FLAG_PULL_UP, &desc->flags);
-		clear_bit(FLAG_PULL_DOWN, &desc->flags);
-		clear_bit(FLAG_BIAS_DISABLE, &desc->flags);
-		clear_bit(FLAG_EDGE_RISING, &desc->flags);
-		clear_bit(FLAG_EDGE_FALLING, &desc->flags);
-		clear_bit(FLAG_IS_HOGGED, &desc->flags);
+	flags = READ_ONCE(desc->flags);
+
+	if (guard.gc && test_bit(FLAG_REQUESTED, &flags)) {
+		if (guard.gc->free)
+			guard.gc->free(guard.gc, gpio_chip_hwgpio(desc));
+
+		clear_bit(FLAG_ACTIVE_LOW, &flags);
+		clear_bit(FLAG_REQUESTED, &flags);
+		clear_bit(FLAG_OPEN_DRAIN, &flags);
+		clear_bit(FLAG_OPEN_SOURCE, &flags);
+		clear_bit(FLAG_PULL_UP, &flags);
+		clear_bit(FLAG_PULL_DOWN, &flags);
+		clear_bit(FLAG_BIAS_DISABLE, &flags);
+		clear_bit(FLAG_EDGE_RISING, &flags);
+		clear_bit(FLAG_EDGE_FALLING, &flags);
+		clear_bit(FLAG_IS_HOGGED, &flags);
 #ifdef CONFIG_OF_DYNAMIC
-		desc->hog = NULL;
+		WRITE_ONCE(desc->hog, NULL);
 #endif
-		ret = true;
-	}
-
-	spin_unlock_irqrestore(&gpio_lock, flags);
-	gpiod_line_state_notify(desc, GPIOLINE_CHANGED_RELEASED);
+		desc_set_label(desc, NULL);
+		WRITE_ONCE(desc->flags, flags);
 
-	return ret;
+		gpiod_line_state_notify(desc, GPIOLINE_CHANGED_RELEASED);
+	}
 }
 
 void gpiod_free(struct gpio_desc *desc)
 {
-	/*
-	 * We must not use VALIDATE_DESC_VOID() as the underlying gdev->chip
-	 * may already be NULL but we still want to put the references.
-	 */
-	if (!desc)
-		return;
-
-	if (!gpiod_free_commit(desc))
-		WARN_ON(1);
+	VALIDATE_DESC_VOID(desc);
 
+	gpiod_free_commit(desc);
 	module_put(desc->gdev->owner);
 	gpio_device_put(desc->gdev);
 }
@@ -2381,20 +2384,12 @@ char *gpiochip_dup_line_label(struct gpio_chip *gc, unsigned int offset)
 	if (IS_ERR(desc))
 		return NULL;
 
-	guard(spinlock_irqsave)(&gpio_lock);
-
 	if (!test_bit(FLAG_REQUESTED, &desc->flags))
 		return NULL;
 
-	/*
-	 * FIXME: Once we mark gpiod_direction_input/output() and
-	 * gpiod_get_direction() with might_sleep(), we'll be able to protect
-	 * the GPIO descriptors with mutex (while value setting operations will
-	 * become lockless).
-	 *
-	 * Until this happens, this allocation needs to be atomic.
-	 */
-	label = kstrdup(desc->label, GFP_ATOMIC);
+	guard(srcu)(&desc->srcu);
+
+	label = kstrdup(gpiod_get_label(desc), GFP_KERNEL);
 	if (!label)
 		return ERR_PTR(-ENOMEM);
 
@@ -2489,11 +2484,14 @@ static int gpio_set_config_with_argument(struct gpio_desc *desc,
 					 enum pin_config_param mode,
 					 u32 argument)
 {
-	struct gpio_chip *gc = desc->gdev->chip;
 	unsigned long config;
 
+	CLASS(gpio_chip_guard, guard)(desc);
+	if (!guard.gc)
+		return -ENODEV;
+
 	config = pinconf_to_config_packed(mode, argument);
-	return gpio_do_set_config(gc, gpio_chip_hwgpio(desc), config);
+	return gpio_do_set_config(guard.gc, gpio_chip_hwgpio(desc), config);
 }
 
 static int gpio_set_config_with_argument_optional(struct gpio_desc *desc,
@@ -2527,13 +2525,16 @@ static int gpio_set_config(struct gpio_desc *desc, enum pin_config_param mode)
 static int gpio_set_bias(struct gpio_desc *desc)
 {
 	enum pin_config_param bias;
+	unsigned long flags;
 	unsigned int arg;
 
-	if (test_bit(FLAG_BIAS_DISABLE, &desc->flags))
+	flags = READ_ONCE(desc->flags);
+
+	if (test_bit(FLAG_BIAS_DISABLE, &flags))
 		bias = PIN_CONFIG_BIAS_DISABLE;
-	else if (test_bit(FLAG_PULL_UP, &desc->flags))
+	else if (test_bit(FLAG_PULL_UP, &flags))
 		bias = PIN_CONFIG_BIAS_PULL_UP;
-	else if (test_bit(FLAG_PULL_DOWN, &desc->flags))
+	else if (test_bit(FLAG_PULL_DOWN, &flags))
 		bias = PIN_CONFIG_BIAS_PULL_DOWN;
 	else
 		return 0;
@@ -2580,18 +2581,20 @@ int gpio_set_debounce_timeout(struct gpio_desc *desc, unsigned int debounce)
  */
 int gpiod_direction_input(struct gpio_desc *desc)
 {
-	struct gpio_chip *gc;
 	int ret = 0;
 
 	VALIDATE_DESC(desc);
-	gc = desc->gdev->chip;
+
+	CLASS(gpio_chip_guard, guard)(desc);
+	if (!guard.gc)
+		return -ENODEV;
 
 	/*
 	 * It is legal to have no .get() and .direction_input() specified if
 	 * the chip is output-only, but you can't specify .direction_input()
 	 * and not support the .get() operation, that doesn't make sense.
 	 */
-	if (!gc->get && gc->direction_input) {
+	if (!guard.gc->get && guard.gc->direction_input) {
 		gpiod_warn(desc,
 			   "%s: missing get() but have direction_input()\n",
 			   __func__);
@@ -2604,10 +2607,12 @@ int gpiod_direction_input(struct gpio_desc *desc)
 	 * direction (if .get_direction() is supported) else we silently
 	 * assume we are in input mode after this.
 	 */
-	if (gc->direction_input) {
-		ret = gc->direction_input(gc, gpio_chip_hwgpio(desc));
-	} else if (gc->get_direction &&
-		  (gc->get_direction(gc, gpio_chip_hwgpio(desc)) != 1)) {
+	if (guard.gc->direction_input) {
+		ret = guard.gc->direction_input(guard.gc,
+						gpio_chip_hwgpio(desc));
+	} else if (guard.gc->get_direction &&
+		  (guard.gc->get_direction(guard.gc,
+					   gpio_chip_hwgpio(desc)) != 1)) {
 		gpiod_warn(desc,
 			   "%s: missing direction_input() operation and line is output\n",
 			   __func__);
@@ -2626,28 +2631,31 @@ EXPORT_SYMBOL_GPL(gpiod_direction_input);
 
 static int gpiod_direction_output_raw_commit(struct gpio_desc *desc, int value)
 {
-	struct gpio_chip *gc = desc->gdev->chip;
-	int val = !!value;
-	int ret = 0;
+	int val = !!value, ret = 0;
+
+	CLASS(gpio_chip_guard, guard)(desc);
+	if (!guard.gc)
+		return -ENODEV;
 
 	/*
 	 * It's OK not to specify .direction_output() if the gpiochip is
 	 * output-only, but if there is then not even a .set() operation it
 	 * is pretty tricky to drive the output line.
 	 */
-	if (!gc->set && !gc->direction_output) {
+	if (!guard.gc->set && !guard.gc->direction_output) {
 		gpiod_warn(desc,
 			   "%s: missing set() and direction_output() operations\n",
 			   __func__);
 		return -EIO;
 	}
 
-	if (gc->direction_output) {
-		ret = gc->direction_output(gc, gpio_chip_hwgpio(desc), val);
+	if (guard.gc->direction_output) {
+		ret = guard.gc->direction_output(guard.gc,
+						 gpio_chip_hwgpio(desc), val);
 	} else {
 		/* Check that we are in output mode if we can */
-		if (gc->get_direction &&
-		    gc->get_direction(gc, gpio_chip_hwgpio(desc))) {
+		if (guard.gc->get_direction &&
+		    guard.gc->get_direction(guard.gc, gpio_chip_hwgpio(desc))) {
 			gpiod_warn(desc,
 				"%s: missing direction_output() operation\n",
 				__func__);
@@ -2657,7 +2665,7 @@ static int gpiod_direction_output_raw_commit(struct gpio_desc *desc, int value)
 		 * If we can't actively set the direction, we are some
 		 * output-only chip, so just drive the output as desired.
 		 */
-		gc->set(gc, gpio_chip_hwgpio(desc), val);
+		guard.gc->set(guard.gc, gpio_chip_hwgpio(desc), val);
 	}
 
 	if (!ret)
@@ -2699,24 +2707,28 @@ EXPORT_SYMBOL_GPL(gpiod_direction_output_raw);
  */
 int gpiod_direction_output(struct gpio_desc *desc, int value)
 {
+	unsigned long flags;
 	int ret;
 
 	VALIDATE_DESC(desc);
-	if (test_bit(FLAG_ACTIVE_LOW, &desc->flags))
+
+	flags = READ_ONCE(desc->flags);
+
+	if (test_bit(FLAG_ACTIVE_LOW, &flags))
 		value = !value;
 	else
 		value = !!value;
 
 	/* GPIOs used for enabled IRQs shall not be set as output */
-	if (test_bit(FLAG_USED_AS_IRQ, &desc->flags) &&
-	    test_bit(FLAG_IRQ_IS_ENABLED, &desc->flags)) {
+	if (test_bit(FLAG_USED_AS_IRQ, &flags) &&
+	    test_bit(FLAG_IRQ_IS_ENABLED, &flags)) {
 		gpiod_err(desc,
 			  "%s: tried to set a GPIO tied to an IRQ as output\n",
 			  __func__);
 		return -EIO;
 	}
 
-	if (test_bit(FLAG_OPEN_DRAIN, &desc->flags)) {
+	if (test_bit(FLAG_OPEN_DRAIN, &flags)) {
 		/* First see if we can enable open drain in hardware */
 		ret = gpio_set_config(desc, PIN_CONFIG_DRIVE_OPEN_DRAIN);
 		if (!ret)
@@ -2726,7 +2738,7 @@ int gpiod_direction_output(struct gpio_desc *desc, int value)
 			ret = gpiod_direction_input(desc);
 			goto set_output_flag;
 		}
-	} else if (test_bit(FLAG_OPEN_SOURCE, &desc->flags)) {
+	} else if (test_bit(FLAG_OPEN_SOURCE, &flags)) {
 		ret = gpio_set_config(desc, PIN_CONFIG_DRIVE_OPEN_SOURCE);
 		if (!ret)
 			goto set_output_value;
@@ -2769,17 +2781,20 @@ EXPORT_SYMBOL_GPL(gpiod_direction_output);
 int gpiod_enable_hw_timestamp_ns(struct gpio_desc *desc, unsigned long flags)
 {
 	int ret = 0;
-	struct gpio_chip *gc;
 
 	VALIDATE_DESC(desc);
 
-	gc = desc->gdev->chip;
-	if (!gc->en_hw_timestamp) {
+	CLASS(gpio_chip_guard, guard)(desc);
+	if (!guard.gc)
+		return -ENODEV;
+
+	if (!guard.gc->en_hw_timestamp) {
 		gpiod_warn(desc, "%s: hw ts not supported\n", __func__);
 		return -ENOTSUPP;
 	}
 
-	ret = gc->en_hw_timestamp(gc, gpio_chip_hwgpio(desc), flags);
+	ret = guard.gc->en_hw_timestamp(guard.gc,
+					gpio_chip_hwgpio(desc), flags);
 	if (ret)
 		gpiod_warn(desc, "%s: hw ts request failed\n", __func__);
 
@@ -2798,17 +2813,20 @@ EXPORT_SYMBOL_GPL(gpiod_enable_hw_timestamp_ns);
 int gpiod_disable_hw_timestamp_ns(struct gpio_desc *desc, unsigned long flags)
 {
 	int ret = 0;
-	struct gpio_chip *gc;
 
 	VALIDATE_DESC(desc);
 
-	gc = desc->gdev->chip;
-	if (!gc->dis_hw_timestamp) {
+	CLASS(gpio_chip_guard, guard)(desc);
+	if (!guard.gc)
+		return -ENODEV;
+
+	if (!guard.gc->dis_hw_timestamp) {
 		gpiod_warn(desc, "%s: hw ts not supported\n", __func__);
 		return -ENOTSUPP;
 	}
 
-	ret = gc->dis_hw_timestamp(gc, gpio_chip_hwgpio(desc), flags);
+	ret = guard.gc->dis_hw_timestamp(guard.gc, gpio_chip_hwgpio(desc),
+					 flags);
 	if (ret)
 		gpiod_warn(desc, "%s: hw ts release failed\n", __func__);
 
@@ -2827,12 +2845,13 @@ EXPORT_SYMBOL_GPL(gpiod_disable_hw_timestamp_ns);
  */
 int gpiod_set_config(struct gpio_desc *desc, unsigned long config)
 {
-	struct gpio_chip *gc;
-
 	VALIDATE_DESC(desc);
-	gc = desc->gdev->chip;
 
-	return gpio_do_set_config(gc, gpio_chip_hwgpio(desc), config);
+	CLASS(gpio_chip_guard, guard)(desc);
+	if (!guard.gc)
+		return -ENODEV;
+
+	return gpio_do_set_config(guard.gc, gpio_chip_hwgpio(desc), config);
 }
 EXPORT_SYMBOL_GPL(gpiod_set_config);
 
@@ -2930,10 +2949,19 @@ static int gpio_chip_get_value(struct gpio_chip *gc, const struct gpio_desc *des
 
 static int gpiod_get_raw_value_commit(const struct gpio_desc *desc)
 {
+	struct gpio_device *gdev;
 	struct gpio_chip *gc;
 	int value;
 
-	gc = desc->gdev->chip;
+	/* FIXME Unable to use gpio_chip_guard due to const desc. */
+	gdev = desc->gdev;
+
+	guard(srcu)(&gdev->srcu);
+
+	gc = srcu_dereference(gdev->chip, &gdev->srcu);
+	if (!gc)
+		return -ENODEV;
+
 	value = gpio_chip_get_value(gc, desc);
 	value = value < 0 ? value : !!value;
 	trace_gpio_value(desc_to_gpio(desc), 1, value);
@@ -2959,6 +2987,14 @@ static int gpio_chip_get_multiple(struct gpio_chip *gc,
 	return -EIO;
 }
 
+/* The 'other' chip must be protected with its GPIO device's SRCU. */
+static bool gpio_device_chip_cmp(struct gpio_device *gdev, struct gpio_chip *gc)
+{
+	guard(srcu)(&gdev->srcu);
+
+	return gc == srcu_dereference(gdev->chip, &gdev->srcu);
+}
+
 int gpiod_get_array_value_complex(bool raw, bool can_sleep,
 				  unsigned int array_size,
 				  struct gpio_desc **desc_array,
@@ -2996,33 +3032,36 @@ int gpiod_get_array_value_complex(bool raw, bool can_sleep,
 	}
 
 	while (i < array_size) {
-		struct gpio_chip *gc = desc_array[i]->gdev->chip;
 		DECLARE_BITMAP(fastpath_mask, FASTPATH_NGPIO);
 		DECLARE_BITMAP(fastpath_bits, FASTPATH_NGPIO);
 		unsigned long *mask, *bits;
 		int first, j;
 
-		if (likely(gc->ngpio <= FASTPATH_NGPIO)) {
+		CLASS(gpio_chip_guard, guard)(desc_array[i]);
+		if (!guard.gc)
+			return -ENODEV;
+
+		if (likely(guard.gc->ngpio <= FASTPATH_NGPIO)) {
 			mask = fastpath_mask;
 			bits = fastpath_bits;
 		} else {
 			gfp_t flags = can_sleep ? GFP_KERNEL : GFP_ATOMIC;
 
-			mask = bitmap_alloc(gc->ngpio, flags);
+			mask = bitmap_alloc(guard.gc->ngpio, flags);
 			if (!mask)
 				return -ENOMEM;
 
-			bits = bitmap_alloc(gc->ngpio, flags);
+			bits = bitmap_alloc(guard.gc->ngpio, flags);
 			if (!bits) {
 				bitmap_free(mask);
 				return -ENOMEM;
 			}
 		}
 
-		bitmap_zero(mask, gc->ngpio);
+		bitmap_zero(mask, guard.gc->ngpio);
 
 		if (!can_sleep)
-			WARN_ON(gc->can_sleep);
+			WARN_ON(guard.gc->can_sleep);
 
 		/* collect all inputs belonging to the same chip */
 		first = i;
@@ -3037,9 +3076,9 @@ int gpiod_get_array_value_complex(bool raw, bool can_sleep,
 				i = find_next_zero_bit(array_info->get_mask,
 						       array_size, i);
 		} while ((i < array_size) &&
-			 (desc_array[i]->gdev->chip == gc));
+			 gpio_device_chip_cmp(desc_array[i]->gdev, guard.gc));
 
-		ret = gpio_chip_get_multiple(gc, mask, bits);
+		ret = gpio_chip_get_multiple(guard.gc, mask, bits);
 		if (ret) {
 			if (mask != fastpath_mask)
 				bitmap_free(mask);
@@ -3086,7 +3125,7 @@ int gpiod_get_raw_value(const struct gpio_desc *desc)
 {
 	VALIDATE_DESC(desc);
 	/* Should be using gpiod_get_raw_value_cansleep() */
-	WARN_ON(desc->gdev->chip->can_sleep);
+	WARN_ON(desc->gdev->can_sleep);
 	return gpiod_get_raw_value_commit(desc);
 }
 EXPORT_SYMBOL_GPL(gpiod_get_raw_value);
@@ -3107,7 +3146,7 @@ int gpiod_get_value(const struct gpio_desc *desc)
 
 	VALIDATE_DESC(desc);
 	/* Should be using gpiod_get_value_cansleep() */
-	WARN_ON(desc->gdev->chip->can_sleep);
+	WARN_ON(desc->gdev->can_sleep);
 
 	value = gpiod_get_raw_value_commit(desc);
 	if (value < 0)
@@ -3180,14 +3219,16 @@ EXPORT_SYMBOL_GPL(gpiod_get_array_value);
  */
 static void gpio_set_open_drain_value_commit(struct gpio_desc *desc, bool value)
 {
-	int ret = 0;
-	struct gpio_chip *gc = desc->gdev->chip;
-	int offset = gpio_chip_hwgpio(desc);
+	int ret = 0, offset = gpio_chip_hwgpio(desc);
+
+	CLASS(gpio_chip_guard, guard)(desc);
+	if (!guard.gc)
+		return;
 
 	if (value) {
-		ret = gc->direction_input(gc, offset);
+		ret = guard.gc->direction_input(guard.gc, offset);
 	} else {
-		ret = gc->direction_output(gc, offset, 0);
+		ret = guard.gc->direction_output(guard.gc, offset, 0);
 		if (!ret)
 			set_bit(FLAG_IS_OUT, &desc->flags);
 	}
@@ -3205,16 +3246,18 @@ static void gpio_set_open_drain_value_commit(struct gpio_desc *desc, bool value)
  */
 static void gpio_set_open_source_value_commit(struct gpio_desc *desc, bool value)
 {
-	int ret = 0;
-	struct gpio_chip *gc = desc->gdev->chip;
-	int offset = gpio_chip_hwgpio(desc);
+	int ret = 0, offset = gpio_chip_hwgpio(desc);
+
+	CLASS(gpio_chip_guard, guard)(desc);
+	if (!guard.gc)
+		return;
 
 	if (value) {
-		ret = gc->direction_output(gc, offset, 1);
+		ret = guard.gc->direction_output(guard.gc, offset, 1);
 		if (!ret)
 			set_bit(FLAG_IS_OUT, &desc->flags);
 	} else {
-		ret = gc->direction_input(gc, offset);
+		ret = guard.gc->direction_input(guard.gc, offset);
 	}
 	trace_gpio_direction(desc_to_gpio(desc), !value, ret);
 	if (ret < 0)
@@ -3225,11 +3268,12 @@ static void gpio_set_open_source_value_commit(struct gpio_desc *desc, bool value
 
 static void gpiod_set_raw_value_commit(struct gpio_desc *desc, bool value)
 {
-	struct gpio_chip *gc;
+	CLASS(gpio_chip_guard, guard)(desc);
+	if (!guard.gc)
+		return;
 
-	gc = desc->gdev->chip;
 	trace_gpio_value(desc_to_gpio(desc), 0, value);
-	gc->set(gc, gpio_chip_hwgpio(desc), value);
+	guard.gc->set(guard.gc, gpio_chip_hwgpio(desc), value);
 }
 
 /*
@@ -3290,33 +3334,36 @@ int gpiod_set_array_value_complex(bool raw, bool can_sleep,
 	}
 
 	while (i < array_size) {
-		struct gpio_chip *gc = desc_array[i]->gdev->chip;
 		DECLARE_BITMAP(fastpath_mask, FASTPATH_NGPIO);
 		DECLARE_BITMAP(fastpath_bits, FASTPATH_NGPIO);
 		unsigned long *mask, *bits;
 		int count = 0;
 
-		if (likely(gc->ngpio <= FASTPATH_NGPIO)) {
+		CLASS(gpio_chip_guard, guard)(desc_array[i]);
+		if (!guard.gc)
+			return -ENODEV;
+
+		if (likely(guard.gc->ngpio <= FASTPATH_NGPIO)) {
 			mask = fastpath_mask;
 			bits = fastpath_bits;
 		} else {
 			gfp_t flags = can_sleep ? GFP_KERNEL : GFP_ATOMIC;
 
-			mask = bitmap_alloc(gc->ngpio, flags);
+			mask = bitmap_alloc(guard.gc->ngpio, flags);
 			if (!mask)
 				return -ENOMEM;
 
-			bits = bitmap_alloc(gc->ngpio, flags);
+			bits = bitmap_alloc(guard.gc->ngpio, flags);
 			if (!bits) {
 				bitmap_free(mask);
 				return -ENOMEM;
 			}
 		}
 
-		bitmap_zero(mask, gc->ngpio);
+		bitmap_zero(mask, guard.gc->ngpio);
 
 		if (!can_sleep)
-			WARN_ON(gc->can_sleep);
+			WARN_ON(guard.gc->can_sleep);
 
 		do {
 			struct gpio_desc *desc = desc_array[i];
@@ -3352,10 +3399,10 @@ int gpiod_set_array_value_complex(bool raw, bool can_sleep,
 				i = find_next_zero_bit(array_info->set_mask,
 						       array_size, i);
 		} while ((i < array_size) &&
-			 (desc_array[i]->gdev->chip == gc));
+			 gpio_device_chip_cmp(desc_array[i]->gdev, guard.gc));
 		/* push collected bits to outputs */
 		if (count != 0)
-			gpio_chip_set_multiple(gc, mask, bits);
+			gpio_chip_set_multiple(guard.gc, mask, bits);
 
 		if (mask != fastpath_mask)
 			bitmap_free(mask);
@@ -3380,7 +3427,7 @@ void gpiod_set_raw_value(struct gpio_desc *desc, int value)
 {
 	VALIDATE_DESC_VOID(desc);
 	/* Should be using gpiod_set_raw_value_cansleep() */
-	WARN_ON(desc->gdev->chip->can_sleep);
+	WARN_ON(desc->gdev->can_sleep);
 	gpiod_set_raw_value_commit(desc, value);
 }
 EXPORT_SYMBOL_GPL(gpiod_set_raw_value);
@@ -3421,7 +3468,7 @@ void gpiod_set_value(struct gpio_desc *desc, int value)
 {
 	VALIDATE_DESC_VOID(desc);
 	/* Should be using gpiod_set_value_cansleep() */
-	WARN_ON(desc->gdev->chip->can_sleep);
+	WARN_ON(desc->gdev->can_sleep);
 	gpiod_set_value_nocheck(desc, value);
 }
 EXPORT_SYMBOL_GPL(gpiod_set_value);
@@ -3485,7 +3532,7 @@ EXPORT_SYMBOL_GPL(gpiod_set_array_value);
 int gpiod_cansleep(const struct gpio_desc *desc)
 {
 	VALIDATE_DESC(desc);
-	return desc->gdev->chip->can_sleep;
+	return desc->gdev->can_sleep;
 }
 EXPORT_SYMBOL_GPL(gpiod_cansleep);
 
@@ -3497,16 +3544,8 @@ EXPORT_SYMBOL_GPL(gpiod_cansleep);
 int gpiod_set_consumer_name(struct gpio_desc *desc, const char *name)
 {
 	VALIDATE_DESC(desc);
-	if (name) {
-		name = kstrdup_const(name, GFP_KERNEL);
-		if (!name)
-			return -ENOMEM;
-	}
 
-	kfree_const(desc->label);
-	desc_set_label(desc, name);
-
-	return 0;
+	return desc_set_label(desc, name);
 }
 EXPORT_SYMBOL_GPL(gpiod_set_consumer_name);
 
@@ -3519,6 +3558,7 @@ EXPORT_SYMBOL_GPL(gpiod_set_consumer_name);
  */
 int gpiod_to_irq(const struct gpio_desc *desc)
 {
+	struct gpio_device *gdev;
 	struct gpio_chip *gc;
 	int offset;
 
@@ -3527,10 +3567,16 @@ int gpiod_to_irq(const struct gpio_desc *desc)
 	 * requires this function to not return zero on an invalid descriptor
 	 * but rather a negative error number.
 	 */
-	if (!desc || IS_ERR(desc) || !desc->gdev || !desc->gdev->chip)
+	if (!desc || IS_ERR(desc))
 		return -EINVAL;
 
-	gc = desc->gdev->chip;
+	gdev = desc->gdev;
+	/* FIXME Cannot use gpio_chip_guard due to const desc. */
+	guard(srcu)(&gdev->srcu);
+	gc = srcu_dereference(gdev->chip, &gdev->srcu);
+	if (!gc)
+		return -ENODEV;
+
 	offset = gpio_chip_hwgpio(desc);
 	if (gc->to_irq) {
 		int retirq = gc->to_irq(gc, offset);
@@ -3597,14 +3643,6 @@ int gpiochip_lock_as_irq(struct gpio_chip *gc, unsigned int offset)
 	set_bit(FLAG_USED_AS_IRQ, &desc->flags);
 	set_bit(FLAG_IRQ_IS_ENABLED, &desc->flags);
 
-	/*
-	 * If the consumer has not set up a label (such as when the
-	 * IRQ is referenced from .to_irq()) we set up a label here
-	 * so it is clear this is used as an interrupt.
-	 */
-	if (!desc->label)
-		desc_set_label(desc, "interrupt");
-
 	return 0;
 }
 EXPORT_SYMBOL_GPL(gpiochip_lock_as_irq);
@@ -3627,10 +3665,6 @@ void gpiochip_unlock_as_irq(struct gpio_chip *gc, unsigned int offset)
 
 	clear_bit(FLAG_USED_AS_IRQ, &desc->flags);
 	clear_bit(FLAG_IRQ_IS_ENABLED, &desc->flags);
-
-	/* If we only had this marking, erase it */
-	if (desc->label && !strcmp(desc->label, "interrupt"))
-		desc_set_label(desc, NULL);
 }
 EXPORT_SYMBOL_GPL(gpiochip_unlock_as_irq);
 
@@ -4138,39 +4172,48 @@ static struct gpio_desc *gpiod_find_by_fwnode(struct fwnode_handle *fwnode,
 	return desc;
 }
 
-static struct gpio_desc *gpiod_find_and_request(struct device *consumer,
-						struct fwnode_handle *fwnode,
-						const char *con_id,
-						unsigned int idx,
-						enum gpiod_flags flags,
-						const char *label,
-						bool platform_lookup_allowed)
+struct gpio_desc *gpiod_find_and_request(struct device *consumer,
+					 struct fwnode_handle *fwnode,
+					 const char *con_id,
+					 unsigned int idx,
+					 enum gpiod_flags flags,
+					 const char *label,
+					 bool platform_lookup_allowed)
 {
 	unsigned long lookupflags = GPIO_LOOKUP_FLAGS_DEFAULT;
-	struct gpio_desc *desc;
-	int ret;
+	/*
+	 * scoped_guard() is implemented as a for loop, meaning static
+	 * analyzers will complain about these two not being initialized.
+	 */
+	struct gpio_desc *desc = NULL;
+	int ret = 0;
+
+	scoped_guard(srcu, &gpio_devices_srcu) {
+		desc = gpiod_find_by_fwnode(fwnode, consumer, con_id, idx,
+					    &flags, &lookupflags);
+		if (gpiod_not_found(desc) && platform_lookup_allowed) {
+			/*
+			 * Either we are not using DT or ACPI, or their lookup
+			 * did not return a result. In that case, use platform
+			 * lookup as a fallback.
+			 */
+			dev_dbg(consumer,
+				"using lookup tables for GPIO lookup\n");
+			desc = gpiod_find(consumer, con_id, idx, &lookupflags);
+		}
+
+		if (IS_ERR(desc)) {
+			dev_dbg(consumer, "No GPIO consumer %s found\n",
+				con_id);
+			return desc;
+		}
 
-	desc = gpiod_find_by_fwnode(fwnode, consumer, con_id, idx, &flags, &lookupflags);
-	if (gpiod_not_found(desc) && platform_lookup_allowed) {
 		/*
-		 * Either we are not using DT or ACPI, or their lookup did not
-		 * return a result. In that case, use platform lookup as a
-		 * fallback.
+		 * If a connection label was passed use that, else attempt to use
+		 * the device name as label
 		 */
-		dev_dbg(consumer, "using lookup tables for GPIO lookup\n");
-		desc = gpiod_find(consumer, con_id, idx, &lookupflags);
-	}
-
-	if (IS_ERR(desc)) {
-		dev_dbg(consumer, "No GPIO consumer %s found\n", con_id);
-		return desc;
+		ret = gpiod_request(desc, label);
 	}
-
-	/*
-	 * If a connection label was passed use that, else attempt to use
-	 * the device name as label
-	 */
-	ret = gpiod_request(desc, label);
 	if (ret) {
 		if (!(ret == -EBUSY && flags & GPIOD_FLAGS_BIT_NONEXCLUSIVE))
 			return ERR_PTR(ret);
@@ -4243,9 +4286,9 @@ int gpiod_count(struct device *dev, const char *con_id)
 	int count = -ENOENT;
 
 	if (is_of_node(fwnode))
-		count = of_gpio_get_count(dev, con_id);
+		count = of_gpio_count(fwnode, con_id);
 	else if (is_acpi_node(fwnode))
-		count = acpi_gpio_count(dev, con_id);
+		count = acpi_gpio_count(fwnode, con_id);
 	else if (is_software_node(fwnode))
 		count = swnode_gpio_count(fwnode, con_id);
 
@@ -4429,26 +4472,30 @@ EXPORT_SYMBOL_GPL(gpiod_get_index_optional);
 int gpiod_hog(struct gpio_desc *desc, const char *name,
 	      unsigned long lflags, enum gpiod_flags dflags)
 {
-	struct gpio_chip *gc;
+	struct gpio_device *gdev = desc->gdev;
 	struct gpio_desc *local_desc;
 	int hwnum;
 	int ret;
 
-	gc = gpiod_to_chip(desc);
+	CLASS(gpio_chip_guard, guard)(desc);
+	if (!guard.gc)
+		return -ENODEV;
+
+	if (test_and_set_bit(FLAG_IS_HOGGED, &desc->flags))
+		return 0;
+
 	hwnum = gpio_chip_hwgpio(desc);
 
-	local_desc = gpiochip_request_own_desc(gc, hwnum, name,
+	local_desc = gpiochip_request_own_desc(guard.gc, hwnum, name,
 					       lflags, dflags);
 	if (IS_ERR(local_desc)) {
+		clear_bit(FLAG_IS_HOGGED, &desc->flags);
 		ret = PTR_ERR(local_desc);
 		pr_err("requesting hog GPIO %s (chip %s, offset %d) failed, %d\n",
-		       name, gc->label, hwnum, ret);
+		       name, gdev->label, hwnum, ret);
 		return ret;
 	}
 
-	/* Mark GPIO as hogged so it can be identified and removed later */
-	set_bit(FLAG_IS_HOGGED, &desc->flags);
-
 	gpiod_dbg(desc, "hogged as %s%s\n",
 		(dflags & GPIOD_FLAGS_BIT_DIR_OUT) ? "output" : "input",
 		(dflags & GPIOD_FLAGS_BIT_DIR_OUT) ?
@@ -4712,13 +4759,22 @@ core_initcall(gpiolib_dev_init);
 
 static void gpiolib_dbg_show(struct seq_file *s, struct gpio_device *gdev)
 {
-	struct gpio_chip *gc = gdev->chip;
 	bool active_low, is_irq, is_out;
 	unsigned int gpio = gdev->base;
 	struct gpio_desc *desc;
+	struct gpio_chip *gc;
 	int value;
 
+	guard(srcu)(&gdev->srcu);
+
+	gc = srcu_dereference(gdev->chip, &gdev->srcu);
+	if (!gc) {
+		seq_puts(s, "Underlying GPIO chip is gone\n");
+		return;
+	}
+
 	for_each_gpio_desc(gc, desc) {
+		guard(srcu)(&desc->srcu);
 		if (test_bit(FLAG_REQUESTED, &desc->flags)) {
 			gpiod_get_direction(desc);
 			is_out = test_bit(FLAG_IS_OUT, &desc->flags);
@@ -4726,7 +4782,7 @@ static void gpiolib_dbg_show(struct seq_file *s, struct gpio_device *gdev)
 			is_irq = test_bit(FLAG_USED_AS_IRQ, &desc->flags);
 			active_low = test_bit(FLAG_ACTIVE_LOW, &desc->flags);
 			seq_printf(s, " gpio-%-3d (%-20.20s|%-20.20s) %s %s %s%s\n",
-				   gpio, desc->name ?: "", desc->label,
+				   gpio, desc->name ?: "", gpiod_get_label(desc),
 				   is_out ? "out" : "in ",
 				   value >= 0 ? (value ? "hi" : "lo") : "?  ",
 				   is_irq ? "IRQ " : "",
@@ -4739,61 +4795,72 @@ static void gpiolib_dbg_show(struct seq_file *s, struct gpio_device *gdev)
 	}
 }
 
+struct gpiolib_seq_priv {
+	bool newline;
+	int idx;
+};
+
 static void *gpiolib_seq_start(struct seq_file *s, loff_t *pos)
 {
-	unsigned long flags;
-	struct gpio_device *gdev = NULL;
+	struct gpiolib_seq_priv *priv;
+	struct gpio_device *gdev;
 	loff_t index = *pos;
 
-	s->private = "";
+	priv = kzalloc(sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		return NULL;
+
+	s->private = priv;
+	priv->idx = srcu_read_lock(&gpio_devices_srcu);
 
-	spin_lock_irqsave(&gpio_lock, flags);
-	list_for_each_entry(gdev, &gpio_devices, list)
-		if (index-- == 0) {
-			spin_unlock_irqrestore(&gpio_lock, flags);
+	list_for_each_entry_srcu(gdev, &gpio_devices, list,
+				 srcu_read_lock_held(&gpio_devices_srcu)) {
+		if (index-- == 0)
 			return gdev;
-		}
-	spin_unlock_irqrestore(&gpio_lock, flags);
+	}
 
 	return NULL;
 }
 
 static void *gpiolib_seq_next(struct seq_file *s, void *v, loff_t *pos)
 {
-	unsigned long flags;
-	struct gpio_device *gdev = v;
-	void *ret = NULL;
-
-	spin_lock_irqsave(&gpio_lock, flags);
-	if (list_is_last(&gdev->list, &gpio_devices))
-		ret = NULL;
-	else
-		ret = list_first_entry(&gdev->list, struct gpio_device, list);
-	spin_unlock_irqrestore(&gpio_lock, flags);
+	struct gpiolib_seq_priv *priv = s->private;
+	struct gpio_device *gdev = v, *next;
 
-	s->private = "\n";
+	next = list_entry_rcu(gdev->list.next, struct gpio_device, list);
+	gdev = &next->list == &gpio_devices ? NULL : next;
+	priv->newline = true;
 	++*pos;
 
-	return ret;
+	return gdev;
 }
 
 static void gpiolib_seq_stop(struct seq_file *s, void *v)
 {
+	struct gpiolib_seq_priv *priv = s->private;
+
+	srcu_read_unlock(&gpio_devices_srcu, priv->idx);
+	kfree(priv);
 }
 
 static int gpiolib_seq_show(struct seq_file *s, void *v)
 {
+	struct gpiolib_seq_priv *priv = s->private;
 	struct gpio_device *gdev = v;
-	struct gpio_chip *gc = gdev->chip;
+	struct gpio_chip *gc;
 	struct device *parent;
 
+	guard(srcu)(&gdev->srcu);
+
+	gc = srcu_dereference(gdev->chip, &gdev->srcu);
 	if (!gc) {
-		seq_printf(s, "%s%s: (dangling chip)", (char *)s->private,
+		seq_printf(s, "%s%s: (dangling chip)",
+			   priv->newline ? "\n" : "",
 			   dev_name(&gdev->dev));
 		return 0;
 	}
 
-	seq_printf(s, "%s%s: GPIOs %d-%d", (char *)s->private,
+	seq_printf(s, "%s%s: GPIOs %d-%d", priv->newline ? "\n" : "",
 		   dev_name(&gdev->dev),
 		   gdev->base, gdev->base + gdev->ngpio - 1);
 	parent = gc->parent;