coccinelle: alloc_cast: drop removed allocatorsgrafted

- pci_alloc_consistent() and pci_zalloc_consistent() were removed by
  commit 7968778914e5
  ("PCI: Remove the deprecated "pci-dma-compat.h" API")

- kmem_alloc() was removed by commit f078d4ea8276
  ("xfs: convert kmem_alloc() to kmalloc()")

- kmem_zalloc() was removed by commit 10634530f7ba
  ("xfs: convert kmem_zalloc() to kzalloc()")

- kmem_zone_alloc() and kmem_zone_zalloc() were removed by commit
  bae633a4a283 ("xfs: remove xfs_zone_{alloc,zalloc} helpers")

So drop them from the rules.

No functional change.

Signed-off-by: Sang-Heon Jeon <ekffu200098@gmail.com>
Signed-off-by: Julia Lawall <Julia.Lawall@inria.fr>

1 files changed, 797 insertions, 0 deletions

diff --git a/drivers/gpio/gpiolib-shared.c b/drivers/gpio/gpiolib-shared.c
new file mode 100644
index 000000000..495bd3d0d
--- /dev/null
+++ b/drivers/gpio/gpiolib-shared.c
@@ -0,0 +1,797 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2025 Linaro Ltd.
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/auxiliary_bus.h>
+#include <linux/cleanup.h>
+#include <linux/device.h>
+#include <linux/fwnode.h>
+#include <linux/gpio/consumer.h>
+#include <linux/gpio/machine.h>
+#include <linux/idr.h>
+#include <linux/kref.h>
+#include <linux/list.h>
+#include <linux/lockdep.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/of.h>
+#include <linux/overflow.h>
+#include <linux/printk.h>
+#include <linux/property.h>
+#include <linux/slab.h>
+#include <linux/string.h>
+
+#include "gpiolib.h"
+#include "gpiolib-shared.h"
+
+/* Represents a single reference to a GPIO pin. */
+struct gpio_shared_ref {
+	struct list_head list;
+	/* Firmware node associated with this GPIO's consumer. */
+	struct fwnode_handle *fwnode;
+	/* GPIO flags this consumer uses for the request. */
+	enum gpiod_flags flags;
+	char *con_id;
+	int dev_id;
+	/* Protects the auxiliary device struct and the lookup table. */
+	struct mutex lock;
+	struct lock_class_key lock_key;
+	struct auxiliary_device adev;
+	struct gpiod_lookup_table *lookup;
+	bool is_reset_gpio;
+};
+
+/* Represents a single GPIO pin. */
+struct gpio_shared_entry {
+	struct list_head list;
+	/* Firmware node associated with the GPIO controller. */
+	struct fwnode_handle *fwnode;
+	/* Hardware offset of the GPIO within its chip. */
+	unsigned int offset;
+	/* Index in the property value array. */
+	size_t index;
+	/* Synchronizes the modification of shared_desc and offset. */
+	struct mutex lock;
+	struct gpio_shared_desc *shared_desc;
+	struct kref ref;
+	struct list_head refs;
+};
+
+static LIST_HEAD(gpio_shared_list);
+static DEFINE_IDA(gpio_shared_ida);
+
+#if IS_ENABLED(CONFIG_OF)
+static struct gpio_shared_entry *
+gpio_shared_find_entry(struct fwnode_handle *controller_node,
+		       unsigned int offset)
+{
+	struct gpio_shared_entry *entry;
+
+	list_for_each_entry(entry, &gpio_shared_list, list) {
+		if (entry->fwnode == controller_node && entry->offset == offset)
+			return entry;
+	}
+
+	return NULL;
+}
+
+static struct gpio_shared_ref *gpio_shared_make_ref(struct fwnode_handle *fwnode,
+						    const char *con_id,
+						    enum gpiod_flags flags)
+{
+	char *con_id_cpy __free(kfree) = NULL;
+
+	struct gpio_shared_ref *ref __free(kfree) = kzalloc_obj(*ref);
+	if (!ref)
+		return NULL;
+
+	if (con_id) {
+		con_id_cpy = kstrdup(con_id, GFP_KERNEL);
+		if (!con_id_cpy)
+			return NULL;
+	}
+
+	ref->dev_id = ida_alloc(&gpio_shared_ida, GFP_KERNEL);
+	if (ref->dev_id < 0)
+		return NULL;
+
+	ref->flags = flags;
+	ref->con_id = no_free_ptr(con_id_cpy);
+	ref->fwnode = fwnode;
+	lockdep_register_key(&ref->lock_key);
+	mutex_init_with_key(&ref->lock, &ref->lock_key);
+
+	return no_free_ptr(ref);
+}
+
+static int gpio_shared_setup_reset_proxy(struct gpio_shared_entry *entry,
+					 enum gpiod_flags flags)
+{
+	struct gpio_shared_ref *ref;
+
+	list_for_each_entry(ref, &entry->refs, list) {
+		if (ref->is_reset_gpio)
+			/* Already set-up. */
+			return 0;
+	}
+
+	ref = gpio_shared_make_ref(NULL, "reset", flags);
+	if (!ref)
+		return -ENOMEM;
+
+	ref->is_reset_gpio = true;
+
+	list_add_tail(&ref->list, &entry->refs);
+
+	pr_debug("Created a secondary shared GPIO reference for potential reset-gpio device for GPIO %u at %s\n",
+		 entry->offset, fwnode_get_name(entry->fwnode));
+
+	return 0;
+}
+
+/* Handle all special nodes that we should ignore. */
+static bool gpio_shared_of_node_ignore(struct device_node *node)
+{
+	/* Ignore disabled devices. */
+	if (!of_device_is_available(node))
+		return true;
+
+	/*
+	 * __symbols__ is a special, internal node and should not be considered
+	 * when scanning for shared GPIOs.
+	 */
+	if (of_node_name_eq(node, "__symbols__"))
+		return true;
+
+	/*
+	 * GPIO hogs have a "gpios" property which is not a phandle and can't
+	 * possibly refer to a shared GPIO.
+	 */
+	if (of_property_present(node, "gpio-hog"))
+		return true;
+
+	return false;
+}
+
+static int gpio_shared_of_traverse(struct device_node *curr)
+{
+	struct gpio_shared_entry *entry;
+	size_t con_id_len, suffix_len;
+	struct fwnode_handle *fwnode;
+	struct of_phandle_args args;
+	struct gpio_shared_ref *ref;
+	struct property *prop;
+	unsigned int offset;
+	const char *suffix;
+	int ret, count, i;
+
+	if (gpio_shared_of_node_ignore(curr))
+		return 0;
+
+	for_each_property_of_node(curr, prop) {
+		/*
+		 * The standard name for a GPIO property is "foo-gpios"
+		 * or "foo-gpio". Some bindings also use "gpios" or "gpio".
+		 * There are some legacy device-trees which have a different
+		 * naming convention and for which we have rename quirks in
+		 * place in gpiolib-of.c. I don't think any of them require
+		 * support for shared GPIOs so for now let's just ignore
+		 * them. We can always just export the quirk list and
+		 * iterate over it here.
+		 */
+		if (!strends(prop->name, "-gpios") &&
+		    !strends(prop->name, "-gpio") &&
+		    strcmp(prop->name, "gpios") != 0 &&
+		    strcmp(prop->name, "gpio") != 0)
+			continue;
+
+		count = of_count_phandle_with_args(curr, prop->name,
+						   "#gpio-cells");
+		if (count <= 0)
+			continue;
+
+		for (i = 0; i < count; i++) {
+			struct device_node *np __free(device_node) = NULL;
+			char *con_id __free(kfree) = NULL;
+
+			ret = of_parse_phandle_with_args(curr, prop->name,
+							 "#gpio-cells", i,
+							 &args);
+			if (ret)
+				continue;
+
+			np = args.np;
+
+			if (!of_property_present(np, "gpio-controller"))
+				continue;
+
+			/*
+			 * We support 1, 2 and 3 cell GPIO bindings in the
+			 * kernel currently. There's only one old MIPS dts that
+			 * has a one-cell binding but there's no associated
+			 * consumer so it may as well be an error. There don't
+			 * seem to be any 3-cell users of non-exclusive GPIOs,
+			 * so we can skip this as well. Let's occupy ourselves
+			 * with the predominant 2-cell binding with the first
+			 * cell indicating the hardware offset of the GPIO and
+			 * the second defining the GPIO flags of the request.
+			 */
+			if (args.args_count != 2)
+				continue;
+
+			fwnode = of_fwnode_handle(args.np);
+			offset = args.args[0];
+
+			entry = gpio_shared_find_entry(fwnode, offset);
+			if (!entry) {
+				entry = kzalloc_obj(*entry);
+				if (!entry)
+					return -ENOMEM;
+
+				entry->fwnode = fwnode_handle_get(fwnode);
+				entry->offset = offset;
+				entry->index = count;
+				INIT_LIST_HEAD(&entry->refs);
+				mutex_init(&entry->lock);
+
+				list_add_tail(&entry->list, &gpio_shared_list);
+			}
+
+			if (strends(prop->name, "gpios"))
+				suffix = "-gpios";
+			else if (strends(prop->name, "gpio"))
+				suffix = "-gpio";
+			else
+				suffix = NULL;
+			if (!suffix)
+				continue;
+
+			/* We only set con_id if there's actually one. */
+			if (strcmp(prop->name, "gpios") && strcmp(prop->name, "gpio")) {
+				con_id = kstrdup(prop->name, GFP_KERNEL);
+				if (!con_id)
+					return -ENOMEM;
+
+				con_id_len = strlen(con_id);
+				suffix_len = strlen(suffix);
+
+				con_id[con_id_len - suffix_len] = '\0';
+			}
+
+			ref = gpio_shared_make_ref(fwnode_handle_get(of_fwnode_handle(curr)),
+						   con_id, args.args[1]);
+			if (!ref)
+				return -ENOMEM;
+
+			if (!list_empty(&entry->refs))
+				pr_debug("GPIO %u at %s is shared by multiple firmware nodes\n",
+					 entry->offset, fwnode_get_name(entry->fwnode));
+
+			list_add_tail(&ref->list, &entry->refs);
+
+			if (strcmp(prop->name, "reset-gpios") == 0) {
+				ret = gpio_shared_setup_reset_proxy(entry, args.args[1]);
+				if (ret)
+					return ret;
+			}
+		}
+	}
+
+	for_each_child_of_node_scoped(curr, child) {
+		ret = gpio_shared_of_traverse(child);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+
+static int gpio_shared_of_scan(void)
+{
+	if (of_root)
+		return gpio_shared_of_traverse(of_root);
+
+	return 0;
+}
+#else
+static int gpio_shared_of_scan(void)
+{
+	return 0;
+}
+#endif /* CONFIG_OF */
+
+static void gpio_shared_adev_release(struct device *dev)
+{
+
+}
+
+static int gpio_shared_make_adev(struct gpio_device *gdev,
+				 struct gpio_shared_entry *entry,
+				 struct gpio_shared_ref *ref)
+{
+	struct auxiliary_device *adev = &ref->adev;
+	int ret;
+
+	guard(mutex)(&ref->lock);
+
+	memset(adev, 0, sizeof(*adev));
+
+	adev->id = ref->dev_id;
+	adev->name = "proxy";
+	adev->dev.parent = gdev->dev.parent;
+	adev->dev.platform_data = entry;
+	adev->dev.release = gpio_shared_adev_release;
+
+	ret = auxiliary_device_init(adev);
+	if (ret)
+		return ret;
+
+	ret = auxiliary_device_add(adev);
+	if (ret) {
+		auxiliary_device_uninit(adev);
+		return ret;
+	}
+
+	pr_debug("Created an auxiliary GPIO proxy %s for GPIO device %s\n",
+		 dev_name(&adev->dev), gpio_device_get_label(gdev));
+
+	return 0;
+}
+
+#if IS_ENABLED(CONFIG_RESET_GPIO)
+/*
+ * Special case: reset-gpio is an auxiliary device that's created dynamically
+ * and put in between the GPIO controller and consumers of shared GPIOs
+ * referred to by the "reset-gpios" property.
+ *
+ * If the supposed consumer of a shared GPIO didn't match any of the mappings
+ * we created when scanning the firmware nodes, it's still possible that it's
+ * the reset-gpio device which didn't exist at the time of the scan.
+ *
+ * This function verifies it an return true if it's the case.
+ */
+static bool gpio_shared_dev_is_reset_gpio(struct device *consumer,
+					  struct gpio_shared_entry *entry,
+					  struct gpio_shared_ref *ref)
+{
+	struct fwnode_handle *reset_fwnode = dev_fwnode(consumer);
+	struct fwnode_reference_args ref_args, aux_args;
+	struct device *parent = consumer->parent;
+	struct gpio_shared_ref *real_ref;
+	bool match;
+	int ret;
+
+	lockdep_assert_held(&ref->lock);
+
+	/* The reset-gpio device must have a parent AND a firmware node. */
+	if (!parent || !reset_fwnode)
+		return false;
+
+	/*
+	 * Parent of the reset-gpio auxiliary device is the GPIO chip whose
+	 * fwnode we stored in the entry structure.
+	 */
+	if (!device_match_fwnode(parent, entry->fwnode))
+		return false;
+
+	/*
+	 * Now we need to find the actual pin we want to assign to this
+	 * reset-gpio device. To that end: iterate over the list of references
+	 * of this entry and see if there's one, whose reset-gpios property's
+	 * arguments match the ones from this consumer's node.
+	 */
+	list_for_each_entry(real_ref, &entry->refs, list) {
+		if (real_ref == ref)
+			continue;
+
+		guard(mutex)(&real_ref->lock);
+
+		if (!real_ref->fwnode)
+			continue;
+
+		/*
+		 * The device associated with the shared reference's firmware
+		 * node is the consumer of the reset control exposed by the
+		 * reset-gpio device. It must have a "reset-gpios" property
+		 * that's referencing the entry's firmware node.
+		 *
+		 * The reference args must agree between the real consumer and
+		 * the auxiliary reset-gpio device.
+		 */
+		ret = fwnode_property_get_reference_args(real_ref->fwnode,
+							 "reset-gpios",
+							 NULL, 2, 0, &ref_args);
+		if (ret)
+			continue;
+
+		ret = fwnode_property_get_reference_args(reset_fwnode, "reset-gpios",
+							 NULL, 2, 0, &aux_args);
+		if (ret) {
+			fwnode_handle_put(ref_args.fwnode);
+			continue;
+		}
+
+		match = ((ref_args.fwnode == entry->fwnode) &&
+			 (aux_args.fwnode == entry->fwnode) &&
+			 (ref_args.args[0] == aux_args.args[0]));
+
+		fwnode_handle_put(ref_args.fwnode);
+		fwnode_handle_put(aux_args.fwnode);
+
+		if (!match)
+			continue;
+
+		/*
+		 * Reuse the fwnode of the real device, next time we'll use it
+		 * in the normal path.
+		 */
+		ref->fwnode = fwnode_handle_get(reset_fwnode);
+		return true;
+	}
+
+	return false;
+}
+#else
+static bool gpio_shared_dev_is_reset_gpio(struct device *consumer,
+					  struct gpio_shared_entry *entry,
+					  struct gpio_shared_ref *ref)
+{
+	return false;
+}
+#endif /* CONFIG_RESET_GPIO */
+
+int gpio_shared_add_proxy_lookup(struct device *consumer, struct fwnode_handle *fwnode,
+				 const char *con_id, unsigned long lflags)
+{
+	const char *dev_id = dev_name(consumer);
+	struct gpiod_lookup_table *lookup;
+	struct gpio_shared_entry *entry;
+	struct gpio_shared_ref *ref;
+
+	list_for_each_entry(entry, &gpio_shared_list, list) {
+		list_for_each_entry(ref, &entry->refs, list) {
+			guard(mutex)(&ref->lock);
+
+			if (!ref->fwnode && device_is_compatible(consumer, "reset-gpio")) {
+				if (!gpio_shared_dev_is_reset_gpio(consumer, entry, ref))
+					continue;
+			} else if (fwnode != ref->fwnode) {
+				continue;
+			}
+
+			if ((!con_id && ref->con_id) || (con_id && !ref->con_id) ||
+			    (con_id && ref->con_id && strcmp(con_id, ref->con_id) != 0))
+				continue;
+
+			/* We've already done that on a previous request. */
+			if (ref->lookup)
+				return 0;
+
+			char *key __free(kfree) =
+				kasprintf(GFP_KERNEL,
+					  KBUILD_MODNAME ".proxy.%u",
+					  ref->adev.id);
+			if (!key)
+				return -ENOMEM;
+
+			lookup = kzalloc_flex(*lookup, table, 2);
+			if (!lookup)
+				return -ENOMEM;
+
+			pr_debug("Adding machine lookup entry for a shared GPIO for consumer %s, with key '%s' and con_id '%s'\n",
+				 dev_id, key, ref->con_id ?: "none");
+
+			lookup->dev_id = dev_id;
+			lookup->table[0] = GPIO_LOOKUP(no_free_ptr(key), 0,
+						       ref->con_id, lflags);
+
+			ref->lookup = lookup;
+			gpiod_add_lookup_table(ref->lookup);
+
+			return 0;
+		}
+	}
+
+	/* We warn here because this can only happen if the programmer borked. */
+	WARN_ON(1);
+	return -ENOENT;
+}
+
+static void gpio_shared_remove_adev(struct auxiliary_device *adev)
+{
+	auxiliary_device_delete(adev);
+	auxiliary_device_uninit(adev);
+}
+
+int gpiochip_setup_shared(struct gpio_chip *gc)
+{
+	struct gpio_device *gdev = gc->gpiodev;
+	struct gpio_shared_entry *entry;
+	struct gpio_shared_ref *ref;
+	struct gpio_desc *desc;
+	int ret;
+
+	list_for_each_entry(entry, &gpio_shared_list, list) {
+		list_for_each_entry(ref, &entry->refs, list) {
+			if (gdev->dev.parent == &ref->adev.dev) {
+				/*
+				 * This is a shared GPIO proxy. Mark its
+				 * descriptor as such and return here.
+				 */
+				__set_bit(GPIOD_FLAG_SHARED_PROXY,
+					  &gdev->descs[0].flags);
+				return 0;
+			}
+		}
+	}
+
+	/*
+	 * This is not a shared GPIO proxy but it still may be the device
+	 * exposing shared pins. Find them and create the proxy devices.
+	 */
+	list_for_each_entry(entry, &gpio_shared_list, list) {
+		if (!device_match_fwnode(&gdev->dev, entry->fwnode))
+			continue;
+
+		if (list_count_nodes(&entry->refs) <= 1)
+			continue;
+
+		scoped_guard(mutex, &entry->lock) {
+#if IS_ENABLED(CONFIG_OF)
+			if (is_of_node(entry->fwnode) && gc->of_xlate) {
+				/*
+				 * This is the earliest that we can tranlate the
+				 * devicetree offset to the chip offset.
+				 */
+				struct of_phandle_args gpiospec = { };
+
+				gpiospec.np = to_of_node(entry->fwnode);
+				gpiospec.args_count = 2;
+				gpiospec.args[0] = entry->offset;
+
+				ret = gc->of_xlate(gc, &gpiospec, NULL);
+				if (ret < 0)
+					return ret;
+
+				entry->offset = ret;
+			}
+#endif /* CONFIG_OF */
+
+			desc = &gdev->descs[entry->offset];
+
+			__set_bit(GPIOD_FLAG_SHARED, &desc->flags);
+			/*
+			 * Shared GPIOs are not requested via the normal path. Make
+			 * them inaccessible to anyone even before we register the
+			 * chip.
+			 */
+			ret = gpiod_request_commit(desc, "shared");
+			if (ret)
+				return ret;
+
+			pr_debug("GPIO %u owned by %s is shared by multiple consumers\n",
+				 entry->offset, gpio_device_get_label(gdev));
+		}
+
+		list_for_each_entry(ref, &entry->refs, list) {
+			pr_debug("Setting up a shared GPIO entry for %s (con_id: '%s')\n",
+				 fwnode_get_name(ref->fwnode) ?: "(no fwnode)",
+				 ref->con_id ?: "(none)");
+
+			ret = gpio_shared_make_adev(gdev, entry, ref);
+			if (ret) {
+				gpiod_free_commit(desc);
+				return ret;
+			}
+		}
+	}
+
+	return 0;
+}
+
+void gpio_device_teardown_shared(struct gpio_device *gdev)
+{
+	struct gpio_shared_entry *entry;
+	struct gpio_shared_ref *ref;
+
+	list_for_each_entry(entry, &gpio_shared_list, list) {
+		if (!device_match_fwnode(&gdev->dev, entry->fwnode))
+			continue;
+
+		scoped_guard(mutex, &entry->lock)
+			gpiod_free_commit(&gdev->descs[entry->offset]);
+
+		list_for_each_entry(ref, &entry->refs, list) {
+			if (ref->lookup) {
+				gpiod_remove_lookup_table(ref->lookup);
+				kfree(ref->lookup->table[0].key);
+				kfree(ref->lookup);
+				ref->lookup = NULL;
+			}
+
+			gpio_shared_remove_adev(&ref->adev);
+		}
+	}
+}
+
+static void gpio_shared_release(struct kref *kref)
+{
+	struct gpio_shared_entry *entry =
+		container_of(kref, struct gpio_shared_entry, ref);
+	struct gpio_shared_desc *shared_desc;
+
+	guard(mutex)(&entry->lock);
+
+	shared_desc = entry->shared_desc;
+	gpio_device_put(shared_desc->desc->gdev);
+	mutex_destroy(&shared_desc->mutex);
+	kfree(shared_desc);
+	entry->shared_desc = NULL;
+}
+
+static void gpiod_shared_put(void *data)
+{
+	struct gpio_shared_entry *entry = data;
+
+	kref_put(&entry->ref, gpio_shared_release);
+}
+
+static struct gpio_shared_desc *
+gpiod_shared_desc_create(struct gpio_shared_entry *entry)
+{
+	struct gpio_shared_desc *shared_desc;
+	struct gpio_device *gdev;
+
+	lockdep_assert_held(&entry->lock);
+
+	shared_desc = kzalloc_obj(*shared_desc);
+	if (!shared_desc)
+		return ERR_PTR(-ENOMEM);
+
+	gdev = gpio_device_find_by_fwnode(entry->fwnode);
+	if (!gdev) {
+		kfree(shared_desc);
+		return ERR_PTR(-EPROBE_DEFER);
+	}
+
+	shared_desc->desc = &gdev->descs[entry->offset];
+	mutex_init(&shared_desc->mutex);
+
+	return shared_desc;
+}
+
+struct gpio_shared_desc *devm_gpiod_shared_get(struct device *dev)
+{
+	struct gpio_shared_desc *shared_desc;
+	struct gpio_shared_entry *entry;
+	int ret;
+
+	entry = dev_get_platdata(dev);
+	if (WARN_ON(!entry))
+		/* Programmer bug */
+		return ERR_PTR(-ENOENT);
+
+	scoped_guard(mutex, &entry->lock) {
+		if (entry->shared_desc) {
+			kref_get(&entry->ref);
+			shared_desc = entry->shared_desc;
+		} else {
+			shared_desc = gpiod_shared_desc_create(entry);
+			if (IS_ERR(shared_desc))
+				return ERR_CAST(shared_desc);
+
+			kref_init(&entry->ref);
+			entry->shared_desc = shared_desc;
+		}
+
+		pr_debug("Device %s acquired a reference to the shared GPIO %u owned by %s\n",
+			 dev_name(dev), gpiod_hwgpio(shared_desc->desc),
+			 gpio_device_get_label(shared_desc->desc->gdev));
+	}
+
+	ret = devm_add_action_or_reset(dev, gpiod_shared_put, entry);
+	if (ret)
+		return ERR_PTR(ret);
+
+	return shared_desc;
+}
+EXPORT_SYMBOL_GPL(devm_gpiod_shared_get);
+
+static void gpio_shared_drop_ref(struct gpio_shared_ref *ref)
+{
+	list_del(&ref->list);
+	mutex_destroy(&ref->lock);
+	lockdep_unregister_key(&ref->lock_key);
+	kfree(ref->con_id);
+	ida_free(&gpio_shared_ida, ref->dev_id);
+	fwnode_handle_put(ref->fwnode);
+	kfree(ref);
+}
+
+static void gpio_shared_drop_entry(struct gpio_shared_entry *entry)
+{
+	list_del(&entry->list);
+	mutex_destroy(&entry->lock);
+	fwnode_handle_put(entry->fwnode);
+	kfree(entry);
+}
+
+/*
+ * This is only called if gpio_shared_init() fails so it's in fact __init and
+ * not __exit.
+ */
+static void __init gpio_shared_teardown(void)
+{
+	struct gpio_shared_entry *entry, *epos;
+	struct gpio_shared_ref *ref, *rpos;
+
+	list_for_each_entry_safe(entry, epos, &gpio_shared_list, list) {
+		list_for_each_entry_safe(ref, rpos, &entry->refs, list)
+			gpio_shared_drop_ref(ref);
+
+		gpio_shared_drop_entry(entry);
+	}
+}
+
+static bool gpio_shared_entry_is_really_shared(struct gpio_shared_entry *entry)
+{
+	size_t num_nodes = list_count_nodes(&entry->refs);
+	struct gpio_shared_ref *ref;
+
+	if (num_nodes <= 1)
+		return false;
+
+	if (num_nodes > 2)
+		return true;
+
+	/* Exactly two references: */
+	list_for_each_entry(ref, &entry->refs, list) {
+		/*
+		 * Corner-case: the second reference comes from the potential
+		 * reset-gpio instance. However, this pin is not really shared
+		 * as it would have three references in this case. Avoid
+		 * creating unnecessary proxies.
+		 */
+		if (ref->is_reset_gpio)
+			return false;
+	}
+
+	return true;
+}
+
+static void gpio_shared_free_exclusive(void)
+{
+	struct gpio_shared_entry *entry, *epos;
+	struct gpio_shared_ref *ref, *rpos;
+
+	list_for_each_entry_safe(entry, epos, &gpio_shared_list, list) {
+		if (gpio_shared_entry_is_really_shared(entry))
+			continue;
+
+		list_for_each_entry_safe(ref, rpos, &entry->refs, list)
+			gpio_shared_drop_ref(ref);
+		gpio_shared_drop_entry(entry);
+	}
+}
+
+static int __init gpio_shared_init(void)
+{
+	int ret;
+
+	/* Right now, we only support OF-based systems. */
+	ret = gpio_shared_of_scan();
+	if (ret) {
+		gpio_shared_teardown();
+		pr_err("Failed to scan OF nodes for shared GPIOs: %d\n", ret);
+		return ret;
+	}
+
+	gpio_shared_free_exclusive();
+
+	pr_debug("Finished scanning firmware nodes for shared GPIOs\n");
+	return 0;
+}
+postcore_initcall(gpio_shared_init);