Merge tag 'gpio-fixes-for-v6.19-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/brgl/linux

Pull gpio fixes from Bartosz Golaszewski:
"There are several ordinary driver fixes and a fix to a race between
the registration of two chips that causes a crash in GPIO core.

The bulk of the changed lines however, concerns the management of
shared GPIOs that landed in v6.19-rc1. Enabling it for ARCH_QCOM
enabled it in defconfig which effectively enabled it for all arm64
platforms and exposed the code to quite a lot of testing (which is
good, right? :)).

As a resukt, I received a number of bug reports, which I progressively
fixed over the course of last weeks. This explains the number of lines
higher than what I normally aim for at this stage.

- balance superio enter/exit calls in error path in gpio-it87

- fix a race where we try to take the SRCU read lock of the GPIO
device before it's been initialized causing a NULL-pointer
dereference

- fix handling of short-pulse interrupts in gpio-pca053x

- fix a reference leak in error path in gpio-mpsse

- mark the GPIO controller as sleeping (it calls sleeping functions)
in gpio-rockchip

- fix several issues in management of shared GPIOs"

* tag 'gpio-fixes-for-v6.19-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/brgl/linux:
gpio: shared: fix a false-positive sharing detection with reset-gpios
gpiolib: fix lookup table matching
gpio: shared: don't allocate the lookup table until we really need it
gpio: shared: fix a race condition
gpio: shared: assign the correct firmware node for reset-gpio use-case
gpio: rockchip: mark the GPIO controller as sleeping
gpio: mpsse: fix reference leak in gpio_mpsse_probe() error paths
gpio: pca953x: handle short interrupt pulses on PCAL devices
gpiolib: fix race condition for gdev->srcu
gpio: shared: allow sharing a reset-gpios pin between reset-gpio and gpiolib
gpio: shared: verify con_id when adding proxy lookup
gpiolib: allow multiple lookup tables per consumer
gpio: it87: balance superio enter/exit calls in error path

drivers/gpio/gpio-it87.c

···
 
 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 
+#include <linux/cleanup.h>
 #include <linux/init.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
···
 	mask = 1 << (gpio_num % 8);
 	group = (gpio_num / 8);
 
-	spin_lock(&it87_gpio->lock);
+	guard(spinlock)(&it87_gpio->lock);
 
 	rc = superio_enter();
 	if (rc)
-		goto exit;
+		return rc;
 
 	/* set the output enable bit */
 	superio_set_mask(mask, group + it87_gpio->output_base);
 
 	rc = it87_gpio_set(chip, gpio_num, val);
-	if (rc)
-		goto exit;
-
 	superio_exit();
-
-exit:
-	spin_unlock(&it87_gpio->lock);
 	return rc;
 }
 

drivers/gpio/gpio-mpsse.c

···
 	ida_free(&gpio_mpsse_ida, priv->id);
 }
 
+static void gpio_mpsse_usb_put_dev(void *data)
+{
+	struct mpsse_priv *priv = data;
+
+	usb_put_dev(priv->udev);
+}
+
 static int mpsse_init_valid_mask(struct gpio_chip *chip,
 				 unsigned long *valid_mask,
 				 unsigned int ngpios)
···
 	INIT_LIST_HEAD(&priv->workers);
 
 	priv->udev = usb_get_dev(interface_to_usbdev(interface));
+	err = devm_add_action_or_reset(dev, gpio_mpsse_usb_put_dev, priv);
+	if (err)
+		return err;
+
 	priv->intf = interface;
 	priv->intf_id = interface->cur_altsetting->desc.bInterfaceNumber;
 
···
 
 	priv->intf = NULL;
 	usb_set_intfdata(intf, NULL);
-	usb_put_dev(priv->udev);
 }
 
 static struct usb_driver gpio_mpsse_driver = {

drivers/gpio/gpio-pca953x.c

···
 	DECLARE_BITMAP(old_stat, MAX_LINE);
 	DECLARE_BITMAP(cur_stat, MAX_LINE);
 	DECLARE_BITMAP(new_stat, MAX_LINE);
+	DECLARE_BITMAP(int_stat, MAX_LINE);
 	DECLARE_BITMAP(trigger, MAX_LINE);
 	DECLARE_BITMAP(edges, MAX_LINE);
 	int ret;
 
+	if (chip->driver_data & PCA_PCAL) {
+		/* Read INT_STAT before it is cleared by the input-port read. */
+		ret = pca953x_read_regs(chip, PCAL953X_INT_STAT, int_stat);
+		if (ret)
+			return false;
+	}
+
 	ret = pca953x_read_regs(chip, chip->regs->input, cur_stat);
 	if (ret)
 		return false;
+
+	if (chip->driver_data & PCA_PCAL) {
+		/* Detect short pulses via INT_STAT. */
+		bitmap_and(trigger, int_stat, chip->irq_mask, gc->ngpio);
+
+		/* Apply filter for rising/falling edge selection. */
+		bitmap_replace(new_stat, chip->irq_trig_fall, chip->irq_trig_raise,
+			       cur_stat, gc->ngpio);
+
+		bitmap_and(int_stat, new_stat, trigger, gc->ngpio);
+	} else {
+		bitmap_zero(int_stat, gc->ngpio);
+	}
 
 	/* Remove output pins from the equation */
 	pca953x_read_regs(chip, chip->regs->direction, reg_direction);
···
 
 	if (bitmap_empty(chip->irq_trig_level_high, gc->ngpio) &&
 	    bitmap_empty(chip->irq_trig_level_low, gc->ngpio)) {
-		if (bitmap_empty(trigger, gc->ngpio))
+		if (bitmap_empty(trigger, gc->ngpio) &&
+		    bitmap_empty(int_stat, gc->ngpio))
 			return false;
 	}
 
···
 	bitmap_and(old_stat, chip->irq_trig_raise, new_stat, gc->ngpio);
 	bitmap_or(edges, old_stat, cur_stat, gc->ngpio);
 	bitmap_and(pending, edges, trigger, gc->ngpio);
+	bitmap_or(pending, pending, int_stat, gc->ngpio);
 
 	bitmap_and(cur_stat, new_stat, chip->irq_trig_level_high, gc->ngpio);
 	bitmap_and(cur_stat, cur_stat, chip->irq_mask, gc->ngpio);

drivers/gpio/gpio-rockchip.c

···
 	gc->ngpio = bank->nr_pins;
 	gc->label = bank->name;
 	gc->parent = bank->dev;
+	gc->can_sleep = true;
 
 	ret = gpiochip_add_data(gc, bank);
 	if (ret) {

drivers/gpio/gpiolib-shared.c

···
 	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. */
···
 	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(sizeof(*ref), GFP_KERNEL);
+	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)
 {
···
 	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;
···
 
 		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,
···
 				list_add_tail(&entry->list, &gpio_shared_list);
 			}
 
-			struct gpio_shared_ref *ref __free(kfree) =
-					kzalloc(sizeof(*ref), GFP_KERNEL);
-			if (!ref)
-				return -ENOMEM;
-
-			ref->fwnode = fwnode_handle_get(of_fwnode_handle(curr));
-			ref->flags = args.args[1];
-			mutex_init(&ref->lock);
-
 			if (strends(prop->name, "gpios"))
 				suffix = "-gpios";
 			else if (strends(prop->name, "gpio"))
···
 
 			/* We only set con_id if there's actually one. */
 			if (strcmp(prop->name, "gpios") && strcmp(prop->name, "gpio")) {
-				ref->con_id = kstrdup(prop->name, GFP_KERNEL);
-				if (!ref->con_id)
+				con_id = kstrdup(prop->name, GFP_KERNEL);
+				if (!con_id)
 					return -ENOMEM;
 
-				con_id_len = strlen(ref->con_id);
+				con_id_len = strlen(con_id);
 				suffix_len = strlen(suffix);
 
-				ref->con_id[con_id_len - suffix_len] = '\0';
+				con_id[con_id_len - suffix_len] = '\0';
 			}
 
-			ref->dev_id = ida_alloc(&gpio_shared_ida, GFP_KERNEL);
-			if (ref->dev_id < 0) {
-				kfree(ref->con_id);
+			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(&no_free_ptr(ref)->list, &entry->refs);
+			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;
+			}
 		}
 	}
 
···
 	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;
-
-	/*
-	 * FIXME: use device_is_compatible() once the reset-gpio drivers gains
-	 * a compatible string which it currently does not have.
-	 */
-	if (!strstarts(dev_name(consumer), "reset.gpio."))
 		return false;
 
 	/*
···
 		return false;
 
 	/*
-	 * 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.
+	 * 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.
 	 */
-	ret = fwnode_property_get_reference_args(ref->fwnode, "reset-gpios",
-						 NULL, 2, 0, &ref_args);
-	if (ret)
-		return false;
+	list_for_each_entry(real_ref, &entry->refs, list) {
+		if (real_ref == ref)
+			continue;
 
-	ret = fwnode_property_get_reference_args(reset_fwnode, "reset-gpios",
-						 NULL, 2, 0, &aux_args);
-	if (ret) {
+		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);
-		return false;
+		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;
 	}
 
-	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);
-	return match;
+	return false;
 }
 #else
 static bool gpio_shared_dev_is_reset_gpio(struct device *consumer,
···
 }
 #endif /* CONFIG_RESET_GPIO */
 
-int gpio_shared_add_proxy_lookup(struct device *consumer, unsigned long lflags)
+int gpio_shared_add_proxy_lookup(struct device *consumer, 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;
 
-	struct gpiod_lookup_table *lookup __free(kfree) =
-			kzalloc(struct_size(lookup, table, 2), GFP_KERNEL);
-	if (!lookup)
-		return -ENOMEM;
-
 	list_for_each_entry(entry, &gpio_shared_list, list) {
 		list_for_each_entry(ref, &entry->refs, list) {
-			if (!device_match_fwnode(consumer, ref->fwnode) &&
-			    !gpio_shared_dev_is_reset_gpio(consumer, entry, ref))
-				continue;
-
 			guard(mutex)(&ref->lock);
+
+			/*
+			 * FIXME: use device_is_compatible() once the reset-gpio
+			 * drivers gains a compatible string which it currently
+			 * does not have.
+			 */
+			if (!ref->fwnode && strstarts(dev_name(consumer), "reset.gpio.")) {
+				if (!gpio_shared_dev_is_reset_gpio(consumer, entry, ref))
+					continue;
+			} else if (!device_match_fwnode(consumer, 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)
···
 			if (!key)
 				return -ENOMEM;
 
+			lookup = kzalloc(struct_size(lookup, table, 2), GFP_KERNEL);
+			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->table[0] = GPIO_LOOKUP(no_free_ptr(key), 0,
 						       ref->con_id, lflags);
 
-			ref->lookup = no_free_ptr(lookup);
+			ref->lookup = lookup;
 			gpiod_add_lookup_table(ref->lookup);
 
 			return 0;
···
 			 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\n",
-				 fwnode_get_name(ref->fwnode));
+			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)
···
 		if (!device_match_fwnode(&gdev->dev, entry->fwnode))
 			continue;
 
-		/*
-		 * For some reason if we call synchronize_srcu() in GPIO core,
-		 * descent here and take this mutex and then recursively call
-		 * synchronize_srcu() again from gpiochip_remove() (which is
-		 * totally fine) called after gpio_shared_remove_adev(),
-		 * lockdep prints a false positive deadlock splat. Disable
-		 * lockdep here.
-		 */
-		lockdep_off();
 		list_for_each_entry(ref, &entry->refs, list) {
 			guard(mutex)(&ref->lock);
 
···
 
 			gpio_shared_remove_adev(&ref->adev);
 		}
-		lockdep_on();
 	}
 }
 
···
 {
 	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);
···
 	}
 }
 
+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;
 
 	list_for_each_entry_safe(entry, epos, &gpio_shared_list, list) {
-		if (list_count_nodes(&entry->refs) > 1)
+		if (gpio_shared_entry_is_really_shared(entry))
 			continue;
 
 		gpio_shared_drop_ref(list_first_entry(&entry->refs,

drivers/gpio/gpiolib-shared.h

···
 
 int gpio_device_setup_shared(struct gpio_device *gdev);
 void gpio_device_teardown_shared(struct gpio_device *gdev);
-int gpio_shared_add_proxy_lookup(struct device *consumer, unsigned long lflags);
+int gpio_shared_add_proxy_lookup(struct device *consumer, const char *con_id,
+				 unsigned long lflags);
 
 #else
 
···
 static inline void gpio_device_teardown_shared(struct gpio_device *gdev) { }
 
 static inline int gpio_shared_add_proxy_lookup(struct device *consumer,
+					       const char *con_id,
 					       unsigned long lflags)
 {
 	return 0;

drivers/gpio/gpiolib.c

···
 	gdev->ngpio = gc->ngpio;
 	gdev->can_sleep = gc->can_sleep;
 
+	rwlock_init(&gdev->line_state_lock);
+	RAW_INIT_NOTIFIER_HEAD(&gdev->line_state_notifier);
+	BLOCKING_INIT_NOTIFIER_HEAD(&gdev->device_notifier);
+
+	ret = init_srcu_struct(&gdev->srcu);
+	if (ret)
+		goto err_free_label;
+
+	ret = init_srcu_struct(&gdev->desc_srcu);
+	if (ret)
+		goto err_cleanup_gdev_srcu;
+
 	scoped_guard(mutex, &gpio_devices_lock) {
 		/*
 		 * TODO: this allocates a Linux GPIO number base in the global
···
 			if (base < 0) {
 				ret = base;
 				base = 0;
-				goto err_free_label;
+				goto err_cleanup_desc_srcu;
 			}
 
 			/*
···
 		ret = gpiodev_add_to_list_unlocked(gdev);
 		if (ret) {
 			gpiochip_err(gc, "GPIO integer space overlap, cannot add chip\n");
-			goto err_free_label;
+			goto err_cleanup_desc_srcu;
 		}
 	}
-
-	rwlock_init(&gdev->line_state_lock);
-	RAW_INIT_NOTIFIER_HEAD(&gdev->line_state_notifier);
-	BLOCKING_INIT_NOTIFIER_HEAD(&gdev->device_notifier);
-
-	ret = init_srcu_struct(&gdev->srcu);
-	if (ret)
-		goto err_remove_from_list;
-
-	ret = init_srcu_struct(&gdev->desc_srcu);
-	if (ret)
-		goto err_cleanup_gdev_srcu;
 
 #ifdef CONFIG_PINCTRL
 	INIT_LIST_HEAD(&gdev->pin_ranges);
···
 
 	ret = gpiochip_set_names(gc);
 	if (ret)
-		goto err_cleanup_desc_srcu;
+		goto err_remove_from_list;
 
 	ret = gpiochip_init_valid_mask(gc);
 	if (ret)
-		goto err_cleanup_desc_srcu;
+		goto err_remove_from_list;
 
 	for (desc_index = 0; desc_index < gc->ngpio; desc_index++) {
 		struct gpio_desc *desc = &gdev->descs[desc_index];
···
 	of_gpiochip_remove(gc);
 err_free_valid_mask:
 	gpiochip_free_valid_mask(gc);
-err_cleanup_desc_srcu:
-	cleanup_srcu_struct(&gdev->desc_srcu);
-err_cleanup_gdev_srcu:
-	cleanup_srcu_struct(&gdev->srcu);
 err_remove_from_list:
 	scoped_guard(mutex, &gpio_devices_lock)
 		list_del_rcu(&gdev->list);
···
 		gpio_device_put(gdev);
 		goto err_print_message;
 	}
+err_cleanup_desc_srcu:
+	cleanup_srcu_struct(&gdev->desc_srcu);
+err_cleanup_gdev_srcu:
+	cleanup_srcu_struct(&gdev->srcu);
 err_free_label:
 	kfree_const(gdev->label);
 err_free_descs:
···
 }
 EXPORT_SYMBOL_GPL(gpiod_remove_hogs);
 
-static struct gpiod_lookup_table *gpiod_find_lookup_table(struct device *dev)
+static bool gpiod_match_lookup_table(struct device *dev,
+				     const struct gpiod_lookup_table *table)
 {
 	const char *dev_id = dev ? dev_name(dev) : NULL;
-	struct gpiod_lookup_table *table;
 
-	list_for_each_entry(table, &gpio_lookup_list, list) {
-		if (table->dev_id && dev_id) {
-			/*
-			 * Valid strings on both ends, must be identical to have
-			 * a match
-			 */
-			if (!strcmp(table->dev_id, dev_id))
-				return table;
-		} else {
-			/*
-			 * One of the pointers is NULL, so both must be to have
-			 * a match
-			 */
-			if (dev_id == table->dev_id)
-				return table;
-		}
+	lockdep_assert_held(&gpio_lookup_lock);
+
+	if (table->dev_id && dev_id) {
+		/*
+		 * Valid strings on both ends, must be identical to have
+		 * a match
+		 */
+		if (!strcmp(table->dev_id, dev_id))
+			return true;
+	} else {
+		/*
+		 * One of the pointers is NULL, so both must be to have
+		 * a match
+		 */
+		if (dev_id == table->dev_id)
+			return true;
 	}
 
-	return NULL;
+	return false;
 }
 
-static struct gpio_desc *gpiod_find(struct device *dev, const char *con_id,
-				    unsigned int idx, unsigned long *flags)
+static struct gpio_desc *gpio_desc_table_match(struct device *dev, const char *con_id,
+					       unsigned int idx, unsigned long *flags,
+					       struct gpiod_lookup_table *table)
 {
-	struct gpio_desc *desc = ERR_PTR(-ENOENT);
-	struct gpiod_lookup_table *table;
+	struct gpio_desc *desc;
 	struct gpiod_lookup *p;
 	struct gpio_chip *gc;
 
-	guard(mutex)(&gpio_lookup_lock);
-
-	table = gpiod_find_lookup_table(dev);
-	if (!table)
-		return desc;
+	lockdep_assert_held(&gpio_lookup_lock);
 
 	for (p = &table->table[0]; p->key; p++) {
 		/* idx must always match exactly */
···
 		return desc;
 	}
 
-	return desc;
+	return NULL;
+}
+
+static struct gpio_desc *gpiod_find(struct device *dev, const char *con_id,
+				    unsigned int idx, unsigned long *flags)
+{
+	struct gpiod_lookup_table *table;
+	struct gpio_desc *desc;
+
+	guard(mutex)(&gpio_lookup_lock);
+
+	list_for_each_entry(table, &gpio_lookup_list, list) {
+		if (!gpiod_match_lookup_table(dev, table))
+			continue;
+
+		desc = gpio_desc_table_match(dev, con_id, idx, flags, table);
+		if (!desc)
+			continue;
+
+		/* On IS_ERR() or match. */
+		return desc;
+	}
+
+	return ERR_PTR(-ENOENT);
 }
 
 static int platform_gpio_count(struct device *dev, const char *con_id)
···
 	unsigned int count = 0;
 
 	scoped_guard(mutex, &gpio_lookup_lock) {
-		table = gpiod_find_lookup_table(dev);
-		if (!table)
-			return -ENOENT;
+		list_for_each_entry(table, &gpio_lookup_list, list) {
+			if (!gpiod_match_lookup_table(dev, table))
+				continue;
 
-		for (p = &table->table[0]; p->key; p++) {
-			if ((con_id && p->con_id && !strcmp(con_id, p->con_id)) ||
-			    (!con_id && !p->con_id))
-				count++;
+			for (p = &table->table[0]; p->key; p++) {
+				if ((con_id && p->con_id &&
+				    !strcmp(con_id, p->con_id)) ||
+				    (!con_id && !p->con_id))
+					count++;
+			}
 		}
 	}
 
···
 			 * lookup table for the proxy device as previously
 			 * we only knew the consumer's fwnode.
 			 */
-			ret = gpio_shared_add_proxy_lookup(consumer, lookupflags);
+			ret = gpio_shared_add_proxy_lookup(consumer, con_id,
+							   lookupflags);
 			if (ret)
 				return ERR_PTR(ret);