Merge tag 'gpio-updates-for-v6.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/brgl/linux

Pull gpio updates from Bartosz Golaszewski:
 "We have two new drivers, an assortment of updates and cleanups to many
  others, and first part of the big rework of the core GPIOLIB that's
  currently underway.

  Add to that some code shrink in the character device module and
  updates to DT bindings and that's pretty much it.

  Core GPIOLIB:
   - protect the global list of GPIO devices with a read-write semaphore
     as it is rarely modified but can be traversed by multiple readers
     at once
   - remove GPIO devices from the global list when they are
     *unregistered* and not when they are *released* (which only happens
     when the last reference is dropped) as this may lead to a
     successful lookup of an unregistered device
   - remove the unnecessary "extra_checks" switch
   - rename functions that are called with a lock taken
   - remove duplicate includes

  Character device handling:
   - use locking guards to reduce the code size
   - allocate the big linereq structure using the more suitable
     kvzalloc()
   - redulce the size of critical sections
   - improve documentation
   - move the debounce_period_us field out of struct gpio_desc

  New drivers:
   - Nuvoton NPCM SGPIO driver for BMC NPCM7xx/NPCM8xx
   - Realtek DHC (Digital Home Center) SoC GPIO driver

  Driver improvements:
   - replace gpiochip_is_requested() with a safer alternative in the
     form of gpiochip_dup_line_label() as the former returns a pointer
     to a string that can be deleted
   - implement the dbg_show() callback in gpio-sim
   - improve the coding style for local variables by removing
     unnecessary tabs
   - use generic device properties instead of OF variants in gpio-mmio
   - use the preferred coding style for __free() in gpio-mockup
   - reuse PM ops from the gpio-tangier in gpio-elkhartlake
   - rework PM and use cleanup helpers in gpio-tangier
   - fix the EIC configuration in gpio-pmic-eic-sprd
   - remove the unneeded call to platform_set_drvdata() in gpio-sifive
   - use generic GPIO helpers for driver callbacks in gpio-dwapb
   - add clock support on certain pins of gpio-ixp4xx
   - don't use the core-specific DEBUG_GPIO switch in drivers
   - kerneldoc improvements

  DT bindings:
   - add bindings for the new Realtek and Nuvoton devices
   - allow gpio-ranges in gpio-dwapb
   - support GPIO hogs in gpio-rockchip
   - describe the label property in gpio-zynqmp-modepin

  Other:
   - header cleanups
   - forward declarations cleanups"

* tag 'gpio-updates-for-v6.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/brgl/linux: (55 commits)
  gpiolib: replace the GPIO device mutex with a read-write semaphore
  gpiolib: remove the GPIO device from the list when it's unregistered
  gpio: nuvoton: Add Nuvoton NPCM sgpio driver
  dt-bindings: gpio: add NPCM sgpio driver bindings
  gpio: rtd: Add support for Realtek DHC(Digital Home Center) RTD SoCs
  dt-bindings: gpio: realtek: Add realtek,rtd-gpio
  gpio: pmic-eic-sprd: Configure the bit corresponding to the EIC through offset
  gpio: dwapb: Use generic request, free and set_config
  gpio: sysfs: drop tabs from local variable declarations
  gpiolib: drop tabs from local variable declarations
  gpiolib: remove extra_checks
  gpio: tps65219: don't use CONFIG_DEBUG_GPIO
  gpiolib: cdev: replace locking wrappers for gpio_device with guards
  gpiolib: cdev: replace locking wrappers for config_mutex with guards
  gpiolib: cdev: allocate linereq using kvzalloc()
  gpiolib: cdev: include overflow.h
  gpiolib: cdev: reduce locking in gpio_desc_to_lineinfo()
  gpiolib: cdev: improve documentation of get/set values
  gpiolib: cdev: fully adopt guard() and scoped_guard()
  gpiolib: remove debounce_period_us from struct gpio_desc
  ...

1 files changed, 134 insertions, 138 deletions

diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index 95d2a7b2ea3e..4c93cf73a826 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>
@@ -15,6 +16,7 @@
 #include <linux/kernel.h>
 #include <linux/list.h>
 #include <linux/module.h>
+#include <linux/mutex.h>
 #include <linux/of.h>
 #include <linux/pinctrl/consumer.h>
 #include <linux/seq_file.h>
@@ -45,19 +47,6 @@
  * GPIOs can sometimes cost only an instruction or two per bit.
  */
 
-
-/* When debugging, extend minimal trust to callers and platform code.
- * Also emit diagnostic messages that may help initial bringup, when
- * board setup or driver bugs are most common.
- *
- * Otherwise, minimize overhead in what may be bitbanging codepaths.
- */
-#ifdef	DEBUG
-#define	extra_checks	1
-#else
-#define	extra_checks	0
-#endif
-
 /* Device and char device-related information */
 static DEFINE_IDA(gpio_ida);
 static dev_t gpio_devt;
@@ -94,7 +83,9 @@ DEFINE_SPINLOCK(gpio_lock);
 
 static DEFINE_MUTEX(gpio_lookup_lock);
 static LIST_HEAD(gpio_lookup_list);
+
 LIST_HEAD(gpio_devices);
+DECLARE_RWSEM(gpio_devices_sem);
 
 static DEFINE_MUTEX(gpio_machine_hogs_mutex);
 static LIST_HEAD(gpio_machine_hogs);
@@ -126,20 +117,15 @@ 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(rwsem_read, &gpio_devices_sem) {
+		list_for_each_entry(gdev, &gpio_devices, list) {
+			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);
 
@@ -255,6 +241,20 @@ int gpio_device_get_base(struct gpio_device *gdev)
 EXPORT_SYMBOL_GPL(gpio_device_get_base);
 
 /**
+ * gpio_device_get_label() - Get the label of this GPIO device
+ * @gdev: GPIO device
+ *
+ * Returns:
+ * Pointer to the string containing the GPIO device label. The string's
+ * lifetime is tied to that of the underlying GPIO device.
+ */
+const char *gpio_device_get_label(struct gpio_device *gdev)
+{
+	return gdev->label;
+}
+EXPORT_SYMBOL(gpio_device_get_label);
+
+/**
  * gpio_device_get_chip() - Get the gpio_chip implementation of this GPIO device
  * @gdev: GPIO device
  *
@@ -276,7 +276,7 @@ struct gpio_chip *gpio_device_get_chip(struct gpio_device *gdev)
 EXPORT_SYMBOL_GPL(gpio_device_get_chip);
 
 /* dynamic allocation of GPIOs, e.g. on a hotplugged device */
-static int gpiochip_find_base(int ngpio)
+static int gpiochip_find_base_unlocked(int ngpio)
 {
 	struct gpio_device *gdev;
 	int base = GPIO_DYNAMIC_BASE;
@@ -349,7 +349,7 @@ EXPORT_SYMBOL_GPL(gpiod_get_direction);
  * Return -EBUSY if the new chip overlaps with some other chip's integer
  * space.
  */
-static int gpiodev_add_to_list(struct gpio_device *gdev)
+static int gpiodev_add_to_list_unlocked(struct gpio_device *gdev)
 {
 	struct gpio_device *prev, *next;
 
@@ -398,26 +398,21 @@ static int gpiodev_add_to_list(struct gpio_device *gdev)
 static struct gpio_desc *gpio_name_to_desc(const char * const name)
 {
 	struct gpio_device *gdev;
-	unsigned long flags;
 
 	if (!name)
 		return NULL;
 
-	spin_lock_irqsave(&gpio_lock, flags);
+	guard(rwsem_read)(&gpio_devices_sem);
 
 	list_for_each_entry(gdev, &gpio_devices, list) {
 		struct gpio_desc *desc;
 
 		for_each_gpio_desc(gdev->chip, desc) {
-			if (desc->name && !strcmp(desc->name, name)) {
-				spin_unlock_irqrestore(&gpio_lock, flags);
+			if (desc->name && !strcmp(desc->name, name))
 				return desc;
-			}
 		}
 	}
 
-	spin_unlock_irqrestore(&gpio_lock, flags);
-
 	return NULL;
 }
 
@@ -655,11 +650,6 @@ EXPORT_SYMBOL_GPL(gpiochip_line_is_valid);
 static void gpiodev_release(struct device *dev)
 {
 	struct gpio_device *gdev = to_gpio_device(dev);
-	unsigned long flags;
-
-	spin_lock_irqsave(&gpio_lock, flags);
-	list_del(&gdev->list);
-	spin_unlock_irqrestore(&gpio_lock, flags);
 
 	ida_free(&gpio_ida, gdev->id);
 	kfree_const(gdev->label);
@@ -817,7 +807,6 @@ 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;
 	int base = 0;
 	int ret = 0;
@@ -882,49 +871,46 @@ int gpiochip_add_data_with_key(struct gpio_chip *gc, void *data,
 
 	gdev->ngpio = gc->ngpio;
 
-	spin_lock_irqsave(&gpio_lock, flags);
+	scoped_guard(rwsem_write, &gpio_devices_sem) {
+		/*
+		 * 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;
 
-	/*
-	 * 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(gc->ngpio);
 		if (base < 0) {
-			spin_unlock_irqrestore(&gpio_lock, flags);
-			ret = base;
-			base = 0;
+			base = gpiochip_find_base_unlocked(gc->ngpio);
+			if (base < 0) {
+				ret = base;
+				base = 0;
+				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;
+
+		ret = gpiodev_add_to_list_unlocked(gdev);
+		if (ret) {
+			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;
 
-	ret = gpiodev_add_to_list(gdev);
-	if (ret) {
-		spin_unlock_irqrestore(&gpio_lock, flags);
-		chip_err(gc, "GPIO integer space overlap, cannot add chip\n");
-		goto err_free_label;
+		for (i = 0; i < gc->ngpio; i++)
+			gdev->descs[i].gdev = gdev;
 	}
 
-	for (i = 0; i < gc->ngpio; i++)
-		gdev->descs[i].gdev = gdev;
-
-	spin_unlock_irqrestore(&gpio_lock, flags);
-
 	BLOCKING_INIT_NOTIFIER_HEAD(&gdev->line_state_notifier);
 	BLOCKING_INIT_NOTIFIER_HEAD(&gdev->device_notifier);
 	init_rwsem(&gdev->sem);
@@ -1015,9 +1001,8 @@ err_free_gpiochip_mask:
 		goto err_print_message;
 	}
 err_remove_from_list:
-	spin_lock_irqsave(&gpio_lock, flags);
-	list_del(&gdev->list);
-	spin_unlock_irqrestore(&gpio_lock, flags);
+	scoped_guard(rwsem_write, &gpio_devices_sem)
+		list_del(&gdev->list);
 err_free_label:
 	kfree_const(gdev->label);
 err_free_descs:
@@ -1048,8 +1033,8 @@ 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;
+	unsigned long flags;
+	unsigned int i;
 
 	down_write(&gdev->sem);
 
@@ -1071,7 +1056,7 @@ void gpiochip_remove(struct gpio_chip *gc)
 
 	spin_lock_irqsave(&gpio_lock, flags);
 	for (i = 0; i < gdev->ngpio; i++) {
-		if (gpiochip_is_requested(gc, i))
+		if (test_bit(FLAG_REQUESTED, &gdev->descs[i].flags))
 			break;
 	}
 	spin_unlock_irqrestore(&gpio_lock, flags);
@@ -1080,6 +1065,9 @@ void gpiochip_remove(struct gpio_chip *gc)
 		dev_crit(&gdev->dev,
 			 "REMOVING GPIOCHIP WITH GPIOS STILL REQUESTED\n");
 
+	scoped_guard(rwsem_write, &gpio_devices_sem)
+		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
@@ -1126,7 +1114,7 @@ struct gpio_device *gpio_device_find(void *data,
 	 */
 	might_sleep();
 
-	guard(spinlock_irqsave)(&gpio_lock);
+	guard(rwsem_read)(&gpio_devices_sem);
 
 	list_for_each_entry(gdev, &gpio_devices, list) {
 		if (gdev->chip && match(gdev->chip, data))
@@ -2185,10 +2173,10 @@ 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;
-	int			ret;
-	unsigned long		flags;
-	unsigned		offset;
+	struct gpio_chip *gc = desc->gdev->chip;
+	unsigned long flags;
+	unsigned int offset;
+	int ret;
 
 	if (label) {
 		label = kstrdup_const(label, GFP_KERNEL);
@@ -2300,9 +2288,9 @@ int gpiod_request(struct gpio_desc *desc, const char *label)
 
 static bool gpiod_free_commit(struct gpio_desc *desc)
 {
-	bool			ret = false;
-	unsigned long		flags;
-	struct gpio_chip	*gc;
+	struct gpio_chip *gc;
+	unsigned long flags;
+	bool ret = false;
 
 	might_sleep();
 
@@ -2331,9 +2319,6 @@ static bool gpiod_free_commit(struct gpio_desc *desc)
 #ifdef CONFIG_OF_DYNAMIC
 		desc->hog = NULL;
 #endif
-#ifdef CONFIG_GPIO_CDEV
-		WRITE_ONCE(desc->debounce_period_us, 0);
-#endif
 		ret = true;
 	}
 
@@ -2353,38 +2338,53 @@ void gpiod_free(struct gpio_desc *desc)
 		return;
 
 	if (!gpiod_free_commit(desc))
-		WARN_ON(extra_checks);
+		WARN_ON(1);
 
 	module_put(desc->gdev->owner);
 	gpio_device_put(desc->gdev);
 }
 
 /**
- * gpiochip_is_requested - return string iff signal was requested
- * @gc: controller managing the signal
- * @offset: of signal within controller's 0..(ngpio - 1) range
+ * gpiochip_dup_line_label - Get a copy of the consumer label.
+ * @gc: GPIO chip controlling this line.
+ * @offset: Hardware offset of the line.
  *
- * Returns NULL if the GPIO is not currently requested, else a string.
- * The string returned is the label passed to gpio_request(); if none has been
- * passed it is a meaningless, non-NULL constant.
+ * Returns:
+ * Pointer to a copy of the consumer label if the line is requested or NULL
+ * if it's not. If a valid pointer was returned, it must be freed using
+ * kfree(). In case of a memory allocation error, the function returns %ENOMEM.
  *
- * This function is for use by GPIO controller drivers.  The label can
- * help with diagnostics, and knowing that the signal is used as a GPIO
- * can help avoid accidentally multiplexing it to another controller.
+ * Must not be called from atomic context.
  */
-const char *gpiochip_is_requested(struct gpio_chip *gc, unsigned int offset)
+char *gpiochip_dup_line_label(struct gpio_chip *gc, unsigned int offset)
 {
 	struct gpio_desc *desc;
+	char *label;
 
 	desc = gpiochip_get_desc(gc, offset);
 	if (IS_ERR(desc))
 		return NULL;
 
-	if (test_bit(FLAG_REQUESTED, &desc->flags) == 0)
+	guard(spinlock_irqsave)(&gpio_lock);
+
+	if (!test_bit(FLAG_REQUESTED, &desc->flags))
 		return NULL;
-	return desc->label;
+
+	/*
+	 * 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);
+	if (!label)
+		return ERR_PTR(-ENOMEM);
+
+	return label;
 }
-EXPORT_SYMBOL_GPL(gpiochip_is_requested);
+EXPORT_SYMBOL_GPL(gpiochip_dup_line_label);
 
 /**
  * gpiochip_request_own_desc - Allow GPIO chip to request its own descriptor
@@ -2564,8 +2564,8 @@ 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;
+	struct gpio_chip *gc;
+	int ret = 0;
 
 	VALIDATE_DESC(desc);
 	gc = desc->gdev->chip;
@@ -2914,7 +2914,7 @@ 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_chip	*gc;
+	struct gpio_chip *gc;
 	int value;
 
 	gc = desc->gdev->chip;
@@ -3209,7 +3209,7 @@ 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;
+	struct gpio_chip *gc;
 
 	gc = desc->gdev->chip;
 	trace_gpio_value(desc_to_gpio(desc), 0, value);
@@ -3716,7 +3716,7 @@ EXPORT_SYMBOL_GPL(gpiochip_line_is_persistent);
  */
 int gpiod_get_raw_value_cansleep(const struct gpio_desc *desc)
 {
-	might_sleep_if(extra_checks);
+	might_sleep();
 	VALIDATE_DESC(desc);
 	return gpiod_get_raw_value_commit(desc);
 }
@@ -3735,7 +3735,7 @@ int gpiod_get_value_cansleep(const struct gpio_desc *desc)
 {
 	int value;
 
-	might_sleep_if(extra_checks);
+	might_sleep();
 	VALIDATE_DESC(desc);
 	value = gpiod_get_raw_value_commit(desc);
 	if (value < 0)
@@ -3766,7 +3766,7 @@ int gpiod_get_raw_array_value_cansleep(unsigned int array_size,
 				       struct gpio_array *array_info,
 				       unsigned long *value_bitmap)
 {
-	might_sleep_if(extra_checks);
+	might_sleep();
 	if (!desc_array)
 		return -EINVAL;
 	return gpiod_get_array_value_complex(true, true, array_size,
@@ -3792,7 +3792,7 @@ int gpiod_get_array_value_cansleep(unsigned int array_size,
 				   struct gpio_array *array_info,
 				   unsigned long *value_bitmap)
 {
-	might_sleep_if(extra_checks);
+	might_sleep();
 	if (!desc_array)
 		return -EINVAL;
 	return gpiod_get_array_value_complex(false, true, array_size,
@@ -3813,7 +3813,7 @@ EXPORT_SYMBOL_GPL(gpiod_get_array_value_cansleep);
  */
 void gpiod_set_raw_value_cansleep(struct gpio_desc *desc, int value)
 {
-	might_sleep_if(extra_checks);
+	might_sleep();
 	VALIDATE_DESC_VOID(desc);
 	gpiod_set_raw_value_commit(desc, value);
 }
@@ -3831,7 +3831,7 @@ EXPORT_SYMBOL_GPL(gpiod_set_raw_value_cansleep);
  */
 void gpiod_set_value_cansleep(struct gpio_desc *desc, int value)
 {
-	might_sleep_if(extra_checks);
+	might_sleep();
 	VALIDATE_DESC_VOID(desc);
 	gpiod_set_value_nocheck(desc, value);
 }
@@ -3854,7 +3854,7 @@ int gpiod_set_raw_array_value_cansleep(unsigned int array_size,
 				       struct gpio_array *array_info,
 				       unsigned long *value_bitmap)
 {
-	might_sleep_if(extra_checks);
+	might_sleep();
 	if (!desc_array)
 		return -EINVAL;
 	return gpiod_set_array_value_complex(true, true, array_size, desc_array,
@@ -3896,7 +3896,7 @@ int gpiod_set_array_value_cansleep(unsigned int array_size,
 				   struct gpio_array *array_info,
 				   unsigned long *value_bitmap)
 {
-	might_sleep_if(extra_checks);
+	might_sleep();
 	if (!desc_array)
 		return -EINVAL;
 	return gpiod_set_array_value_complex(false, true, array_size,
@@ -4696,13 +4696,11 @@ core_initcall(gpiolib_dev_init);
 
 static void gpiolib_dbg_show(struct seq_file *s, struct gpio_device *gdev)
 {
-	struct gpio_chip	*gc = gdev->chip;
-	struct gpio_desc	*desc;
-	unsigned		gpio = gdev->base;
-	int			value;
-	bool			is_out;
-	bool			is_irq;
-	bool			active_low;
+	struct gpio_chip *gc = gdev->chip;
+	bool active_low, is_irq, is_out;
+	unsigned int gpio = gdev->base;
+	struct gpio_desc *desc;
+	int value;
 
 	for_each_gpio_desc(gc, desc) {
 		if (test_bit(FLAG_REQUESTED, &desc->flags)) {
@@ -4727,35 +4725,33 @@ static void gpiolib_dbg_show(struct seq_file *s, struct gpio_device *gdev)
 
 static void *gpiolib_seq_start(struct seq_file *s, loff_t *pos)
 {
-	unsigned long flags;
 	struct gpio_device *gdev = NULL;
 	loff_t index = *pos;
 
 	s->private = "";
 
-	spin_lock_irqsave(&gpio_lock, flags);
-	list_for_each_entry(gdev, &gpio_devices, list)
-		if (index-- == 0) {
-			spin_unlock_irqrestore(&gpio_lock, flags);
+	guard(rwsem_read)(&gpio_devices_sem);
+
+	list_for_each_entry(gdev, &gpio_devices, list) {
+		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);
+	scoped_guard(rwsem_read, &gpio_devices_sem) {
+		if (list_is_last(&gdev->list, &gpio_devices))
+			ret = NULL;
+		else
+			ret = list_first_entry(&gdev->list, struct gpio_device,
+					       list);
+	}
 
 	s->private = "\n";
 	++*pos;