gpiolib: Update the kernel documentation - add Return sections

$ scripts/kernel-doc -v -none -Wall drivers/gpio/gpiolib* 2>&1 | grep -w warning | wc -l
67

Fix these by adding Return sections. While at it, make sure all of
Return sections use the same style.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Randy Dunlap <rdunlap@infradead.org>
Tested-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20240828164449.2777666-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

Author: andy-shev

drivers/gpio/gpiolib-acpi.c

@@ -153,8 +153,12 @@ static int acpi_gpiochip_find(struct gpio_chip *gc, const void *data)
  * @path:	ACPI GPIO controller full path name, (e.g. "\\_SB.GPO1")
  * @pin:	ACPI GPIO pin number (0-based, controller-relative)
  *
- * Return: GPIO descriptor to use with Linux generic GPIO API, or ERR_PTR
- * error value. Specifically returns %-EPROBE_DEFER if the referenced GPIO
+ * Returns:
+ * GPIO descriptor to use with Linux generic GPIO API.
+ * If the GPIO cannot be translated or there is an error an ERR_PTR is
+ * returned.
+ *
+ * Specifically returns %-EPROBE_DEFER if the referenced GPIO
  * controller does not have GPIO chip registered at the moment. This is to
  * support probe deferral.
  */
@@ -224,6 +228,9 @@ EXPORT_SYMBOL_GPL(acpi_gpio_get_irq_resource);
  *			       I/O resource or return False if not.
  * @ares:	Pointer to the ACPI resource to fetch
  * @agpio:	Pointer to a &struct acpi_resource_gpio to store the output pointer
+ *
+ * Returns:
+ * %true if GpioIo resource is found, %false otherwise.
  */
 bool acpi_gpio_get_io_resource(struct acpi_resource *ares,
 			       struct acpi_resource_gpio **agpio)
@@ -876,7 +883,9 @@ static int acpi_gpio_property_lookup(struct fwnode_handle *fwnode,
  * that case @index is used to select the GPIO entry in the property value
  * (in case of multiple).
  *
- * If the GPIO cannot be translated or there is an error, an ERR_PTR is
+ * Returns:
+ * GPIO descriptor to use with Linux generic GPIO API.
+ * If the GPIO cannot be translated or there is an error an ERR_PTR is
  * returned.
  *
  * Note: if the GPIO resource has multiple entries in the pin list, this
@@ -924,6 +933,8 @@ static struct gpio_desc *acpi_get_gpiod_by_index(struct acpi_device *adev,
  * resource with the relevant information from a data-only ACPI firmware node
  * and uses that to obtain the GPIO descriptor to return.
  *
+ * Returns:
+ * GPIO descriptor to use with Linux generic GPIO API.
  * If the GPIO cannot be translated or there is an error an ERR_PTR is
  * returned.
  */
@@ -1042,7 +1053,8 @@ struct gpio_desc *acpi_find_gpio(struct fwnode_handle *fwnode,
  * The GPIO is considered wake capable if the GpioInt resource specifies
  * SharedAndWake or ExclusiveAndWake.
  *
- * Return: Linux IRQ number (> %0) on success, negative errno on failure.
+ * Returns:
+ * Linux IRQ number (> 0) on success, negative errno on failure.
  */
 int acpi_dev_gpio_irq_wake_get_by(struct acpi_device *adev, const char *con_id, int index,
 				  bool *wake_capable)
@@ -1429,7 +1441,7 @@ static int acpi_find_gpio_count(struct acpi_resource *ares, void *data)
  * @fwnode:	firmware node of the GPIO consumer
  * @con_id:	function within the GPIO consumer
  *
- * Return:
+ * Returns:
  * The number of GPIOs associated with a firmware node / function or %-ENOENT,
  * if no GPIO has been assigned to the requested function.
  */

drivers/gpio/gpiolib-cdev.c

@@ -2748,7 +2748,9 @@ static ssize_t lineinfo_watch_read(struct file *file, char __user *buf,
  * gpio_chrdev_open() - open the chardev for ioctl operations
  * @inode: inode for this chardev
  * @file: file struct for storing private data
- * Returns 0 on success
+ *
+ * Returns:
+ * 0 on success, or negative errno on failure.
  */
 static int gpio_chrdev_open(struct inode *inode, struct file *file)
 {
@@ -2814,7 +2816,9 @@ static int gpio_chrdev_open(struct inode *inode, struct file *file)
  * gpio_chrdev_release() - close chardev after ioctl operations
  * @inode: inode for this chardev
  * @file: file struct for storing private data
- * Returns 0 on success
+ *
+ * Returns:
+ * 0 on success, or negative errno on failure.
  */
 static int gpio_chrdev_release(struct inode *inode, struct file *file)
 {

drivers/gpio/gpiolib-devres.c

@@ -52,6 +52,11 @@ static int devm_gpiod_match_array(struct device *dev, void *res, void *data)
  * Managed gpiod_get(). GPIO descriptors returned from this function are
  * automatically disposed on driver detach. See gpiod_get() for detailed
  * information about behavior and return values.
+ *
+ * Returns:
+ * The GPIO descriptor corresponding to the function @con_id of device
+ * dev, %-ENOENT if no GPIO has been assigned to the requested function, or
+ * another IS_ERR() code if an error occurred while trying to acquire the GPIO.
  */
 struct gpio_desc *__must_check devm_gpiod_get(struct device *dev,
 					      const char *con_id,
@@ -70,6 +75,11 @@ EXPORT_SYMBOL_GPL(devm_gpiod_get);
  * Managed gpiod_get_optional(). GPIO descriptors returned from this function
  * are automatically disposed on driver detach. See gpiod_get_optional() for
  * detailed information about behavior and return values.
+ *
+ * Returns:
+ * The GPIO descriptor corresponding to the function @con_id of device
+ * dev, NULL if no GPIO has been assigned to the requested function, or
+ * another IS_ERR() code if an error occurred while trying to acquire the GPIO.
  */
 struct gpio_desc *__must_check devm_gpiod_get_optional(struct device *dev,
 						       const char *con_id,
@@ -89,6 +99,11 @@ EXPORT_SYMBOL_GPL(devm_gpiod_get_optional);
  * Managed gpiod_get_index(). GPIO descriptors returned from this function are
  * automatically disposed on driver detach. See gpiod_get_index() for detailed
  * information about behavior and return values.
+ *
+ * Returns:
+ * The GPIO descriptor corresponding to the function @con_id of device
+ * dev, %-ENOENT if no GPIO has been assigned to the requested function, or
+ * another IS_ERR() code if an error occurred while trying to acquire the GPIO.
  */
 struct gpio_desc *__must_check devm_gpiod_get_index(struct device *dev,
 						    const char *con_id,
@@ -141,8 +156,10 @@ EXPORT_SYMBOL_GPL(devm_gpiod_get_index);
  * GPIO descriptors returned from this function are automatically disposed on
  * driver detach.
  *
- * On successful request the GPIO pin is configured in accordance with
- * provided @flags.
+ * Returns:
+ * The GPIO descriptor corresponding to the function @con_id of device
+ * dev, %-ENOENT if no GPIO has been assigned to the requested function, or
+ * another IS_ERR() code if an error occurred while trying to acquire the GPIO.
  */
 struct gpio_desc *devm_fwnode_gpiod_get_index(struct device *dev,
 					      struct fwnode_handle *fwnode,
@@ -182,6 +199,11 @@ EXPORT_SYMBOL_GPL(devm_fwnode_gpiod_get_index);
  * function are automatically disposed on driver detach. See
  * gpiod_get_index_optional() for detailed information about behavior and
  * return values.
+ *
+ * Returns:
+ * The GPIO descriptor corresponding to the function @con_id of device
+ * dev, %NULL if no GPIO has been assigned to the requested function, or
+ * another IS_ERR() code if an error occurred while trying to acquire the GPIO.
  */
 struct gpio_desc *__must_check devm_gpiod_get_index_optional(struct device *dev,
 							     const char *con_id,
@@ -207,6 +229,12 @@ EXPORT_SYMBOL_GPL(devm_gpiod_get_index_optional);
  * Managed gpiod_get_array(). GPIO descriptors returned from this function are
  * automatically disposed on driver detach. See gpiod_get_array() for detailed
  * information about behavior and return values.
+ *
+ * Returns:
+ * The GPIO descriptors corresponding to the function @con_id of device
+ * dev, %-ENOENT if no GPIO has been assigned to the requested function,
+ * or another IS_ERR() code if an error occurred while trying to acquire
+ * the GPIOs.
  */
 struct gpio_descs *__must_check devm_gpiod_get_array(struct device *dev,
 						     const char *con_id,
@@ -243,6 +271,12 @@ EXPORT_SYMBOL_GPL(devm_gpiod_get_array);
  * function are automatically disposed on driver detach.
  * See gpiod_get_array_optional() for detailed information about behavior and
  * return values.
+ *
+ * Returns:
+ * The GPIO descriptors corresponding to the function @con_id of device
+ * dev, %NULL if no GPIO has been assigned to the requested function,
+ * or another IS_ERR() code if an error occurred while trying to acquire
+ * the GPIOs.
  */
 struct gpio_descs *__must_check
 devm_gpiod_get_array_optional(struct device *dev, const char *con_id,

drivers/gpio/gpiolib-legacy.c

@@ -22,6 +22,9 @@ EXPORT_SYMBOL_GPL(gpio_free);
  * @label:	a literal description string of this GPIO
  *
  * **DEPRECATED** This function is deprecated and must not be used in new code.
+ *
+ * Returns:
+ * 0 on success, or negative errno on failure.
  */
 int gpio_request_one(unsigned gpio, unsigned long flags, const char *label)
 {

drivers/gpio/gpiolib-of.c

@@ -46,16 +46,19 @@ enum of_gpio_flags {
  * @propname:	property name containing gpio specifier(s)
  *
  * The function returns the count of GPIOs specified for a node.
- * Note that the empty GPIO specifiers count too. Returns either
- *   Number of gpios defined in property,
- *   -EINVAL for an incorrectly formed gpios property, or
- *   -ENOENT for a missing gpios property
+ * NOTE: The empty GPIO specifiers count too.
  *
- * Example:
- * gpios = <0
- *          &gpio1 1 2
- *          0
- *          &gpio2 3 4>;
+ * Returns:
+ * Either number of GPIOs defined in the property, or
+ * *  %-EINVAL for an incorrectly formed "gpios" property, or
+ * *  %-ENOENT for a missing "gpios" property.
+ *
+ * Example::
+ *
+ *     gpios = <0
+ *              &gpio1 1 2
+ *              0
+ *              &gpio2 3 4>;
  *
  * The above example defines four GPIOs, two of which are not specified.
  * This function will return '4'
@@ -77,6 +80,11 @@ static int of_gpio_named_count(const struct device_node *np,
  * "gpios" for the chip select lines. If we detect this, we redirect
  * the counting of "cs-gpios" to count "gpios" transparent to the
  * driver.
+ *
+ * Returns:
+ * Either number of GPIOs defined in the property, or
+ * *  %-EINVAL for an incorrectly formed "gpios" property, or
+ * *  %-ENOENT for a missing "gpios" property.
  */
 static int of_gpio_spi_cs_get_count(const struct device_node *np,
 				    const char *con_id)
@@ -373,7 +381,8 @@ static void of_gpio_flags_quirks(const struct device_node *np,
  * @index:	index of the GPIO
  * @flags:	a flags pointer to fill in
  *
- * Returns GPIO descriptor to use with Linux GPIO API, or one of the errno
+ * Returns:
+ * GPIO descriptor to use with Linux GPIO API, or one of the errno
  * value on the error condition. If @flags is not NULL the function also fills
  * in flags for the GPIO.
  */
@@ -425,7 +434,8 @@ static struct gpio_desc *of_get_named_gpiod_flags(const struct device_node *np,
  *
  * **DEPRECATED** This function is deprecated and must not be used in new code.
  *
- * Returns GPIO number to use with Linux generic GPIO API, or one of the errno
+ * Returns:
+ * GPIO number to use with Linux generic GPIO API, or one of the errno
  * value on the error condition.
  */
 int of_get_named_gpio(const struct device_node *np, const char *propname,
@@ -711,7 +721,8 @@ struct gpio_desc *of_find_gpio(struct device_node *np, const char *con_id,
  *		of_find_gpio() or of_parse_own_gpio()
  * @dflags:	gpiod_flags - optional GPIO initialization flags
  *
- * Returns GPIO descriptor to use with Linux GPIO API, or one of the errno
+ * Returns:
+ * GPIO descriptor to use with Linux GPIO API, or one of the errno
  * value on the error condition.
  */
 static struct gpio_desc *of_parse_own_gpio(struct device_node *np,
@@ -779,7 +790,8 @@ static struct gpio_desc *of_parse_own_gpio(struct device_node *np,
  * @chip:	gpio chip to act on
  * @hog:	device node describing the hogs
  *
- * Returns error if it fails otherwise 0 on success.
+ * Returns:
+ * 0 on success, or negative errno on failure.
  */
 static int of_gpiochip_add_hog(struct gpio_chip *chip, struct device_node *hog)
 {
@@ -813,7 +825,9 @@ static int of_gpiochip_add_hog(struct gpio_chip *chip, struct device_node *hog)
  *
  * This is only used by of_gpiochip_add to request/set GPIO initial
  * configuration.
- * It returns error if it fails otherwise 0 on success.
+ *
+ * Returns:
+ * 0 on success, or negative errno on failure.
  */
 static int of_gpiochip_scan_gpios(struct gpio_chip *chip)
 {
@@ -923,6 +937,9 @@ struct notifier_block gpio_of_notifier = {
  * This is simple translation function, suitable for the most 1:1 mapped
  * GPIO chips. This function performs only one sanity check: whether GPIO
  * is less than ngpios (that is specified in the gpio_chip).
+ *
+ * Returns:
+ * GPIO number (>= 0) on success, negative errno on failure.
  */
 static int of_gpio_simple_xlate(struct gpio_chip *gc,
 				const struct of_phandle_args *gpiospec,
@@ -972,6 +989,9 @@ static int of_gpio_simple_xlate(struct gpio_chip *gc,
  * If succeeded, this function will map bank's memory and will
  * do all necessary work for you. Then you'll able to use .regs
  * to manage GPIOs from the callbacks.
+ *
+ * Returns:
+ * 0 on success, or negative errno on failure.
  */
 int of_mm_gpiochip_add_data(struct device_node *np,
 			    struct of_mm_gpio_chip *mm_gc,

drivers/gpio/gpiolib-swnode.c

@@ -106,7 +106,7 @@ struct gpio_desc *swnode_find_gpio(struct fwnode_handle *fwnode,
  *		system-global GPIOs
  * @con_id:	function within the GPIO consumer
  *
- * Return:
+ * Returns:
  * The number of GPIOs associated with a device / function or %-ENOENT,
  * if no GPIO has been assigned to the requested function.
  */

drivers/gpio/gpiolib-sysfs.c

@@ -568,7 +568,8 @@ static struct class gpio_class = {
  * will see "direction" sysfs attribute which may be used to change
  * the gpio's direction.  A "value" attribute will always be provided.
  *
- * Returns zero on success, else an error.
+ * Returns:
+ * 0 on success, or negative errno on failure.
  */
 int gpiod_export(struct gpio_desc *desc, bool direction_may_change)
 {
@@ -667,7 +668,8 @@ static int match_export(struct device *dev, const void *desc)
  * Set up a symlink from /sys/.../dev/name to /sys/class/gpio/gpioN
  * node. Caller is responsible for unlinking.
  *
- * Returns zero on success, else an error.
+ * Returns:
+ * 0 on success, or negative errno on failure.
  */
 int gpiod_export_link(struct device *dev, const char *name,
 		      struct gpio_desc *desc)