[PATCH RFC] drivers:gpio: introduce variants of gpiod_get_array

[Song Chen <chensong_2000@xxxxxx>]

This patch introduces another two variants of gpiod_get_array,
fwnode_gpiod_get_array and devm_fwnode_gpiod_get_array, to
return GPIO descriptor array to comsumers.

Unlike gpiod_get_array, which calls dev_fwnode(dev) to get
firmware node in gpiod_get_index, new variants allow consumers
to pass firmware node by themselves.

It's applicable to below circumstance:

fwnode_for_each_child_node(fw_parent, fw_child)
or for_each_child_of_node
	struct gpio_descs *array = devm_fwnode_gpiod_get_array(
				dev, fw_child,...).
	or fwnode_gpiod_get_array

Signed-off-by: Song Chen <chensong_2000@xxxxxx>
---
 drivers/gpio/gpiolib-devres.c | 43 ++++++++++++++++
 drivers/gpio/gpiolib.c        | 96 +++++++++++++++++++++++++++++------
 include/linux/gpio/consumer.h | 28 ++++++++++
 3 files changed, 151 insertions(+), 16 deletions(-)

diff --git a/drivers/gpio/gpiolib-devres.c b/drivers/gpio/gpiolib-devres.c
index 08205f355ceb..f8b2a3fe02ba 100644
--- a/drivers/gpio/gpiolib-devres.c
+++ b/drivers/gpio/gpiolib-devres.c
@@ -192,6 +192,49 @@ struct gpio_desc *devm_fwnode_gpiod_get_index(struct device *dev,
 }
 EXPORT_SYMBOL_GPL(devm_fwnode_gpiod_get_index);
 
+/**
+ * devm_fwnode_gpiod_get_array - Resource-managed gpiod_get_array_by_fwnode()
+ * @dev:	GPIO consumer
+ * @fwnode:	firmware node containing GPIO reference
+ * @con_id:	function within the GPIO consumer
+ * @flags:	optional GPIO initialization flags
+ *
+ * Managed gpiod_get_array_by_fwnode(). GPIO descriptors returned from this function are
+ * automatically disposed on driver detach. See gpiod_get_array_by_fwnode() 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 *devm_fwnode_gpiod_get_array(struct device *dev,
+							 struct fwnode_handle *fwnode,
+						     const char *con_id,
+						     enum gpiod_flags flags)
+{
+	struct gpio_descs **dr;
+	struct gpio_descs *descs;
+
+	dr = devres_alloc(devm_gpiod_release_array,
+			  sizeof(struct gpio_descs *), GFP_KERNEL);
+	if (!dr)
+		return ERR_PTR(-ENOMEM);
+
+	descs = gpiod_get_array_by_fwnode(dev, fwnode, con_id, flags);
+	if (IS_ERR(descs)) {
+		devres_free(dr);
+		return descs;
+	}
+
+	*dr = descs;
+	devres_add(dev, dr);
+
+	return descs;
+}
+EXPORT_SYMBOL_GPL(devm_fwnode_gpiod_get_array);
+
 /**
  * devm_gpiod_get_index_optional - Resource-managed gpiod_get_index_optional()
  * @dev: GPIO consumer
diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index 679ed764cb14..dbb39e6bb568 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -4469,6 +4469,33 @@ struct gpio_desc *fwnode_gpiod_get_index(struct fwnode_handle *fwnode,
 }
 EXPORT_SYMBOL_GPL(fwnode_gpiod_get_index);
 
+/**
+ * fwnode_gpiod_get_array - obtain multiple GPIOs from a multi-index GPIO function
+ * @fwnode:	handle of the firmware node
+ * @con_id:	function within the GPIO consumer
+ * @flags:	GPIO initialization flags
+ *
+ * This function can be used for drivers that get their configuration
+ * from opaque firmware.
+ *
+ * The function properly finds the corresponding GPIOs using whatever is the
+ * underlying firmware interface and then makes sure that the GPIO
+ * descriptors are requested before they are returned to the caller.
+ *
+ * Returns:
+ * On successful request the GPIO descriptors are configured in accordance with
+ * provided @flags.
+ *
+ * In case of error an ERR_PTR() is returned.
+ */
+struct gpio_descs *fwnode_gpiod_get_array(struct fwnode_handle *fwnode,
+					 const char *con_id,
+					 enum gpiod_flags flags)
+{
+	return gpiod_get_array_by_fwnode(NULL, fwnode, con_id, flags);
+}
+EXPORT_SYMBOL_GPL(fwnode_gpiod_get_array);
+
 /**
  * gpiod_count - return the number of GPIOs associated with a device / function
  * @dev:	GPIO consumer, can be NULL for system-global GPIOs
@@ -4731,21 +4758,8 @@ static void gpiochip_free_hogs(struct gpio_chip *gc)
 		gpiochip_free_own_desc(desc);
 }
 
-/**
- * gpiod_get_array - obtain multiple GPIOs from a multi-index GPIO function
- * @dev:	GPIO consumer, can be NULL for system-global GPIOs
- * @con_id:	function within the GPIO consumer
- * @flags:	optional GPIO initialization flags
- *
- * This function acquires all the GPIOs defined under a given function.
- *
- * 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 gpiod_get_array(struct device *dev,
+static struct gpio_descs *__gpiod_get_array(struct device *dev,
+						struct fwnode_handle *fwnode,
 						const char *con_id,
 						enum gpiod_flags flags)
 {
@@ -4766,7 +4780,12 @@ struct gpio_descs *__must_check gpiod_get_array(struct device *dev,
 		return ERR_PTR(-ENOMEM);
 
 	for (descs->ndescs = 0; descs->ndescs < count; descs->ndescs++) {
-		desc = gpiod_get_index(dev, con_id, descs->ndescs, flags);
+		if (fwnode)
+			desc = gpiod_find_and_request(dev, fwnode, con_id, descs->ndescs,
+					  flags, NULL, false);
+		else
+			desc = gpiod_get_index(dev, con_id, descs->ndescs, flags);
+
 		if (IS_ERR(desc)) {
 			gpiod_put_array(descs);
 			return ERR_CAST(desc);
@@ -4858,8 +4877,53 @@ struct gpio_descs *__must_check gpiod_get_array(struct device *dev,
 			*array_info->invert_mask);
 	return descs;
 }
+
+/**
+ * gpiod_get_array - obtain multiple GPIOs from a multi-index GPIO function
+ * @dev:	GPIO consumer, can be NULL for system-global GPIOs
+ * @con_id:	function within the GPIO consumer
+ * @flags:	optional GPIO initialization flags
+ *
+ * This function acquires all the GPIOs defined under a given function.
+ *
+ * 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 gpiod_get_array(struct device *dev,
+						const char *con_id,
+						enum gpiod_flags flags)
+{
+	return __gpiod_get_array(dev, NULL, con_id, flags);
+}
 EXPORT_SYMBOL_GPL(gpiod_get_array);
 
+/**
+ * gpiod_get_array_by_fwnode - obtain multiple GPIOs from a multi-index GPIO function
+ * @dev:	GPIO consumer, can be NULL for system-global GPIOs
+ * @fwnode: Firmware node to lookup
+ * @con_id:	function within the GPIO consumer
+ * @flags:	optional GPIO initialization flags
+ *
+ * This function acquires all the GPIOs defined under a given function.
+ *
+ * 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 gpiod_get_array_by_fwnode(struct device *dev,
+						struct fwnode_handle *fwnode,
+						const char *con_id,
+						enum gpiod_flags flags)
+{
+	return __gpiod_get_array(dev, fwnode, con_id, flags);
+}
+EXPORT_SYMBOL_GPL(gpiod_get_array_by_fwnode);
+
 /**
  * gpiod_get_array_optional - obtain multiple GPIOs from a multi-index GPIO
  *                            function
diff --git a/include/linux/gpio/consumer.h b/include/linux/gpio/consumer.h
index db2dfbae8edb..7143bf7045ce 100644
--- a/include/linux/gpio/consumer.h
+++ b/include/linux/gpio/consumer.h
@@ -80,6 +80,10 @@ struct gpio_descs *__must_check gpiod_get_array(struct device *dev,
 struct gpio_descs *__must_check gpiod_get_array_optional(struct device *dev,
 							const char *con_id,
 							enum gpiod_flags flags);
+struct gpio_descs *__must_check gpiod_get_array_by_fwnode(struct device *dev,
+						struct fwnode_handle *fwnode,
+						const char *con_id,
+						enum gpiod_flags flags);
 void gpiod_put(struct gpio_desc *desc);
 void gpiod_put_array(struct gpio_descs *descs);
 
@@ -175,11 +179,18 @@ struct gpio_desc *fwnode_gpiod_get_index(struct fwnode_handle *fwnode,
 					 const char *con_id, int index,
 					 enum gpiod_flags flags,
 					 const char *label);
+struct gpio_descs *fwnode_gpiod_get_array(struct fwnode_handle *fwnode,
+					 const char *con_id,
+					 enum gpiod_flags flags);
 struct gpio_desc *devm_fwnode_gpiod_get_index(struct device *dev,
 					      struct fwnode_handle *child,
 					      const char *con_id, int index,
 					      enum gpiod_flags flags,
 					      const char *label);
+struct gpio_descs *devm_fwnode_gpiod_get_array(struct device *dev,
+					      struct fwnode_handle *fwnode,
+					      const char *con_id,
+						  enum gpiod_flags flags);
 
 #else /* CONFIG_GPIOLIB */
 
@@ -548,6 +559,14 @@ struct gpio_desc *fwnode_gpiod_get_index(struct fwnode_handle *fwnode,
 	return ERR_PTR(-ENOSYS);
 }
 
+static inline
+struct gpio_descs *fwnode_gpiod_get_array(struct fwnode_handle *fwnode,
+					 const char *con_id,
+					 enum gpiod_flags flags)
+{
+	return ERR_PTR(-ENOSYS);
+}
+
 static inline
 struct gpio_desc *devm_fwnode_gpiod_get_index(struct device *dev,
 					      struct fwnode_handle *fwnode,
@@ -558,6 +577,15 @@ struct gpio_desc *devm_fwnode_gpiod_get_index(struct device *dev,
 	return ERR_PTR(-ENOSYS);
 }
 
+static inline
+struct gpio_descs *devm_fwnode_gpiod_get_array(struct device *dev,
+					      struct fwnode_handle *fwnode,
+					      const char *con_id,
+						  enum gpiod_flags flags)
+{
+	return ERR_PTR(-ENOSYS);
+}
+
 #endif /* CONFIG_GPIOLIB */
 
 static inline
-- 
2.25.1