block: introduce add_disk_fwnode()

Introduce add_disk_fwnode() as a replacement of device_add_disk() that
permits to pass and attach a fwnode to disk dev.

This variant can be useful for eMMC that might have the partition table
for the disk defined in DT. A parser can later make use of the attached
fwnode to parse the related table and init the hardcoded partition for
the disk.

device_add_disk() is converted to a simple wrapper of add_disk_fwnode()
with the fwnode entry set as NULL.

Signed-off-by: Christian Marangi <[e-mail]>
Reviewed-by: Christoph Hellwig <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Jens Axboe <[e-mail]>

block/genhd.c

···
 }
 
 /**
- * device_add_disk - add disk information to kernel list
+ * add_disk_fwnode - add disk information to kernel list with fwnode
  * @parent: parent device for the disk
  * @disk: per-device partitioning information
  * @groups: Additional per-device sysfs groups
+ * @fwnode: attached disk fwnode
  *
  * This function registers the partitioning information in @disk
- * with the kernel.
+ * with the kernel. Also attach a fwnode to the disk device.
  */
-int __must_check device_add_disk(struct device *parent, struct gendisk *disk,
-				 const struct attribute_group **groups)
+int __must_check add_disk_fwnode(struct device *parent, struct gendisk *disk,
+				 const struct attribute_group **groups,
+				 struct fwnode_handle *fwnode)
 
 {
 	struct device *ddev = disk_to_dev(disk);
···
 	ddev->parent = parent;
 	ddev->groups = groups;
 	dev_set_name(ddev, "%s", disk->disk_name);
+	if (fwnode)
+		device_set_node(ddev, fwnode);
 	if (!(disk->flags & GENHD_FL_HIDDEN))
 		ddev->devt = MKDEV(disk->major, disk->first_minor);
 	ret = device_add(ddev);
···
 	if (disk->queue->elevator)
 		elevator_exit(disk->queue);
 	return ret;
+}
+EXPORT_SYMBOL_GPL(add_disk_fwnode);
+
+/**
+ * device_add_disk - add disk information to kernel list
+ * @parent: parent device for the disk
+ * @disk: per-device partitioning information
+ * @groups: Additional per-device sysfs groups
+ *
+ * This function registers the partitioning information in @disk
+ * with the kernel.
+ */
+int __must_check device_add_disk(struct device *parent, struct gendisk *disk,
+				 const struct attribute_group **groups)
+{
+	return add_disk_fwnode(parent, disk, groups, NULL);
 }
 EXPORT_SYMBOL(device_add_disk);
 

include/linux/blkdev.h

···
 #define for_each_bio(_bio)		\
 	for (; _bio; _bio = _bio->bi_next)
 
+int __must_check add_disk_fwnode(struct device *parent, struct gendisk *disk,
+				 const struct attribute_group **groups,
+				 struct fwnode_handle *fwnode);
 int __must_check device_add_disk(struct device *parent, struct gendisk *disk,
 				 const struct attribute_group **groups);
 static inline int __must_check add_disk(struct gendisk *disk)