1 files changed, 51 insertions, 0 deletions

diff --git a/drivers/base/core.c b/drivers/base/core.c
index cadf165651d8..21d13038534e 100644
--- a/drivers/base/core.c
+++ b/drivers/base/core.c
@@ -12,6 +12,7 @@
 
 #include <linux/device.h>
 #include <linux/err.h>
+#include <linux/fwnode.h>
 #include <linux/init.h>
 #include <linux/module.h>
 #include <linux/slab.h>
@@ -2144,3 +2145,53 @@ define_dev_printk_level(dev_notice, KERN_NOTICE);
 define_dev_printk_level(_dev_info, KERN_INFO);
 
 #endif
+
+static inline bool fwnode_is_primary(struct fwnode_handle *fwnode)
+{
+        return fwnode && !IS_ERR(fwnode->secondary);
+}
+
+/**
+ * set_primary_fwnode - Change the primary firmware node of a given device.
+ * @dev: Device to handle.
+ * @fwnode: New primary firmware node of the device.
+ *
+ * Set the device's firmware node pointer to @fwnode, but if a secondary
+ * firmware node of the device is present, preserve it.
+ */
+void set_primary_fwnode(struct device *dev, struct fwnode_handle *fwnode)
+{
+        if (fwnode) {
+                struct fwnode_handle *fn = dev->fwnode;
+
+                if (fwnode_is_primary(fn))
+                        fn = fn->secondary;
+
+                fwnode->secondary = fn;
+                dev->fwnode = fwnode;
+        } else {
+                dev->fwnode = fwnode_is_primary(dev->fwnode) ?
+                        dev->fwnode->secondary : NULL;
+        }
+}
+EXPORT_SYMBOL_GPL(set_primary_fwnode);
+
+/**
+ * set_secondary_fwnode - Change the secondary firmware node of a given device.
+ * @dev: Device to handle.
+ * @fwnode: New secondary firmware node of the device.
+ *
+ * If a primary firmware node of the device is present, set its secondary
+ * pointer to @fwnode.  Otherwise, set the device's firmware node pointer to
+ * @fwnode.
+ */
+void set_secondary_fwnode(struct device *dev, struct fwnode_handle *fwnode)
+{
+        if (fwnode)
+                fwnode->secondary = ERR_PTR(-ENODEV);
+
+        if (fwnode_is_primary(dev->fwnode))
+                dev->fwnode->secondary = fwnode;
+        else
+                dev->fwnode = fwnode;
+}