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authorBard Liao <yung-chuan.liao@linux.intel.com>2021-01-05 17:11:46 +0800
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2021-01-07 17:55:55 +0100
commit3f7bddaf5d5a83aa2eb1e6d72db221d3ec43c813 (patch)
treeafe9a44d1665d343d22ea26da000d4ca3da6a52f
parent47f4469970d8861bc06d2d4d45ac8200ff07c693 (diff)
downloadlinux-3f7bddaf5d5a83aa2eb1e6d72db221d3ec43c813.tar.bz2
device property: add description of fwnode cases
There are only four valid fwnode cases which are - primary --> secondary --> -ENODEV - primary --> NULL - secondary --> -ENODEV - NULL dev->fwnode should be converted between the 4 cases above no matter how/when set_primary_fwnode() and set_secondary_fwnode() are called. Describe it in the code so people will keep it in mind. Signed-off-by: Bard Liao <yung-chuan.liao@linux.intel.com> Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com> [ rjw: Comment edit ] Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
-rw-r--r--drivers/base/core.c7
1 files changed, 7 insertions, 0 deletions
diff --git a/drivers/base/core.c b/drivers/base/core.c
index 51b9545a050b..14f165816742 100644
--- a/drivers/base/core.c
+++ b/drivers/base/core.c
@@ -4414,6 +4414,12 @@ static inline bool fwnode_is_primary(struct fwnode_handle *fwnode)
*
* Set the device's firmware node pointer to @fwnode, but if a secondary
* firmware node of the device is present, preserve it.
+ *
+ * Valid fwnode cases are:
+ * - primary --> secondary --> -ENODEV
+ * - primary --> NULL
+ * - secondary --> -ENODEV
+ * - NULL
*/
void set_primary_fwnode(struct device *dev, struct fwnode_handle *fwnode)
{
@@ -4432,6 +4438,7 @@ void set_primary_fwnode(struct device *dev, struct fwnode_handle *fwnode)
} else {
if (fwnode_is_primary(fn)) {
dev->fwnode = fn->secondary;
+ /* Set fn->secondary = NULL, so fn remains the primary fwnode */
if (!(parent && fn == parent->fwnode))
fn->secondary = NULL;
} else {