On Tue, Jan 05, 2021 at 05:11:46PM +0800, Bard Liao wrote:
> 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@xxxxxxxxxxxxxxx>
Reviewed-by: Heikki Krogerus <heikki.krogerus@xxxxxxxxxxxxxxx>
> ---
> drivers/base/core.c | 7 +++++++
> 1 file changed, 7 insertions(+)
>
> diff --git a/drivers/base/core.c b/drivers/base/core.c
> index 51b9545a050b..17eb14607074 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 to keep fn as a primary fwnode */
> if (!(parent && fn == parent->fwnode))
> fn->secondary = NULL;
> } else {
> --
> 2.17.1
thanks,
--
heikki
