Re: [PATCH v2 08/17] driver core: Add fwnode link support

Leon Romanovsky
2020-12-06T07:49:42Z

On Fri, Nov 20, 2020 at 06:02:23PM -0800, Saravana Kannan wrote:
> Add support for creating supplier-consumer links between fwnodes. It is
> intended for internal use the driver core and generic firmware support
> code (eg. Device Tree, ACPI), so it is simple by design and the API
> provided is limited.
>
> Signed-off-by: Saravana Kannan <saravanak@google.com>
> ---
> drivers/base/core.c | 98 ++++++++++++++++++++++++++++++++++++++++++
> drivers/of/dynamic.c | 1 +
> include/linux/fwnode.h | 14 ++++++
> 3 files changed, 113 insertions(+)
>
> diff --git a/drivers/base/core.c b/drivers/base/core.c
> index 401fa7e3505c..e2b246a44d1a 100644
> --- a/drivers/base/core.c
> +++ b/drivers/base/core.c
> @@ -50,6 +50,104 @@ static LIST_HEAD(wait_for_suppliers);
> static DEFINE_MUTEX(wfs_lock);
> static LIST_HEAD(deferred_sync);
> static unsigned int defer_sync_state_count = 1;
> +static DEFINE_MUTEX(fwnode_link_lock);
> +
> +/**
> + * fwnode_link_add - Create a link between two fwnode_handles.
> + * @con: Consumer end of the link.
> + * @sup: Supplier end of the link.
> + *
> + * Create a fwnode link between fwnode handles @con and @sup. The fwnode link
> + * represents the detail that the firmware lists @sup fwnode as supplying a
> + * resource to @con.
> + *
> + * The driver core will use the fwnode link to create a device link between the
> + * two device objects corresponding to @con and @sup when they are created. The
> + * driver core will automatically delete the fwnode link between @con and @sup
> + * after doing that.
> + *
> + * Attempts to create duplicate links between the same pair of fwnode handles
> + * are ignored and there is no reference counting.

Sorry to ask, but why is that?
Isn't this a programmer error?

Thanks