Manually add sysfs groups after the faux_device_ops's probe succeeds.
Likewise remove these groups just before calling the faux_devices_ops's
remove callback. This approach approximates the order in which the
driver core adds and removes the driver's .dev_groups of a device to
avoid lifetime issues.
This is done specifically to avoid using the device's .groups member,
which adds groups before the device is even registered to the bus.
This lets consumers of this API, initialize resources on the .probe
callback and then use them inside is_visible/show/store methods, through
dev_get_drvdata() without races.
Cc: Rafael J. Wysocki <rafael@kernel.org>
Cc: Danilo Krummrich <dakr@kernel.org>
Signed-off-by: Kurt Borja <kuurtb@gmail.com>
Link: https://lore.kernel.org/r/20250327-faux-groups-v2-1-745a3cf0bc16@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
It's really hard to know if a faux device properly passes the callback
to probe() without having to poke around in the faux_device structure
and then clean up. Instead of having to have every user of the api do
this logic, just do it in the faux device core itself.
This makes the use of a custom probe() callback for a faux device much
simpler overall.
Suggested-by: Kurt Borja <kuurtb@gmail.com>
Cc: Rafael J. Wysocki <rafael@kernel.org>
Reviewed-by: Kurt Borja <kuurtb@gmail.com>
Reviewed-by: Danilo Krummrich <dakr@kernel.org>
Link: https://lore.kernel.org/r/2025022545-unroasted-common-fa0e@gregkh
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
