From: Bartosz Golaszewski <bgolaszewski@xxxxxxxxxxxx>
We can currently only register nvmem cells from device tree or by
manually calling nvmem_add_cells(). The latter options however forces
users to make sure that the nvmem provider with which the cells are
associated is registered before the call.
This patch proposes a new solution inspired by other frameworks that
offer resource lookups (GPIO, PWM etc.). It adds functions that allow
machine code to register nvmem lookup which are later lazily used to
add corresponding nvmem cells and remove them if no longer needed.
Signed-off-by: Bartosz Golaszewski <bgolaszewski@xxxxxxxxxxxx>