[PATCH 0/2] mtd/nvmem: don't defer forever on absent NVMEM suppliers

[Manikandan Muralidharan <manikandan.m@microchip.com>]

A consumer that gets its MAC address from an NVMEM cell can be deferred
forever when the cell will never appear, instead of falling back to
another address source. These came up while testing the SFDP EUI-48
series [1], where macb reads its MAC address from a cell exposed by the
QSPI flash, but both are generic:

 - 1/2: when the SPI NOR flash is not populated or not reachable, nothing
   below its node is ever registered, yet fw_devlink keeps waiting on it
   and the NVMEM lookup keeps returning -EPROBE_DEFER. Drop the fw_devlink
   links below a flash that failed to probe, and return -ENOENT for a cell
   on a node fw_devlink has marked as never becoming a device.

 - 2/2: a layout adds its cells from its probe and may add none, e.g. when
   the data the cell describes is not programmed on the device. Only defer
   while the layout is not bound yet, and return -ENOENT once it is.

In both cases the consumer then falls back, e.g. macb uses the address
left by the bootloader or a random one.

This series depends on the SFDP EUI-48 series [1] and applies on top of it.

[1] https://lore.kernel.org/all/cover.1794391660.git.manikandan.m@microchip.com/

Manikandan Muralidharan (2):
  mtd: spi-nor: drop fw_devlink suppliers below a flash that failed to
    probe
  nvmem: core: don't defer for a missing cell once the layout is bound

 drivers/mtd/spi-nor/core.c | 26 ++++++++++++++++++++++++-
 drivers/nvmem/core.c       | 40 ++++++++++++++++++++++++++++++++++++--
 2 files changed, 63 insertions(+), 3 deletions(-)


base-commit: 05441d697f7f9a927264f4058cbbc6a03dfcac9d
prerequisite-patch-id: 76d8b1168f88c3e7912ac2ce01a705f7e69d8a3b
prerequisite-patch-id: b360d0d00ac1a6feb76d4b3f9412b6f1741f6161
prerequisite-patch-id: 659801d6f415ba79ce51f21b3a4f5e132348c150
prerequisite-patch-id: bd1a5a10983aa3cfd99c93ee58fdeb04cdd87b76
prerequisite-patch-id: 94ede38b6c2480cb1e0e102e9bbeb6ffd5b276ef
prerequisite-patch-id: ae3977b6c56c5bd4f352d77bd8a7883a69d390af
prerequisite-patch-id: 58d0ad25e81f16f60864d624eed7ff481607e960
prerequisite-patch-id: ba140b71fdbfc992861ae4c34b6acc737d4e4528
-- 
2.43.0