[PATCH 0/6] mtd: ubi: allow UBI volumes to provide NVMEM

[Daniel Golle]

The series is a follow-up and contains all patches of the previous
series "mtd: ubi: behave like a good MTD citizen"[1] which was meant in
preparation for implementing the NVMEM provider.

The goal is to support embedded Linux devices which got NVMEM bits
stored inside a UBI volume. Representing the UBI volume in the Device
Tree, adding a phandle to be referenced by NVMEM consumers allows such
devices to come up with their correct MAC addresses and device-specific
Wi-Fi calibration data loaded.

In order to be available for other drivers, attaching UBI devices has
to be moved from late_initcall (which is too late for other drivers) to
happen earlier. As an alternative to the existing kernel cmdline
parameter the Device Tree property 'compatible = "linux,ubi";' inside
an MTD partition can be used to have that MTD device attached as UBI
device. MTD partitions which serve as UBI devices may have a "volumes"
firmware subnode with volumes which may be compatible with
"nvmem-cells".

In this way, other drivers (think: Ethernet, Wi-Fi) can resolve and
acquire NVMEM bits using the usual device tree phandle, just this time
the NVMEM content is read from a UBI volume.

[1]: https://patchwork.ozlabs.org/project/linux-mtd/list/?series=353177&state=%2A&archive=both

Daniel Golle (6):
  mtd: ubi: block: don't return on error when removing
  mtd: ubi: block: use notifier to create ubiblock from parameter
  mtd: ubi: attach MTD partition from device-tree
  mtd: ubi: introduce pre-removal notification for UBI volumes
  mtd: ubi: populate ubi volume fwnode
  mtd: ubi: provide NVMEM layer over UBI volumes

 drivers/mtd/ubi/Kconfig  |  12 +++
 drivers/mtd/ubi/Makefile |   1 +
 drivers/mtd/ubi/block.c  | 186 +++++++++++++++++++++++---------------
 drivers/mtd/ubi/build.c  | 160 ++++++++++++++++++++++++---------
 drivers/mtd/ubi/cdev.c   |   4 +-
 drivers/mtd/ubi/nvmem.c  | 189 +++++++++++++++++++++++++++++++++++++++
 drivers/mtd/ubi/ubi.h    |   6 +-
 drivers/mtd/ubi/vmt.c    |  36 ++++++++
 include/linux/mtd/ubi.h  |   2 +
 9 files changed, 477 insertions(+), 119 deletions(-)
 create mode 100644 drivers/mtd/ubi/nvmem.c

-- 
2.41.0