[PATCH 0/2] nvmem: Add byte-mask support for non-contiguous byte selection

[Hongmei Xu <hongmei.xu@oss.qualcomm.com>]

Some hardware stores NVMEM cell data in non-contiguous bytes. For
example, a MAC address cell may span 7 physical bytes with one byte
unused, requiring the driver to skip that byte during readout.

The existing 'bits' property only handles sub-byte granularity and
cannot express byte-level gaps. This series adds a 'byte-mask'
property to the fixed-cell binding and implements it in the nvmem
core, allowing consumers to describe and read such cells.

An example: assume a MAC address is assembled from efuse registers
0xFFFF4320[31:0] (bytes 0-3), 0xFFFF4324[7:0] (byte 4), and
0xFFFF4324[23:16] (byte 6), with 0xFFFF4324[15:8] unused (byte 5).
Map the efuse region as an 8-byte nvmem device and define the cell
skipping byte 5:

  efuse: efuse@ffff4320 {
    compatible = "...";
    reg = <0x0 0xffff4320 0x0 0x8>;
    #address-cells = <1>;
    #size-cells = <1>;

    mac_addr: mac-addr@0 {
      reg = <0x0 0x6>;
      byte-mask = <0x5f>;
    };
  };

  With byte-mask = 0x5f (0101_1111), bytes 0-4 and 6 are selected
  (byte 5 is skipped), forming the 6-byte MAC address output.

Signed-off-by: Hongmei Xu <hongmei.xu@oss.qualcomm.com>
---
Hongmei Xu (2):
      dt-bindings: nvmem: add byte-mask property for non-contiguous byte selection
      nvmem: core: add byte-mask support for non-contiguous cell bytes

 .../bindings/nvmem/layouts/fixed-cell.yaml         |  22 +++++
 drivers/nvmem/core.c                               | 101 +++++++++++++++++++--
 include/linux/nvmem-provider.h                     |   7 ++
 3 files changed, 123 insertions(+), 7 deletions(-)
---
base-commit: d26955e57475434b59d43ba372b2a50d33d5e0ed
change-id: 20261110-nvmem-byte-mask-for-split-macaddr-a4698a128057

Best regards,
--  
Hongmei Xu <hongmei.xu@oss.qualcomm.com>