[PATCH v2 0/2] nvmem: fix a const-unsoundness in reg_write

[Link Mauve]

This callback used to take a mutable void * for no reason, which causes
the compiler to be unaware that the val buffer should never be modified
by the callback.

This was found while drafting the nvmem-provider Rust abstraction.

Thanks to the guidance of Andy Shevchenko, this now introduces a new
callback and deprecates the existing one, with the goal of renaming the
new one into the old one once no user remains in the kernel.

Changes since v1:
- Link to v1:
  https://lore.kernel.org/rust-for-linux/20260715175229.24672-1-linkmauve@xxxxxxxxxxxx/
- Removed all changes to other subsystems than nvmem.
- Added a new reg_write_const callback instead of changing the exisitng
  reg_write.
- Deprecated the existing reg_write callback, it will get removed once
  all users in the kernel will be done migrating to the new one.

Link Mauve (2):
  nvmem: core: deprecate reg_write callback and add reg_write_const
  nvmem: make all reg_write callbacks take const void *

 drivers/nvmem/apple-spmi-nvmem.c    |  2 +-
 drivers/nvmem/bcm-ocotp.c           |  6 +++---
 drivers/nvmem/core.c                | 26 +++++++++++++++++---------
 drivers/nvmem/imx-ocotp-scu.c       |  6 +++---
 drivers/nvmem/imx-ocotp.c           |  6 +++---
 drivers/nvmem/internals.h           |  1 +
 drivers/nvmem/lan9662-otpc.c        |  6 +++---
 drivers/nvmem/lpc18xx_eeprom.c      |  6 +++---
 drivers/nvmem/max77759-nvmem.c      |  4 ++--
 drivers/nvmem/meson-efuse.c         |  6 +++---
 drivers/nvmem/qcom-spmi-sdam.c      |  4 ++--
 drivers/nvmem/qfprom.c              |  6 +++---
 drivers/nvmem/rave-sp-eeprom.c      |  6 +++---
 drivers/nvmem/snvs_lpgpr.c          |  4 ++--
 drivers/nvmem/sprd-efuse.c          |  6 +++---
 drivers/nvmem/stm32-bsec-optee-ta.c |  2 +-
 drivers/nvmem/stm32-bsec-optee-ta.h |  4 ++--
 drivers/nvmem/stm32-romem.c         | 10 +++++-----
 drivers/nvmem/zynqmp_nvmem.c        |  6 +++---
 include/linux/nvmem-provider.h      |  6 +++++-
 20 files changed, 68 insertions(+), 55 deletions(-)

-- 
2.55.0