Hi Hans,

quoted

As PMICs are typically linked to the kernel (vs. being modules),
there's no issue with the module name. I would suppose few if any
PMICs will be compiled as modules in general.

Good point about the OpRegion driver usually being built-in, in my experience it
MUST always be built-in, so the Kconfig option should be a bool. Note this is
useless unless the mfd driver is also a bool (I would advice to go that
route) and the mfd driver's Kconfig should select the right i2c bus driver to
make sure that is built-in too, see for example:

https://git.kernel.org/pub/scm/linux/kernel/git/lee/mfd.git/commit/?h=for-
mfd-next&id=2f91ded5f8f4fdd67d8daae514b0d434c98ab1e0
https://git.kernel.org/pub/scm/linux/kernel/git/lee/mfd.git/commit/?h=for-
mfd-next&id=c5065d8625ebdc164199b99d838ac0636faa7f0b
https://git.kernel.org/pub/scm/linux/kernel/git/lee/mfd.git/commit/?h=for-
mfd-next&id=5f125f1f570568a29edf783fba1ebb606d5c6b24

Which are all recent commits from me dealing with making the mfd driver built-
in / selecting the i2c bus driver.

Thanks for these links.
I will update the Kconfig and commit messages with relevant description around this.