On Tue, Dec 17, 2019 at 11:22:19AM +0100, Enrico Weigelt, metux IT consult wrote:

A large portion of platform drivers doesn't need their own init/exit
functions. At source level, the boilerplate is already replaced by
module_platform_driver() macro call, which creates this code under
the hood. But in the binary, the code is still there.

This patch is an attempt to remove them it, by the same approach
already used for the init functions: collect pointers to the driver
structs in special sections, which are then processed by the init
code which already calls the init function vectors. For each level,
the structs are processed right after the init funcs, so we guarantee
the existing order, and explicit inits always come before the automatic
registering.

No, what is so "special" about platform drivers that they require this?

If anything, we should be moving _AWAY_ from platform drivers and use
real bus drivers instead.

Downside of apprach: cluttering init code w/ a little bit knowledge
about driver related stuff (calls to platform_driver_register(), etc).

Exactly, don't.

For now, only implemented for the built-in case (modules still go the
old route). The module case is a little bit trickier: either we have to
extend the module header (and modpost tool) or do some dynamic symbol
lookup.

This patch is just a PoC for further discussions, not ready for mainline.
It also changes a few drivers, just for illustration. In case the general
approach is accepted, it will be cleaned up and splitted.

Please no, I don't see why this is even needed.

greg k-h