Revert "drivers: pinmux: build as static library"

[tejlmand]

This reverts commit 4330929.

Fixes: #38403

The referred commit introduced zephyr_library() for pinmux drivers but
also resulting in #38403 because several boards has CONFIG_PINMUX=y
without selecting any pinmux drivers from drivers/pinmux thus
generating the following warning:

No SOURCES given to Zephyr library: drivers__pinmux

Excluding target from build.

This commit reverts the changes so that this warning disappears.
This results in pinmux drivers from drivers/pinmux to be located in
libzephyr.a which is messy, but has been so for a long time, even before
Zephyr 1.14 LTS.

The future pinctrl API will be designed in such a way that this problem
will not occur. Thus the old behavior is acceptable until the transition
to pinctrl API has completed.

Signed-off-by: Torsten Rasmussen [email protected]

[tejlmand]

This is an alternative fix to: #38608

[nashif]

too fast, should have let @dcpleung at least review this since it is reverting his commit? How is this going to be solved on 2.7 with no pinctrl? The original commit is solving another issue which would allow post linking of applications with a prebuilt zephyr library.

[tejlmand]

too fast, should have let @dcpleung at least review this since it is reverting his commit?

Agree, always nice to have the author of the original commit approve.

How is this going to be solved on 2.7 with no pinctrl?

This is not solving that. That will be in future.
For 2.7, it will avoid the empty library warning by restoring old behavior, as described.
Because there seemed to be too much resistance to this proposal: #38608

The original commit is solving another issue which would allow post linking of applications with a prebuilt zephyr library.

@nashif How so ?
The Zephyr libraries must still be inside the whole-archive flags so how will the original commit help to do post-linking from the app ?
The original commit only moved files from the libzephyr.a library into a dedicated libdrivers__pinmux.a lib, and thus reducing the mess in libzephyr.a`.
Also the original PR doesn't mention anything on post linking possibilities.
#37512