RFC: build config via DT names

[Enrico Weigelt, metux IT consult]

Hi folks,

I've regularily have the task of configuring a kernel for a given DT.
To make this a little bit easier, I'd like to do this automatically.

The tuff task here is getting a mapping between dt compatible strings
and corresponding CONFIG_* flags. Automatically extracting it from the
source code seems pretty tricky, especially w/ corner cases (eg. some
drivers support groups of devices, depending on config options) - IMHO
it will need some code changes anyways.

Therefore I propose a simple approach using the existing Kconfig system:

Add an extra (toplevel) menu and config flag naming scheme which
directly map DT compatible strings to config flags. For example:

> fsl,mpc5200-gpio <=> CONFIG_DTDEV_FSL_MPC5200_GPIO

> config CONFIG_DTDEV_FSL_MPC5200_GPIO
>    tristate "fsl,mpc5200-gpio"
>    select GPIO_MPC5200

Note that these flags are separate from the actual drivers - they just
enable them automatically. Of course they'll have to be maintained by
the driver maintainers.


What do you think about this idea ?


--mtx

--
Enrico Weigelt, metux IT consult
Free software and Linux embedded engineering
info@xxxxxxxxx -- +49-151-27565287