On Tuesday 22 December 2020 16:02:38 CET Kalle Valo wrote:
> Jerome Pouiller <[email protected]> writes:
>
> > From: Jérôme Pouiller <[email protected]>
> >
> > Signed-off-by: Jérôme Pouiller <[email protected]>
>
> [...]
>
> > +wfx-$(CONFIG_SPI) += bus_spi.o
> > +wfx-$(subst m,y,$(CONFIG_MMC)) += bus_sdio.o
>
> Why this subst? And why only for MMC?
CONFIG_SPI is a boolean (y or empty). The both values make senses.
CONFIG_MMC is a tristate (y, m or empty). The substitution above
ensure that bus_sdio.o will included in wfx.ko if CONFIG_MMC is 'm'
("wfx-$(CONFIG_MMC) += bus_sdio.o" wouldn't make the job).
You may want to know what it happens if CONFIG_MMC=m while CONFIG_WFX=y.
This line in Kconfig prevents to compile wfx statically if MMC is a
module:
depends on MMC || !MMC # do not allow WFX=y if MMC=m
--
Jérôme Pouiller
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