[alsa-devel] [Uclinux-dist-devel] [PATCH 2/2] ASoC: Blackfin AD1836/AD1938 machine drivers: require SPI master

Mike Frysinger vapier.adi at gmail.com
Tue Oct 6 23:09:42 CEST 2009

On Tue, Oct 6, 2009 at 07:52, Mark Brown wrote:
> On Tue, Oct 06, 2009 at 07:32:30AM -0400, Mike Frysinger wrote:
>> back to the original issue.  the AD1836/AD1938 have their registers
>> programed via SPI, but they dont care what SPI bus they're connected
>> to.  that is specified in the board resources.  because of the way the
>> Kconfig options are handled (machine drivers select codecs), the
>> SPI_MASTER dependency cannot be added to the codec Kconfigs in
>> codecs/Kconfig.  so even though the SPI dependency is only in the
>> codec and not the machine driver, the machine driver needs to declare
>> the SPI_MASTER dependency to prevent incorrect config selections and
>> link failures.
> Or, like I say, the drivers for the CODEC should be changed to allow
> build with no control bus.  This is a general problem for all the ASoC
> drivers and I'm still not sure which way to go.  Depending on just SPI
> support fixes the random build case but doesn't help end users get the
> driver working so it doesn't seem so useful.  If we're only going to be
> able to fix the random build case then it seems more useful to do so by
> having the CODEC driver able to build without the control bus, that way
> individual machine drivers don't need to worry about it.

i dont see how abstracting away the bus such that codec drivers are
allowed to build without proper bus support is useful.  the
AD1836/AD1938 only work with the SPI bus, so if support for that is
disabled, having the driver compiled and installed is pointless.

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