Guennadi Liakhovetski wrote:
> Hi Mauro
>
> we just discussed this with Hans on IRC, and if I understood him
> correctly, he was of the same opinion, that adding such a variable could
> help.
>
> The problem is the following: this automatic selection works in a way,
> that various bridge drivers select "helper" chip drivers (i2c subdevice
> drivers" if this autoselection is enabled, e.g.
>
> config VIDEO_MXB
> tristate "Siemens-Nixdorf 'Multimedia eXtension Board'"
> depends on PCI && VIDEO_V4L1 && I2C
> select VIDEO_SAA7146_VV
> select VIDEO_TUNER
> select VIDEO_SAA711X if VIDEO_HELPER_CHIPS_AUTO
> select VIDEO_TDA9840 if VIDEO_HELPER_CHIPS_AUTO
> select VIDEO_TEA6415C if VIDEO_HELPER_CHIPS_AUTO
> select VIDEO_TEA6420 if VIDEO_HELPER_CHIPS_AUTO
>
> With SoC-based set ups this cannot work. The only location where this
> information is available is platform code under arch/... and selecting
> these drivers from there would be awkward imho.
Kconfig works fine if the var is on another place. So, you could do things
like:
config VIDEO_xxx
select VIDEO_foo if VIDEO_HELPER_CHIPS_AUTO && ARCH_bar
You may even convert it into dependencies like:
config VIDEO_I2C_foo
depends on ARCH_bar && config VIDEO_xxx
default y if VIDEO_HELPER_CHIPS_AUTO
The depends on syntax generally works better than using select. We've converted
some select into depends on a few places like tuner, like, for example:
config MEDIA_TUNER_TDA827X
tristate "Philips TDA827X silicon tuner"
depends on VIDEO_MEDIA && I2C
default m if MEDIA_TUNER_CUSTOMISE
> So, for example, we want
> to put the ak881x video encoder driver under
>
> comment "Video encoders"
>
> and those drivers are only visible if VIDEO_HELPER_CHIPS_AUTO is
> unselected, and if it is selected, which it is by default, there is noone
> to automatically select ak881x. So, I think, the proposed patch is not a
> work-around, but a reasonable solution for this issue.
Even the menu being invisible, any of the above logic would work, if you do
something like:
config VIDEO_AK881X
depends on ARCH_MX1 && I2C
default y if VIDEO_HELPER_CHIPS_AUTO && SOC_CAMERA
or:
config SOC_CAMERA
select VIDEO_AK881X if VIDEO_HELPER_CHIPS_AUTO && ARCH_MX1
You should just take some care, since there are some combinations that won't work.
For example, if SOC_CAMERA is a module, any ancillary drivers used by it should also
be 'm', otherwise, the driver will break. That's why, when having multiple
dependencies, the better is to use the "depends on" way.
>
> Thanks
> Guennadi
> ---
> Guennadi Liakhovetski, Ph.D.
> Freelance Open-Source Software Developer
> http://www.open-technology.de/
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--
Cheers,
Mauro
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