[PATCH] [media] staging: allow omap4iss to be modular

[tony@atomide.com (Tony Lindgren)]

* Arnd Bergmann <arnd@arndb.de> [140611 07:51]:
> On Wednesday 11 June 2014 09:42:04 Nishanth Menon wrote:
> > On 06/11/2014 09:35 AM, Arnd Bergmann wrote:
> > > The OMAP4 camera support depends on I2C and VIDEO_V4L2, both
> > > of which can be loadable modules. This causes build failures
> > > if we want the camera driver to be built-in.
> > > 
> > > This can be solved by turning the option into "tristate",
> > > which unfortunately causes another problem, because the
> > > driver incorrectly calls a platform-internal interface
> > > for omap4_ctrl_pad_readl/omap4_ctrl_pad_writel.
> > > To work around that, we can export those symbols, but
> > > that isn't really the correct solution, as we should not
> > > have dependencies on platform code this way.
> > > 
> > > Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> > > ---
> > > This is one of just two patches we currently need to get
> > > 'make allmodconfig' to build again on ARM.
> > > 
> > > diff --git a/arch/arm/mach-omap2/control.c b/arch/arm/mach-omap2/control.c
> > > index 751f354..05d2d98 100644
> > > --- a/arch/arm/mach-omap2/control.c
> > > +++ b/arch/arm/mach-omap2/control.c
> > > @@ -190,11 +190,13 @@ u32 omap4_ctrl_pad_readl(u16 offset)
> > >  {
> > >  	return readl_relaxed(OMAP4_CTRL_PAD_REGADDR(offset));
> > >  }
> > > +EXPORT_SYMBOL_GPL(omap4_ctrl_pad_readl);
> > >  
> > >  void omap4_ctrl_pad_writel(u32 val, u16 offset)
> > >  {
> > >  	writel_relaxed(val, OMAP4_CTRL_PAD_REGADDR(offset));
> > >  }
> > > +EXPORT_SYMBOL_GPL(omap4_ctrl_pad_writel);
> > >  
> > >  #ifdef CONFIG_ARCH_OMAP3
> > >  
> > > diff --git a/drivers/staging/media/omap4iss/Kconfig b/drivers/staging/media/omap4iss/Kconfig
> > > index 78b0fba..0c3e3c1 100644
> > > --- a/drivers/staging/media/omap4iss/Kconfig
> > > +++ b/drivers/staging/media/omap4iss/Kconfig
> > > @@ -1,5 +1,5 @@
> > >  config VIDEO_OMAP4
> > > -	bool "OMAP 4 Camera support"
> > > +	tristate "OMAP 4 Camera support"
> > >  	depends on VIDEO_V4L2 && VIDEO_V4L2_SUBDEV_API && I2C && ARCH_OMAP4
> > >  	select VIDEOBUF2_DMA_CONTIG
> > >  	---help---
> > > 
> > 
> > This was discussed in detail here:
> > http://marc.info/?t=140198692500001&r=1&w=2
> > Direct dependency from a staging driver to mach-omap2 driver is not
> > something we'd like, right?
> 
> So it was decided to just leave ARM allmodconfig broken?
> 
> Why not at least do this instead?
> 
> 8<----
> From 3a965f4fd5a6b3ef4a66aa4e7c916cfd34fd5706 Mon Sep 17 00:00:00 2001
> From: Arnd Bergmann <arnd@arndb.de>
> Date: Tue, 21 Jan 2014 09:32:43 +0100
> Subject: [PATCH] [media] staging: tighten omap4iss dependencies
> 
> The OMAP4 camera support depends on I2C and VIDEO_V4L2, both
> of which can be loadable modules. This causes build failures
> if we want the camera driver to be built-in.
> 
> This can be solved by turning the option into "tristate",
> which unfortunately causes another problem, because the
> driver incorrectly calls a platform-internal interface
> for omap4_ctrl_pad_readl/omap4_ctrl_pad_writel.
> 
> Instead, this patch just forbids the invalid configurations
> and ensures that the driver can only be built if all its
> dependencies are built-in.
 
Makes sense to me if the media people are OK with this:

Acked-by: Tony Lindgren <tony@atomide.com>

> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> 
> diff --git a/drivers/staging/media/omap4iss/Kconfig b/drivers/staging/media/omap4iss/Kconfig
> index 78b0fba..8afc6fe 100644
> --- a/drivers/staging/media/omap4iss/Kconfig
> +++ b/drivers/staging/media/omap4iss/Kconfig
> @@ -1,6 +1,6 @@
>  config VIDEO_OMAP4
>  	bool "OMAP 4 Camera support"
> -	depends on VIDEO_V4L2 && VIDEO_V4L2_SUBDEV_API && I2C && ARCH_OMAP4
> +	depends on VIDEO_V4L2=y && VIDEO_V4L2_SUBDEV_API && I2C=y && ARCH_OMAP4
>  	select VIDEOBUF2_DMA_CONTIG
>  	---help---
>  	  Driver for an OMAP 4 ISS controller.
>