[PATCH RFC 26/46] drivers/base: provide an infrastructure for componentised subsystems

Greg Kroah-Hartman
2014-01-03T03:10:55Z

On Thu, Jan 02, 2014 at 09:27:58PM +0000, Russell King wrote:
> Subsystems such as ALSA, DRM and others require a single card-level
> device structure to represent a subsystem. However, firmware tends to
> describe the individual devices and the connections between them.
>
> Therefore, we need a way to gather up the individual component devices
> together, and indicate when we have all the component devices.
>
> We do this in DT by providing a "superdevice" node which specifies
> the components, eg:
>
> imx-drm {
> compatible = "fsl,drm";
> crtcs = <&ipu1>;
> connectors = <&hdmi>;
> };
>
> The superdevice is declared into the component support, along with the
> subcomponents. The superdevice receives callbacks to locate the
> subcomponents, and identify when all components are present. At this
> point, we bind the superdevice, which causes the appropriate subsystem
> to be initialised in the conventional way.
>
> When any of the components or superdevice are removed from the system,
> we unbind the superdevice, thereby taking the subsystem down.

This sounds a lot like the "containers" code that Rafael just submitted
and I acked for 3.14. Look at the lkml post:
Subject: [PATCH 2/2] ACPI / hotplug / driver core: Handle containers in a special way
Message-ID: <1991202.gilW172FBV@vostro.rjw.lan>

And see if that could possibly be used instead?

thanks,

greg k-h