Re: [RFC v2 5/5] drm: Add NVIDIA Tegra support

["Terje Bergström" <tbergstrom-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>]

On 21.05.2012 16:58, Thierry Reding wrote:

> I agree that reflecting the hardware hierarchy within the device tree makes
> sense. I'll need to add some code to tear down child devices in the cleanup
> path, but that shouldn't be too difficult.
> 
> However, adding a whole bus_type implementation would pretty much duplicate
> the platform bus code. I guess host1x could just provide struct host1x_client
> a set of corresponding APIs to create them, request channels, etc.


Hi,

There is a reason for existence of bus_type in Linux kernel. It exposes
the various busses to developers, and give a framework for drivers to
work in. It just makes the drivers easier to develop, and makes the big
picture easier to understand.

The problem is that bus_type is cumbersome to implement, and most
implementations seem to duplicate significant amount of code from
platform bus. This is the problem that we should tackle.

If I manage to get the boilerplate code in nvhost for bus_type small
enough, that's the structure we should use. If bus_type is just
inherently fat and broken, I'll need to migrate nvhost away from it.

Terje