From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stephen Warren Subject: Re: Tegra DRM device tree bindings Date: Tue, 26 Jun 2012 11:46:42 -0600 Message-ID: <4FE9F582.6010805@wwwdotorg.org> References: <20120626105513.GA9552@avionic-0098.mockup.avionic-design.de> <4FE9B291.2020305@nvidia.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: <4FE9B291.2020305-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org> Sender: linux-tegra-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: =?ISO-8859-1?Q?Terje_Bergstr=F6m?= Cc: Thierry Reding , "linux-tegra-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , "devicetree-discuss-uLR06cmDAlY/bJ5BZ2RsiQ@public.gmane.org" , "dri-devel-PD4FTy7X32lNgt0PjOBp9y5qC8QIuHrW@public.gmane.org" List-Id: devicetree@vger.kernel.org On 06/26/2012 07:01 AM, Terje Bergstr=F6m wrote: > On 26.06.2012 13:55, Thierry Reding wrote: =2E.. >> An alternative would be to call of_platform_populate() from the host= 1x [alternative to making the host1x node contain compatible=3D"simple-bus= ".] >> driver. This has the advantage that it could integrate better with t= he >> host1x bus implementation that Terje is working on, but it also need= s >> additional code to tear down the devices when the host1x driver is >> unloaded because a module reload would try to create duplicate devic= es >> otherwise. >=20 > Yes, we already have a bus_type for nvhost, and we have nvhost_device > and nvhost_driver that device from device and device_driver > respectively. They all accommodate some host1x client device common > behavior and data that we need to store. We use the bus_type also to > match each device and driver together, but the matching is version > sensitive. For example, Tegra2 3D needs different driver than Tegra3 = 3D. I'd certainly like to see some upstream discussion re: why exactly we have a custom bus type here. What does it do that a regular platform bu= s doesn't do? Are those features something that would be generally useful to add to the existing platform bus? Can we instead add hooks into platform bus rather than creating a new bus? I recall you saying that the nvhost_bus duplicated a lot of code from the existing platform bus.