From mboxrd@z Thu Jan 1 00:00:00 1970 From: Thierry Reding Subject: Re: Tegra DRM device tree bindings Date: Wed, 27 Jun 2012 08:37:30 +0200 Message-ID: <20120627063730.GC8496@avionic-0098.adnet.avionic-design.de> References: <20120626105513.GA9552@avionic-0098.mockup.avionic-design.de> <4FE9B291.2020305@nvidia.com> <4FE9F582.6010805@wwwdotorg.org> <4FEAA4A0.3060407@nvidia.com> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="+xNpyl7Qekk2NvDX" Return-path: Content-Disposition: inline In-Reply-To: <4FEAA4A0.3060407-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org> Sender: linux-tegra-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Terje =?utf-8?Q?Bergstr=C3=B6m?= Cc: Stephen Warren , "linux-tegra-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , "devicetree-discuss-uLR06cmDAlY/bJ5BZ2RsiQ@public.gmane.org" , "dri-devel-PD4FTy7X32lNgt0PjOBp9y5qC8QIuHrW@public.gmane.org" List-Id: linux-tegra@vger.kernel.org --+xNpyl7Qekk2NvDX Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Wed, Jun 27, 2012 at 09:13:52AM +0300, Terje Bergstr=C3=B6m wrote: > On 26.06.2012 20:46, Stephen Warren wrote: >=20 > > 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 bus > > 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. >=20 > Yes, the code is largely a copy of platform bus. One big difference is > type safety - all the nvhost_bus APIs take in and give out nvhost_device > or nvhost_driver pointers. At the registration time I also enforce > parent-child relationship to host1x and bus clients. I don't know where NVIDIA wants to go with respect to device trees in their downstream kernels, but at least for mainline (with DT-only support on Tegra) the parent-child relationship will be rooted in the DT anyway. > Another is that I am able to enumerate all host1x related devices. The > latter could of course be done via listing the children of host1x. >=20 > And third is that I was able to add version field to device to > distinguish between Tegra2 and Tegra3 3D (for example) and make the bus > use that information for binding driver and device. As the sysfs entry > path is determined by the device name, this allows keeping the old sysfs > APIs. Again this can easily be represented by the DT compatible property. Thierry --+xNpyl7Qekk2NvDX Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.19 (GNU/Linux) iQIcBAEBAgAGBQJP6qoqAAoJEN0jrNd/PrOhAukP/23FExDqn6SrTAyQZRKzZPIn FStdFrHx/rp1RAU0r15iVM6LmJhECgtqQDZ6cXNFKR7/CWBkEWT7336/dGUyaltu 2XNte6f9rspJ2moWC4LyAxPEDGkwR1lQT0IKmetKCjmMSZdDSGgz5ylvGVDmG5ur JtGNL3EQpP14uOyLyPqGAd3dxeKGKUAxx6Tz1lLZjmi2Rd9uLh8JMmbFtKwiSz99 zBF042YfC1zca290FXrTXn+eIkjENguNUYViLV9OXIqT9y4+CrMkKdxew7e8inl4 s4ji67ku+2vZ8WHNyhfFIMRyxxFB7yEvqCdeW/FaEEARlNlGjCXEJXh7hSBNYMUm FotisZLOCTC0y3f04siJ9O5dZZ0prpz9tUgC55+CbW6cmdCk/kMaDSu0iFj1YCmx S4NI7kXMKqZfqMMdHN7FiK9MwvvTa5ameN6h68hNnhuQ5lPsjr5CefIyLyGDa0AV HlcM429Qj4pgSwKwnhf7/dkn/EtSSHT3Mdjnz2UmVMvF5k39qVlP9ivzo+YDy6zA YSIaSD/atwCUWI1TOGoxa4ZbnE4NQmDWCcZZEbbIVn58FOr29NictfgEHre+oh/s p5/M3hKBxxx2F1Xm/msxuhKLGUNvolgwp8VZMe82MCyu4esh0wbDIeCxIqjvFUzZ nOwNOHR6eFPnVvi0Lgfc =03a5 -----END PGP SIGNATURE----- --+xNpyl7Qekk2NvDX--