On Mon, Jul 15, 2013 at 02:23:30PM -0600, Daniel Drake wrote: > On Fri, Jul 12, 2013 at 10:44 AM, Daniel Drake <dsd@xxxxxxxxxx> wrote: > > Based on the outcomes of the "Best practice device tree design for display > > subsystems" discussion I have drafted a DT binding. Comments much appreciated. > > > > At a high level, it uses a "super node" as something for the driver to bind > > to, needed because there is no clear one device that controls all the > > others, and also to distinguish between the Armada 510 possible use cases > > of having one video card with two outputs, or two independent video cards. > > It uses node-to-node linking beyond that point, V4L2 style. > > As this hasn't been shot down very far, I've started to implement the > driver side of this binding. I have already run into a couple of > little problems. > > First, interrupts. In the dt binding, each "lcd controller" node > defines which interrupt it listens to, and in the armada 510 case > there are indeed 2 interrupts (47 and 46, one for each LCD > controller). And remember that the drm driver itself binds to the > super-node. > > Looking at drm_irq_install(), it looks like DRM only supports 1 > interrupt line per drm_device. You don't have to call drm_irq_install(). Both the exynos and i.MX driver do without it and at least the i.MX driver uses multiple irqs per drm_device. > > Secondly, devm. I understand from the "best practices" thread that we > want to have exactly one platform_device which corresponds to the > "super node", and all of the individual display controller components > will be represented by DT nodes but *without* their own > platform_device. A super node approach doesn't mean that there's only one platform device. You can still have a platform device for each component. The super node should rather be seen as a node which contains phandles to the different components.. Sascha -- Pengutronix e.K. | | Industrial Linux Solutions | http://www.pengutronix.de/ | Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 | _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/dri-devel
