On Mon, Jul 15, 2013 at 3:09 PM, Sascha Hauer <s.hauer@xxxxxxxxxxxxxx> wrote: > 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. Good point, thanks. That unblocks that item. >> 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. Yes. As noted, this was simply a preference that seemed to emerge in the previous discussion. If in practice it causes too many headaches, maybe we will change our minds. For now devm is the only issue I have seen; I am avoiding devm where it is no longer possible under this design. The goal of getting this driver working properly on OLPC XO seems to be a twisty path that presents a new issue at every turn. In the above work I am trying to first implement the DT binding for Armada 510/cubox, as that is what the current code is aimed at. I am now facing a problem with i2c/TDA998x which Russell already noted: http://lists.freedesktop.org/archives/dri-devel/2013-June/039632.html What *can't* be done without a rewrite of the DRM slave encoder backend is to have the TDA998x I2C device provided by DT. There are mumblings about redoing the slave encoder API, hopefully this will be fixed there. This is because the existing DRM/encoder system works something like this: 1. i2c driver (e.g. tda998x_drv) registers as an i2c_driver via drm_i2c_encoder_register() 2. The drm driver (i.e. armada) later has to know that it is expecting a tda998x instance. It calls drm_i2c_encoder_init() to set this up. drm_i2c_encoder init requires: 1. The i2c_adapter in question. In a DT world, we could get this from finding the parent node of the tda998x node (this is the i2c bus master), and then using i2c_for_each_dev to find the first i2c adapter instance that has the same of_node. 2. i2c_board_info - basically the address of the device on the i2c bus. This is basically the way of instantiating i2c devices from platform data. Not the DT way :( In a DT world the i2c driver would be instantiated from a node in the DT, which already includes the info that would come in i2c_board_info. Then later it would have to be linked to a DRM slave/encoder, perhaps when the DRM device finds the of_node corresponding to it. So I think the next step is fixing up DRM, as Russell hinted. Unless someone sees another acceptable option that doesn't break our DT design. I am going away for 3-4 weeks now, so you won't be hearing for me for a while. Just in case someone else wants to pick up the task in the mean time, here is my work in progress. I'm still reading and learning, so please don't do any detailed reviews yet :) http://dev.laptop.org/~dsd/20130717/0001-dove-clk-dt-wip.patch It includes the previous clock selection patch as this stuff is quite closely bound with DT support. Thanks Daniel _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/dri-devel
