Hi Tony, On Thursday 12 December 2013 21:59:13 Tony Lindgren wrote: > On Thu, Dec 12, 2013 at 10:38:34AM +0200, Tomi Valkeinen wrote: > > On 2013-12-12 01:44, Laurent Pinchart wrote: > > > > So, are they independent? I don't know =). I think they lean on the > > independent side. dss_core is always needed for the submodules to work, > > but for example DSI could be used without DISPC, using system DMA to > > transfer data from memory to DSI. Not a very useful thing to do, but > > still, there are dedicated DMA channels for that. > > If they have separate hwmod entries, they should be considered separate > independent devices for sure. > > To summarize, here are few reasons why they need to be treated as > separate devices: Are you talking generally here, or about the DSS modules in particular ? > 1. The modules maybe clocked/powered/idled separately and can have their > own idle configuration so they can do the hardware based idling > separately. I don't think this applies to the DSS modules. > 2. Doing a readback after a write to one module will not flush the write > to the other modules on the (bus depending on the SoC version AFAIK). > That can lead to nasty bugs caused by the ordering. How does separate devices solve this ? > 3. If the devices are described in a different way in the .dts files > from the hwmod data, we will not have 1-to-1 mapping and will never > be able to replace ti,hwmods with just the compatible string. -- Regards, Laurent Pinchart -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
