On Mon, 19 Dec 2011, javier Martin wrote: > On 19 December 2011 11:41, Guennadi Liakhovetski <g.liakhovetski@xxxxxx> wrote: > > On Mon, 19 Dec 2011, Laurent Pinchart wrote: > > > >> Hi Guennadi, > >> > >> On Monday 19 December 2011 11:13:58 Guennadi Liakhovetski wrote: > >> > On Mon, 19 Dec 2011, Laurent Pinchart wrote: > >> > > On Monday 19 December 2011 09:09:34 Guennadi Liakhovetski wrote: > >> > > > On Mon, 19 Dec 2011, Laurent Pinchart wrote: > >> > > > > On Friday 16 December 2011 10:50:21 Guennadi Liakhovetski wrote: > >> > > > > > On Fri, 16 Dec 2011, Scott Jiang wrote: > >> > > > > > > >> How about this implementation? I know it's not for soc, but I > >> > > > > > > >> post it to give my idea. > >> > > > > > > >> Bridge knows the layout, so it doesn't need to query the > >> > > > > > > >> subdevice. > >> > > > > > > > > >> > > > > > > > Where from? AFAIU, we are talking here about subdevice inputs, > >> > > > > > > > right? In this case about various inputs of the TV decoder. How > >> > > > > > > > shall the bridge driver know about that? > >> > > > > > > > >> > > > > > > I have asked this question before. Laurent reply me: > >> > > > > > > > >> ENUMINPUT as defined by V4L2 enumerates input connectors > >> > > > > > > > >> available on the board. Which inputs the board designer > >> > > > > > > > >> hooked up is something that only the top-level V4L driver > >> > > > > > > > >> will know. Subdevices do not have that information, so > >> > > > > > > > >> enuminputs is not applicable there. > >> > > > > > > > >> > >> > > > > > > > >> Of course, subdevices do have input pins and output pins, > >> > > > > > > > >> but these are assumed to be fixed. With the s_routing ops > >> > > > > > > > >> the top level driver selects which input and output pins > >> > > > > > > > >> are active. Enumeration of those inputs and outputs > >> > > > > > > > >> wouldn't gain you anything as far as I can tell since the > >> > > > > > > > >> subdevice simply does not know which inputs/outputs are > >> > > > > > > > >> actually hooked up. It's the top level driver that has that > >> > > > > > > > >> information (usually passed in through board/card info > >> > > > > > > > >> structures). > >> > > > > > > >> > > > > > Laurent, right, I now remember reading this discussion before. But > >> > > > > > I'm not sure I completely agree:-) Yes, you're right - the board > >> > > > > > decides which pins are routed to which connectors. And it has to > >> > > > > > provide this information to the driver in its platform data. But - > >> > > > > > I think, this information should be provided not to the bridge > >> > > > > > driver, but to respective subdevice drivers, because only they > >> > > > > > know what exactly those interfaces are good for and how to report > >> > > > > > them to the bridge or the user, if we decide to also export this > >> > > > > > information over the subdevice user-space API. > >> > > > > > > >> > > > > > So, I would say, the board has to tell the subdevice driver: yes, > >> > > > > > your inputs 0 and 1 are routed to external connectors. On input 1 > >> > > > > > I've put a pullup, it is connected to connector of type X over a > >> > > > > > circuit Y, clocked from your output Z, if the driver needs to know > >> > > > > > all that. And the subdev driver will just tell the bridge only > >> > > > > > what that one needs to know - number of inputs and their > >> > > > > > capabilities. > >> > > > > > >> > > > > That sounds reasonable. > >> > > > > >> > > > Good, this would mean, we need additional subdevice operations along > >> > > > the lines of enum_input and enum_output, and maybe also g_input and > >> > > > g_output? > >> > > > >> > > What about implementing pad support in the subdevice ? Input enumeration > >> > > could then be performed without a subdev operation. > >> > > >> > soc-camera doesn't support pad operations yet. > >> > >> soc-camera doesn't support enum_input yet either, so you need to implement > >> something anyway ;-) > >> > >> You wouldn't need to call a pad operation here, you would just need to iterate > >> through the pads provided by the subdev. > > > > tvp5150 doesn't implement it either yet. So, I would say, it is a better > > solution ATM to fix this functionality independent of the pad-level API. > > I agree, > I cannot contribute to implement pad-level API stuff since I can't > test it with tvp5150. > > Would you accept a patch implementing only S_INPUT? Sorry, maybe I'm missing something, but how would it work? I mean, how can we accept from the user any S_INPUT request with index != 0, if we always return only 0 in reply to ENUM_INPUT? Ok, G_INPUT we could implement internally in soc-camera: return 0 by default, then remember last set input number per soc-camera device / subdev. But ENUM_INPUT?... Thanks Guennadi --- Guennadi Liakhovetski, Ph.D. Freelance Open-Source Software Developer http://www.open-technology.de/ -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
