On 19 December 2011 11:58, Guennadi Liakhovetski <g.liakhovetski@xxxxxx> wrote: > 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?... It clearly is not a complete solution but at least it allows setting input 0 in broken drivers such as tvp5150 which have input 1 enabled by default, while soc-camera assumes input 0 is enabled. -- Javier Martin Vista Silicon S.L. CDTUC - FASE C - Oficina S-345 Avda de los Castros s/n 39005- Santander. Cantabria. 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