Hi, On Fri, Nov 04, 2016 at 01:05:01AM +0200, Sakari Ailus wrote: > On Thu, Nov 03, 2016 at 11:48:43PM +0100, Sebastian Reichel wrote: > > On Tue, Nov 01, 2016 at 12:54:08AM +0200, Sakari Ailus wrote: > > > > > Thanks, this answered half of my questions already. ;-) > > > > :-). > > > > > > > > I'll have to go through the patches, et8ek8 driver is probably not > > > > enough to get useful video. platform/video-bus-switch.c is needed for > > > > camera switching, then some omap3isp patches to bind flash and > > > > autofocus into the subdevice. > > > > > > > > Then, device tree support on n900 can be added. > > > > > > I briefly discussed with with Sebastian. > > > > > > Do you think the elusive support for the secondary camera is worth keeping > > > out the main camera from the DT in mainline? As long as there's a reasonable > > > way to get it working, I'd just merge that. If someone ever gets the > > > secondary camera working properly and nicely with the video bus switch, > > > that's cool, we'll somehow deal with the problem then. But frankly I don't > > > think it's very useful even if we get there: the quality is really bad. > > > > If we want to keep open the option to add proper support for the > > second camera, we could also add the bus switch and not add the > > front camera node in DT. Then adding the front camera does not > > require DT or userspace API changes. It would need an additional > > DT quirk in arch/arm/mach-omap2/board-generic.c for RX51, which > > adds the CCP2 bus settings from the camera node to the bus > > switch node to keep isp_of_parse_node happy. That should be > > easy to implement and not add much delay in upstreaming. > > By adding the video bus switch we have a little bit more complex system as a > whole. The V4L2 async does not currently support this. There's more here: > > <URL:http://www.spinics.net/lists/linux-media/msg107262.html> I'm not sure what part relevant for video-bus-switch is currently not supported? video-bus-switch registers its own async notifier and only registers itself as subdevices to omap3isp, once its own subdevices have been registered successfully. > What I thought was that once we have everything that's required in > place, we can just change what's in DT. But the software needs to > continue to work with the old DT content. Right, so DT is not a problem. But adding the switch would change the media-graph, which is exposed to userspace. > > For actually getting both cameras available with runtime-switching > > the proper solution would probably involve moving the parsing of > > the bus-settings to the sensor driver and providing a callback. > > This callback can be called by omap3isp when it wants to configure > > the phy (which is basically when it starts streaming). That seems > > to be the only place needing the buscfg anyways. > > > > Then the video-bus-switch could do something like this (pseudocode): > > > > static void get_buscfg(struct *this, struct *buscfg) { > > if (selected_cam == 0) > > return this->sensor_a->get_buscfg(buscfg); > > else > > return this->sensor_b->get_buscfg(buscfg); > > } > > > > Regarding the usefulness: I noticed, that the Neo900 people also > > plan to have the bus-switch [0]. It's still the same crappy front-cam, > > though. Nevertheless it might be useful for testing. It has nice > > test-image capabilities, which might be useful for regression > > testing once everything is in place. > > > > [0] http://neo900.org/stuff/block-diagrams/neo900/neo900.html > > Seriously? I suppose there should be no need for that anymore, is there? > > I think they wanted to save one GPIO in order to shave off 0,0001 cents from > the manufacturing costs or something like that. And the result is... > painful. :-I CSI1/CCP2 is more than a single I/O pin, isn't it? Or do you reference to the GPIO dual use to enable frontcam and switch between the cameras? That is indeed a really ugly solution :( -- Sebastian
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