On Tue, Sep 23, 2014 at 02:52:24PM +0300, Laurent Pinchart wrote: > On Tuesday 23 September 2014 13:47:40 Andrzej Hajda wrote: > > On 09/23/2014 01:23 PM, Laurent Pinchart wrote: [...] > > > This becomes an issue even on Linux when considering video-related devices > > > that can be part of either a capture pipeline or a display pipeline. If > > > the link always goes in the data flow direction, then it will be easy to > > > locate the downstream device (bridge or panel) from the display controller > > > driver, but it would be much more difficult to locate the same device from > > > a camera driver as all of a sudden the device would become an upstream > > > device. > > > > Why? > > > > If you have graph: > > sensor --> camera > > > > Then camera register itself in some framework as a destination device > > and sensor looks in this framework for the device identified by remote > > endpoint. > > Then sensor tells camera it is connected to it and voila. > > Except that both kernelspace and userspace deal with cameras the other way > around, the master device is the camera receiver, not the camera sensor. DRM > is architected the same way, with the component that performs DMA operations > being the master device. I don't see what's wrong with having the camera reference the sensor by phandle instead. That's much more natural in my opinion. Thierry
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