Hi Guennadi, On Fri, 24 Aug 2012 23:23:37 +0200 (CEST) Guennadi Liakhovetski <g.liakhovetski@xxxxxx> wrote: ... > > Every time the sensor is reset, it resets this register. Without setting > > the register after sensor reset to the needed value I only get garbage data > > from the sensor. Since the possibility to reset the sensor is provided on > > the hardware and also used, the register has to be set after each sensor > > reset. Only the instance controlling the reset gpio pin "knows" the time, > > when the register should be initialized again, so it is asynchronously and > > not related to the standard camera activities. But since the stuff is _not_ > > documented, I can only speculate. Maybe it can be set to different values > > to achieve different things, currently I do not know. > > How about adding that register write (if required by platform data) to > mt9v022_s_power() in the "on" case? This is called (on soc-camera hosts at > least) on each first open(), would this suffice? This would suffice. But now I found some more info for this register. Rev3. errata mentions that the bit 9 of the register should be set when in snapshot mode (in my case this is the only mode that we can use). Additionally the errata recommends to set bit 2 when the high dynamic range mode is used. Now I'm not sure how to realise these settings. The bit 9 should be set/unset when configuring the master/snapshot mode in mt9v022_s_stream(), I think. For setting bit 2 we could add V4L2_CID_WIDE_DYNAMIC_RANGE control which primarily configures the HiDy mode in register 0x0f and additionally sets/unsets bit 2 in register 0x20. But setting this bit 2 seems to be needed also in linear mode when manual exposure control is used. With the recommended register value 0x03D1 in linear mode the image quality is really bad when manual exposure mode is used, independent of the configured exposure time. Using 0x03D5 in linear mode however gives good image quality here. So setting bit 2 should be independent of HiDy control. The errata states "the register setting recommendations are based on the characterization of the image sensor only and that camera module makers should test these recommendations on their module and evaluate the overall performance". These settings should be configurable independently of each other, I think. Thanks, Anatolij -- 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
