On Fri, 19 Feb 2010, Philipp Wiesner wrote: > Hi, > > I'm working with µCs (i.MX27) and cameras (Aptina) at the moment. > > Now I encountered a problem introduced by serializing and deserializing > (lvds) camera data on its way to the µC. > > The serializer expects a specific pixclk polarity which can be > configured in hardware. In most cases this is no problem as it is > permanently connected to only one sensor chip, but camera sensors with > configurable pixclk could negotiate the wrong polarity. > > The deserializer generates pixclk from data, its polarity again can be > configured in hardware. This leads to pixclk inversion depending on > wheter serdes is happening or not, so its not an attribute of the > platform (in opposition to what SOCAM_SENSOR_INVERT_PCLK is meant for) > > What would be the correct way to address this? > > Do we need another platform flag, e.g. SOCAM_PCLK_SAMPLE_RISING_FIXED? > The only solution coming to my mind is checking for the SerDes on boot > time and setting flags like SOCAM_PCLK_SAMPLE_RISING_FIXED and > SOCAM_SENSOR_INVERT_PCLK if necessary. Hm, how is any new flag better than the existing one? If it is just a static flag - it doesn't change anything, right? As far as I understand, on one and the same platform the signal polarity can be different, depending on some switch / jumper / hard-soldered pin, right? I think your boot-time verification is good then - just put it in your platform code and set the flag(s) accordingly. 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
