Hi, I tried using the aptina_pll_calculate for a "new" imager and ran into problems. After filling out aptina_pll_limits from the data sheet, I was having a hard time finding a valid pix_clock. Most of the ones I tried are rejected by aptina_pll_calculate for various reasons. In particular, no pix_clock close to pix_clock_max is allowed. Why does the calculation method insist on exact division and avoiding fractional numbers? I'm using an ext_clock of 50 MHz. This clock is derived from a 33 MHz clock and the 50 MHz is not attained exactly. Rather it ends up being more like 49.999976 Hz. This raises the question, what value I should put into ext_clock (or the corresponding device tree property). Should I use the requested frequency or the actual frequency? Worse, depending on the precise value of the ext_clock, aptina_pll_calculate may or may not be able to compute pll parameters. On the other hand, the manufacturer provided configuration tool happily computes pll parameters that result in close, but not exactly, the requested pix_clock. In particular, the pll parameters do not necessarily result in a whole number. It appears to merely approximate the requested frequency. Can you explain where the requirement to avoid fractional numbers comes from? Would it be reasonable to use a different algorithm that avoids this requirement? Helmut
