I need to setup a VPIF interface (ala V4L2) using a Mity OMAP-L138F SoM platform running DaVinci Linux to support, BT.656, 8-bit, 720x480, composite (CVBS) video output only.
I have attempted to make customizations to the Linux kernel code in the board configuration module, board-mityomal138.c. Which derives from board-da850.c. I added software changes to perform the pin mux setup of the VPIF display pins, register the VPIF chip, the VPIF display device interface, and the video encoder chip.
Thus far, using TI’s ‘vpif_test_display’ application, and the V4L2 video stack. I have been able to successfully display color bars directly from the ADV7391 video encoder, to a analog display that’s connected to the SoM’s custom baseboard.
However, if I try to display a frame from memory using a known Y/C pattern. I get a blank screen. Connecting a scope to a few of the VPIF’s pins, such as CLKOUT2, DOUT7, and DOUT3. We were able to verify that the VPIF’s CLKOUT2 pin is putting out a 27 MHz clock. But pins DOUT3 and DOUT7 are flat lined at about 0V.
