I have a custom board derived from the DM6467T EVM. I need read/write access to the CPLD registers Reg0 and Reg1. I find in board-dm-646x-evm.c reference to "cpld_video" associated with Reg1, and reference to "cpld_reg0" associated with Reg0, but this hasn't helped me yet in my goal, which is APPLICATION and DRIVER access to these registers.
More specifically, I want to produce a splash screen during startup, using my ADV7171 ntsc output chip by raising high (releasing) an active-low reset line controlled by CPLD Reg1 bit 1. I want to modify the ADV7170 driver to configure the ADV7171 for color bars and then release this reset, as soon as the driver is loaded. This will allow the clock (clkout2) to flow through to the ADV7171 and allow it to show the color bars within less than 16 seconds of power up. Otherwise, the NAND boot process takes a couple of minutes, and one doesn't know if the hardware is working or broken during that time. As things stand, as soon as the application configures the video output device, that reset line is released and I can get color bars out. But I want to do this more directly and much earlier, from the driver. This is DRIVER access to write Reg1.
Also, I want to input a rotary encoder on the GPIO lines, which wire into the CPLD. I'm thinking I'll code the CPLD to make it track the gray code coming from the encoder, and produce a knob position (24 position will take 5 bits). Reg0 is substantially unused on my custom board, so I can stuff this knob position into Reg0. Then, my application wants to read Reg0 to determine the knob position. Here's where I want APPLICATION access to read Reg0. I'll probably be doing a single bit switch input as well. I have 6 free bits in Reg0.
So, I repeat, how can I get access APPLICATION as well as DRIVER access to these registers? (Video DRIVER write Reg1, APPLICATION read Reg0)
Thanks very much,
Helmut