Add support for LTC2325-16

[sputnik2019]

The LTC2325-16 is Quad, 16-Bit, 5Msps/Ch Simultaneous Sampling ADC.
The LTC2325-16 has a high speed SPI-compatible serial interface that supports CMOS or LVDS. The fast 5Msps per channel throughput.

[AndreiGrozav]

Hi,
As a group we don't have an evaluation board with this device. So we can't fully support it. I can point you to a similar device.
Looking at the datasheet the interface si similar with ad4853. https://github.com/analogdevicesinc/hdl/blob/main/library/axi_ad485x/axi_ad485x.v#L155C51-L155C57
You can use the axi_ad485x interface as a reference for LTC2325-16. The axi_ad4858x has more features.
Here you can find more documentation about it https://analogdevicesinc.github.io/hdl/library/axi_ad485x/index.html
https://analogdevicesinc.github.io/hdl/projects/ad485x_fmcz/index.html

AD4853 is not released yet. The closest example is on AD4857. For which there is a reference design, HW/HDL/Linux.

The difference I see between LTC2325-16 and AD485x:

• AD485x family has a SPI interface for control
• Through the config interface you can set packet format modes which you don't need.
• Options for resolution or oversampling
• AD485x has a busy signal. You can remove it an only use the conversion start.

In our design we use the axi_pwm_gen IP that generates the conversion start pulses.