Hello,We are trying to bring up the example design for the 9375 (using the 2018_r2 adrv9371x project) on custom hardware. The design and example project are based on the Xilinx ZCU102. We have built the project in Vivado and set the constraints properly. We also tweaked the device tree and simply used the root file system and kernel from the example project. However, the 9371 probe fails with the following message:[ 2.260827] ad9371 spi1.1: ad9371_probe : enter[ 2.267736] ad9528 spi1.0: spi1.0 supply vcc not found, using dummy regulator[ 2.284870] iio iio:device1: SPI Read Verify failed (0xFFFFFF)[ 2.290582] ad9528: probe of spi1.0 failed with error -5I've noted the discussion in https://ez.analog.com/linux-device-drivers/linux-software-drivers/f/q-a/102410/iio-device0-spi-read-verify-failed-0x0-problem-on-custom-carrier-and-ad9234-evaluation-board, but we have already reviewed the pin constraints. Any advice on how to approach debugging this would be appreciated!Thanks,Trent
From what I see, we're using the MISO for communications and it's not grounded. Can you point to the source code where it's grounded ?
You can try probing the SPI lines an see if there is communication on them. Also, in some cases, the SPI rate can be reduce for the system to work, depending on the custom board design.
Hi Adrian,We've probed the SPI lines and we can see data being transferred. All looks normal with the 9528 but the 9375 chip select doesn't seem to ever toggle. I'm not sure if this is abnormal or if the driver isn't doing anything since the 9528 fails. We also tried lowering the max frequency in the device tree settings to no avail. Unfortunately, the ZCU102 we used to verify the project is currently unavailable so we cannot use it as a reference. I noticed in the example design the MISO line is grounded, but we left ours floating. Could this be causing any issue with the drivers?
It seems that is where our mistake must be. Tracing the line back to the 9375, we saw it went to a test pad (not ground as I mistakenly said). I was able to probe the 102 this morning and verify there was indeed a signal on that pad. I'll hard-wire the line and give that a test. Thank you very much for the prompt responses! From 102 schematic:
From 9375 schematic: