SPI read problem on iMX6.UL (no MISO data)

[colinhelliwell]

Has anyone had (and ideally solved!) problems with SPI master on the UL?

I’m using a 4.4.40 kernel, and trying a simple loopback test (MOSI shorted to MISO) with the spi_imx driver module and “spidev_test” utility.

I also have a bus analyser hooked up and this sees the data on MISO as well as MOSI, but the utility just gets zeroes back.

My board uses an SOM and I can swap the UL for a iMX6.S and it works – so I know there isn’t a wiring fault on the board. I don't think there's any significant difference in kernel config (though obviously the device trees are quite different).

I feel the device tree is probably correct, because Clk/SS/MOSI are all working; just not MISO. I have my own top-level dts for my board, but it includes the imx6ul-tx6ul.dtsi and imx6ul.dtsi from the kernel source.

Any thoughts please as to where the problem could be? Thanks.

[igorpadykov]

Hi colinhelliwell 

4.4.40 kernel is not supported by nxp, one can try with official nxp releases described on

i.MX Software|NXP 

below example dts from L4.1.15 kernel,  linux/arch/arm/boot/dts/imx6ul-14x14-evk.dts

imx6ul-14x14-evk.dts\dts\boot\arm\arch - linux-imx - i.MX Linux kernel 

Best regards
igor
-----------------------------------------------------------------------------------------------------------------------
Note: If this post answers your question, please click the Correct Answer button. Thank you!
-----------------------------------------------------------------------------------------------------------------------