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iMx6Solo SPI interface: No data read on MISO

Question asked by Arthur Bousquet on May 16, 2017
Latest reply on Jan 18, 2018 by Arthur Bousquet

Hello,

 

I have setup SPI in Linux with an iMx6Solo Wandboard on a custom carrier board. I am trying to establish communication with a peripheral. However, I never see any data come back from the MISO line.

 

MOSI line, clock and chip select all have good transitions and I have scoped the data coming back on MISO to confirm it's being sent. On the iMx6 [master], the IRQ goes off but I only ever get a blank buffer reported. I have used the user-space tools spi-pipe & spi-config as well as the Ruby SPIDev gem. Same result with both.

 

I am inclined to believe this might be an issue with either spi_imx, spidev or both. Perhaps one reads the data and clears the buffer before the other can retrieve the data for my application? Or there's a hand-off that's mistimed/failing?

 

I am using the SPI1 interface. I am confident my DTS entries and pin assignments are correct.

 

System, drivers and software courtesy of the Freescale BSP on Yocto, Krogoth branch.

 

Any questions or insight appreciated. Thanks.

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