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imx6q spidev_test loopback test no RX

Question asked by jongjyh hsieh on Dec 18, 2016
Latest reply on Sep 29, 2017 by Pavle Boskoski

my goal is run a loopback test on the spi device. 

So far, I configured pin map for SPI1 and SPI3 and enabled them on the board-specific file. 

I can see spi1.0 and spi3.0 device node under /dev/. 

 

I connected the SPI3's MISO to MOSI to run the loopback. 

 

For the testing application used spidev_test.c which is under kernel document and just modified the device name to spidev3.0.

 

when I run the test app, below is what I get, 

spi mode: 0
bits per word: 8
max speed: 500000 Hz (500 KHz)

00 00 00 00 00 00
00 00 00 00 00 00
00 00 00 00 00 00
00 00 00 00 00 00
00 00 00 00 00 00
00 00 00 00 00 00
00 00

 

I am expecting to get the same tx data for rx but I get 0 as above.

 

Let me know if anythig I have missed.

 

Thanks in advance, 

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