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SPI with T4 and Android 8.1. Not working.

Moderators: chensy, FATechsupport

I have rebuilt the OS to change the GPIO header to use SPI1 instead of UART4.

The device shows up in /dev/spidev1/0 and I can open and close it, send ioctl commands to configure it, but I cannot get it to accept writes. I get the following error in the debug terminal.

rockchip-spi ff1d0000.spi: spi controller is in busy state!

Anyone got SPI to work? I am not using the FriendlyThings as that requires platform keys etc. A mess to try and debug your code with. Instead, I modified the OS build to allow user space access to the GPIO and SPI interfaces.
HI v8dave

I have the same problem with the SPI bus.
I have also rebuilt the operating system to activate spidev1. I enable chmod 777 permissions from boot to read and write.

in my android application I am using the FriendlyArm library (libfriendlyarm-things.so). I can open and close the bus, but I cannot write or read with this native library.

How you modificaste the OS to allow user space access to GPIO and SPI interfaces?

If you have any information to write and read to SPI bus I apreciate you.

I am using nanoPc t4 with Android 10 operating system

Best Regards

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