pi@raspberrypi:~/rpi_sparkfun $ .out/example_assembly_test_rpi_sparkfun_a111_r2c 00:20:37.547 [ 2032] (E) (driver_gpio_linux_sysfs) Could not write to gpio export: Device or resource busy 00:20:37.547 [ 2032] (E) (driver_gpio_linux_sysfs) Could not write to gpio export: Device or resource busy
Our "acc_board_*" files tries to open the GPIO 8/SPI0 CS0 as a GPIO and configure it as an output. In later linux kernel versions this fails as the kernel spi driver (spi-bcm2835.c) will request ownership of them
Resolve by:
Do not configure GPIO 8/SPI0 CS0 in the "acc_board_*" files. (Remove the #define PIN_SS_N/PIN_SPI_SS_N and the lines using them)