Simple SPI loopback test using spidev.
Usage: spiloop [-s <speed>] [-d <device>] [-c <count>] [-i <iterations>] [-vh]
-s <speed> Set SPI bus speed in Hz
-d <device> Device, defaults to /dev/spidev1.0
-b <bytes> Number of bytes per transfer, default 32, min 1, max 4096
-i <iterations> Number of times to repeat, default is 1, 0 means forever
-v Be verbose
-h Show this help
Use Ctrl-C to stop.