Plan 9 from Bell Labs’s /usr/web/sources/contrib/blstuart/pi/sys/man/3
--rw-rw-r-- bootes sys 2330 Dec 29 2015 gpio --rw-r--r-- blstuart sys 2133 Dec 29 2015 i2c --rw-rw-r-- blstuart sys 1683 Dec 29 2015 spi