Pinmux modification by PRU
There is a comment on the page that the PRU cannot change the pinmux. This is not strictly true. The PRU has access to the OCP bus and can therefore access the pinmux control registers. There is a potential issue of conflict if the ARM expects to be the only processor modifying these registers and does not check for updates when it might be necessary. In practice, it is unlikely an issue if the PRU changes the mux for pins dedicated to its own purposes.