You have to be in privileged mode to change pinmux. My approach is creating a kernel module for it like this ( https://github.com/chunsj/nxctrl/tree/master/nxpmx) Or you can use PRU for this, I've heard that someone really do this in his library (I cannot remember its name). However to control PRU you might need to be in privileged mode to enable PRU and others...
Last but most official method is use of device tree and reboot. If your kernel is 3.8.16, you can use device tree overlay. I hope this can help you. On Wed, Nov 5, 2014 at 1:46 AM, Nic Cyn <[email protected]> wrote: > I have attempted to adjust the pinmux settings for a gpio programatically > using mmap() and a write out to the appropriate register. This does not > throw exception or any other error however no changes are made. Reading the > mmap()'ed location returns pretty reasonable and believable results so I > know I am hitting the right location. > > For example, on my BBB GPIOs 50 and 51 are currently in mux mode 6 > (ehrpwm1A_mux1 and ehrpwm1B_mux1) and the pinmux control registers for > these are at offsets 0x848 and 0x84c from the 0x44e1000 control register. I > can read the memory at these positions just fine and the return values are > 0x06 (mux mode 6). Attempting to write a 0x07 to either of these locations > to enable mux mode 7 does not error but the value at that memory location > remains 0x06. > > Is there any reason why this should not work? After all the capemanager > and cape universal drivers seem to be able to change these settings at > runtime. > > I would very much appreciate any advice and insights anybody has into this > issue. > > Oh yeah, before anybody goes to the trouble of beating me up about it, I > am aware that the Device Tree is the recommended way of changing this sort > of pinmuxing and for my project I could, and probably will, do it that way. > Nevertheless, is there a reason the ocp muxing cannot be adjusted at > runtime (as root) by writing to the appropriate GPIO control register > location? > > > -- > For more options, visit http://beagleboard.org/discuss > --- > You received this message because you are subscribed to the Google Groups > "BeagleBoard" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > For more options, visit https://groups.google.com/d/optout. > -- For more options, visit http://beagleboard.org/discuss --- You received this message because you are subscribed to the Google Groups "BeagleBoard" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/d/optout.
