If other pins exist in that location and others are writeable but this one isn't, this means that pin has been claimed by some other device already. Like if you try to use HDMI pins, but don't disable HDMI first... you'll get what you got.
The other scenario is you are using the wrong build and those pins don't exist at all. On Friday, April 19, 2019 at 4:08:19 PM UTC-4, Jeff Pollard wrote: > > Hi, > That makes sense, but.... > > I can use config-pin to set the value to something like: > * pwm* > for example: > * config-pin P8.14 pwm* > will work just fine > as will *gpio* > and > *gpio_pd, etc.* > > But, *gpmc* (mode 0) is not a valid choice i.e. config-pin p8.14 gpmc > is invalid > I tried adding it to the config-pin script for pin 8_14, but that didn't > help as it appears the problem is deeper than than. I can't change the > value of state in: > > /sys/devices/platform/ocp/ocp:P8_14_pinmux/state > > the error I get is: > > *Cannot write pinmux File: > /sys/devices/platform/ocp/ocp:P8_14_pinmux/state* > > Jeff > > On Friday, April 19, 2019 at 12:39:21 PM UTC-7, Mala Dies wrote: >> >> Hello, >> >> The config-pin utility can be used in user land or user land w/ a .sh >> script and .service file to boot the board w/ the required config-pin >> utility being present. >> >> Seth >> >> P.S. If you know how to do this instead, this may work for you. So, use: >> config-pin P8.14 <mode> <--- this would be your mode, i.e. GPIO, UART, >> and etc. >> >> So, if you wanted to put in gpio in <mode>, you could if this is what you >> want. Does this sort of make sense? >> >> On Friday, April 19, 2019 at 1:55:21 PM UTC-5, Jeff Pollard wrote: >>> >>> >>> Hi, >>> >>> I'm using:* Linux beaglebone 4.14.106-bone-rt-r19 #1 PREEMPT RT Tue >>> Mar 26 19:02:06 UTC 2019 armv7l GNU/Linux* >>> >>> I started by disabling the emmc in uEnv.txt >>> >>> I then tried to modify the config-pin script for P8_14 (which would be >>> gpmc_AD14 as a starting example), but I get >>> >>> *Cannot write pinmux File: >>> /sys/devices/platform/ocp/ocp:P8_14_pinmux/state* >>> >>> Can anyone give a pointer on how to go about configuring pins to use >>> gmpc mode with the config-pin script (or any other method)? >>> >>> Thanks, >>> >>> Jeff >>> >> -- website: http://www.machinekit.io blog: http://blog.machinekit.io github: https://github.com/machinekit --- You received this message because you are subscribed to the Google Groups "Machinekit" group. To unsubscribe from this group and stop receiving emails from it, send an email to machinekit+unsubscr...@googlegroups.com. Visit this group at https://groups.google.com/group/machinekit. For more options, visit https://groups.google.com/d/optout.
