raspberry pi gpio command line sysfs does not set gpio output high

Question

So I've been trying to get my Raspberry Pi GPIO to behave correctly by writing to and reading from /sys/class/gpio/ using the command line and sysfs. Based on the following tutorials, I am not able to replicate setting a GPIO to output and setting it's value high (1).

this one

and this one

What I expect to happen is that when I run the following commands

$ echo 18 > /sys/class/gpio/export
$ echo out > /sys/class/gpio/gpio18/direction
$ echo 1 > /sys/class/gpio/gpio18/value

that I see the result from the following command

$ cat /sys/class/gpio/gpio18/value
1

To clarify, I have nothing hooked up to the GPIO pins, I really am only interested in reading the output value back and for it to be the same as what I set it. For what it's worth, I'm trying to make my own Ruby driver for the Pi's GPIO pins and I am checking that I am able to read back the same gpio value that I set it to if it's an output.

The following is a shell session as proof.

Permissions and OS versioning

pi@raspberrypi:~ $ uname -a
Linux raspberrypi 4.14.34+ #1110 Mon Apr 16 14:51:42 BST 2018 armv6l GNU/Linux
pi@raspberrypi:~ $ lsb_release -a
No LSB modules are available.
Distributor ID: Raspbian
Description:    Raspbian GNU/Linux 9.4 (stretch)
Release:    9.4
Codename:   stretch
pi@raspberrypi:~ $ groups
pi adm dialout cdrom sudo audio video plugdev games users input netdev gpio i2c spi

GPIO 18

pi@raspberrypi:~ $ cd /sys/class/gpio/
pi@raspberrypi:/sys/class/gpio $ ls -a
.  ..  export  gpiochip0  unexport
pi@raspberrypi:/sys/class/gpio $ echo 18 > export 
pi@raspberrypi:/sys/class/gpio $ ls -a
.  ..  export  gpio18  gpiochip0  unexport
pi@raspberrypi:/sys/class/gpio $ cd gpio18/

Permissions and groups for GPIO 18

pi@raspberrypi:/sys/class/gpio/gpio18 $ stat value 
  File: value
  Size: 4096        Blocks: 0          IO Block: 4096   regular file
Device: fh/15d  Inode: 16223       Links: 1
Access: (0770/-rwxrwx---)  Uid: (    0/    root)   Gid: (  997/    gpio)
Access: 2018-05-01 00:41:52.493284419 +0000
Modify: 2018-05-01 00:41:52.493284419 +0000
Change: 2018-05-01 00:41:52.500207389 +0000
 Birth: -

Try setting it to out and high

pi@raspberrypi:/sys/class/gpio/gpio18 $ ls -a
.  ..  active_low  device  direction  edge  power  subsystem  uevent  value
pi@raspberrypi:/sys/class/gpio/gpio18 $ cat active_low direction edge value 
0
in
none
0
pi@raspberrypi:/sys/class/gpio/gpio18 $ echo out > direction 
pi@raspberrypi:/sys/class/gpio/gpio18 $ echo 1 > value 

Here is where I expect the content of the value file to be 1

pi@raspberrypi:/sys/class/gpio/gpio18 $ cat active_low direction edge value 
0
out
none
0
pi@raspberrypi:/sys/class/gpio/gpio18 $ echo in > direction 
pi@raspberrypi:/sys/class/gpio/gpio18 $ cat active_low direction edge value 
0
in
none
0

More checks

pi@raspberrypi:/sys/class/gpio/gpio18 $ echo high > direction 
pi@raspberrypi:/sys/class/gpio/gpio18 $ cat active_low direction edge value 
0
out
none
0
pi@raspberrypi:/sys/class/gpio/gpio18 $ echo low > direction 
pi@raspberrypi:/sys/class/gpio/gpio18 $ cat active_low direction edge value 
0
out
none
0

Try the same for GPIO 23

pi@raspberrypi:/sys/class/gpio/gpio18 $ cd ..
pi@raspberrypi:/sys/class/gpio $ echo 23 > export 
pi@raspberrypi:/sys/class/gpio $ ls -a
.  ..  export  gpio18  gpio23  gpiochip0  unexport
pi@raspberrypi:/sys/class/gpio $ cd gpio23/

Permissions and groups

pi@raspberrypi:/sys/class/gpio/gpio23 $ stat value
  File: value
  Size: 4096        Blocks: 0          IO Block: 4096   regular file
Device: fh/15d  Inode: 16238       Links: 1
Access: (0770/-rwxrwx---)  Uid: (    0/    root)   Gid: (  997/    gpio)
Access: 2018-05-01 01:26:37.121782992 +0000
Modify: 2018-05-01 01:26:37.121782992 +0000
Change: 2018-05-01 01:26:37.126033971 +0000
 Birth: -

Try setting it to out and high

pi@raspberrypi:/sys/class/gpio/gpio23 $ ls -a
.  ..  active_low  device  direction  edge  power  subsystem  uevent  value
pi@raspberrypi:/sys/class/gpio/gpio23 $ cat active_low direction edge value 
0
in
none
0
pi@raspberrypi:/sys/class/gpio/gpio23 $ echo out > direction 
pi@raspberrypi:/sys/class/gpio/gpio23 $ echo 1 > value  

Here is where I expect the content of the value file to be 1

pi@raspberrypi:/sys/class/gpio/gpio23 $ cat active_low direction edge value 
0
out
none
0
pi@raspberrypi:/sys/class/gpio/gpio23 $ echo in > direction 
pi@raspberrypi:/sys/class/gpio/gpio23 $ cat active_low direction edge value 
0
in
none
0

More checks

pi@raspberrypi:/sys/class/gpio/gpio23 $ echo high > direction 
pi@raspberrypi:/sys/class/gpio/gpio23 $ cat active_low direction edge value 
0
out
none
0
pi@raspberrypi:/sys/class/gpio/gpio23 $ echo low > direction 
pi@raspberrypi:/sys/class/gpio/gpio23 $ cat active_low direction edge value 
0
out
none
0

Clean up

pi@raspberrypi:/sys/class/gpio/gpio23 $ cd ..
pi@raspberrypi:/sys/class/gpio $ echo 18 > unexport 
pi@raspberrypi:/sys/class/gpio $ echo 23 > unexport 
pi@raspberrypi:/sys/class/gpio $ ls -a
.  ..  export  gpiochip0  unexport
pi@raspberrypi:/sys/class/gpio $

This is with a fresh install of NOOBS and the very first commands run on it. It seems like all other sysfs functionality works as expected except for the value file of a GPIO. The only explanation I have for this actual behavior to differ from my expected behavior is that either there are inherit pull up/downs that hold the output to a certain value without a sink to some circuitry (which still wouldn't make sense to me but I've been wrong before) OR that my expectation is flat wrong and that the value file does not reflect the actual physical voltage level that the pin is set to.

Perhaps some more useful information is that I do not want to use a command line utility to do this, I would like to only work with with the file system for my driver I am building. That being said, I have used

gpio write 18 1

but the results were the same as above when reading the contents of the value file for GPIO 18.

Answer 1

It was a bad Raspberry Pi. I just received a new one. This is a session.

pi@raspberrypi:~ $ cd /sys/class/gpio/
pi@raspberrypi:/sys/class/gpio $ ls -a
.  ..  export  gpiochip0  unexport
pi@raspberrypi:/sys/class/gpio $ echo 18 > export 
pi@raspberrypi:/sys/class/gpio $ ls -a
.  ..  export  gpio18  gpiochip0  unexport
pi@raspberrypi:/sys/class/gpio $ cd gpio18/
pi@raspberrypi:/sys/class/gpio/gpio18 $ ls -a
.  ..  active_low  device  direction  edge  power  subsystem  uevent  value
pi@raspberrypi:/sys/class/gpio/gpio18 $ cat active_low direction edge value 
0
in
none
0
pi@raspberrypi:/sys/class/gpio/gpio18 $ echo out > direction 
pi@raspberrypi:/sys/class/gpio/gpio18 $ cat active_low direction edge value 
0
out
none
0
pi@raspberrypi:/sys/class/gpio/gpio18 $ echo 1 > value 
pi@raspberrypi:/sys/class/gpio/gpio18 $ cat active_low direction edge value 
0
out
none
1