[Arm-dev] gpio device ownership

Tue Jun 30 13:38:13 UTC 2020
R C <cjvijf at gmail.com>

On 6/30/20 5:35 AM, Pablo Sebastián Greco wrote:
>
> On 29/6/20 16:49, R C wrote:
>> Hello,
>>
>> ownership/permissions on gpio device are like tis:
>>
>> crw-------.  1 root root    254,   0 Jan  1  1970 gpiochip0
>> crw-------.  1 root root    254,   1 Jan  1  1970 gpiochip1
>> crw-------.  1 root root    254,   2 Jan  1  1970 gpiochip2
>> crw-------.  1 root root    246,   0 Jan  1  1970 gpiomem
>>
>>
>> while other device like ttys, are owned by root and "group owned" by 
>> tty, similar for video, disk, dialout etc.
>>
>> wouldn't it be 'better' to  have these gpio devices  owned by root, 
>> "group owned" by a group other then root (gpio)?
>>
>> (or did 'we' inherit that from further up/down the development chain?)
> Yeap, that's inherited, I'm guessing you could write some udev rule to 
> set the permissions you need (or even setfacl)


I didn't even go that route,  I just created a group, called gpio, added 
myself and the uid stuff is running under to it, changed the group 
permission on the devices to rw .  That way a user that is in the gpio 
group can use the devices,  it's easy and similar to how serial devices 
etc (by being a member of dialout) work

Would be convenient if the gpio devices in /dev could be treated the 
same, permission wise, as modem/ACM0-n  etc.


>>
>>
>> Ron
>>
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> Pablo.