No /dev/gpiochip[n] on RockPro64.
#1
SBC:    Rockpro64 v2.1 4Gb
OS:     ubuntu 18.04 minimal w / Mate' DE     
        Linux rockpro64 4.4.190-1233-rockchip-ayufan-gd3f1be0ed310 #1 SMP 
        Wed Aug 28 08:59:34 UTC 2019 aarch64 aarch64 aarch64 GNU/Linux

I'm working with the libgpiod library and noticed there is no GPIO
character device on the RockPro64. The GPIO character device exists
on the Odroid XU4, N2 & the Pi 3B. Is this unique to the Rockchip
family of ARM processors?

TIA,
/Faradn
~ Rockpro64 ~ Odroid N2 ~ Odroid XU4 ~ Pi 3B ~
  Reply
#2
(03-18-2020, 12:27 PM)Faradn Wrote: SBC:    Rockpro64 v2.1 4Gb
OS:     ubuntu 18.04 minimal w / Mate' DE     
        Linux rockpro64 4.4.190-1233-rockchip-ayufan-gd3f1be0ed310 #1 SMP 
        Wed Aug 28 08:59:34 UTC 2019 aarch64 aarch64 aarch64 GNU/Linux

I'm working with the libgpiod library and noticed there is no GPIO
character device on the RockPro64. The GPIO character device exists
on the Odroid XU4, N2 & the Pi 3B. Is this unique to the Rockchip
family of ARM processors?

TIA,
/Faradn
~ Rockpro64 ~ Odroid N2 ~ Odroid XU4 ~ Pi 3B ~

https://forum.frank-mankel.org/topic/292...p64-gpio/2
  Reply
#3
(03-21-2020, 04:41 PM)tllim Wrote:
(03-18-2020, 12:27 PM)Faradn Wrote: SBC:    Rockpro64 v2.1 4Gb
OS:     ubuntu 18.04 minimal w / Mate' DE     
        Linux rockpro64 4.4.190-1233-rockchip-ayufan-gd3f1be0ed310 #1 SMP 
        Wed Aug 28 08:59:34 UTC 2019 aarch64 aarch64 aarch64 GNU/Linux

I'm working with the libgpiod library and noticed there is no GPIO
character device on the RockPro64. The GPIO character device exists
on the Odroid XU4, N2 & the Pi 3B. Is this unique to the Rockchip
family of ARM processors?

TIA,
/Faradn
~ Rockpro64 ~ Odroid N2 ~ Odroid XU4 ~ Pi 3B ~

https://forum.frank-mankel.org/topic/292...p64-gpio/2

SBC:    Rockpro64 v2.1 4Gb
OS:     ubuntu 18.04 minimal w / Mate' DE     
        Linux rockpro64 4.4.190-1233-rockchip-ayufan-gd3f1be0ed310 #1 SMP 
        Wed Aug 28 08:59:34 UTC 2019 aarch64 aarch64 aarch64 GNU/Linux

Thank you TlLim.
My interest is with the libgoiod [C] library.
Hope all is well with you and yours.

TIA,

~ Rockpro64 ~ Odroid N2 ~ Odroid XU4 ~ Pi 3B ~

https://www.youtube.com/watch?v=ljOoGyCso8s
  Reply
#4
Hello,
  According to this article:
https://www.beyondlogic.org/an-introduct...pberry-pi/
the new chardev GPIO interface has been introduced as of Linux 4.8.
I am using a recent Linux release from Mrfixit2001, and it has kernel 4.4.207.
Maybe it is necessary to wait for newer releases, to get the new GPIO interface?
  Best regards,
  Gienek.
  Reply
#5
(04-20-2020, 04:31 AM)Gienek Wrote: Hello,
  According to this article:
https://www.beyondlogic.org/an-introduct...pberry-pi/
the new chardev GPIO interface has been introduced as of Linux 4.8.
I am using a recent Linux release from Mrfixit2001, and it has kernel 4.4.207.
Maybe it is necessary to wait for newer releases, to get the new GPIO interface?
  Best regards,
  Gienek.

Thanks @Gienek.
I'm now running Manjaro Arm v20.04 with kernel 5.6.0 and all (4)
gpiochip character devices exist.

/Faradn
  Reply
#6
O! I did not know about such difference between Linux releases for ROCKPro64.
Have you already gathered experience about performance of this new interface? It is very interresting!
I am using a set of own C-functions to handle GPIO. This is very fast and simple, but I miss one functionality: A possibility of async reaction to interrupt from GPIO. I have no clue, how to achieve this in purely user-space process.
Does this new interface allow for something, like select() which returns when GPIO pin changes state?
  BR,
  Gienek.
  Reply
#7
(04-21-2020, 06:41 AM)Gienek Wrote: O! I did not know about such difference between Linux releases for ROCKPro64.
Have you already gathered experience about performance of this new interface? It is very interresting!
I am using a set of own C-functions to handle GPIO. This is very fast and simple, but I miss one functionality: A possibility of async reaction to interrupt from GPIO. I have no clue, how to achieve this in purely user-space process.
Does this new interface allow for something, like select() which returns when GPIO pin changes state?
  BR,
  Gienek.
I'm using libgpiod-1.4.1.
Works very well on my Odroid N2.
Will begin testing on my RockPro64 shortly.

/Faradn
  Reply


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