Error when using linuxgpio

[JanLuudi]

I am trying to use avrdude in a similar way as @MCUdude described it in PR #1299 .

I am using a Raspberry Pi 4B (40 pin header)
Unfortunately, there seems to be something wrong and I need your help to solve it.

This is the error I am getting

janno@raspberrypi:~ $ lsb_release -a
No LSB modules are available.
Distributor ID:	Raspbian
Description:	Raspbian GNU/Linux 12 (bookworm)
Release:	12
Codename:	bookworm

janno@raspberrypi:~ $ uname -a
Linux raspberrypi 6.6.20+rpt-rpi-v8 #1 SMP PREEMPT Debian 1:6.6.20-1+rpt1 (2024-03-07) aarch64 GNU/Linux
janno@raspberrypi:~ $ sudo avrdude -c spi_mfm -p m328p -P gpiochip0 -v

avrdude: Version 7.3-20240330 (cb611715)
         Copyright the AVRDUDE authors;
         see https://github.com/avrdudes/avrdude/blob/main/AUTHORS

         System wide configuration file is /usr/local/etc/avrdude.conf
         User configuration file is /root/.avrduderc
         User configuration file does not exist or is not a regular file, skipping

         Using port            : gpiochip0
         Using programmer      : spi_mfm
avrdude linuxgpio_sysfs_open() OS error: cannot export GPIO 25, already exported/busy?: Invalid argument
avrdude main() error: unable to open port gpiochip0 for programmer spi_mfm

avrdude done.  Thank you.

It's the same for -P GPIO

Snippet of my avrdude.conf

avrdude_conf_version = "7.3-20240330 (cb611715)";
...
default_linuxgpio  = "gpiochip0";
...

#------------------------------------------------------------
# Program from a Raspberry Pi GPIO port using linuxgpio
#------------------------------------------------------------

programmer # raspberry_pi_gpio
    id                     = "raspberry_pi_gpio";
    desc                   = "Bitbang Raspberry Pi GPIO via linuxgpio (sysfs or libgpiod)";
    type                   = "linuxgpio";
    prog_modes             = PM_ISP;
    connection_type        = linuxgpio;
    reset                  = 22;
    sck                    = 24;
    sdo                    = 23;
    sdi                    = 18;
;

programmer
    id                   = "spi_mfm";
    desc                 = "Use RPi GPIO for mains frequency monitor unit";
    type                 = "linuxgpio";
    prog_modes           = PM_ISP;
    connection_type      = linuxgpio;
    reset                = 25;
    sck                  = 11;
    sdo                 = 10;
    sdi                 = 9;
;

And the content of /sys/class/gpio/

janno@raspberrypi:~ $ ls /sys/class/gpio
export  gpiochip512  gpiochip570  unexport

I did not export or use GPIO25 before, so I don't thinks that's the issue.

Does anyone have a clue what is going wrong?

[mcuee]

Not so sure what is the issue.

But I just tested linuxgpio and linuxspi under my Raspberry Pi 400 and both are okay.

[mcuee]

@JanLuudi

Hmm, you seem to still use the older sysfs API, please install libgpiod-dev and the rebuild avrdue to use libgpiod instead.

• Add optional libgpiod support to linuxgpio #1299
• linuxgpio issues #932

mcuee@raspberrypi400arm64:~/build/avrdude_pr1725 $ sudo apt search libgpiod
Sorting... Done
Full Text Search... Done
gpiod/stable,now 1.6.3-1+b3 arm64 [installed]
  Tools for interacting with Linux GPIO character device - binary

libgpiod-dev/stable,now 1.6.3-1+b3 arm64 [installed]
  C library for interacting with Linux GPIO device - static libraries and headers

libgpiod-doc/stable,stable 1.6.3-1 all
  C library for interacting with Linux GPIO device - library documentation

libgpiod2/stable,now 1.6.3-1+b3 arm64 [installed,automatic]
  C library for interacting with Linux GPIO device - shared libraries

python3-libgpiod/stable,now 1.6.3-1+b3 arm64 [installed]
  Python bindings for libgpiod (Python 3)

mcuee@raspberrypi400arm64:~/build $ pkg-config --version libgpiod
1.8.1
mcuee@raspberrypi400arm64:~/build $ pkg-config --cflags libgpiod

mcuee@raspberrypi400arm64:~/build $ pkg-config --libs libgpiod
-lgpiod 

[mcuee]

My config.

# #------------------------------------------------------------
# # linuxgpio
# #------------------------------------------------------------
#
programmer
    id                   = "linuxgpio";
    desc                 = "Use the Linux sysfs interface to bitbang GPIO lines";
    type                 = "linuxgpio";
    prog_modes           = PM_ISP;
    connection_type      = linuxgpio;
    reset                = 25;
    sck                  = 11;
    sdo                  = 10;
    sdi                  = 9;

I am testing PR #1714 and it works. It is very much like git main.

mcuee@raspberrypi400arm64:~/build/avrdude_jw/build_linux/src $ ./avrdude -c linuxgpio -P gpiochip0 -p m328p
using libgpiod for linuxgpio
avrdude: AVR device initialized and ready to accept instructions
avrdude: device signature = 0x1e950f (probably m328p)

avrdude done.  Thank you.

mcuee@raspberrypi400arm64:~/build/avrdude_jw/build_linux/src $ ./avrdude -c linuxgpio -P gpiochip0 -p m328p -v

avrdude: Version 7.3-20240405 (69672a84)
         Copyright the AVRDUDE authors;
         see https://github.com/avrdudes/avrdude/blob/main/AUTHORS

         System wide configuration file is /home/mcuee/build/avrdude_jw/build_linux/src/avrdude.conf
         User configuration file is /home/mcuee/.avrduderc
         User configuration file does not exist or is not a regular file, skipping

using libgpiod for linuxgpio
         Using port            : gpiochip0
         Using programmer      : linuxgpio
         AVR Part              : ATmega328P
         Programming modes     : ISP, HVPP, debugWIRE, SPM
         Programmer Type       : linuxgpio
         Description           : Use the Linux sysfs interface to bitbang GPIO lines
         Pin assignment        : libgpiod
           RESET   =  25
           SCK     =  11
           SDO     =  10
           SDI     =  9
avrdude: AVR device initialized and ready to accept instructions
avrdude: device signature = 0x1e950f (probably m328p)

avrdude done.  Thank you.

[JanLuudi]

Hey @mcuee, thanks a lot!
This really solved to problem.

[gadget-man]

I'm having exactly the same issue, so would like to test the PR. I see it was just merged a couple of days ago, but apt-get install still uses a previous version. I'm new to this - please could you give me some guidance how I can install avrdude including PR #1714?

[JanLuudi]

Hi @gadget-man and sorry for the late reply.
Here are the steps I did:

1. First install libgpiod-dev: sudo apt-get install -y libgpiod-dev
2. Install AVRDude with the code from the main branch following these instructions
3. Then add the programmer to avrdude.conf (note new format)
   programmer
   id = “spi_mfm”;
   desc = “Use the Raspberry Pi GPIO via linuxgpio”;
   type = “linuxgpio”;
   prog_modes = PM_ISP;
   connection_type = linuxgpio;
   reset = 25;
   sck = 11;
   sdo = 10;
   sdi = 9;
   ;

I hope this is still valid and works for you!

[ndim]

Just for reference: We have recently released avrdude 8.0. According to repology.org, the newest avrdude shipped on Debian and therefore on Ubuntu and Raspbian is 7.1, not 7.2 or 7.3.