Adding libgpiod to Yocto Warrior 4.19.35 image?

Adding libgpiod to Yocto Warrior 4.19.35 image?

[Scott Whitney]

I'm using Yocto Warrior 4.19.35 on a Variscite i.MX8M MINI SoM.  I need to be able to respond to some interrupt events on GPIO events from userspace.
I saw on kernel.org that the sysfs ABI is being deprecated, and the recommendation is to use libgpiod. https://www.kernel.org/doc/html/latest/driver-api/gpio/using-gpio.html

I modified my local.conf file to add libgpiod to IMAGE_INSTALL_append:
IMAGE_INSTALL_append = " \
    tcf-agent \
    openssh-sftp-server \
    libgpiod \
    "
I then ran "bitbake fsl-image-qt5", and programmed the new image onto an SD card.  After booting, I can now see "/dev/gpiochip*" as expected.  However, gpiod.h does not appear to be installed to /usr/include nore any other directory.

Can someone explain what I need to do to correctly deploy libgpiod onto my target?  Thanks!

Re: Adding libgpiod to Yocto Warrior 4.19.35 image?

[Scott Whitney]

I should also note that gpioinfo and other tools from libgpiod run as expected on the target, and that /usr/lib has libgpiod.so.2 (libgpiod.so.2.1.1) in it.
I would also like the header file to be put into the image so that I can build/run executables using libgpiod on the target.

Re: [yocto] Adding libgpiod to Yocto Warrior 4.19.35 image?

[Joel A Cohen]

[-- Attachment #1: Type: text/plain, Size: 458 bytes --]

You would need to add libgpiod-dev, presumably, to get the build
requirements.

On Fri, Jul 17, 2020 at 4:23 PM Scott Whitney <sdw@inea.com> wrote:

> I should also note that gpioinfo and other tools from libgpiod run as
> expected on the target, and that /usr/lib has libgpiod.so.2
> (libgpiod.so.2.1.1) in it.
> I would also like the header file to be put into the image so that I can
> build/run executables using libgpiod on the target.
> 
>

[-- Attachment #2: Type: text/html, Size: 784 bytes --]

Re: Adding libgpiod to Yocto Warrior 4.19.35 image?

[Scott Whitney]

Thanks for the tip, Joel.  I'm still new to this.  How should libgpiod-dev be added to my local.conf?
Do I just need to add it to EXTRA_IMAGE_FEATURES?  Do I still need to add libgpiod to IMAGE_INSTALL_append?

Your help is greatly appreciated!

Re: [yocto] Adding libgpiod to Yocto Warrior 4.19.35 image?

[Quentin Schulz]

Hi Scott,

On Mon, Jul 20, 2020 at 10:48:52AM -0700, Scott Whitney wrote:
> Thanks for the tip, Joel.  I'm still new to this.  How should libgpiod-dev be added to my local.conf?
> Do I just need to add it to EXTRA_IMAGE_FEATURES?  Do I still need to add libgpiod to IMAGE_INSTALL_append?
> 

IMAGE_INSTALL is the way to go.

I recommend spending some time on watching
https://www.youtube.com/playlist?list=PLD4M5FoHz-TxMfBFrDKfIS_GLY25Qsfyj

Here you'll learn that you shouldn't really use local.conf for that
purpose and how to add packages to your image (and many other things).
Consider to subscribe, Jozef streams on Twitch every month or so and
then uploads the videos to the Youtube channel.

Cheers,
Quentin

Re: Adding libgpiod to Yocto Warrior 4.19.35 image?

[Scott Whitney]

Thanks, Quentin,  I'll take a look at Jozef's videos as time permits.  Getting lots of time pressure to get something working, and even our SoM vendor provides examples that modify local.conf... so much for helping us with the "right" way to do things.  I appreciate your advice, and can now see gpiod.h and libgpiod.so in my image.

Best regards,
Scott