[yocto] Building a out of tree kernel module on target system

[Zoran Stojsavljevic]

I have this all standardized for BBB, and here are pointers how to
build an out of tree kernel module on BBB target system (with some
specifics):
local.conf (with added systemd service):
https://github.com/ZoranStojsavljevic/bbb-yocto/blob/master/bbb-releases/bbb-warrior/local.conf_full

Compiling out of tree kernel modules:
https://github.com/ZoranStojsavljevic/bbb-yocto/blob/master/Issues/LKM/prepare_modules.log

Zoran
_______

On Wed, Oct 9, 2019 at 12:48 PM Shravan Singh <shravan at bluesparq.com> wrote:
>
> Hello Bruce,
>
> So I was finally able to compile the kernel module by creating a patch and then applying that patch to linux recipe file.
> However now, I am facing a different issue and have been trying to figure that one out, Hence the delay in my response.
>
> After creating an appropriate device tree overlay file. After loading the module, the I2C driver still reads the screen abs_x_max=800 and abs_y_max=480.
> I have specified the frame_buffer_width and frame_buffer height as 1024 X 600. Also I have specifically provided touchscreen-x-size and touchscreen-y-size in my device tree overlay to match the same.
>
> Why could this be happening?
>
> Regards,
> Shravan Singh
> (239) 243-0838
>
> Blue Sparq, Inc.
> 928 NE 24th Lane unit 4 and 5.
> Cape Coral, FL 33993
>
> IMPORTANT: The contents of this email and any attachments are confidential. They are intended for the named recipient(s) only. If you have received this email by mistake, please notify the sender immediately and do not disclose the contents to anyone or make copies thereof.
>
>
> On Fri, Oct 4, 2019 at 1:42 PM Bruce Ashfield <bruce.ashfield at gmail.com> wrote:
>>
>> On Fri, Oct 4, 2019 at 11:40 AM Shravan Singh <shravan at bluesparq.com> wrote:
>> >
>> > Hello,
>> >
>> > I am trying to build an out of tree service module on a yocto raspberry pi image(target system).
>> > I am using yocto version warrior
>> > and my machine is Raspberrypi-cm3
>> > Kernel version is 4.19.58
>> >
>> > I was able to get the build directory by including
>> >
>> > IMAGE_INSTALL_append = " kernel-modules kernel-dev kernel-devsrc"
>> > After that, I saw a build directory on raspberrypi-image
>> >
>> > Now I am trying to compile my source file with the command
>> >
>> > make ARCH=arm CROSS_COMPILE=arm-poky-linux-gnueabi- KSRC="/lib/modules/4.19.58/source" -C /lib/modules/$(shell uname -r)/build M=/home/root/tsDriver modules
>> >
>> > After that I get an error saying asm/bitsperlong.h: no such file or directory
>> >
>> > Am I missing something in my make command?
>>
>> You need to rebuild/regenerate some file on target (they can't be packaged).
>> So have you gone to /usr/src/kernel and done a "make scripts prepare" ?
>>
>> Bruce
>>
>> >
>> >
>> > Regards,
>> > Shravan Singh
>> > (239) 243-0838
>> >
>> > Blue Sparq, Inc.
>> > 928 NE 24th Lane unit 4 and 5.
>> > Cape Coral, FL 33993
>> >
>> > IMPORTANT: The contents of this email and any attachments are confidential. They are intended for the named recipient(s) only. If you have received this email by mistake, please notify the sender immediately and do not disclose the contents to anyone or make copies thereof.
>> > --
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>>
>>
>>
>> --
>> - Thou shalt not follow the NULL pointer, for chaos and madness await
>> thee at its end
>> - "Use the force Harry" - Gandalf, Star Trek II
>
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