[Buildroot] Include kernel's dtsi from customised dts in buiuldroot-external

[Buildroot] Include kernel's dtsi from customised dts in buiuldroot-external

[Bruno Kremel]

Hello All,

I have set up buildroot external for Toradex Colibri iMX6 board. I would
like to customise kernel default dts, so I have made a copy of this dts
to my external board/toradex/colibiri-imx6 and then in the defconfig I
set up the path to custom dts:
BR2_LINUX_KERNEL_USE_CUSTOM_DTS=y
BR2_LINUX_KERNEL_CUSTOM_DTS_PATH="$(BR2_EXTERNAL)/board/toradex/colibri-imx6/imx6dl-colibri-mcp-25.dts"

This successfully makes buildroot use my modified dts file. But this
file inludes some kernel dtsi files.
Namely:
#include <dt-bindings/input/input.h>
#include <dt-bindings/interrupt-controller/irq.h>
#include "imx6dl.dtsi"
#include "imx6qdl-colibri.dtsi"

These are however not found by dts compiler during build and I end up
with dtc failing on undefined symbols in devicetree.

How can I specify dts include path such that it will use kernel dtsi
files or what is the correct way to include these from external?

Thanks
Bruno

[Buildroot] Include kernel's dtsi from customised dts in buiuldroot-external

[Baruch Siach]

Hi Bruno,

On Tue, Aug 22, 2017 at 01:01:10AM +0200, Bruno Kremel wrote:
> I have set up buildroot external for Toradex Colibri iMX6 board. I would
> like to customise kernel default dts, so I have made a copy of this dts
> to my external board/toradex/colibiri-imx6 and then in the defconfig I
> set up the path to custom dts:
> BR2_LINUX_KERNEL_USE_CUSTOM_DTS=y
> BR2_LINUX_KERNEL_CUSTOM_DTS_PATH="$(BR2_EXTERNAL)/board/toradex/colibri-imx6/imx6dl-colibri-mcp-25.dts"
> 
> This successfully makes buildroot use my modified dts file. But this
> file inludes some kernel dtsi files.
> Namely:
> #include <dt-bindings/input/input.h>
> #include <dt-bindings/interrupt-controller/irq.h>
> #include "imx6dl.dtsi"
> #include "imx6qdl-colibri.dtsi"
> 
> These are however not found by dts compiler during build and I end up
> with dtc failing on undefined symbols in devicetree.

So the pre-processor find the include files, but some symbols are missing. Is 
that correct?

> How can I specify dts include path such that it will use kernel dtsi
> files or what is the correct way to include these from external?

The LINUX_BUILD_CMDS macro should copy your custom dts to arch/arm/boot/dts, 
which is where the .dtsi files should be located. Can you verify that?

What errors do you see?

Does the kernel you took your base dts file from match the kernel you build?

baruch

-- 
     http://baruch.siach.name/blog/                  ~. .~   Tk Open Systems
=}------------------------------------------------ooO--U--Ooo------------{=
   - baruch at tkos.co.il - tel: +972.2.679.5364, http://www.tkos.co.il -

[Buildroot] Include kernel's dtsi from customised dts in buiuldroot-external

[Bruno Kremel]

Hi Baruch,


Baruch Siach <baruch@tkos.co.il> writes:

> Hi Bruno,
>
> On Tue, Aug 22, 2017 at 01:01:10AM +0200, Bruno Kremel wrote:
>> I have set up buildroot external for Toradex Colibri iMX6 board. I would
>> like to customise kernel default dts, so I have made a copy of this dts
>> to my external board/toradex/colibiri-imx6 and then in the defconfig I
>> set up the path to custom dts:
>> BR2_LINUX_KERNEL_USE_CUSTOM_DTS=y
>> BR2_LINUX_KERNEL_CUSTOM_DTS_PATH="$(BR2_EXTERNAL)/board/toradex/colibri-imx6/imx6dl-colibri-mcp-25.dts"
>>
>> This successfully makes buildroot use my modified dts file. But this
>> file inludes some kernel dtsi files.
>> Namely:
>> #include <dt-bindings/input/input.h>
>> #include <dt-bindings/interrupt-controller/irq.h>
>> #include "imx6dl.dtsi"
>> #include "imx6qdl-colibri.dtsi"
>>
>> These are however not found by dts compiler during build and I end up
>> with dtc failing on undefined symbols in devicetree.
>
> So the pre-processor find the include files, but some symbols are missing. Is
> that correct?
>
>> How can I specify dts include path such that it will use kernel dtsi
>> files or what is the correct way to include these from external?
>
> The LINUX_BUILD_CMDS macro should copy your custom dts to arch/arm/boot/dts,
> which is where the .dtsi files should be located. Can you verify that?
This helps a lot. I was suspicious about file not being copied.
I just did a copy of vanilla dts from kernel over my modified one and
now it works.

So it is indeed error in my dts (don't know exactly where, but at least
I know that it's not the include)

Anyway for anybody having the same problem it was these kind of errors:
Error: arch/arm/boot/dts/imx6dl-colibri-mcp-25.dts:113.1-12 Label or path hdmi_audio not found
(more of those)

>
> What errors do you see?
>
> Does the kernel you took your base dts file from match the kernel you build?
>
> baruch

Thanks a lot.