On 22/09/2023 21:58, Stephan Gerhold wrote:
On Fri, Sep 22, 2023 at 09:47:07PM +0100, Bryan O'Donoghue wrote:
On 22/09/2023 16:11, Stephan Gerhold wrote:
Follow the example of the recently added apq8016-sbc-usb-host.dtso and
convert apq8016-sbc-d3-camera-mezzanine.dts to a DT overlay that can be
applied on top of the apq8016-sbc.dtb. This makes it more clear that
this is not a special type of DB410c but just an addon board that can
be added on top.
I also prepended a patch that cleans up the node names a bit.
Signed-off-by: Stephan Gerhold <stephan@xxxxxxxxxxx>
---
Stephan Gerhold (2):
arm64: dts: qcom: apq8016-sbc-d3-camera: Use more generic node names
arm64: dts: qcom: apq8016-sbc-d3-camera: Convert to DT overlay
arch/arm64/boot/dts/qcom/Makefile | 5 +++--
...nine.dts => apq8016-sbc-d3-camera-mezzanine.dtso} | 20 ++++++++++++++------
2 files changed, 17 insertions(+), 8 deletions(-)
---
base-commit: 7236e86ce5c8198b01c30933c2334d07d877cf48
change-id: 20230922-apq8016-sbc-camera-dtso-f247bea40f99
Best regards,
db410c doesn't ship with a bootloader that is capable of applying a dtbo
though, so this conversion mandates an updated or chainloaded bootloader or
out-of-tree kernel patch to support.
__adding__ is fine but, converting implies imposes a new requirement on the
bootchain.
Perhaps a middle road solution is to
- Add, not convert a standalone dtbo or
- Add a dtbo that includes the mezzanine dts but amends it
Option 2 for preference but, I'm not sure the dts syntax can be meaningfully
made to do that.
With these patches the apq8016-sbc-d3-camera-mezzanine.dtb is still
magically built, by running fdtoverlay on apq8016-sbc.dtb and applying
the dtbo. It's applied during the build process so you don't need a
bootloader that supports DTBOs.
There is literally *no change* for you in terms of usage. :-)
Ah I see
+apq8016-sbc-d3-camera-mezzanine-dtbs := apq8016-sbc.dtb
apq8016-sbc-d3-camera-mezzanine.dtbo
I guess I like the idea of having the base board dtb a mezzanine.dtb and
a dtbo that could be applied as an overlay to the base board dtb,
optionally.
Our model then for mezzanine enablement wouild be
1. baseboard.dtb
2. baseboard-mezzanine.dtb
3. baseboard-mezzanine.dtbo
With booting #2 or #1+#3 resulting in the same image but, potentially
allowing for
1. baseboard.dtb
2. baseboard-mezzanine.dtb
3. baseboard-mezzanine.dtbo
4. baseboard-some-other-mezzanine.dtb
5. baseboard-some-other-mezzanine.dtbo
#1 + #3 + #5 which would represent a hypothetical stacking of mezzanine
boards.
As a model, I think that has merit.
Reviewed-by: Bryan O'Donoghue <bryan.odonoghue@xxxxxxxxxx>
