2023-06-19 17:03:13

by Dario Binacchi

[permalink] [raw]
Subject: [PATCH v4 0/6] Add display support on the stm32f746-disco board

The series adds support for the display on the stm32f746-disco board,
along with a generic patch that adds the "bpp" parameter to the stm-drm
module. The intention is to allow users to size, within certain limits,
the memory footprint required by the framebuffer.

Changes in v4:
- Use DTS property instead of module parameter to set the framebuffer bit depth.

Changes in v3:
- rename ltdc-pins-a-0 to ltdc-0.
- drop [4/6] dt-bindings: display: simple: add Rocktech RK043FN48H
Applied to https://anongit.freedesktop.org/git/drm/drm-misc.git (drm-misc-next):
https://cgit.freedesktop.org/drm/drm-misc/commit/?id=c42a37a27c777d63961dd634a30f7c887949491a
- drop [5/6] drm/panel: simple: add support for Rocktech RK043FN48H panel
Applied to https://anongit.freedesktop.org/git/drm/drm-misc.git (drm-misc-next)
https://cgit.freedesktop.org/drm/drm-misc/commit/?id=13cdd12a9f934158f4ec817cf048fcb4384aa9dc

Dario Binacchi (6):
ARM: dts: stm32: add ltdc support on stm32f746 MCU
ARM: dts: stm32: add pin map for LTDC on stm32f7
ARM: dts: stm32: support display on stm32f746-disco board
dt-bindings: display: stm32-ltdc: add optional st,fb-bpp property
ARM: dts: stm32: set framebuffer bit depth on stm32f746-disco
drm/stm: set framebuffer bit depth through DTS property

.../bindings/display/st,stm32-ltdc.yaml | 6 +++
arch/arm/boot/dts/stm32f7-pinctrl.dtsi | 35 +++++++++++++
arch/arm/boot/dts/stm32f746-disco.dts | 52 +++++++++++++++++++
arch/arm/boot/dts/stm32f746.dtsi | 10 ++++
drivers/gpu/drm/stm/drv.c | 6 ++-
5 files changed, 108 insertions(+), 1 deletion(-)

--
2.32.0



2023-06-19 17:03:30

by Dario Binacchi

[permalink] [raw]
Subject: [PATCH v4 4/6] dt-bindings: display: stm32-ltdc: add optional st,fb-bpp property

Boards that use the STM32F{4,7} series have limited amounts of RAM. The
added property allows to size, within certain limits, the memory footprint
required by the framebuffer.

Signed-off-by: Dario Binacchi <[email protected]>
---

(no changes since v1)

.../devicetree/bindings/display/st,stm32-ltdc.yaml | 6 ++++++
1 file changed, 6 insertions(+)

diff --git a/Documentation/devicetree/bindings/display/st,stm32-ltdc.yaml b/Documentation/devicetree/bindings/display/st,stm32-ltdc.yaml
index d6ea4d62a2cf..1c3a3653579f 100644
--- a/Documentation/devicetree/bindings/display/st,stm32-ltdc.yaml
+++ b/Documentation/devicetree/bindings/display/st,stm32-ltdc.yaml
@@ -42,6 +42,12 @@ properties:
- for internal dpi input of the MIPI DSI host controller.
Note: These 2 endpoints cannot be activated simultaneously.

+ st,fb-bpp:
+ $ref: /schemas/types.yaml#/definitions/uint32
+ description: |
+ bit depth of framebuffer (8, 16 or 32)
+ maxItems: 1
+
required:
- compatible
- reg
--
2.32.0


2023-06-19 17:43:54

by Rob Herring (Arm)

[permalink] [raw]
Subject: Re: [PATCH v4 4/6] dt-bindings: display: stm32-ltdc: add optional st,fb-bpp property


On Mon, 19 Jun 2023 18:55:23 +0200, Dario Binacchi wrote:
> Boards that use the STM32F{4,7} series have limited amounts of RAM. The
> added property allows to size, within certain limits, the memory footprint
> required by the framebuffer.
>
> Signed-off-by: Dario Binacchi <[email protected]>
> ---
>
> (no changes since v1)
>
> .../devicetree/bindings/display/st,stm32-ltdc.yaml | 6 ++++++
> 1 file changed, 6 insertions(+)
>

My bot found errors running 'make DT_CHECKER_FLAGS=-m dt_binding_check'
on your patch (DT_CHECKER_FLAGS is new in v5.13):

yamllint warnings/errors:

dtschema/dtc warnings/errors:
/builds/robherring/dt-review-ci/linux/Documentation/devicetree/bindings/display/st,stm32-ltdc.yaml: properties:st,fb-bpp:maxItems: False schema does not allow 1
from schema $id: http://devicetree.org/meta-schemas/core.yaml#

doc reference errors (make refcheckdocs):

See https://patchwork.ozlabs.org/project/devicetree-bindings/patch/[email protected]

The base for the series is generally the latest rc1. A different dependency
should be noted in *this* patch.

If you already ran 'make dt_binding_check' and didn't see the above
error(s), then make sure 'yamllint' is installed and dt-schema is up to
date:

pip3 install dtschema --upgrade

Please check and re-submit after running the above command yourself. Note
that DT_SCHEMA_FILES can be set to your schema file to speed up checking
your schema. However, it must be unset to test all examples with your schema.


2023-06-19 20:25:08

by Conor Dooley

[permalink] [raw]
Subject: Re: [PATCH v4 4/6] dt-bindings: display: stm32-ltdc: add optional st,fb-bpp property

Hey,

On Mon, Jun 19, 2023 at 06:55:23PM +0200, Dario Binacchi wrote:
> Boards that use the STM32F{4,7} series have limited amounts of RAM. The
> added property allows to size, within certain limits, the memory footprint
> required by the framebuffer.

Hmm, this sounds quite a lot like "software policy", since the actual
display doesn't have these limitations. Rob, Krzysztof?

>
> Signed-off-by: Dario Binacchi <[email protected]>
> ---
>
> (no changes since v1)

Really?
https://lore.kernel.org/all/?q=dfn:st,stm32-ltdc.yaml%20

You sure this shouldn't be "new in v4"?

> .../devicetree/bindings/display/st,stm32-ltdc.yaml | 6 ++++++
> 1 file changed, 6 insertions(+)
>
> diff --git a/Documentation/devicetree/bindings/display/st,stm32-ltdc.yaml b/Documentation/devicetree/bindings/display/st,stm32-ltdc.yaml
> index d6ea4d62a2cf..1c3a3653579f 100644
> --- a/Documentation/devicetree/bindings/display/st,stm32-ltdc.yaml
> +++ b/Documentation/devicetree/bindings/display/st,stm32-ltdc.yaml
> @@ -42,6 +42,12 @@ properties:
> - for internal dpi input of the MIPI DSI host controller.
> Note: These 2 endpoints cannot be activated simultaneously.
>
> + st,fb-bpp:

Is there not a more understandable property name than this?
Maybe I just had to think about it because fbdev stuff aint something
I've worked with...

> + $ref: /schemas/types.yaml#/definitions/uint32
> + description: |
> + bit depth of framebuffer (8, 16 or 32)
> + maxItems: 1

Why not make it an enum, since there are only 4 values?

Cheers,
Conor.

> +
> required:
> - compatible
> - reg
> --
> 2.32.0
>


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2023-06-19 22:32:02

by Rob Herring (Arm)

[permalink] [raw]
Subject: Re: [PATCH v4 4/6] dt-bindings: display: stm32-ltdc: add optional st,fb-bpp property

On Mon, Jun 19, 2023 at 09:18:25PM +0100, Conor Dooley wrote:
> Hey,
>
> On Mon, Jun 19, 2023 at 06:55:23PM +0200, Dario Binacchi wrote:
> > Boards that use the STM32F{4,7} series have limited amounts of RAM. The
> > added property allows to size, within certain limits, the memory footprint
> > required by the framebuffer.
>
> Hmm, this sounds quite a lot like "software policy", since the actual
> display doesn't have these limitations. Rob, Krzysztof?

Indeed. This doesn't belong in DT.

Rob