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[0/2] dt-bindings: Add macros for video interface bus types

Message ID 20220227203352.17314-1-laurent.pinchart@ideasonboard.com
Headers show
Series dt-bindings: Add macros for video interface bus types | expand

Message

Laurent Pinchart Feb. 27, 2022, 8:33 p.m. UTC 
Hello,

This small patch series is the result of me getting a bus-type numerical
value wrong in a device tree file and spending too long debugging the
issue. Hopefully there's nothing controversial here.

If the idea is accepted, and if desired, I can convert the DT sources to
use the new macros. How should I then split that, one big patch, one
patch per SoC vendor (easy for arm64, but how about arm ?), ... ?

Laurent Pinchart (2):
  dt-bindings: media: Add macros for video interface bus types
  dt-bindings: Use new video interface bus type macros in examples

 .../display/bridge/analogix,anx7625.yaml         |  3 ++-
 .../devicetree/bindings/media/i2c/mipi-ccs.yaml  |  3 ++-
 .../bindings/media/i2c/ovti,ov772x.yaml          |  3 ++-
 .../bindings/media/marvell,mmp2-ccic.yaml        |  3 ++-
 .../bindings/media/microchip,xisc.yaml           |  3 ++-
 .../devicetree/bindings/media/st,stm32-dcmi.yaml |  4 +++-
 include/dt-bindings/media/video-interfaces.h     | 16 ++++++++++++++++
 7 files changed, 29 insertions(+), 6 deletions(-)
 create mode 100644 include/dt-bindings/media/video-interfaces.h

Comments

Sakari Ailus Feb. 27, 2022, 9:07 p.m. UTC | #1 
Hi Laurent,

Thanks for the set.

On Sun, Feb 27, 2022 at 10:33:51PM +0200, Laurent Pinchart wrote:
> Add a new dt-bindings/media/video-interfaces.h header that defines
> macros corresponding to the bus types from media/video-interfaces.yaml.
> This allows avoiding hardcoded constants in device tree sources.
> 
> Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> ---
>  include/dt-bindings/media/video-interfaces.h | 16 ++++++++++++++++
>  1 file changed, 16 insertions(+)
>  create mode 100644 include/dt-bindings/media/video-interfaces.h
> 
> diff --git a/include/dt-bindings/media/video-interfaces.h b/include/dt-bindings/media/video-interfaces.h
> new file mode 100644
> index 000000000000..e38058e1cca7
> --- /dev/null
> +++ b/include/dt-bindings/media/video-interfaces.h
> @@ -0,0 +1,16 @@
> +/* SPDX-License-Identifier: GPL-2.0-only */
> +/*
> + * Copyright (C) 2022 Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> + */
> +
> +#ifndef __DT_BINDINGS_MEDIA_VIDEO_INTERFACES_H__
> +#define __DT_BINDINGS_MEDIA_VIDEO_INTERFACES_H__
> +
> +#define MEDIA_BUS_TYPE_CSI2_CPHY		1
> +#define MEDIA_BUS_TYPE_CSI1			2
> +#define MEDIA_BUS_TYPE_CCP2			3
> +#define MEDIA_BUS_TYPE_CSI2_DPHY		4
> +#define MEDIA_BUS_TYPE_PARALLEL			5

I've been long thinkin of renaming "PARALLEL" as "BT.601" which it really
is. I don't mind postponing that, but I think you could as well start here.
Up to you.

Should this be somehow visible in video-interfaces.yaml?

> +#define MEDIA_BUS_TYPE_BT656			6
> +
> +#endif /* __DT_BINDINGS_MEDIA_VIDEO_INTERFACES_H__ */
Rob Herring March 1, 2022, 3:04 p.m. UTC | #2 
On Sun, Feb 27, 2022 at 11:16:28PM +0200, Laurent Pinchart wrote:
> Hi Sakari,
> 
> On Sun, Feb 27, 2022 at 11:07:23PM +0200, Sakari Ailus wrote:
> > On Sun, Feb 27, 2022 at 10:33:51PM +0200, Laurent Pinchart wrote:
> > > Add a new dt-bindings/media/video-interfaces.h header that defines
> > > macros corresponding to the bus types from media/video-interfaces.yaml.
> > > This allows avoiding hardcoded constants in device tree sources.
> > > 
> > > Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> > > ---
> > >  include/dt-bindings/media/video-interfaces.h | 16 ++++++++++++++++
> > >  1 file changed, 16 insertions(+)
> > >  create mode 100644 include/dt-bindings/media/video-interfaces.h
> > > 
> > > diff --git a/include/dt-bindings/media/video-interfaces.h b/include/dt-bindings/media/video-interfaces.h
> > > new file mode 100644
> > > index 000000000000..e38058e1cca7
> > > --- /dev/null
> > > +++ b/include/dt-bindings/media/video-interfaces.h
> > > @@ -0,0 +1,16 @@
> > > +/* SPDX-License-Identifier: GPL-2.0-only */
> > > +/*
> > > + * Copyright (C) 2022 Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> > > + */
> > > +
> > > +#ifndef __DT_BINDINGS_MEDIA_VIDEO_INTERFACES_H__
> > > +#define __DT_BINDINGS_MEDIA_VIDEO_INTERFACES_H__
> > > +
> > > +#define MEDIA_BUS_TYPE_CSI2_CPHY		1
> > > +#define MEDIA_BUS_TYPE_CSI1			2
> > > +#define MEDIA_BUS_TYPE_CCP2			3
> > > +#define MEDIA_BUS_TYPE_CSI2_DPHY		4
> > > +#define MEDIA_BUS_TYPE_PARALLEL			5
> > 
> > I've been long thinkin of renaming "PARALLEL" as "BT.601" which it really
> > is. I don't mind postponing that, but I think you could as well start here.
> > Up to you.
> 
> I think it's a good idea, but we then need to decide what to do with
> other types of parallel buses. Let's start this discussion now, and
> implement it in a patch on top of this series.

5 and what it means is an ABI. If it is ambiguous and needs to be more 
specific, then you need new numbers for all of those specific types.

If it is just a rename, I prefer it is done from the start.

> > Should this be somehow visible in video-interfaces.yaml?
> 
> I wish we could use macros in .yaml files instead of numerical values,
> but I don't think that's possible. I can do this:
> 
>    bus-type:
>      $ref: /schemas/types.yaml#/definitions/uint32
>      enum:
> -      - 1 # MIPI CSI-2 C-PHY
> -      - 2 # MIPI CSI1
> -      - 3 # CCP2
> -      - 4 # MIPI CSI-2 D-PHY
> -      - 5 # Parallel
> -      - 6 # BT.656
> +      - 1 # MIPI CSI-2 C-PHY (MEDIA_BUS_TYPE_CSI2_CPHY)
> +      - 2 # MIPI CSI1 (MEDIA_BUS_TYPE_CSI1)
> +      - 3 # CCP2 (MEDIA_BUS_TYPE_CCP2)
> +      - 4 # MIPI CSI-2 D-PHY (MEDIA_BUS_TYPE_CSI2_DPHY)
> +      - 5 # Parallel (MEDIA_BUS_TYPE_PARALLEL)
> +      - 6 # BT.656 (MEDIA_BUS_TYPE_BT656)

Seems a bit redundant to have both comment text and define. The only 
part missing from the defines is 'MIPI'.

>      description:
> -      Data bus type.
> +      Data bus type. Use the macros listed above (defined in
> +      dt-bindings/video-interfaces.h) instead of numerical values.
> 
> Any better proposal ?
> 
> > > +#define MEDIA_BUS_TYPE_BT656			6
> > > +
> > > +#endif /* __DT_BINDINGS_MEDIA_VIDEO_INTERFACES_H__ */
> 
> -- 
> Regards,
> 
> Laurent Pinchart
>
Laurent Pinchart March 6, 2022, 4:54 p.m. UTC | #3 
Hi Rob,

On Tue, Mar 01, 2022 at 09:04:10AM -0600, Rob Herring wrote:
> On Sun, Feb 27, 2022 at 11:16:28PM +0200, Laurent Pinchart wrote:
> > On Sun, Feb 27, 2022 at 11:07:23PM +0200, Sakari Ailus wrote:
> > > On Sun, Feb 27, 2022 at 10:33:51PM +0200, Laurent Pinchart wrote:
> > > > Add a new dt-bindings/media/video-interfaces.h header that defines
> > > > macros corresponding to the bus types from media/video-interfaces.yaml.
> > > > This allows avoiding hardcoded constants in device tree sources.
> > > > 
> > > > Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> > > > ---
> > > >  include/dt-bindings/media/video-interfaces.h | 16 ++++++++++++++++
> > > >  1 file changed, 16 insertions(+)
> > > >  create mode 100644 include/dt-bindings/media/video-interfaces.h
> > > > 
> > > > diff --git a/include/dt-bindings/media/video-interfaces.h b/include/dt-bindings/media/video-interfaces.h
> > > > new file mode 100644
> > > > index 000000000000..e38058e1cca7
> > > > --- /dev/null
> > > > +++ b/include/dt-bindings/media/video-interfaces.h
> > > > @@ -0,0 +1,16 @@
> > > > +/* SPDX-License-Identifier: GPL-2.0-only */
> > > > +/*
> > > > + * Copyright (C) 2022 Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> > > > + */
> > > > +
> > > > +#ifndef __DT_BINDINGS_MEDIA_VIDEO_INTERFACES_H__
> > > > +#define __DT_BINDINGS_MEDIA_VIDEO_INTERFACES_H__
> > > > +
> > > > +#define MEDIA_BUS_TYPE_CSI2_CPHY		1
> > > > +#define MEDIA_BUS_TYPE_CSI1			2
> > > > +#define MEDIA_BUS_TYPE_CCP2			3
> > > > +#define MEDIA_BUS_TYPE_CSI2_DPHY		4
> > > > +#define MEDIA_BUS_TYPE_PARALLEL			5
> > > 
> > > I've been long thinkin of renaming "PARALLEL" as "BT.601" which it really
> > > is. I don't mind postponing that, but I think you could as well start here.
> > > Up to you.
> > 
> > I think it's a good idea, but we then need to decide what to do with
> > other types of parallel buses. Let's start this discussion now, and
> > implement it in a patch on top of this series.
> 
> 5 and what it means is an ABI. If it is ambiguous and needs to be more 
> specific, then you need new numbers for all of those specific types.
> 
> If it is just a rename, I prefer it is done from the start.

It's both :-) It's ambiguous, but only used to refer to BT.601-liked
buses today in mainline, so I'll rename it. The number may be used to
refer to different types of parallel buses out-of-tree, and we can add
new types for that in mainline later when/if needed.

> > > Should this be somehow visible in video-interfaces.yaml?
> > 
> > I wish we could use macros in .yaml files instead of numerical values,
> > but I don't think that's possible. I can do this:
> > 
> >    bus-type:
> >      $ref: /schemas/types.yaml#/definitions/uint32
> >      enum:
> > -      - 1 # MIPI CSI-2 C-PHY
> > -      - 2 # MIPI CSI1
> > -      - 3 # CCP2
> > -      - 4 # MIPI CSI-2 D-PHY
> > -      - 5 # Parallel
> > -      - 6 # BT.656
> > +      - 1 # MIPI CSI-2 C-PHY (MEDIA_BUS_TYPE_CSI2_CPHY)
> > +      - 2 # MIPI CSI1 (MEDIA_BUS_TYPE_CSI1)
> > +      - 3 # CCP2 (MEDIA_BUS_TYPE_CCP2)
> > +      - 4 # MIPI CSI-2 D-PHY (MEDIA_BUS_TYPE_CSI2_DPHY)
> > +      - 5 # Parallel (MEDIA_BUS_TYPE_PARALLEL)
> > +      - 6 # BT.656 (MEDIA_BUS_TYPE_BT656)
> 
> Seems a bit redundant to have both comment text and define. The only 
> part missing from the defines is 'MIPI'.

I agree. I'll use the macros.

It would be nice if macros could be used instead of numerical values in
the YAML schema, but that's certainly not high on the wishlist.

> >      description:
> > -      Data bus type.
> > +      Data bus type. Use the macros listed above (defined in
> > +      dt-bindings/video-interfaces.h) instead of numerical values.
> > 
> > Any better proposal ?
> > 
> > > > +#define MEDIA_BUS_TYPE_BT656			6
> > > > +
> > > > +#endif /* __DT_BINDINGS_MEDIA_VIDEO_INTERFACES_H__ */