2022-10-13 10:17:28

by Maxime Ripard

Subject: [PATCH 4/7] drm/vc4: dpi: Support RGB565 format

From: Chris Morgan <[email protected]>

The RGB565 format with padding over 24 bits
(MEDIA_BUS_FMT_RGB565_1X24_CPADHI) is supported by the vc4 DPI
controller as "mode 3". This is what the Geekworm MZP280 DPI display
uses, so let's add support for it in the DPI controller driver.

Reviewed-by: Dave Stevenson <[email protected]>
Signed-off-by: Chris Morgan <[email protected]>
Signed-off-by: Maxime Ripard <[email protected]>
---
drivers/gpu/drm/vc4/vc4_dpi.c | 4 ++++
1 file changed, 4 insertions(+)

diff --git a/drivers/gpu/drm/vc4/vc4_dpi.c b/drivers/gpu/drm/vc4/vc4_dpi.c
index 1f8f44b7b5a5..7da3dd1db50e 100644
--- a/drivers/gpu/drm/vc4/vc4_dpi.c
+++ b/drivers/gpu/drm/vc4/vc4_dpi.c
@@ -182,6 +182,10 @@ static void vc4_dpi_encoder_enable(struct drm_encoder *encoder)
dpi_c |= VC4_SET_FIELD(DPI_FORMAT_16BIT_565_RGB_3,
DPI_FORMAT);
break;
+ case MEDIA_BUS_FMT_RGB565_1X24_CPADHI:
+ dpi_c |= VC4_SET_FIELD(DPI_FORMAT_16BIT_565_RGB_2,
+ DPI_FORMAT);
+ break;
default:
DRM_ERROR("Unknown media bus format %d\n",
bus_format);

--
b4 0.11.0-dev-7da52

2022-10-15 18:31:47

by Laurent Pinchart

Subject: Re: [PATCH 4/7] drm/vc4: dpi: Support RGB565 format

Hi Maxime and Chris,

Thank you for the patch.

On Thu, Oct 13, 2022 at 11:56:48AM +0200, Maxime Ripard wrote:
> From: Chris Morgan <[email protected]>
>
> The RGB565 format with padding over 24 bits
> (MEDIA_BUS_FMT_RGB565_1X24_CPADHI) is supported by the vc4 DPI
> controller as "mode 3". This is what the Geekworm MZP280 DPI display

The code below uses DPI_FORMAT_16BIT_565_RGB_2. Is that mode 3, or
should the commit message refer to mode 2 ?

With this fixed,

Reviewed-by: Laurent Pinchart <[email protected]>

> uses, so let's add support for it in the DPI controller driver.
>
> Reviewed-by: Dave Stevenson <[email protected]>
> Signed-off-by: Chris Morgan <[email protected]>
> Signed-off-by: Maxime Ripard <[email protected]>
> ---
> drivers/gpu/drm/vc4/vc4_dpi.c | 4 ++++
> 1 file changed, 4 insertions(+)
>
> diff --git a/drivers/gpu/drm/vc4/vc4_dpi.c b/drivers/gpu/drm/vc4/vc4_dpi.c
> index 1f8f44b7b5a5..7da3dd1db50e 100644
> --- a/drivers/gpu/drm/vc4/vc4_dpi.c
> +++ b/drivers/gpu/drm/vc4/vc4_dpi.c
> @@ -182,6 +182,10 @@ static void vc4_dpi_encoder_enable(struct drm_encoder *encoder)
> dpi_c |= VC4_SET_FIELD(DPI_FORMAT_16BIT_565_RGB_3,
> DPI_FORMAT);
> break;
> + case MEDIA_BUS_FMT_RGB565_1X24_CPADHI:
> + dpi_c |= VC4_SET_FIELD(DPI_FORMAT_16BIT_565_RGB_2,
> + DPI_FORMAT);
> + break;
> default:
> DRM_ERROR("Unknown media bus format %d\n",
> bus_format);
>

--
Regards,

Laurent Pinchart

2022-10-17 17:40:20

by Dave Stevenson

Subject: Re: [PATCH 4/7] drm/vc4: dpi: Support RGB565 format

Hi Laurent

On Sat, 15 Oct 2022 at 18:29, Laurent Pinchart
<[email protected]> wrote:
>
> Hi Maxime and Chris,
>
> Thank you for the patch.
>
> On Thu, Oct 13, 2022 at 11:56:48AM +0200, Maxime Ripard wrote:
> > From: Chris Morgan <[email protected]>
> >
> > The RGB565 format with padding over 24 bits
> > (MEDIA_BUS_FMT_RGB565_1X24_CPADHI) is supported by the vc4 DPI
> > controller as "mode 3". This is what the Geekworm MZP280 DPI display
>
> The code below uses DPI_FORMAT_16BIT_565_RGB_2. Is that mode 3, or
> should the commit message refer to mode 2 ?

It's a mis-mash of documentation from the firmware stack.
[1] lists the firmware modes, which start at 1 for the equivalent of
DPI_FORMAT_9BIT_666_RGB, so there padded RGB565 is mode 3.

I'd advocate dropping the reference to which mode it is:
The RGB565 format with padding over 24 bits
(MEDIA_BUS_FMT_RGB565_1X24_CPADHI) is supported by the vc4 DPI controller.

Dave

[1] https://www.raspberrypi.com/documentation/computers/raspberry-pi.html#parallel-display-interface-dpi

> With this fixed,
>
> Reviewed-by: Laurent Pinchart <[email protected]>
>
> > uses, so let's add support for it in the DPI controller driver.
> >
> > Reviewed-by: Dave Stevenson <[email protected]>
> > Signed-off-by: Chris Morgan <[email protected]>
> > Signed-off-by: Maxime Ripard <[email protected]>
> > ---
> > drivers/gpu/drm/vc4/vc4_dpi.c | 4 ++++
> > 1 file changed, 4 insertions(+)
> >
> > diff --git a/drivers/gpu/drm/vc4/vc4_dpi.c b/drivers/gpu/drm/vc4/vc4_dpi.c
> > index 1f8f44b7b5a5..7da3dd1db50e 100644
> > --- a/drivers/gpu/drm/vc4/vc4_dpi.c
> > +++ b/drivers/gpu/drm/vc4/vc4_dpi.c
> > @@ -182,6 +182,10 @@ static void vc4_dpi_encoder_enable(struct drm_encoder *encoder)
> > dpi_c |= VC4_SET_FIELD(DPI_FORMAT_16BIT_565_RGB_3,
> > DPI_FORMAT);
> > break;
> > + case MEDIA_BUS_FMT_RGB565_1X24_CPADHI:
> > + dpi_c |= VC4_SET_FIELD(DPI_FORMAT_16BIT_565_RGB_2,
> > + DPI_FORMAT);
> > + break;
> > default:
> > DRM_ERROR("Unknown media bus format %d\n",
> > bus_format);
> >
>
> --
> Regards,
>
> Laurent Pinchart