Re: [PATCH v8 09/14] drm: bridge: samsung-dsim: Add atomic_get_input_bus_fmts

[Jagan Teki <jagan@amarulasolutions.com>]

On Sun, Nov 13, 2022 at 5:51 AM Marek Vasut <marex@denx.de> wrote:
>
> On 11/10/22 19:38, Jagan Teki wrote:
> > Finding the right input bus format throughout the pipeline is hard
> > so add atomic_get_input_bus_fmts callback and initialize with the
> > proper input format from list of supported output formats.
> >
> > This format can be used in pipeline for negotiating bus format between
> > the DSI-end of this bridge and the other component closer to pipeline
> > components.
> >
> > List of Pixel formats are taken from,
> > AN13573 i.MX 8/RT MIPI DSI/CSI-2, Rev. 0, 21 March 2022
> > 3.7.4 Pixel formats
> > Table 14. DSI pixel packing formats
> >
> > v8:
> > * added pixel formats supported by NXP AN13573 i.MX 8/RT MIPI DSI/CSI-2
> >
> > v7, v6, v5, v4:
> > * none
> >
> > v3:
> > * include media-bus-format.h
> >
> > v2:
> > * none
> >
> > v1:
> > * new patch
> >
> > Signed-off-by: Jagan Teki <jagan@amarulasolutions.com>
> > ---
> >   drivers/gpu/drm/bridge/samsung-dsim.c | 53 +++++++++++++++++++++++++++
> >   1 file changed, 53 insertions(+)
> >
> > diff --git a/drivers/gpu/drm/bridge/samsung-dsim.c b/drivers/gpu/drm/bridge/samsung-dsim.c
> > index 0fe153b29e4f..33e5ae9c865f 100644
> > --- a/drivers/gpu/drm/bridge/samsung-dsim.c
> > +++ b/drivers/gpu/drm/bridge/samsung-dsim.c
> > @@ -15,6 +15,7 @@
> >   #include <linux/clk.h>
> >   #include <linux/delay.h>
> >   #include <linux/irq.h>
> > +#include <linux/media-bus-format.h>
> >   #include <linux/of_device.h>
> >   #include <linux/phy/phy.h>
> >
> > @@ -1321,6 +1322,57 @@ static void samsung_dsim_atomic_post_disable(struct drm_bridge *bridge,
> >       pm_runtime_put_sync(dsi->dev);
> >   }
> >
> > +/*
> > + * This pixel output formats list referenced from,
> > + * AN13573 i.MX 8/RT MIPI DSI/CSI-2, Rev. 0, 21 March 2022
> > + * 3.7.4 Pixel formats
> > + * Table 14. DSI pixel packing formats
> > + */
> > +static const u32 samsung_dsim_pixel_output_fmts[] = {
>
> You can also add :
>
> MEDIA_BUS_FMT_YUYV10_1X20
>
> MEDIA_BUS_FMT_YUYV12_1X24

Are these for the below formats?

"Loosely Packed Pixel Stream, 20-bit YCbCr, 4:2:2
 Packed Pixel Stream, 24-bit YCbCr, 4:2:2"
>
> > +     MEDIA_BUS_FMT_UYVY8_1X16,
> > +     MEDIA_BUS_FMT_RGB101010_1X30,
> > +     MEDIA_BUS_FMT_RGB121212_1X36,
> > +     MEDIA_BUS_FMT_RGB565_1X16,
> > +     MEDIA_BUS_FMT_RGB666_1X18,
> > +     MEDIA_BUS_FMT_RGB888_1X24,
> > +};
> > +
> > +static bool samsung_dsim_pixel_output_fmt_supported(u32 fmt)
> > +{
> > +     int i;
> > +
> > +     for (i = 0; i < ARRAY_SIZE(samsung_dsim_pixel_output_fmts); i++) {
> > +             if (samsung_dsim_pixel_output_fmts[i] == fmt)
> > +                     return true;
> > +     }
> > +
> > +     return false;
> > +}
> > +
> > +static u32 *
> > +samsung_dsim_atomic_get_input_bus_fmts(struct drm_bridge *bridge,
> > +                                    struct drm_bridge_state *bridge_state,
> > +                                    struct drm_crtc_state *crtc_state,
> > +                                    struct drm_connector_state *conn_state,
> > +                                    u32 output_fmt,
> > +                                    unsigned int *num_input_fmts)
> > +{
> > +     u32 *input_fmts;
> > +
> > +     if (!samsung_dsim_pixel_output_fmt_supported(output_fmt))
> > +             return NULL;
> > +
> > +     *num_input_fmts = 1;
>
> Shouldn't this be 6 ?
>
> > +     input_fmts = kmalloc(sizeof(*input_fmts), GFP_KERNEL);
> > +     if (!input_fmts)
> > +             return NULL;
> > +
> > +     input_fmts[0] = output_fmt;
>
> Shouldn't this be a list of all 6 supported pixel formats ?

Negotiation would settle to return one input_fmt from the list of
supporting output_fmts. so the num_input_fmts would be 1 rather than
the number of fmts in the supporting list. This is what I understood
from the atomic_get_input_bus_fmts API. let me know if I miss
something here.

Jagan.

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