Re: [PATCH v7 07/10] drm: bridge: samsung-dsim: Add atomic_get_input_bus_fmts

Jagan Teki
2022-11-03T17:29:02Z

On Thu, Nov 3, 2022 at 9:56 PM Marek Vasut <marex@denx.de> wrote:
>
> On 11/3/22 10:39, Jagan Teki wrote:
> > On Sun, Oct 16, 2022 at 3:31 AM Marek Vasut <marex@denx.de> wrote:
> >>
> >> On 10/5/22 17:13, Jagan Teki wrote:
> >>
> >> [...]
> >>
> >>> @@ -1321,6 +1322,32 @@ static void samsung_dsim_atomic_post_disable(struct drm_bridge *bridge,
> >>> pm_runtime_put_sync(dsi->dev);
> >>> }
> >>>
> >>> +#define MAX_INPUT_SEL_FORMATS 1
> >>> +
> >>> +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;
> >>> +
> >>> + *num_input_fmts = 0;
> >>> +
> >>> + input_fmts = kcalloc(MAX_INPUT_SEL_FORMATS, sizeof(*input_fmts),
> >>> + GFP_KERNEL);
> >>> + if (!input_fmts)
> >>> + return NULL;
> >>> +
> >>> + /* This is the DSI-end bus format */
> >>> + input_fmts[0] = MEDIA_BUS_FMT_RGB888_1X24;
> >>> + *num_input_fmts = 1;
> >>
> >> Is this the only supported format ? NXP AN13573 lists the following:
> >>
> >> i.MX 8/RT MIPI DSI/CSI-2, Rev. 0, 21 March 2022
> >> 3.7.4 Pixel formats
> >> Table 14. DSI pixel packing formats
> >>
> >> Loosely Packed Pixel Stream, 20-bit YCbCr, 4:2:2
> >> Packed Pixel Stream, 24-bit YCbCr, 4:2:2
> >> Packed Pixel Stream, 16-bit YCbCr, 4:2:2
> >
> > Look like these are unsupported in media-bus-format.h list.
>
> Aren't those:
>
> MEDIA_BUS_FMT_UYVY12_1X24

Why is UYVY12 - YCbCr, 4:2:2 is 4+2+2 = 8 then it has UYVY8 ?

> MEDIA_BUS_FMT_UYVY8_1X16

If YCbCr is UYVY (I still don't get this notation, sorry) then Packed
Pixel Stream, 24-bit YCbCr, 4:2:2 with 2 Pixels per packet from Table
14 can be

MEDIA_BUS_FMT_UYVY8_2X24
(YCbCr 4:2:2 is UYVY8)

" based on a reference example from media bus format doc
4.13.3.4.1.1.3. Packed YUV Formats, For instance, a format where
pixels are encoded as 8-bit YUV values downsampled to 4:2:2 and
transferred as 2 8-bit bus samples per pixel in the U, Y, V, Y order
will be named MEDIA_BUS_FMT_UYVY8_2X8."

https://www.kernel.org/doc/html/latest/userspace-api/media/v4l/subdev-formats.html

_2X24 here 2 Pixels per packet is the exact packets to consider or we
can consider 1 Pixel per packet also. If later is true then _1X24 from
your notation is correct.

Thanks,
Jagan.