[PATCH v4 7/7] drm/mediatek: mtk_dsi: Create connector for bridges
Chun-Kuang Hu
chunkuang.hu at kernel.org
Thu May 14 16:44:43 UTC 2020
Hi, Enric:
Enric Balletbo i Serra <enric.balletbo at collabora.com> 於 2020年5月14日 週四 下午11:42寫道：
>
> Hi Chun-Kuang,
>
> On 14/5/20 16:28, Chun-Kuang Hu wrote:
> > Hi, Enric:
> >
> > Enric Balletbo Serra <eballetbo at gmail.com> 於 2020年5月14日 週四 上午12:41寫道：
> >>
> >> Hi Chun-Kuang,
> >>
> >> Missatge de Enric Balletbo i Serra <enric.balletbo at collabora.com> del
> >> dia dv., 1 de maig 2020 a les 17:25:
> >>>
> >>> Use the drm_bridge_connector helper to create a connector for pipelines
> >>> that use drm_bridge. This allows splitting connector operations across
> >>> multiple bridges when necessary, instead of having the last bridge in
> >>> the chain creating the connector and handling all connector operations
> >>> internally.
> >>>
> >>> Signed-off-by: Enric Balletbo i Serra <enric.balletbo at collabora.com>
> >>> Acked-by: Sam Ravnborg <sam at ravnborg.org>
> >>
> >> A gentle ping on this, I think that this one is the only one that
> >> still needs a review in the series.
> >
> > This is what I reply in patch v3:
> >
>
> Sorry for missing this.
>
> > I think the panel is wrapped into next_bridge here,
> >
>
> Yes, you can have for example:
>
> 1. drm_bridge (mtk_dsi) -> drm_bridge (ps8640 - dsi-to-edp) -> drm_panel_bridge
> (edp panel)
>
> or a
>
> 2. drm_bridge (mtk_dsi)-> drm_panel_bridge (dsi panel)
>
> The _first_ one is my use case
>
> > if (panel) {
>
> This handles the second case, where you attach a dsi panel.
>
> > dsi->next_bridge = devm_drm_panel_bridge_add(dev, panel);
> >
> > so the next_bridge is a panel_bridge, in its attach function
> > panel_bridge_attach(),
> > according to the flag DRM_BRIDGE_ATTACH_NO_CONNECTOR, if not exist,
> > it would create connector and attach connector to panel.
> >
> > I'm not sure this flag would exist or not, but for both case, it's strange.
> > If exist, you create connector in this patch but no where to attach
> > connector to panel.
>
> Yes, in fact, this is transitional patch needed, as once I converted mtk_dpi,
> mtk_dsi and mtk_hdmi to the new drm_bridge API the drm_bridge_connector_init()
> will be done in mtk_drm_drv. We will need to call drm_bridge_connector_init for
> dpi and dsi pipes and remove that call from mtk_dsi and mtk_dpi drivers. The
> graphic controller driver should create connectors and CRTCs, as example you can
> take a look at drivers/gpu/drm/omapdrm/omap_drv.c
>
I have such question because I've reviewed omap's driver. In omap's
driver, after it call drm_bridge_connector_init(), it does this:
if (pipe->output->panel) {
ret = drm_panel_attach(pipe->output->panel,
pipe->connector);
if (ret < 0)
return ret;
}
In this patch, you does not do this.
> > If not exist, the next_brige would create one connector and this brige
> > would create another connector.
> >
> > I think in your case, mtk_dsi does not directly connect to a panel, so
>
> Exactly
>
> > I need a exact explain. Or someone could test this on a
> > directly-connect-panel platform.
>
> I don't think I am breaking this use case but AFAICS there is no users in
> mainline that directly connect a panel using the mediatek driver. As I said my
> use case is the other so I can't really test. Do you know anyone that can test this?
I'm not sure who can test this, but [1], which is sent by YT Shen in a
series, is a patch to support dsi command mode so dsi could directly
connect to panel.
[1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/drivers/gpu/drm/mediatek?h=v5.7-rc5&id=21898816831fc60c92dd634ab4316a24da7eb4af
It's better that someone could test this case, but if no one would
test this, I could also accept a good-look patch.
Regards,
Chun-Kuang.
>
> Thanks,
> Enric
>
> >
> > Regards,
> > Chun-Kuang.
> >
> >>
> >> Thanks,
> >> Enric
> >>
> >>> ---
> >>>
> >>> Changes in v4: None
> >>> Changes in v3:
> >>> - Move the bridge.type line to the patch that adds drm_bridge support. (Laurent Pinchart)
> >>>
> >>> Changes in v2: None
> >>>
> >>> drivers/gpu/drm/mediatek/mtk_dsi.c | 13 ++++++++++++-
> >>> 1 file changed, 12 insertions(+), 1 deletion(-)
> >>>
> >>> diff --git a/drivers/gpu/drm/mediatek/mtk_dsi.c b/drivers/gpu/drm/mediatek/mtk_dsi.c
> >>> index 4f3bd095c1ee..471fcafdf348 100644
> >>> --- a/drivers/gpu/drm/mediatek/mtk_dsi.c
> >>> +++ b/drivers/gpu/drm/mediatek/mtk_dsi.c
> >>> @@ -17,6 +17,7 @@
> >>>
> >>> #include <drm/drm_atomic_helper.h>
> >>> #include <drm/drm_bridge.h>
> >>> +#include <drm/drm_bridge_connector.h>
> >>> #include <drm/drm_mipi_dsi.h>
> >>> #include <drm/drm_of.h>
> >>> #include <drm/drm_panel.h>
> >>> @@ -183,6 +184,7 @@ struct mtk_dsi {
> >>> struct drm_encoder encoder;
> >>> struct drm_bridge bridge;
> >>> struct drm_bridge *next_bridge;
> >>> + struct drm_connector *connector;
> >>> struct phy *phy;
> >>>
> >>> void __iomem *regs;
> >>> @@ -977,10 +979,19 @@ static int mtk_dsi_encoder_init(struct drm_device *drm, struct mtk_dsi *dsi)
> >>> */
> >>> dsi->encoder.possible_crtcs = 1;
> >>>
> >>> - ret = drm_bridge_attach(&dsi->encoder, &dsi->bridge, NULL, 0);
> >>> + ret = drm_bridge_attach(&dsi->encoder, &dsi->bridge, NULL,
> >>> + DRM_BRIDGE_ATTACH_NO_CONNECTOR);
> >>> if (ret)
> >>> goto err_cleanup_encoder;
> >>>
> >>> + dsi->connector = drm_bridge_connector_init(drm, &dsi->encoder);
> >>> + if (IS_ERR(dsi->connector)) {
> >>> + DRM_ERROR("Unable to create bridge connector\n");
> >>> + ret = PTR_ERR(dsi->connector);
> >>> + goto err_cleanup_encoder;
> >>> + }
> >>> + drm_connector_attach_encoder(dsi->connector, &dsi->encoder);
> >>> +
> >>> return 0;
> >>>
> >>> err_cleanup_encoder:
> >>> --
> >>> 2.26.2
> >>>
> >>>
> >>> _______________________________________________
> >>> Linux-mediatek mailing list
> >>> Linux-mediatek at lists.infradead.org
> >>> http://lists.infradead.org/mailman/listinfo/linux-mediatek
More information about the dri-devel
mailing list