Re: [PATCH v5 3/7] drm: sun4i: dsi: Convert to bridge driver

[Maxime Ripard <maxime@cerno.tech>]

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On Wed, Nov 24, 2021 at 12:02:47AM +0530, Jagan Teki wrote:
> > > > > > +     dsi->panel = of_drm_find_panel(remote);
> > > > > > +     if (IS_ERR(dsi->panel)) {
> > > > > > +             dsi->panel = NULL;
> > > > > > +
> > > > > > +             dsi->next_bridge = of_drm_find_bridge(remote);
> > > > > > +             if (IS_ERR(dsi->next_bridge)) {
> > > > > > +                     dev_err(dsi->dev, "failed to find bridge\n");
> > > > > > +                     return PTR_ERR(dsi->next_bridge);
> > > > > > +             }
> > > > > > +     } else {
> > > > > > +             dsi->next_bridge = NULL;
> > > > > > +     }
> > > > > > +
> > > > > > +     of_node_put(remote);
> > > > >
> > > > > Using devm_drm_of_get_bridge would greatly simplify the driver
> > > >
> > > > I'm aware of this and this would break the existing sunxi dsi binding,
> > > > we are not using ports based pipeline in dsi node. Of-course you have
> > > > pointed the same before, please check below
> > > > https://patchwork.kernel.org/project/dri-devel/patch/20210322140152.101709-2-jagan@amarulasolutions.com/
> > >
> > > Then drm_of_find_panel_or_bridge needs to be adjusted to handle the DSI
> > > bindings and look for a panel or bridge not only through the OF graph,
> > > but also on the child nodes
> >
> > Okay. I need to check this.
> 
> devm_drm_of_get_bridge is not working with legacy binding like the one
> used in sun6i dsi

There's nothing legacy about it.

> https://patchwork.kernel.org/project/dri-devel/patch/20211122065223.88059-6-jagan@amarulasolutions.com/
> 
> dsi->next_bridge = devm_drm_of_get_bridge(dsi->dev, dsi->dev->of_node, 0, 0);
> if (IS_ERR(dsi->next_bridge))
>            return PTR_ERR(dsi->next_bridge);
> 
> It is only working if we have ports on the pipeline, something like this
> https://patchwork.kernel.org/project/dri-devel/patch/20210214194102.126146-8-jagan@amarulasolutions.com/
> 
> Please have a look and let me know if I miss anything?

Yes, you're missing the answer you quoted earlier:

> > > Then drm_of_find_panel_or_bridge needs to be adjusted to handle the DSI
> > > bindings and look for a panel or bridge not only through the OF graph,
> > > but also on the child nodes

Maxime

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