On Tue, Mar 8, 2022 at 3:19 PM Marek Vasut <marex@xxxxxxx> wrote: > > On 3/8/22 09:03, Jagan Teki wrote: > > Hi, > > [...] > > >> @@ -314,7 +321,9 @@ static const struct drm_bridge_funcs chipone_bridge_funcs = { > >> static int chipone_parse_dt(struct chipone *icn) > >> { > >> struct device *dev = icn->dev; > >> + struct device_node *endpoint; > >> struct drm_panel *panel; > >> + int dsi_lanes; > >> int ret; > >> > >> icn->vdd1 = devm_regulator_get_optional(dev, "vdd1"); > >> @@ -350,15 +359,42 @@ static int chipone_parse_dt(struct chipone *icn) > >> return PTR_ERR(icn->enable_gpio); > >> } > >> > >> + endpoint = of_graph_get_endpoint_by_regs(dev->of_node, 0, 0); > >> + dsi_lanes = of_property_count_u32_elems(endpoint, "data-lanes"); > >> + icn->host_node = of_graph_get_remote_port_parent(endpoint); > >> + of_node_put(endpoint); > >> + > >> + if (!icn->host_node) > >> + return -ENODEV; > > > > The non-ports-based OF graph returns a -19 example on the Allwinner > > Display pipeline in R16 [1]. > > > > We need to have a helper to return host_node for non-ports as I have > > done it for drm_of_find_bridge. > > > > [1] https://patchwork.amarulasolutions.com/patch/1805/ > > The link points to a patch marked "DO NOT MERGE", maybe that patch is > missing the DSI host port@0 OF graph link ? Both port@0 and port@1 are > required, see: > > https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/devicetree/bindings/display/bridge/chipone,icn6211.yaml#n53 > > What is "non-ports-based OF graph" ? > > I don't see drm_of_find_bridge() in linux-next , what is that ? port@0 is optional as some of the DSI host OF-graph represent the bridge or panel as child nodes instead of ports. (i think dt-binding has to fix it to make port@0 optional) Example OF-graph is on the commit message. https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/drivers/gpu/drm/drm_of.c?id=80253168dbfd256bca97cf7f13312863c5a7f2e5 Jagan.