From e39a82bf56e6a74254d1bf2e2c304b0261f3473b Mon Sep 17 00:00:00 2001 From: Jagan Teki Date: Wed, 8 Mar 2023 22:09:39 +0530 Subject: [PATCH] drm: exynos: dsi: Lookup OF-graph or Child node devices In general, for MIPI DSI there are three ways to represent the pipeline for an upstream bridge to find the connected downstream panel or bridge. 1. Child panel or bridge as a conventional device tree child node. 2. Child panel or bridge as an OF-graph port node. 3. Child panel or bridge as an OF-graph ports node. There are three different downstream panels or bridges that are possible to connect an upstream DSI host bridge - DSI Panel, DSI Bridge, and I2C-Configured DSI bridge. An example of the downstream panel represented as a child node, &dsi { compatible = "samsung,exynos5433-mipi-dsi"; ports { port@0 { reg = <0>; dsi_to_mic: endpoint { remote-endpoint = <&mic_to_dsi>; }; }; }; panel@0 { reg = <0>; }; }; An example of the downstream bridge represented as a port node, &i2c4 { bridge@2c { compatible = "ti,sn65dsi84"; ports { port@0 { reg = <0>; bridge_in_dsi: endpoint { remote-endpoint = <&dsi_out_bridge>; data-lanes = <1 2>; }; }; port@2 { reg = <2>; bridge_out_panel: endpoint { remote-endpoint = <&panel_out_bridge>; }; }; }; }; }; &dsi { compatible = "fsl,imx8mm-mipi-dsim"; port { dsi_in_lcdif: endpoint@0 { reg = <0>; remote-endpoint = <&lcdif_out_dsi>; }; dsi_out_bridge: endpoint@1 { reg = <1>; remote-endpoint = <&bridge_in_dsi>; }; }; }; An example of the downstream bridge represented as a ports node, &dsi { compatible = "fsl,imx8mm-mipi-dsim"; ports { port@0 { reg = <0>; dsi_in_lcdif: endpoint@0 { reg = <0>; remote-endpoint = <&lcdif_out_dsi>; }; }; port@1 { reg = <1>; dsi_out_bridge: endpoint { remote-endpoint = <&bridge_in_dsi>; }; }; }; In, summary it is possible to represent all three downstream slaves devices using OF-graph port or ports node however only DSI Panel and DSI Bridge are possible but not possible to represent I2C-Configured DSI bridge child nodes since I2C-Configure bridges are child of I2C node, not upstream DSI host bridge and it is must represent them endpoint port linking. This indeed means, the OF-graph port or ports representation is mandatory for I2C-Configured DSI bridges. This patch tries to add an OF-graph port or ports representation detection code on top of existing child node detection. It is possible to replace the entire detection code using existing drm_of helper drm_of_find_panel_or_bridge but it will break the Exynos DSI since the pipeline doesn't support OF-graph port or ports node. Overall, this patch has a combination of child and OF-graph pipeline detections in order to support the backward compatibility of Exynos DSI child node and i.MX8M Mini/Nano/Plus OF-graph port or ports node pipelines. This is the first common DSI host bridge driver that needs to support all possible downstream connection pipeline combinations. Tested-by: Marek Szyprowski Reviewed-by: Marek Vasut Signed-off-by: Jagan Teki Signed-off-by: Inki Dae --- drivers/gpu/drm/exynos/exynos_drm_dsi.c | 38 +++++++++++++++++++++++++++++++-- 1 file changed, 36 insertions(+), 2 deletions(-) diff --git a/drivers/gpu/drm/exynos/exynos_drm_dsi.c b/drivers/gpu/drm/exynos/exynos_drm_dsi.c index df15501..bb0d250 100644 --- a/drivers/gpu/drm/exynos/exynos_drm_dsi.c +++ b/drivers/gpu/drm/exynos/exynos_drm_dsi.c @@ -1470,18 +1470,52 @@ static int exynos_dsi_host_attach(struct mipi_dsi_host *host, struct device *dev = dsi->dev; struct drm_encoder *encoder = &dsi->encoder; struct drm_device *drm = encoder->dev; + struct device_node *np = dev->of_node; + struct device_node *remote; struct drm_panel *panel; int ret; - panel = of_drm_find_panel(device->dev.of_node); + /* + * Devices can also be child nodes when we also control that device + * through the upstream device (ie, MIPI-DCS for a MIPI-DSI device). + * + * Lookup for a child node of the given parent that isn't either port + * or ports. + */ + for_each_available_child_of_node(np, remote) { + if (of_node_name_eq(remote, "port") || + of_node_name_eq(remote, "ports")) + continue; + + goto of_find_panel_or_bridge; + } + + /* + * of_graph_get_remote_node() produces a noisy error message if port + * node isn't found and the absence of the port is a legit case here, + * so at first we silently check whether graph presents in the + * device-tree node. + */ + if (!of_graph_is_present(np)) + return -ENODEV; + + remote = of_graph_get_remote_node(np, 1, 0); + +of_find_panel_or_bridge: + if (!remote) + return -ENODEV; + + panel = of_drm_find_panel(remote); if (!IS_ERR(panel)) { dsi->out_bridge = devm_drm_panel_bridge_add(dev, panel); } else { - dsi->out_bridge = of_drm_find_bridge(device->dev.of_node); + dsi->out_bridge = of_drm_find_bridge(remote); if (!dsi->out_bridge) dsi->out_bridge = ERR_PTR(-EINVAL); } + of_node_put(remote); + if (IS_ERR(dsi->out_bridge)) { ret = PTR_ERR(dsi->out_bridge); DRM_DEV_ERROR(dev, "failed to find the bridge: %d\n", ret); -- 2.7.4