video: tegra20: dc: add video bridge support

Rework existing DC driver configuration to support bridges (both external
and internal DSI and HDMI controllers) and align video devices chain logic
with Linux implementation. Additionally, this should improve communication
between DC and internal DSI/HDMI controllers.

Signed-off-by: Svyatoslav Ryhel <clamor95@gmail.com>

drivers/video/tegra20/tegra-dc.c

@@ -1,6 +1,7 @@
 // SPDX-License-Identifier: GPL-2.0+
 /*
  * Copyright (c) 2011 The Chromium OS Authors.
+ * Copyright (c) 2024 Svyatoslav Ryhel <clamor95@gmail.com>
  */
 
 #include <backlight.h>
@@ -11,6 +12,7 @@
 #include <log.h>
 #include <panel.h>
 #include <video.h>
+#include <video_bridge.h>
 #include <asm/system.h>
 #include <asm/io.h>
 #include <asm/arch/clock.h>
@@ -31,7 +33,8 @@ struct tegra_lcd_priv {
 	int height;			/* height in pixels */
 	enum video_log2_bpp log2_bpp;	/* colour depth */
 	struct display_timing timing;
-	struct udevice *panel;
+	struct udevice *panel;		/* Panels attached to RGB */
+	struct udevice *bridge;		/* Bridge linked with DC */
 	struct dc_ctlr *dc;		/* Display controller regmap */
 	const struct tegra_dc_soc_info *soc;
 	fdt_addr_t frame_buffer;	/* Address of frame buffer */
@@ -373,11 +376,12 @@ static int tegra_lcd_probe(struct udevice *dev)
 	}
 
 	/* Get shift clock divider from Tegra DSI if used */
-	if (!strcmp(priv->panel->name, TEGRA_DSI_A) ||
-	    !strcmp(priv->panel->name, TEGRA_DSI_B)) {
-		struct tegra_dc_plat *dc_plat = dev_get_plat(priv->panel);
+	if (priv->bridge) {
+		if (!strcmp(priv->bridge->driver->name, "tegra_dsi")) {
+			struct tegra_dc_plat *dc_plat = dev_get_plat(priv->bridge);
 
-		priv->scdiv = dc_plat->scdiv;
+			priv->scdiv = dc_plat->scdiv;
+		}
 	}
 
 	/* Clean the framebuffer area */
@@ -390,10 +394,20 @@ static int tegra_lcd_probe(struct udevice *dev)
 		return ret;
 	}
 
-	ret = panel_enable_backlight(priv->panel);
-	if (ret) {
-		log_debug("%s: Cannot enable backlight, ret=%d\n", __func__, ret);
-		return ret;
+	if (priv->panel) {
+		ret = panel_enable_backlight(priv->panel);
+		if (ret) {
+			log_debug("%s: Cannot enable backlight, ret=%d\n", __func__, ret);
+			return ret;
+		}
+	}
+
+	if (priv->bridge) {
+		ret = video_bridge_attach(priv->bridge);
+		if (ret) {
+			log_debug("%s: Cannot attach bridge, ret=%d\n", __func__, ret);
+			return ret;
+		}
 	}
 
 	mmu_set_region_dcache_behaviour(priv->frame_buffer, plat->size,
@@ -408,17 +422,110 @@ static int tegra_lcd_probe(struct udevice *dev)
 	log_debug("LCD frame buffer at %08x, size %x\n", priv->frame_buffer,
 		  plat->size);
 
-	return panel_set_backlight(priv->panel, BACKLIGHT_DEFAULT);
+	if (priv->panel) {
+		ret = panel_set_backlight(priv->panel, BACKLIGHT_DEFAULT);
+		if (ret)
+			return ret;
+	}
+
+	if (priv->bridge) {
+		ret = video_bridge_set_backlight(priv->bridge, BACKLIGHT_DEFAULT);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+
+static int tegra_lcd_configure_rgb(struct udevice *dev, ofnode rgb)
+{
+	struct tegra_lcd_priv *priv = dev_get_priv(dev);
+	ofnode remote;
+	int ret;
+
+	remote = ofnode_parse_phandle(rgb, "nvidia,panel", 0);
+	if (!ofnode_valid(remote))
+		return -EINVAL;
+
+	ret = uclass_get_device_by_ofnode(UCLASS_PANEL, remote, &priv->panel);
+	if (ret) {
+		log_debug("%s: Cannot find panel for '%s' (ret=%d)\n",
+			  __func__, dev->name, ret);
+
+		ret = uclass_get_device_by_ofnode(UCLASS_VIDEO_BRIDGE, remote,
+						  &priv->bridge);
+		if (ret) {
+			log_err("%s: Cannot find panel or bridge for '%s' (ret=%d)\n",
+				__func__, dev->name, ret);
+			return ret;
+		}
+	}
+
+	return 0;
+}
+
+static int tegra_lcd_configure_internal(struct udevice *dev)
+{
+	struct tegra_lcd_priv *priv = dev_get_priv(dev);
+	struct tegra_dc_plat *dc_plat;
+	ofnode host1x = ofnode_get_parent(dev_ofnode(dev));
+	ofnode node;
+	int ret;
+
+	switch (priv->pipe) {
+	case 0: /* DC0 is usually used for DSI */
+		/* Check for ganged DSI configuration */
+		ofnode_for_each_subnode(node, host1x)
+			if (ofnode_name_eq(node, "dsi") && ofnode_is_enabled(node) &&
+			    ofnode_read_bool(node, "nvidia,ganged-mode"))
+				goto exit;
+
+		/* If no master DSI found loop for any active DSI */
+		ofnode_for_each_subnode(node, host1x)
+			if (ofnode_name_eq(node, "dsi") && ofnode_is_enabled(node))
+				goto exit;
+
+		log_err("%s: failed to find DSI device for '%s'\n",
+			__func__, dev->name);
+
+		return -ENODEV;
+	case 1: /* DC1 is usually used for HDMI */
+		ofnode_for_each_subnode(node, host1x)
+			if (ofnode_name_eq(node, "hdmi"))
+				goto exit;
+
+		log_err("%s: failed to find HDMI device for '%s'\n",
+			__func__, dev->name);
+
+		return -ENODEV;
+	default:
+		log_debug("Unsupported DC selection\n");
+		return -EINVAL;
+	}
+
+exit:
+	ret = uclass_get_device_by_ofnode(UCLASS_VIDEO_BRIDGE, node, &priv->bridge);
+	if (ret) {
+		log_err("%s: failed to get DSI/HDMI device for '%s' (ret %d)\n",
+			__func__, dev->name, ret);
+		return ret;
+	}
+
+	dc_plat = dev_get_plat(priv->bridge);
+
+	/* Fill the platform data for internal devices */
+	dc_plat->dev = dev;
+	dc_plat->dc = priv->dc;
+	dc_plat->pipe = priv->pipe;
+
+	return 0;
 }
 
 static int tegra_lcd_of_to_plat(struct udevice *dev)
 {
 	struct tegra_lcd_priv *priv = dev_get_priv(dev);
-	const void *blob = gd->fdt_blob;
 	struct display_timing *timing;
-	int node = dev_of_offset(dev);
-	int panel_node;
-	int rgb;
+	ofnode rgb;
 	int ret;
 
 	priv->dc = (struct dc_ctlr *)dev_read_addr_ptr(dev);
@@ -446,44 +553,42 @@ static int tegra_lcd_of_to_plat(struct udevice *dev)
 	priv->rotation = dev_read_bool(dev, "nvidia,180-rotation");
 	priv->pipe = dev_read_u32_default(dev, "nvidia,head", 0);
 
-	rgb = fdt_subnode_offset(blob, node, "rgb");
-	if (rgb < 0) {
-		log_debug("%s: Cannot find rgb subnode for '%s' (ret=%d)\n",
-			  __func__, dev->name, rgb);
-		return -EINVAL;
-	}
-
 	/*
-	 * Sadly the panel phandle is in an rgb subnode so we cannot use
-	 * uclass_get_device_by_phandle().
+	 * Usual logic of Tegra video routing should be next:
+	 * 1. Check rgb subnode for RGB/LVDS panels or bridges
+	 * 2. If none found, then iterate through bridges bound,
+	 *    looking for DSIA or DSIB for DC0 and HDMI for DC1.
+	 * If none of above is valid, then configuration is not
+	 * valid.
 	 */
-	panel_node = fdtdec_lookup_phandle(blob, rgb, "nvidia,panel");
-	if (panel_node < 0) {
-		log_debug("%s: Cannot find panel information\n", __func__);
-		return -EINVAL;
+
+	rgb = dev_read_subnode(dev, "rgb");
+	if (ofnode_valid(rgb) && ofnode_is_enabled(rgb)) {
+		/* RGB is available, use it */
+		ret = tegra_lcd_configure_rgb(dev, rgb);
+		if (ret)
+			return ret;
+	} else {
+		/* RGB is not available, check for internal devices */
+		ret = tegra_lcd_configure_internal(dev);
+		if (ret)
+			return ret;
 	}
 
-	ret = uclass_get_device_by_of_offset(UCLASS_PANEL, panel_node,
-					     &priv->panel);
-	if (ret) {
-		log_debug("%s: Cannot find panel for '%s' (ret=%d)\n", __func__,
-			  dev->name, ret);
-		return ret;
+	if (priv->panel) {
+		ret = panel_get_display_timing(priv->panel, &priv->timing);
+		if (ret) {
+			ret = ofnode_decode_display_timing(rgb, 0, &priv->timing);
+			if (ret) {
+				log_debug("%s: Cannot read display timing for '%s' (ret=%d)\n",
+					  __func__, dev->name, ret);
+				return -EINVAL;
+			}
+		}
 	}
 
-	/* Fill the platform data for internal devices */
-	if (!strcmp(priv->panel->name, TEGRA_DSI_A) ||
-	    !strcmp(priv->panel->name, TEGRA_DSI_B)) {
-		struct tegra_dc_plat *dc_plat = dev_get_plat(priv->panel);
-
-		dc_plat->dev = dev;
-		dc_plat->dc = priv->dc;
-		dc_plat->pipe = priv->pipe;
-	}
-
-	ret = panel_get_display_timing(priv->panel, &priv->timing);
-	if (ret) {
-		ret = fdtdec_decode_display_timing(blob, rgb, 0, &priv->timing);
+	if (priv->bridge) {
+		ret = video_bridge_get_display_timing(priv->bridge, &priv->timing);
 		if (ret) {
 			log_debug("%s: Cannot read display timing for '%s' (ret=%d)\n",
 				  __func__, dev->name, ret);
@@ -503,13 +608,6 @@ static int tegra_lcd_of_to_plat(struct udevice *dev)
 static int tegra_lcd_bind(struct udevice *dev)
 {
 	struct video_uc_plat *plat = dev_get_uclass_plat(dev);
-	const void *blob = gd->fdt_blob;
-	int node = dev_of_offset(dev);
-	int rgb;
-
-	rgb = fdt_subnode_offset(blob, node, "rgb");
-	if ((rgb < 0) || !fdtdec_get_is_enabled(blob, rgb))
-		return -ENODEV;
 
 	plat->size = LCD_MAX_WIDTH * LCD_MAX_HEIGHT *
 		(1 << LCD_MAX_LOG2_BPP) / 8;

drivers/video/tegra20/tegra-dc.h

@@ -14,9 +14,6 @@
 /* arch-tegra/dc exists only because T124 uses it */
 #include <asm/arch-tegra/dc.h>
 
-#define TEGRA_DSI_A		"dsi@54300000"
-#define TEGRA_DSI_B		"dsi@54400000"
-
 struct tegra_dc_plat {
 	struct udevice *dev;		/* Display controller device */
 	struct dc_ctlr *dc;		/* Display controller regmap */