drm: lcdif: Add multiple encoders and first bridges support

The single LCDIF embedded in i.MX93 SoC may drive multiple displays
simultaneously.  Look at LCDIF output port's remote port parents to
find all enabled first bridges.  Add an encoder for each found bridge
and attach the bridge to the encoder.  This is a preparation for
adding i.MX93 LCDIF support.

Tested-by: Alexander Stein <alexander.stein@ew.tq-group.com>
Acked-by: Alexander Stein <alexander.stein@ew.tq-group.com>
Signed-off-by: Liu Ying <victor.liu@nxp.com>
Reviewed-by: Marek Vasut <marex@denx.de>
Signed-off-by: Marek Vasut <marex@denx.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20230510092450.4024730-6-victor.liu@nxp.com

Author: Liu Ying

drivers/gpu/drm/mxsfb/lcdif_drv.c

@@ -9,13 +9,16 @@
 #include <linux/dma-mapping.h>
 #include <linux/io.h>
 #include <linux/module.h>
+#include <linux/of.h>
 #include <linux/of_device.h>
+#include <linux/of_graph.h>
 #include <linux/platform_device.h>
 #include <linux/pm_runtime.h>
 
 #include <drm/drm_atomic_helper.h>
 #include <drm/drm_bridge.h>
 #include <drm/drm_drv.h>
+#include <drm/drm_encoder.h>
 #include <drm/drm_fbdev_dma.h>
 #include <drm/drm_gem_dma_helper.h>
 #include <drm/drm_gem_framebuffer_helper.h>
@@ -38,19 +41,70 @@ static const struct drm_mode_config_helper_funcs lcdif_mode_config_helpers = {
 	.atomic_commit_tail = drm_atomic_helper_commit_tail_rpm,
 };
 
+static const struct drm_encoder_funcs lcdif_encoder_funcs = {
+	.destroy = drm_encoder_cleanup,
+};
+
 static int lcdif_attach_bridge(struct lcdif_drm_private *lcdif)
 {
-	struct drm_device *drm = lcdif->drm;
+	struct device *dev = lcdif->drm->dev;
+	struct device_node *ep;
 	struct drm_bridge *bridge;
 	int ret;
 
-	bridge = devm_drm_of_get_bridge(drm->dev, drm->dev->of_node, 0, 0);
-	if (IS_ERR(bridge))
-		return PTR_ERR(bridge);
-
-	ret = drm_bridge_attach(&lcdif->encoder, bridge, NULL, 0);
-	if (ret)
-		return dev_err_probe(drm->dev, ret, "Failed to attach bridge\n");
+	for_each_endpoint_of_node(dev->of_node, ep) {
+		struct device_node *remote;
+		struct of_endpoint of_ep;
+		struct drm_encoder *encoder;
+
+		remote = of_graph_get_remote_port_parent(ep);
+		if (!of_device_is_available(remote)) {
+			of_node_put(remote);
+			continue;
+		}
+		of_node_put(remote);
+
+		ret = of_graph_parse_endpoint(ep, &of_ep);
+		if (ret < 0) {
+			dev_err(dev, "Failed to parse endpoint %pOF\n", ep);
+			of_node_put(ep);
+			return ret;
+		}
+
+		bridge = devm_drm_of_get_bridge(dev, dev->of_node, 0, of_ep.id);
+		if (IS_ERR(bridge)) {
+			of_node_put(ep);
+			return dev_err_probe(dev, PTR_ERR(bridge),
+					     "Failed to get bridge for endpoint%u\n",
+					     of_ep.id);
+		}
+
+		encoder = devm_kzalloc(dev, sizeof(*encoder), GFP_KERNEL);
+		if (!encoder) {
+			dev_err(dev, "Failed to allocate encoder for endpoint%u\n",
+				of_ep.id);
+			of_node_put(ep);
+			return -ENOMEM;
+		}
+
+		encoder->possible_crtcs = drm_crtc_mask(&lcdif->crtc);
+		ret = drm_encoder_init(lcdif->drm, encoder, &lcdif_encoder_funcs,
+				       DRM_MODE_ENCODER_NONE, NULL);
+		if (ret) {
+			dev_err(dev, "Failed to initialize encoder for endpoint%u: %d\n",
+				of_ep.id, ret);
+			of_node_put(ep);
+			return ret;
+		}
+
+		ret = drm_bridge_attach(encoder, bridge, NULL, 0);
+		if (ret) {
+			of_node_put(ep);
+			return dev_err_probe(dev, ret,
+					     "Failed to attach bridge for endpoint%u\n",
+					     of_ep.id);
+		}
+	}
 
 	return 0;
 }

drivers/gpu/drm/mxsfb/lcdif_drv.h

@@ -11,7 +11,6 @@
 #include <drm/drm_bridge.h>
 #include <drm/drm_crtc.h>
 #include <drm/drm_device.h>
-#include <drm/drm_encoder.h>
 #include <drm/drm_plane.h>
 
 struct clk;
@@ -30,7 +29,6 @@ struct lcdif_drm_private {
 		/* i.MXRT does support overlay planes, add them here. */
 	} planes;
 	struct drm_crtc			crtc;
-	struct drm_encoder		encoder;
 };
 
 static inline struct lcdif_drm_private *

drivers/gpu/drm/mxsfb/lcdif_kms.c

@@ -659,14 +659,6 @@ static const struct drm_crtc_funcs lcdif_crtc_funcs = {
 	.disable_vblank = lcdif_crtc_disable_vblank,
 };
 
-/* -----------------------------------------------------------------------------
- * Encoder
- */
-
-static const struct drm_encoder_funcs lcdif_encoder_funcs = {
-	.destroy = drm_encoder_cleanup,
-};
-
 /* -----------------------------------------------------------------------------
  * Planes
  */
@@ -759,7 +751,6 @@ int lcdif_kms_init(struct lcdif_drm_private *lcdif)
 					BIT(DRM_COLOR_YCBCR_BT2020);
 	const u32 supported_ranges = BIT(DRM_COLOR_YCBCR_LIMITED_RANGE) |
 				     BIT(DRM_COLOR_YCBCR_FULL_RANGE);
-	struct drm_encoder *encoder = &lcdif->encoder;
 	struct drm_crtc *crtc = &lcdif->crtc;
 	int ret;
 
@@ -783,13 +774,7 @@ int lcdif_kms_init(struct lcdif_drm_private *lcdif)
 		return ret;
 
 	drm_crtc_helper_add(crtc, &lcdif_crtc_helper_funcs);
-	ret = drm_crtc_init_with_planes(lcdif->drm, crtc,
-					&lcdif->planes.primary, NULL,
-					&lcdif_crtc_funcs, NULL);
-	if (ret)
-		return ret;
-
-	encoder->possible_crtcs = drm_crtc_mask(crtc);
-	return drm_encoder_init(lcdif->drm, encoder, &lcdif_encoder_funcs,
-				DRM_MODE_ENCODER_NONE, NULL);
+	return drm_crtc_init_with_planes(lcdif->drm, crtc,
+					 &lcdif->planes.primary, NULL,
+					 &lcdif_crtc_funcs, NULL);
 }