drm/tve200: Replace custom connector with panel bridge

This replaces the custom connector in the TVE200 with the
panel bridge helper. As long as we're just using panels
and no other bridges, this works just fine.
Reviewed-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20170902200711.29298-1-linus.walleij@linaro.org

drivers/gpu/drm/tve200/Kconfig

@@ -4,7 +4,8 @@ config DRM_TVE200
 	depends on CMA
 	depends on ARM || COMPILE_TEST
 	depends on OF
-	select DRM_PANEL
+	select DRM_BRIDGE
+	select DRM_PANEL_BRIDGE
 	select DRM_KMS_HELPER
 	select DRM_KMS_CMA_HELPER
 	select DRM_GEM_CMA_HELPER

drivers/gpu/drm/tve200/Makefile

-tve200_drm-y +=	tve200_connector.o \
-		tve200_display.o \
+tve200_drm-y +=	tve200_display.o \
 		tve200_drv.o
 
 obj-$(CONFIG_DRM_TVE200) += tve200_drm.o

drivers/gpu/drm/tve200/tve200_connector.c

-/*
- * Copyright (C) 2017 Linus Walleij <linus.walleij@linaro.org>
- * Parts of this file were based on sources as follows:
- *
- * Copyright (C) 2006-2008 Intel Corporation
- * Copyright (C) 2007 Amos Lee <amos_lee@storlinksemi.com>
- * Copyright (C) 2007 Dave Airlie <airlied@linux.ie>
- * Copyright (C) 2011 Texas Instruments
- * Copyright (C) 2017 Eric Anholt
- *
- * This program is free software and is provided to you under the terms of the
- * GNU General Public License version 2 as published by the Free Software
- * Foundation, and any use by you of this program is subject to the terms of
- * such GNU licence.
- */
-
-/**
- * tve200_drm_connector.c
- * Implementation of the connector functions for the Faraday TV Encoder
- */
-#include <linux/version.h>
-#include <linux/shmem_fs.h>
-#include <linux/dma-buf.h>
-
-#include <drm/drmP.h>
-#include <drm/drm_atomic_helper.h>
-#include <drm/drm_crtc_helper.h>
-#include <drm/drm_of.h>
-#include <drm/drm_panel.h>
-
-#include "tve200_drm.h"
-
-static void tve200_connector_destroy(struct drm_connector *connector)
-{
-	struct tve200_drm_connector *tve200con =
-		to_tve200_connector(connector);
-
-	if (tve200con->panel)
-		drm_panel_detach(tve200con->panel);
-
-	drm_connector_unregister(connector);
-	drm_connector_cleanup(connector);
-}
-
-static enum drm_connector_status tve200_connector_detect(struct drm_connector
-							*connector, bool force)
-{
-	struct tve200_drm_connector *tve200con =
-		to_tve200_connector(connector);
-
-	return (tve200con->panel ?
-		connector_status_connected :
-		connector_status_disconnected);
-}
-
-static int tve200_connector_helper_get_modes(struct drm_connector *connector)
-{
-	struct tve200_drm_connector *tve200con =
-		to_tve200_connector(connector);
-
-	if (!tve200con->panel)
-		return 0;
-
-	return drm_panel_get_modes(tve200con->panel);
-}
-
-static const struct drm_connector_funcs connector_funcs = {
-	.fill_modes = drm_helper_probe_single_connector_modes,
-	.destroy = tve200_connector_destroy,
-	.detect = tve200_connector_detect,
-	.reset = drm_atomic_helper_connector_reset,
-	.atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state,
-	.atomic_destroy_state = drm_atomic_helper_connector_destroy_state,
-};
-
-static const struct drm_connector_helper_funcs connector_helper_funcs = {
-	.get_modes = tve200_connector_helper_get_modes,
-};
-
-/*
- * Walks the OF graph to find the panel node and then asks DRM to look
- * up the panel.
- */
-static struct drm_panel *tve200_get_panel(struct device *dev)
-{
-	struct device_node *endpoint, *panel_node;
-	struct device_node *np = dev->of_node;
-	struct drm_panel *panel;
-
-	endpoint = of_graph_get_next_endpoint(np, NULL);
-	if (!endpoint) {
-		dev_err(dev, "no endpoint to fetch panel\n");
-		return NULL;
-	}
-
-	/* Don't proceed if we have an endpoint but no panel_node tied to it */
-	panel_node = of_graph_get_remote_port_parent(endpoint);
-	of_node_put(endpoint);
-	if (!panel_node) {
-		dev_err(dev, "no valid panel node\n");
-		return NULL;
-	}
-
-	panel = of_drm_find_panel(panel_node);
-	of_node_put(panel_node);
-
-	return panel;
-}
-
-int tve200_connector_init(struct drm_device *dev)
-{
-	struct tve200_drm_dev_private *priv = dev->dev_private;
-	struct tve200_drm_connector *tve200con = &priv->connector;
-	struct drm_connector *connector = &tve200con->connector;
-
-	drm_connector_init(dev, connector, &connector_funcs,
-			   DRM_MODE_CONNECTOR_DPI);
-	drm_connector_helper_add(connector, &connector_helper_funcs);
-
-	tve200con->panel = tve200_get_panel(dev->dev);
-	if (tve200con->panel)
-		drm_panel_attach(tve200con->panel, connector);
-
-	return 0;
-}

drivers/gpu/drm/tve200/tve200_display.c

@@ -127,7 +127,7 @@ static void tve200_display_enable(struct drm_simple_display_pipe *pipe,
 	struct tve200_drm_dev_private *priv = drm->dev_private;
 	const struct drm_display_mode *mode = &cstate->mode;
 	struct drm_framebuffer *fb = plane->state->fb;
-	struct drm_connector *connector = &priv->connector.connector;
+	struct drm_connector *connector = priv->connector;
 	u32 format = fb->format->format;
 	u32 ctrl1 = 0;
 
@@ -215,13 +215,9 @@ static void tve200_display_enable(struct drm_simple_display_pipe *pipe,
 
 	ctrl1 |= TVE200_TVEEN;
 
-	drm_panel_prepare(priv->connector.panel);
-
 	/* Turn it on */
 	writel(ctrl1, priv->regs + TVE200_CTRL);
 
-	drm_panel_enable(priv->connector.panel);
-
 	drm_crtc_vblank_on(crtc);
 }
 
@@ -233,13 +229,9 @@ void tve200_display_disable(struct drm_simple_display_pipe *pipe)
 
 	drm_crtc_vblank_off(crtc);
 
-	drm_panel_disable(priv->connector.panel);
-
 	/* Disable and Power Down */
 	writel(0, priv->regs + TVE200_CTRL);
 
-	drm_panel_unprepare(priv->connector.panel);
-
 	clk_disable_unprepare(priv->clk);
 }
 
@@ -337,9 +329,12 @@ int tve200_display_init(struct drm_device *drm)
 					   &tve200_display_funcs,
 					   formats, ARRAY_SIZE(formats),
 					   NULL,
-					   &priv->connector.connector);
+					   priv->connector);
 	if (ret)
 		return ret;
 
+	/* We need the encoder to attach the bridge */
+	priv->encoder = &priv->pipe.encoder;
+
 	return 0;
 }

drivers/gpu/drm/tve200/tve200_drm.h

@@ -96,15 +96,13 @@
 #include <drm/drm_gem.h>
 #include <drm/drm_simple_kms_helper.h>
 
-struct tve200_drm_connector {
-	struct drm_connector connector;
-	struct drm_panel *panel;
-};
-
 struct tve200_drm_dev_private {
 	struct drm_device *drm;
 
-	struct tve200_drm_connector connector;
+	struct drm_connector *connector;
+	struct drm_encoder *encoder;
+	struct drm_panel *panel;
+	struct drm_bridge *bridge;
 	struct drm_simple_display_pipe pipe;
 	struct drm_fbdev_cma *fbdev;
 

drivers/gpu/drm/tve200/tve200_drv.c

@@ -47,6 +47,8 @@
 #include <drm/drm_gem_cma_helper.h>
 #include <drm/drm_fb_cma_helper.h>
 #include <drm/drm_panel.h>
+#include <drm/drm_of.h>
+#include <drm/drm_bridge.h>
 
 #include "tve200_drm.h"
 
@@ -62,6 +64,8 @@ static int tve200_modeset_init(struct drm_device *dev)
 {
 	struct drm_mode_config *mode_config;
 	struct tve200_drm_dev_private *priv = dev->dev_private;
+	struct drm_panel *panel;
+	struct drm_bridge *bridge;
 	int ret = 0;
 
 	drm_mode_config_init(dev);
@@ -72,35 +76,51 @@ static int tve200_modeset_init(struct drm_device *dev)
 	mode_config->min_height = 240;
 	mode_config->max_height = 576;
 
-	ret = tve200_connector_init(dev);
+	ret = drm_of_find_panel_or_bridge(dev->dev->of_node,
+					  0, 0, &panel, &bridge);
+	if (ret && ret != -ENODEV)
+		return ret;
+	if (panel) {
+		bridge = drm_panel_bridge_add(panel,
+					      DRM_MODE_CONNECTOR_Unknown);
+		if (IS_ERR(bridge)) {
+			ret = PTR_ERR(bridge);
+			goto out_bridge;
+		}
+	}
+
+	ret = tve200_display_init(dev);
 	if (ret) {
-		dev_err(dev->dev, "Failed to create tve200_drm_connector\n");
-		goto out_config;
+		dev_err(dev->dev, "failed to init display\n");
+		goto out_bridge;
+	}
+
+	if (bridge) {
+		ret = drm_bridge_attach(priv->encoder, bridge, NULL);
+		if (ret)
+			goto out_bridge;
 	}
 
 	/*
-	 * Don't actually attach if we didn't find a drm_panel
-	 * attached to us.
+	 * TODO: when we are using a different bridge than a panel
+	 * (such as a dumb VGA connector) we need to devise a different
+	 * method to get the connector out of the bridge.
 	 */
-	if (!priv->connector.panel) {
-		dev_info(dev->dev,
-			 "deferring due to lack of DRM panel device\n");
-		ret = -EPROBE_DEFER;
-		goto out_config;
+	if (!panel) {
+		dev_err(dev->dev, "the bridge is not a panel\n");
+		goto out_bridge;
 	}
-	dev_info(dev->dev, "attached to panel %s\n",
-		 dev_name(priv->connector.panel->dev));
+	priv->panel = panel;
+	priv->connector = panel->connector;
+	priv->bridge = bridge;
 
-	ret = tve200_display_init(dev);
-	if (ret) {
-		dev_err(dev->dev, "failed to init display\n");
-		goto out_config;
-	}
+	dev_info(dev->dev, "attached to panel %s\n",
+		 dev_name(panel->dev));
 
 	ret = drm_vblank_init(dev, 1);
 	if (ret) {
 		dev_err(dev->dev, "failed to init vblank\n");
-		goto out_config;
+		goto out_bridge;
 	}
 
 	drm_mode_config_reset(dev);
@@ -115,7 +135,11 @@ static int tve200_modeset_init(struct drm_device *dev)
 
 	goto finish;
 
-out_config:
+out_bridge:
+	if (panel)
+		drm_panel_bridge_remove(bridge);
+	else
+		drm_bridge_remove(bridge);
 	drm_mode_config_cleanup(dev);
 finish:
 	return ret;
@@ -249,6 +273,10 @@ static int tve200_remove(struct platform_device *pdev)
 	drm_dev_unregister(drm);
 	if (priv->fbdev)
 		drm_fbdev_cma_fini(priv->fbdev);
+	if (priv->panel)
+		drm_panel_bridge_remove(priv->bridge);
+	else
+		drm_bridge_remove(priv->bridge);
 	drm_mode_config_cleanup(drm);
 	clk_disable_unprepare(priv->pclk);
 	drm_dev_unref(drm);