From 4280e1a0ba1dca1e7c4c35d0c790dc8977d840a0 Mon Sep 17 00:00:00 2001
From: Maxime Ripard <maxime@cerno.tech>
Date: Mon, 25 Oct 2021 17:15:35 +0200
Subject: [PATCH] drm/kirin: dsi: Adjust probe order

Without proper care and an agreement between how DSI hosts and devices
drivers register their MIPI-DSI entities and potential components, we can
end up in a situation where the drivers can never probe.

Most drivers were taking evasive maneuvers to try to workaround this,
but not all of them were following the same conventions, resulting in
various incompatibilities between DSI hosts and devices.

Now that we have a sequence agreed upon and documented, let's convert
kirin to it.

Acked-by: John Stultz <john.stultz@linaro.org>
Tested-by: John Stultz <john.stultz@linaro.org>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Link: https://patchwork.freedesktop.org/patch/msgid/20211025151536.1048186-21-maxime@cerno.tech
---
 drivers/gpu/drm/hisilicon/kirin/dw_drm_dsi.c | 52 ++++++++++++++++++----------
 1 file changed, 33 insertions(+), 19 deletions(-)

diff --git a/drivers/gpu/drm/hisilicon/kirin/dw_drm_dsi.c b/drivers/gpu/drm/hisilicon/kirin/dw_drm_dsi.c
index 952cfdb..1d55648 100644
--- a/drivers/gpu/drm/hisilicon/kirin/dw_drm_dsi.c
+++ b/drivers/gpu/drm/hisilicon/kirin/dw_drm_dsi.c
@@ -81,7 +81,7 @@ struct dsi_hw_ctx {
 
 struct dw_dsi {
 	struct drm_encoder encoder;
-	struct drm_bridge *bridge;
+	struct device *dev;
 	struct mipi_dsi_host host;
 	struct drm_display_mode cur_mode;
 	struct dsi_hw_ctx *ctx;
@@ -720,10 +720,13 @@ static int dw_drm_encoder_init(struct device *dev,
 	return 0;
 }
 
+static const struct component_ops dsi_ops;
 static int dsi_host_attach(struct mipi_dsi_host *host,
 			   struct mipi_dsi_device *mdsi)
 {
 	struct dw_dsi *dsi = host_to_dsi(host);
+	struct device *dev = host->dev;
+	int ret;
 
 	if (mdsi->lanes < 1 || mdsi->lanes > 4) {
 		DRM_ERROR("dsi device params invalid\n");
@@ -734,13 +737,20 @@ static int dsi_host_attach(struct mipi_dsi_host *host,
 	dsi->format = mdsi->format;
 	dsi->mode_flags = mdsi->mode_flags;
 
+	ret = component_add(dev, &dsi_ops);
+	if (ret)
+		return ret;
+
 	return 0;
 }
 
 static int dsi_host_detach(struct mipi_dsi_host *host,
 			   struct mipi_dsi_device *mdsi)
 {
-	/* do nothing */
+	struct device *dev = host->dev;
+
+	component_del(dev, &dsi_ops);
+
 	return 0;
 }
 
@@ -768,7 +778,17 @@ static int dsi_host_init(struct device *dev, struct dw_dsi *dsi)
 static int dsi_bridge_init(struct drm_device *dev, struct dw_dsi *dsi)
 {
 	struct drm_encoder *encoder = &dsi->encoder;
-	struct drm_bridge *bridge = dsi->bridge;
+	struct drm_bridge *bridge;
+	struct device_node *np = dsi->dev->of_node;
+	int ret;
+
+	/*
+	 * Get the endpoint node. In our case, dsi has one output port1
+	 * to which the external HDMI bridge is connected.
+	 */
+	ret = drm_of_find_panel_or_bridge(np, 1, 0, NULL, &bridge);
+	if (ret)
+		return ret;
 
 	/* associate the bridge to dsi encoder */
 	return drm_bridge_attach(encoder, bridge, NULL, 0);
@@ -785,10 +805,6 @@ static int dsi_bind(struct device *dev, struct device *master, void *data)
 	if (ret)
 		return ret;
 
-	ret = dsi_host_init(dev, dsi);
-	if (ret)
-		return ret;
-
 	ret = dsi_bridge_init(drm_dev, dsi);
 	if (ret)
 		return ret;
@@ -809,17 +825,7 @@ static const struct component_ops dsi_ops = {
 static int dsi_parse_dt(struct platform_device *pdev, struct dw_dsi *dsi)
 {
 	struct dsi_hw_ctx *ctx = dsi->ctx;
-	struct device_node *np = pdev->dev.of_node;
 	struct resource *res;
-	int ret;
-
-	/*
-	 * Get the endpoint node. In our case, dsi has one output port1
-	 * to which the external HDMI bridge is connected.
-	 */
-	ret = drm_of_find_panel_or_bridge(np, 1, 0, NULL, &dsi->bridge);
-	if (ret)
-		return ret;
 
 	ctx->pclk = devm_clk_get(&pdev->dev, "pclk");
 	if (IS_ERR(ctx->pclk)) {
@@ -852,6 +858,7 @@ static int dsi_probe(struct platform_device *pdev)
 	dsi = &data->dsi;
 	ctx = &data->ctx;
 	dsi->ctx = ctx;
+	dsi->dev = &pdev->dev;
 
 	ret = dsi_parse_dt(pdev, dsi);
 	if (ret)
@@ -859,12 +866,19 @@ static int dsi_probe(struct platform_device *pdev)
 
 	platform_set_drvdata(pdev, data);
 
-	return component_add(&pdev->dev, &dsi_ops);
+	ret = dsi_host_init(&pdev->dev, dsi);
+	if (ret)
+		return ret;
+
+	return 0;
 }
 
 static int dsi_remove(struct platform_device *pdev)
 {
-	component_del(&pdev->dev, &dsi_ops);
+	struct dsi_data *data = platform_get_drvdata(pdev);
+	struct dw_dsi *dsi = &data->dsi;
+
+	mipi_dsi_host_unregister(&dsi->host);
 
 	return 0;
 }
-- 
2.7.4