From 13712a710f9e329b0e50f7b860ffb00642eec15b Mon Sep 17 00:00:00 2001
From: Rob Clark <robdclark@chromium.org>
Date: Tue, 7 Dec 2021 13:57:52 -0800
Subject: drm/bridge: sn65dsi86: defer if there is no dsi host
Git-commit: 03848335b5b1faa4a4641fcf30b7c233579a45aa
Patch-mainline: v5.17-rc1
References: jsc#PED-1166 jsc#PED-1168 jsc#PED-1170 jsc#PED-1218 jsc#PED-1220 jsc#PED-1222 jsc#PED-1223 jsc#PED-1225

Otherwise we don't get another shot at it if the bridge probes before
the dsi host is registered.  It seems like this is what *most* (but not
all) of the other bridges do.

It looks like this was missed in the conversion to attach dsi host at
probe time.

Fixes: c3b75d4734cb ("drm/bridge: sn65dsi86: Register and attach our DSI device at probe")
Signed-off-by: Rob Clark <robdclark@chromium.org>
Reviewed-by: Doug Anderson <dianders@chromium.org>
Tested-by: Doug Anderson <dianders@chromium.org>
Reviewed-by: Stephen Boyd <swboyd@chromium.org>
[dianders: squashed in Stephen's simplification]
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20211207215753.635841-1-robdclark@gmail.com
Acked-by: Patrik Jakobsson <pjakobsson@suse.de>
---
 drivers/gpu/drm/bridge/ti-sn65dsi86.c | 24 ++++++++----------------
 1 file changed, 8 insertions(+), 16 deletions(-)

diff --git a/drivers/gpu/drm/bridge/ti-sn65dsi86.c b/drivers/gpu/drm/bridge/ti-sn65dsi86.c
index 02b490671f8f..c9452eec968b 100644
--- a/drivers/gpu/drm/bridge/ti-sn65dsi86.c
+++ b/drivers/gpu/drm/bridge/ti-sn65dsi86.c
@@ -704,7 +704,7 @@ static struct ti_sn65dsi86 *bridge_to_ti_sn65dsi86(struct drm_bridge *bridge)
 
 static int ti_sn_attach_host(struct ti_sn65dsi86 *pdata)
 {
-	int ret, val;
+	int val;
 	struct mipi_dsi_host *host;
 	struct mipi_dsi_device *dsi;
 	struct device *dev = pdata->dev;
@@ -714,16 +714,12 @@ static int ti_sn_attach_host(struct ti_sn65dsi86 *pdata)
 	};
 
 	host = of_find_mipi_dsi_host_by_node(pdata->host_node);
-	if (!host) {
-		DRM_ERROR("failed to find dsi host\n");
-		return -ENODEV;
-	}
+	if (!host)
+		return -EPROBE_DEFER;
 
 	dsi = devm_mipi_dsi_device_register_full(dev, host, &info);
-	if (IS_ERR(dsi)) {
-		DRM_ERROR("failed to create dsi device\n");
+	if (IS_ERR(dsi))
 		return PTR_ERR(dsi);
-	}
 
 	/* TODO: setting to 4 MIPI lanes always for now */
 	dsi->lanes = 4;
@@ -739,13 +735,7 @@ static int ti_sn_attach_host(struct ti_sn65dsi86 *pdata)
 
 	pdata->dsi = dsi;
 
-	ret = devm_mipi_dsi_attach(dev, dsi);
-	if (ret < 0) {
-		DRM_ERROR("failed to attach dsi to host\n");
-		return ret;
-	}
-
-	return 0;
+	return devm_mipi_dsi_attach(dev, dsi);
 }
 
 static int ti_sn_bridge_attach(struct drm_bridge *bridge,
@@ -1267,8 +1257,10 @@ static int ti_sn_bridge_probe(struct auxiliary_device *adev,
 	drm_bridge_add(&pdata->bridge);
 
 	ret = ti_sn_attach_host(pdata);
-	if (ret)
+	if (ret) {
+		dev_err_probe(pdata->dev, ret, "failed to attach dsi host\n");
 		goto err_remove_bridge;
+	}
 
 	return 0;
 
-- 
2.38.1