linux-kernel - [PATCH v3] drm/bridge: sn65dsi86: defer if there is no dsi host

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Message-Id: <20211207215753.635841-1-robdclark@gmail.com>
Date:   Tue,  7 Dec 2021 13:57:52 -0800
From:   Rob Clark <robdclark@...il.com>
To:     dri-devel@...ts.freedesktop.org
Cc:     linux-arm-msm@...r.kernel.org, Maxime Ripard <maxime@...no.tech>,
        Douglas Anderson <dianders@...omium.org>,
        Stephen Boyd <swboyd@...omium.org>,
        Jernej Škrabec <jernej.skrabec@...il.com>,
        Rob Clark <robdclark@...omium.org>,
        Andrzej Hajda <a.hajda@...sung.com>,
        Neil Armstrong <narmstrong@...libre.com>,
        Robert Foss <robert.foss@...aro.org>,
        Laurent Pinchart <Laurent.pinchart@...asonboard.com>,
        Jonas Karlman <jonas@...boo.se>,
        David Airlie <airlied@...ux.ie>,
        Daniel Vetter <daniel@...ll.ch>,
        Sam Ravnborg <sam@...nborg.org>,
        linux-kernel@...r.kernel.org (open list)
Subject: [PATCH v3] drm/bridge: sn65dsi86: defer if there is no dsi host

From: Rob Clark <robdclark@...omium.org>

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@...omium.org>
Reviewed-by: Doug Anderson <dianders@...omium.org>
---
v2: Drop DRM_ERROR() in favor of drm_err_probe() and shift around the
    spot where we report the error
v3: Add \n and cull error msgs a bit further

 drivers/gpu/drm/bridge/ti-sn65dsi86.c | 18 +++++++-----------
 1 file changed, 7 insertions(+), 11 deletions(-)

diff --git a/drivers/gpu/drm/bridge/ti-sn65dsi86.c b/drivers/gpu/drm/bridge/ti-sn65dsi86.c
index 02b490671f8f..c2928a6409b1 100644
--- a/drivers/gpu/drm/bridge/ti-sn65dsi86.c
+++ b/drivers/gpu/drm/bridge/ti-sn65dsi86.c
@@ -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;
@@ -740,10 +736,8 @@ 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");
+	if (ret < 0)
 		return ret;
-	}
 
 	return 0;
 }
@@ -1267,8 +1261,10 @@ 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;
 
-- 
2.33.1