linux-kernel - [PATCH v2 7/9] drm/bridge: dpc3433: Don't log an error when DSI host can't be found

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Message-Id: <20240229-anx7625-defer-log-no-dsi-host-v2-7-00506941049a@collabora.com>
Date: Thu, 29 Feb 2024 19:12:13 -0500
From: Nícolas F. R. A. Prado <nfraprado@...labora.com>
To: Andrzej Hajda <andrzej.hajda@...el.com>, 
 Neil Armstrong <neil.armstrong@...aro.org>, Robert Foss <rfoss@...nel.org>, 
 Laurent Pinchart <Laurent.pinchart@...asonboard.com>, 
 Jonas Karlman <jonas@...boo.se>, Jernej Skrabec <jernej.skrabec@...il.com>, 
 Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>, 
 Maxime Ripard <mripard@...nel.org>, Thomas Zimmermann <tzimmermann@...e.de>, 
 David Airlie <airlied@...il.com>, Daniel Vetter <daniel@...ll.ch>, 
 owen <qwt9588@...il.com>, Jagan Teki <jagan@...rulasolutions.com>, 
 Marek Vasut <marex@...x.de>, Adrien Grassein <adrien.grassein@...il.com>, 
 Srinivas Kandagatla <srinivas.kandagatla@...aro.org>, 
 Sam Ravnborg <sam@...nborg.org>, Bjorn Andersson <andersson@...nel.org>, 
 Vinod Koul <vkoul@...nel.org>, 
 Dmitry Baryshkov <dmitry.baryshkov@...aro.org>, 
 Vinay Simha BN <simhavcs@...il.com>, 
 Christopher Vollo <chris@...ewoutreach.org>, 
 Jessica Zhang <quic_jesszhan@...cinc.com>, 
 Marijn Suijten <marijn.suijten@...ainline.org>, 
 AngeloGioacchino Del Regno <angelogioacchino.delregno@...ainline.org>
Cc: kernel@...labora.com, dri-devel@...ts.freedesktop.org, 
 linux-kernel@...r.kernel.org, 
 AngeloGioacchino Del Regno <angelogioacchino.delregno@...labora.com>, 
 Nícolas F. R. A. Prado <nfraprado@...labora.com>
Subject: [PATCH v2 7/9] drm/bridge: dpc3433: Don't log an error when DSI
 host can't be found

Given that failing to find a DSI host causes the driver to defer probe,
make use of dev_err_probe() to log the reason. This makes the defer
probe reason available and avoids alerting userspace about something
that is not necessarily an error.

Also move the "failed to attach" error message so that it's only printed
when the devm_mipi_dsi_attach() call fails.

Fixes: 6352cd451ddb ("drm: bridge: Add TI DLPC3433 DSI to DMD bridge")
Suggested-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@...labora.com>
Signed-off-by: Nícolas F. R. A. Prado <nfraprado@...labora.com>
---
 drivers/gpu/drm/bridge/ti-dlpc3433.c | 17 +++++++++--------
 1 file changed, 9 insertions(+), 8 deletions(-)

diff --git a/drivers/gpu/drm/bridge/ti-dlpc3433.c b/drivers/gpu/drm/bridge/ti-dlpc3433.c
index ca3348109bcd..6b559e071301 100644
--- a/drivers/gpu/drm/bridge/ti-dlpc3433.c
+++ b/drivers/gpu/drm/bridge/ti-dlpc3433.c
@@ -319,12 +319,11 @@ static int dlpc_host_attach(struct dlpc *dlpc)
 		.channel = 0,
 		.node = NULL,
 	};
+	int ret;

 	host = of_find_mipi_dsi_host_by_node(dlpc->host_node);
-	if (!host) {
-		DRM_DEV_ERROR(dev, "failed to find dsi host\n");
-		return -EPROBE_DEFER;
-	}
+	if (!host)
+		return dev_err_probe(dev, -EPROBE_DEFER, "failed to find dsi host\n");

 	dlpc->dsi = mipi_dsi_device_register_full(host, &info);
 	if (IS_ERR(dlpc->dsi)) {
@@ -336,7 +335,11 @@ static int dlpc_host_attach(struct dlpc *dlpc)
 	dlpc->dsi->format = MIPI_DSI_FMT_RGB565;
 	dlpc->dsi->lanes = dlpc->dsi_lanes;

-	return devm_mipi_dsi_attach(dev, dlpc->dsi);
+	ret = devm_mipi_dsi_attach(dev, dlpc->dsi);
+	if (ret)
+		DRM_DEV_ERROR(dev, "failed to attach dsi host\n");
+
+	return ret;
 }

 static int dlpc3433_probe(struct i2c_client *client)
@@ -367,10 +370,8 @@ static int dlpc3433_probe(struct i2c_client *client)
 	drm_bridge_add(&dlpc->bridge);

 	ret = dlpc_host_attach(dlpc);
-	if (ret) {
-		DRM_DEV_ERROR(dev, "failed to attach dsi host\n");
+	if (ret)
 		goto err_remove_bridge;
-	}

 	return 0;

-- 
2.44.0