linux-kernel - [PATCH 2/3] rcar-csi2: Do not try to recover after transfer error

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Message-ID: <1652983210-1194-3-git-send-email-mrodin@de.adit-jv.com>
Date:   Thu, 19 May 2022 20:00:08 +0200
From:   Michael Rodin <mrodin@...adit-jv.com>
To:     Mauro Carvalho Chehab <mchehab@...nel.org>,
        Niklas Söderlund <niklas.soderlund@...natech.se>,
        <linux-media@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        <linux-renesas-soc@...r.kernel.org>
CC:     Michael Rodin <mrodin@...adit-jv.com>, <michael@...in.online>,
        <erosca@...adit-jv.com>,
        Niklas Söderlund 
        <niklas.soderlund+renesas@...natech.se>
Subject: [PATCH 2/3] rcar-csi2: Do not try to recover after transfer error

From: Niklas Söderlund <niklas.soderlund+renesas@...natech.se>

Instead of restarting the R-Car CSI-2 receiver if a transmission error
is detected, inform the R-Car VIN driver of the error so it can stop the
whole pipeline and inform user-space. This is done to reflect a updated
usage recommendation in later versions of the datasheet.

Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@...natech.se>
Reviewed-by: Jacopo Mondi <jacopo+renesas@...ndi.org>
---
 drivers/media/platform/renesas/rcar-vin/rcar-csi2.c | 17 +++++++++--------
 1 file changed, 9 insertions(+), 8 deletions(-)

diff --git a/drivers/media/platform/renesas/rcar-vin/rcar-csi2.c b/drivers/media/platform/renesas/rcar-vin/rcar-csi2.c
index fea8f00..5a64941 100644
--- a/drivers/media/platform/renesas/rcar-vin/rcar-csi2.c
+++ b/drivers/media/platform/renesas/rcar-vin/rcar-csi2.c
@@ -943,21 +943,22 @@ static irqreturn_t rcsi2_irq(int irq, void *data)
 
 	rcsi2_write(priv, INTERRSTATE_REG, err_status);
 
-	dev_info(priv->dev, "Transfer error, restarting CSI-2 receiver\n");
-
 	return IRQ_WAKE_THREAD;
 }
 
 static irqreturn_t rcsi2_irq_thread(int irq, void *data)
 {
 	struct rcar_csi2 *priv = data;
+	struct v4l2_event event = {
+		.type = V4L2_EVENT_XFER_ERROR,
+	};
 
-	mutex_lock(&priv->lock);
-	rcsi2_stop(priv);
-	usleep_range(1000, 2000);
-	if (rcsi2_start(priv))
-		dev_warn(priv->dev, "Failed to restart CSI-2 receiver\n");
-	mutex_unlock(&priv->lock);
+	/* Disable further interrupts to not spam the transfer error event. */
+	rcsi2_write(priv, INTEN_REG, 0);
+
+	dev_err(priv->dev, "Transfer error detected.\n");
+
+	v4l2_subdev_notify_event(&priv->subdev, &event);
 
 	return IRQ_HANDLED;
 }
-- 
2.7.4