Patch "media: cadence: csi2rx: configure DPHY before starting source stream" has been added to the 6.8-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    media: cadence: csi2rx: configure DPHY before starting source stream

to the 6.8-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     media-cadence-csi2rx-configure-dphy-before-starting-.patch
and it can be found in the queue-6.8 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit bdfaf9e93149bf1e773431323d573edd4e440bb5
Author: Pratyush Yadav <p.yadav@xxxxxx>
Date:   Fri Feb 23 13:53:01 2024 +0530

    media: cadence: csi2rx: configure DPHY before starting source stream
    
    [ Upstream commit fd64dda48f7e3f67ada1e1fe47e784ab350da72e ]
    
    When the source device is operating above 1.5 Gbps per lane, it needs to
    send the Skew Calibration Sequence before sending any HS data. If the
    DPHY is initialized after the source stream is started, then it might
    miss the sequence and not be able to receive data properly. Move the
    start of source subdev to the end of the sequence to make sure
    everything is ready to receive data before the source starts streaming.
    
    Signed-off-by: Pratyush Yadav <p.yadav@xxxxxx>
    Fixes: 3295cf1241d3 ("media: cadence: Add support for external dphy")
    Tested-by: Julien Massot <julien.massot@xxxxxxxxxxxxx>
    Tested-by: Changhuang Liang <Changhuang.liang@xxxxxxxxxxxxxxxx>
    Reviewed-by: Julien Massot <julien.massot@xxxxxxxxxxxxx>
    Reviewed-by: Changhuang Liang <Changhuang.liang@xxxxxxxxxxxxxxxx>
    Signed-off-by: Jai Luthra <j-luthra@xxxxxx>
    Signed-off-by: Sakari Ailus <sakari.ailus@xxxxxxxxxxxxxxx>
    Signed-off-by: Hans Verkuil <hverkuil-cisco@xxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/drivers/media/platform/cadence/cdns-csi2rx.c b/drivers/media/platform/cadence/cdns-csi2rx.c
index 0ea5fa956fe9a..5be75bd4add39 100644
--- a/drivers/media/platform/cadence/cdns-csi2rx.c
+++ b/drivers/media/platform/cadence/cdns-csi2rx.c
@@ -235,10 +235,6 @@ static int csi2rx_start(struct csi2rx_priv *csi2rx)
 
 	writel(reg, csi2rx->base + CSI2RX_STATIC_CFG_REG);
 
-	ret = v4l2_subdev_call(csi2rx->source_subdev, video, s_stream, true);
-	if (ret)
-		goto err_disable_pclk;
-
 	/* Enable DPHY clk and data lanes. */
 	if (csi2rx->dphy) {
 		reg = CSI2RX_DPHY_CL_EN | CSI2RX_DPHY_CL_RST;
@@ -248,6 +244,13 @@ static int csi2rx_start(struct csi2rx_priv *csi2rx)
 		}
 
 		writel(reg, csi2rx->base + CSI2RX_DPHY_LANE_CTRL_REG);
+
+		ret = csi2rx_configure_ext_dphy(csi2rx);
+		if (ret) {
+			dev_err(csi2rx->dev,
+				"Failed to configure external DPHY: %d\n", ret);
+			goto err_disable_pclk;
+		}
 	}
 
 	/*
@@ -287,14 +290,9 @@ static int csi2rx_start(struct csi2rx_priv *csi2rx)
 
 	reset_control_deassert(csi2rx->sys_rst);
 
-	if (csi2rx->dphy) {
-		ret = csi2rx_configure_ext_dphy(csi2rx);
-		if (ret) {
-			dev_err(csi2rx->dev,
-				"Failed to configure external DPHY: %d\n", ret);
-			goto err_disable_sysclk;
-		}
-	}
+	ret = v4l2_subdev_call(csi2rx->source_subdev, video, s_stream, true);
+	if (ret)
+		goto err_disable_sysclk;
 
 	clk_disable_unprepare(csi2rx->p_clk);
 
@@ -308,6 +306,10 @@ static int csi2rx_start(struct csi2rx_priv *csi2rx)
 		clk_disable_unprepare(csi2rx->pixel_clk[i - 1]);
 	}
 
+	if (csi2rx->dphy) {
+		writel(0, csi2rx->base + CSI2RX_DPHY_LANE_CTRL_REG);
+		phy_power_off(csi2rx->dphy);
+	}
 err_disable_pclk:
 	clk_disable_unprepare(csi2rx->p_clk);