linux-kernel - [PATCH 07/16] media: cadence: csi2rx: Set the STOP bit when stopping a stream

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Date:   Tue, 30 Mar 2021 23:03:39 +0530
From:   Pratyush Yadav <p.yadav@...com>
To:     Mauro Carvalho Chehab <mchehab@...nel.org>,
        Rob Herring <robh+dt@...nel.org>,
        Kishon Vijay Abraham I <kishon@...com>,
        Vinod Koul <vkoul@...nel.org>,
        Peter Ujfalusi <peter.ujfalusi@...il.com>,
        Maxime Ripard <mripard@...nel.org>,
        Benoit Parrot <bparrot@...com>,
        Hans Verkuil <hverkuil-cisco@...all.nl>,
        Alexandre Courbot <acourbot@...omium.org>,
        Laurent Pinchart <laurent.pinchart@...asonboard.com>,
        Stanimir Varbanov <stanimir.varbanov@...aro.org>,
        Helen Koike <helen.koike@...labora.com>,
        Michael Tretter <m.tretter@...gutronix.de>,
        Peter Chen <peter.chen@....com>,
        Chunfeng Yun <chunfeng.yun@...iatek.com>,
        <linux-media@...r.kernel.org>, <devicetree@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>, <linux-phy@...ts.infradead.org>,
        <dmaengine@...r.kernel.org>
CC:     Pratyush Yadav <p.yadav@...com>,
        Vignesh Raghavendra <vigneshr@...com>,
        Tomi Valkeinen <tomi.valkeinen@...asonboard.com>
Subject: [PATCH 07/16] media: cadence: csi2rx: Set the STOP bit when stopping a stream

The stream stop procedure says that the STOP bit should be set when the
stream is to be stopped, and then the ready bit in stream status
register polled to make sure the STOP operation is finished.

Signed-off-by: Pratyush Yadav <p.yadav@...com>
---
 drivers/media/platform/cadence/cdns-csi2rx.c | 18 +++++++++++++++++-
 1 file changed, 17 insertions(+), 1 deletion(-)

diff --git a/drivers/media/platform/cadence/cdns-csi2rx.c b/drivers/media/platform/cadence/cdns-csi2rx.c
index b03d2d2e6762..eca65b157f59 100644
--- a/drivers/media/platform/cadence/cdns-csi2rx.c
+++ b/drivers/media/platform/cadence/cdns-csi2rx.c
@@ -8,6 +8,7 @@
 #include <linux/clk.h>
 #include <linux/delay.h>
 #include <linux/io.h>
+#include <linux/iopoll.h>
 #include <linux/module.h>
 #include <linux/of.h>
 #include <linux/of_graph.h>
@@ -40,8 +41,12 @@
 
 #define CSI2RX_STREAM_CTRL_REG(n)		(CSI2RX_STREAM_BASE(n) + 0x000)
 #define CSI2RX_STREAM_CTRL_SOFT_RST			BIT(4)
+#define CSI2RX_STREAM_CTRL_STOP				BIT(1)
 #define CSI2RX_STREAM_CTRL_START			BIT(0)
 
+#define CSI2RX_STREAM_STATUS_REG(n)		(CSI2RX_STREAM_BASE(n) + 0x004)
+#define CSI2RX_STREAM_STATUS_RDY			BIT(31)
+
 #define CSI2RX_STREAM_DATA_CFG_REG(n)		(CSI2RX_STREAM_BASE(n) + 0x008)
 #define CSI2RX_STREAM_DATA_CFG_EN_VC_SELECT		BIT(31)
 #define CSI2RX_STREAM_DATA_CFG_VC_SELECT(n)		BIT((n) + 16)
@@ -325,12 +330,23 @@ static int csi2rx_start(struct csi2rx_priv *csi2rx)
 static void csi2rx_stop(struct csi2rx_priv *csi2rx)
 {
 	unsigned int i;
+	u32 val;
+	int ret;
 
 	clk_prepare_enable(csi2rx->p_clk);
 	clk_disable_unprepare(csi2rx->sys_clk);
 
 	for (i = 0; i < csi2rx->max_streams; i++) {
-		writel(0, csi2rx->base + CSI2RX_STREAM_CTRL_REG(i));
+		writel(CSI2RX_STREAM_CTRL_STOP,
+		       csi2rx->base + CSI2RX_STREAM_CTRL_REG(i));
+
+		ret = readl_relaxed_poll_timeout(csi2rx->base +
+						 CSI2RX_STREAM_STATUS_REG(i),
+						 val,
+						 (val & CSI2RX_STREAM_STATUS_RDY),
+						 10, 10000);
+		if (ret)
+			dev_warn(csi2rx->dev, "Failed to stop stream%d\n", i);
 
 		clk_disable_unprepare(csi2rx->pixel_clk[i]);
 	}
-- 
2.30.0