From 2a1061af333ef2d62972cf33d5880e9b18a1cc8b Mon Sep 17 00:00:00 2001
From: Dirk Bender <d.bender@phytec.de>
Date: Mon, 26 Jul 2021 09:35:15 +0200
Subject: [PATCH] media: mt9p031: Fix corrupted frame after restarting stream
Git-commit: 0961ba6dd211a4a52d1dd4c2d59be60ac2dc08c7
Patch-mainline: v5.16-rc1
References: stable-5.14.19
[ Upstream commit 0961ba6dd211a4a52d1dd4c2d59be60ac2dc08c7 ]
To prevent corrupted frames after starting and stopping the sensor its
datasheet specifies a specific pause sequence to follow:
Stopping: Set Pause_Restart Bit -> Set Restart Bit -> Set Chip_Enable Off
Restarting: Set Chip_Enable On -> Clear Pause_Restart Bit
The Restart Bit is cleared automatically and must not be cleared
manually as this would cause undefined behavior.
Signed-off-by: Dirk Bender <d.bender@phytec.de>
Signed-off-by: Stefan Riedmueller <s.riedmueller@phytec.de>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Acked-by: Takashi Iwai <tiwai@suse.de>
---
drivers/media/i2c/mt9p031.c | 28 +++++++++++++++++++++++++++-
1 file changed, 27 insertions(+), 1 deletion(-)
diff --git a/drivers/media/i2c/mt9p031.c b/drivers/media/i2c/mt9p031.c
index 6eb88ef99783..3ae1b28c8351 100644
--- a/drivers/media/i2c/mt9p031.c
+++ b/drivers/media/i2c/mt9p031.c
@@ -78,7 +78,9 @@
#define MT9P031_PIXEL_CLOCK_INVERT (1 << 15)
#define MT9P031_PIXEL_CLOCK_SHIFT(n) ((n) << 8)
#define MT9P031_PIXEL_CLOCK_DIVIDE(n) ((n) << 0)
-#define MT9P031_FRAME_RESTART 0x0b
+#define MT9P031_RESTART 0x0b
+#define MT9P031_FRAME_PAUSE_RESTART (1 << 1)
+#define MT9P031_FRAME_RESTART (1 << 0)
#define MT9P031_SHUTTER_DELAY 0x0c
#define MT9P031_RST 0x0d
#define MT9P031_RST_ENABLE 1
@@ -444,9 +446,23 @@ static int mt9p031_set_params(struct mt9p031 *mt9p031)
static int mt9p031_s_stream(struct v4l2_subdev *subdev, int enable)
{
struct mt9p031 *mt9p031 = to_mt9p031(subdev);
+ struct i2c_client *client = v4l2_get_subdevdata(subdev);
+ int val;
int ret;
if (!enable) {
+ /* enable pause restart */
+ val = MT9P031_FRAME_PAUSE_RESTART;
+ ret = mt9p031_write(client, MT9P031_RESTART, val);
+ if (ret < 0)
+ return ret;
+
+ /* enable restart + keep pause restart set */
+ val |= MT9P031_FRAME_RESTART;
+ ret = mt9p031_write(client, MT9P031_RESTART, val);
+ if (ret < 0)
+ return ret;
+
/* Stop sensor readout */
ret = mt9p031_set_output_control(mt9p031,
MT9P031_OUTPUT_CONTROL_CEN, 0);
@@ -466,6 +482,16 @@ static int mt9p031_s_stream(struct v4l2_subdev *subdev, int enable)
if (ret < 0)
return ret;
+ /*
+ * - clear pause restart
+ * - don't clear restart as clearing restart manually can cause
+ * undefined behavior
+ */
+ val = MT9P031_FRAME_RESTART;
+ ret = mt9p031_write(client, MT9P031_RESTART, val);
+ if (ret < 0)
+ return ret;
+
return mt9p031_pll_enable(mt9p031);
}
--
2.26.2