From: Stefan Riedmueller <s.riedmueller@phytec.de>
To: Laurent Pinchart <laurent.pinchart@ideasonboard.com>,
Mauro Carvalho Chehab <mchehab@kernel.org>,
Rob Herring <robh+dt@kernel.org>
Cc: Dirk Bender <d.bender@phytec.de>,
Stefan Riedmueller <s.riedmueller@phytec.de>,
Sakari Ailus <sakari.ailus@linux.intel.com>,
linux-media@vger.kernel.org, devicetree@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: [PATCH v7 3/6] media: mt9p031: Fix corrupted frame after restarting stream
Date: Mon, 26 Jul 2021 09:35:15 +0200 [thread overview]
Message-ID: <20210726073518.2167398-4-s.riedmueller@phytec.de> (raw)
In-Reply-To: <20210726073518.2167398-1-s.riedmueller@phytec.de>
From: Dirk Bender <d.bender@phytec.de>
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>
---
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 ea90aff576ba..ee2777059682 100644
--- a/drivers/media/i2c/mt9p031.c
+++ b/drivers/media/i2c/mt9p031.c
@@ -79,7 +79,9 @@
#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
@@ -456,9 +458,23 @@ 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);
@@ -478,6 +494,16 @@ 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);
}
--
2.25.1
next prev parent reply other threads:[~2021-07-26 7:35 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-07-26 7:35 [PATCH v7 0/6] media: mt9p031: Read back the real clock rate Stefan Riedmueller
2021-07-26 7:35 ` [PATCH v7 1/6] " Stefan Riedmueller
2021-07-26 7:35 ` [PATCH v7 2/6] media: mt9p031: Make pixel clock polarity configurable by DT Stefan Riedmueller
2021-07-26 7:35 ` Stefan Riedmueller [this message]
2021-07-26 7:35 ` [PATCH v7 4/6] media: mt9p031: Use BIT macro Stefan Riedmueller
2021-07-26 7:35 ` [PATCH v7 5/6] media: dt-bindings: mt9p031: Convert bindings to yaml Stefan Riedmueller
2021-07-26 22:21 ` Rob Herring
2021-07-26 7:35 ` [PATCH v7 6/6] media: dt-bindings: mt9p031: Add missing required properties Stefan Riedmueller
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20210726073518.2167398-4-s.riedmueller@phytec.de \
--to=s.riedmueller@phytec.de \
--cc=d.bender@phytec.de \
--cc=devicetree@vger.kernel.org \
--cc=laurent.pinchart@ideasonboard.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-media@vger.kernel.org \
--cc=mchehab@kernel.org \
--cc=robh+dt@kernel.org \
--cc=sakari.ailus@linux.intel.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).