diff options
| author | Dirk Bender <d.bender@phytec.de> | 2021-07-26 10:35:15 +0300 |
|---|---|---|
| committer | Mauro Carvalho Chehab <mchehab+huawei@kernel.org> | 2021-09-30 11:07:35 +0300 |
| commit | 0961ba6dd211a4a52d1dd4c2d59be60ac2dc08c7 (patch) | |
| tree | b4c91a87196c901f5e86a6756db40c0c863f1fa9 | |
| parent | ae47ee5fc4703bb55278c4185f76c81f980f91eb (diff) | |
| download | linux-0961ba6dd211a4a52d1dd4c2d59be60ac2dc08c7.tar.xz | |
media: mt9p031: Fix corrupted frame after restarting stream
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>
| -rw-r--r-- | drivers/media/i2c/mt9p031.c | 28 |
1 files changed, 27 insertions, 1 deletions
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); } |