Hi Stefan, Thank you for the patch.
On Wed, Sep 30, 2020 at 12:51:33PM +0200, Stefan Riedmueller wrote: > From: Dirk Bender <[email protected]> > > To prevent corrupted frames after starting and stopping the sensor it's s/it's/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 <[email protected]> > Signed-off-by: Stefan Riedmueller <[email protected]> > --- > No changes in v2 > --- > drivers/media/i2c/mt9p031.c | 25 +++++++++++++++++++++++++ > 1 file changed, 25 insertions(+) > > diff --git a/drivers/media/i2c/mt9p031.c b/drivers/media/i2c/mt9p031.c > index d10457361e6c..d59f66e3dcf3 100644 > --- a/drivers/media/i2c/mt9p031.c > +++ b/drivers/media/i2c/mt9p031.c > @@ -80,6 +80,8 @@ > #define MT9P031_PIXEL_CLOCK_SHIFT(n) ((n) << 8) > #define MT9P031_PIXEL_CLOCK_DIVIDE(n) ((n) << 0) > #define MT9P031_FRAME_RESTART 0x0b > +#define MT9P031_FRAME_RESTART_SET (1 << 0) > +#define MT9P031_FRAME_PAUSE_RESTART_SET (1 << 1) The fields are named Restart and Pause_Restart, I would drop _SET. Could you also sort them from MSB to LSB as for the other registers ? Using BIT() would be good too, although this could be done as an additional patch to convert all the existing macros. > #define MT9P031_SHUTTER_DELAY 0x0c > #define MT9P031_RST 0x0d > #define MT9P031_RST_ENABLE 1 > @@ -483,9 +485,25 @@ 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) { > + val = mt9p031_read(client, MT9P031_FRAME_RESTART); Do you need to read the register ? Can't you write MT9P031_FRAME_PAUSE_RESTART_SET and then MT9P031_FRAME_PAUSE_RESTART_SET | MT9P031_FRAME_RESTART_SET ? And actually, can't we just write both bits in one go, do we need two writes ? > + > + /* enable pause restart */ > + val |= MT9P031_FRAME_PAUSE_RESTART_SET; > + ret = mt9p031_write(client, MT9P031_FRAME_RESTART, val); > + if (ret < 0) > + return ret; > + > + /* enable restart + keep pause restart set */ > + val |= MT9P031_FRAME_RESTART_SET; > + ret = mt9p031_write(client, MT9P031_FRAME_RESTART, val); > + if (ret < 0) > + return ret; > + > /* Stop sensor readout */ > ret = mt9p031_set_output_control(mt9p031, > MT9P031_OUTPUT_CONTROL_CEN, 0); > @@ -505,6 +523,13 @@ static int mt9p031_s_stream(struct v4l2_subdev *subdev, > int enable) > if (ret < 0) > return ret; > > + val = mt9p031_read(client, MT9P031_FRAME_RESTART); > + /* disable reset + pause restart */ > + val &= ~MT9P031_FRAME_PAUSE_RESTART_SET; Same here, I think you can simply write MT9P031_FRAME_PAUSE_RESTART_SET. > + ret = mt9p031_write(client, MT9P031_FRAME_RESTART, val); > + if (ret < 0) > + return ret; > + > return mt9p031_pll_enable(mt9p031); > } > -- Regards, Laurent Pinchart
