Re: [PATCH 1/2] media: i2c: ov5640: Enable data pins on startup for DVP mode

From: Laurent Pinchart
Date: Fri Jul 31 2020 - 11:32:04 EST

Hi Prabhakar,

On Fri, Jul 31, 2020 at 02:18:12PM +0100, Lad, Prabhakar wrote:
> On Fri, Jul 31, 2020 at 2:03 PM Sakari Ailus wrote:
> > On Fri, Jul 31, 2020 at 10:24:46AM +0100, Lad Prabhakar wrote:
> > > During testing this sensor on iW-RainboW-G21D-Qseven platform noticed the
> > > capture worked only for first run and for subsequent runs it failed.
> > >
> > > This patch does the following in DVP mode:
> > > 1: Enables data lines on power up
> > > 2: Configures HVP lines on power up instead of configuring everytime on
> > > stream ON/OFF
> > > 3: Disables MIPI interface.
> > > 4: Puts the sensor in power down mode during stream OFF.
> >
> > Could you detail a little the underlying problem, the environment where it
> > can be reproduced and how the patch addresses it, please?
>
> my bad.
>
> > Are you using CSI-2 or the parallel interface, for instance?
>
> while using the sensor in parallel interface mode (DVP) 8-bit mode,
> with rcar-vin bridge noticed the capture worked fine for the first run
> (with yavta), but for subsequent runs the bridge driver waited for the
> frame to be captured. Debugging further noticed the data lines were
> enabled/disabled in stream on/off callback. But enabling the data
> lines in startup (as done in the patch) fixed this issue.

This looks like a hack though. We should disable the outputs somewhere,
if not at stream off time, at least in ov5640_set_power(0). Leaving
everything powered on will increase power consumption.

This issue needs to be debugged further to understand what's going on,
and a proper fix needs to then be submitted.

> Without this patch I can confirm the i2c writes were happening in
> stream on/off callback and the values were updated in the respective
> register to enable/disable datalines. (I didn't find any information
> relating to sequence of enabling the data lines in data sheet [1])
>
> [1] https://cdn.sparkfun.com/datasheets/Sensors/LightImaging/OV5640_datasheet.pdf
>
> > >
> > > Fixes: f22996db44e2d ("media: ov5640: add support of DVP parallel interface")
> > > Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@xxxxxxxxxxxxxx>
> > > Reviewed-by: Biju Das <biju.das.jz@xxxxxxxxxxxxxx>
> > > ---
> > > drivers/media/i2c/ov5640.c | 253 +++++++++++++++++++++------------------------
> > > 1 file changed, 120 insertions(+), 133 deletions(-)
> > >
> > > diff --git a/drivers/media/i2c/ov5640.c b/drivers/media/i2c/ov5640.c
> > > index 2fe4a7a..ac305a5 100644
> > > --- a/drivers/media/i2c/ov5640.c
> > > +++ b/drivers/media/i2c/ov5640.c
> > > @@ -274,7 +274,7 @@ static inline struct v4l2_subdev *ctrl_to_sd(struct v4l2_ctrl *ctrl)
> > > /* YUV422 UYVY VGA@30fps */
> > > static const struct reg_value ov5640_init_setting_30fps_VGA[] = {
> > > {0x3103, 0x11, 0, 0}, {0x3008, 0x82, 0, 5}, {0x3008, 0x42, 0, 0},
> > > - {0x3103, 0x03, 0, 0}, {0x3017, 0x00, 0, 0}, {0x3018, 0x00, 0, 0},
> > > + {0x3103, 0x03, 0, 0},
> > > {0x3630, 0x36, 0, 0},
> > > {0x3631, 0x0e, 0, 0}, {0x3632, 0xe2, 0, 0}, {0x3633, 0x12, 0, 0},
> > > {0x3621, 0xe0, 0, 0}, {0x3704, 0xa0, 0, 0}, {0x3703, 0x5a, 0, 0},
> > > @@ -1210,96 +1210,7 @@ static int ov5640_set_autogain(struct ov5640_dev *sensor, bool on)
> > >
> > > static int ov5640_set_stream_dvp(struct ov5640_dev *sensor, bool on)
> > > {
> > > - int ret;
> > > - unsigned int flags = sensor->ep.bus.parallel.flags;
> > > - u8 pclk_pol = 0;
> > > - u8 hsync_pol = 0;
> > > - u8 vsync_pol = 0;
> > > -
> > > - /*
> > > - * Note about parallel port configuration.
> > > - *
> > > - * When configured in parallel mode, the OV5640 will
> > > - * output 10 bits data on DVP data lines [9:0].
> > > - * If only 8 bits data are wanted, the 8 bits data lines
> > > - * of the camera interface must be physically connected
> > > - * on the DVP data lines [9:2].
> > > - *
> > > - * Control lines polarity can be configured through
> > > - * devicetree endpoint control lines properties.
> > > - * If no endpoint control lines properties are set,
> > > - * polarity will be as below:
> > > - * - VSYNC: active high
> > > - * - HREF: active low
> > > - * - PCLK: active low
> > > - */
> > > -
> > > - if (on) {
> > > - /*
> > > - * configure parallel port control lines polarity
> > > - *
> > > - * POLARITY CTRL0
> > > - * - [5]: PCLK polarity (0: active low, 1: active high)
> > > - * - [1]: HREF polarity (0: active low, 1: active high)
> > > - * - [0]: VSYNC polarity (mismatch here between
> > > - * datasheet and hardware, 0 is active high
> > > - * and 1 is active low...)
> > > - */
> > > - if (flags & V4L2_MBUS_PCLK_SAMPLE_RISING)
> > > - pclk_pol = 1;
> > > - if (flags & V4L2_MBUS_HSYNC_ACTIVE_HIGH)
> > > - hsync_pol = 1;
> > > - if (flags & V4L2_MBUS_VSYNC_ACTIVE_LOW)
> > > - vsync_pol = 1;
> > > -
> > > - ret = ov5640_write_reg(sensor,
> > > - OV5640_REG_POLARITY_CTRL00,
> > > - (pclk_pol << 5) |
> > > - (hsync_pol << 1) |
> > > - vsync_pol);
> > > -
> > > - if (ret)
> > > - return ret;
> > > - }
> > > -
> > > - /*
> > > - * powerdown MIPI TX/RX PHY & disable MIPI
> > > - *
> > > - * MIPI CONTROL 00
> > > - * 4: PWDN PHY TX
> > > - * 3: PWDN PHY RX
> > > - * 2: MIPI enable
> > > - */
> > > - ret = ov5640_write_reg(sensor,
> > > - OV5640_REG_IO_MIPI_CTRL00, on ? 0x18 : 0);
> > > - if (ret)
> > > - return ret;
> > > -
> > > - /*
> > > - * enable VSYNC/HREF/PCLK DVP control lines
> > > - * & D[9:6] DVP data lines
> > > - *
> > > - * PAD OUTPUT ENABLE 01
> > > - * - 6: VSYNC output enable
> > > - * - 5: HREF output enable
> > > - * - 4: PCLK output enable
> > > - * - [3:0]: D[9:6] output enable
> > > - */
> > > - ret = ov5640_write_reg(sensor,
> > > - OV5640_REG_PAD_OUTPUT_ENABLE01,
> > > - on ? 0x7f : 0);
> > > - if (ret)
> > > - return ret;
> > > -
> > > - /*
> > > - * enable D[5:0] DVP data lines
> > > - *
> > > - * PAD OUTPUT ENABLE 02
> > > - * - [7:2]: D[5:0] output enable
> > > - */
> > > - return ov5640_write_reg(sensor,
> > > - OV5640_REG_PAD_OUTPUT_ENABLE02,
> > > - on ? 0xfc : 0);
> > > + return ov5640_write_reg(sensor, OV5640_REG_SYS_CTRL0, on ? 0x2 : 0x42);
> > > }
> > >
> > > static int ov5640_set_stream_mipi(struct ov5640_dev *sensor, bool on)
> > > @@ -2003,6 +1914,10 @@ static void ov5640_set_power_off(struct ov5640_dev *sensor)
> > >
> > > static int ov5640_set_power(struct ov5640_dev *sensor, bool on)
> > > {
> > > + unsigned int flags = sensor->ep.bus.parallel.flags;
> > > + u8 pclk_pol = 0;
> > > + u8 hsync_pol = 0;
> > > + u8 vsync_pol = 0;
> > > int ret = 0;
> > >
> > > if (on) {
> > > @@ -2014,52 +1929,124 @@ static int ov5640_set_power(struct ov5640_dev *sensor, bool on)
> > > if (ret)
> > > goto power_off;
> > >
> > > - /* We're done here for DVP bus, while CSI-2 needs setup. */
> > > - if (sensor->ep.bus_type != V4L2_MBUS_CSI2_DPHY)
> > > - return 0;
> > > + /* CSI-2 setup. */
> > > + if (sensor->ep.bus_type == V4L2_MBUS_CSI2_DPHY) {
> > > + /*
> > > + * Power up MIPI HS Tx and LS Rx; 2 data lanes mode
> > > + *
> > > + * 0x300e = 0x40
> > > + * [7:5] = 010 : 2 data lanes mode (see FIXME note in
> > > + * "ov5640_set_stream_mipi()")
> > > + * [4] = 0 : Power up MIPI HS Tx
> > > + * [3] = 0 : Power up MIPI LS Rx
> > > + * [2] = 0 : MIPI interface disabled
> > > + */
> > > + ret = ov5640_write_reg(sensor, OV5640_REG_IO_MIPI_CTRL00, 0x40);
> >
> > Please wrap lines over 80 if it can be reasonably one.
>
> checkpatch doesn't complain about it (size is increased to 100)?

--
Regards,

Laurent Pinchart