Hi Tomasz,

Thanks for the review.

On Mon, 2020-06-22 at 15:23 +0000, Tomasz Figa wrote:

On Sat, Jun 20, 2020 at 03:48:04PM +0800, Dongchun Zhu wrote:

quoted

Hi Tomasz,

Thanks for the review.

On Thu, 2020-06-18 at 19:10 +0000, Tomasz Figa wrote:

quoted

Hi Dongchun,

On Mon, Jun 15, 2020 at 08:29:37PM +0800, Dongchun Zhu wrote:

quoted

Add a V4L2 sub-device driver for OV02A10 image sensor.

Signed-off-by: Dongchun Zhu <redacted>
---
 MAINTAINERS                 |    1 +
 drivers/media/i2c/Kconfig   |   13 +
 drivers/media/i2c/Makefile  |    1 +
 drivers/media/i2c/ov02a10.c | 1042 +++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 1057 insertions(+)
 create mode 100644 drivers/media/i2c/ov02a10.c

Thank you for the patch. Please see my comments inline.

[snip]

quoted

+static int ov02a10_set_fmt(struct v4l2_subdev *sd,
+			   struct v4l2_subdev_pad_config *cfg,
+			   struct v4l2_subdev_format *fmt)
+{
+	struct ov02a10 *ov02a10 = to_ov02a10(sd);
+	struct v4l2_mbus_framefmt *mbus_fmt = &fmt->format;
+
+	mutex_lock(&ov02a10->mutex);
+
+	if (ov02a10->streaming) {
+		mutex_unlock(&ov02a10->mutex);
+		return -EBUSY;
+	}
+
+	/* Only one sensor mode supported */
+	mbus_fmt->code = ov02a10->fmt.code;
+	ov02a10_fill_fmt(ov02a10->cur_mode, mbus_fmt);
+	ov02a10->fmt = fmt->format;
+
+	if (fmt->which == V4L2_SUBDEV_FORMAT_TRY)
+		*v4l2_subdev_get_try_format(sd, cfg, fmt->pad) = fmt->format;

If fmt->which is V4L2_SUBDEV_FORMAT_TRY, the internal driver state must not
be affected. It also should not depend on whether the sensor is streaming
or not. Basically it should be considered a special "candidate" format,
which isn't programmed to the hardware, but just stored aside.

Hmm. Maybe we shall use FORMAT_TRY like this:
struct v4l2_mbus_framefmt *frame_fmt;
...
if (fmt->which == V4L2_SUBDEV_FORMAT_TRY)
	frame_fmt = v4l2_subdev_get_try_format(sd, cfg, 0);
else
	frame_fmt = &ov02a10->fmt;

*frame_fmt = *mbus_fmt;

(Remove 'ov02a10->fmt = fmt->format;' above)

Yes, I guess that should work. Also the ov02a10->streaming condition
shouldn't be checked if fmt->which is V4L2_SUBDEV_FORMAT_TRY).

Maybe we shall use more strict condition to check streaming state:
'if (ov02a10->streaming)' --> 'if (ov02a10->streaming && fmt->which ==
V4L2_SUBDEV_FORMAT_ACTIVE)'

Best regards,
Tomasz

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