Hi Sakari,
On Thu, 2020-06-11 at 13:03 +0300, Sakari Ailus wrote:
> On Thu, Jun 11, 2020 at 11:57:43AM +0200, Tomasz Figa wrote:
> > On Thu, Jun 11, 2020 at 11:53 AM Sakari Ailus
> > <sakari.ailus@xxxxxxxxxxxxxxx> wrote:
> > >
> > > Hi Tomasz,
> > >
> > > On Wed, Jun 10, 2020 at 07:44:55PM +0000, Tomasz Figa wrote:
> > > > Hi Dongchun,
> > > >
> > > > On Sat, May 23, 2020 at 04:41:03PM +0800, Dongchun Zhu wrote:
> > > > > Add a V4L2 sub-device driver for OV02A10 image sensor.
> > > > >
> > > > > Signed-off-by: Dongchun Zhu <dongchun.zhu@xxxxxxxxxxxx>
> > > > > ---
> > > > > MAINTAINERS | 1 +
> > > > > drivers/media/i2c/Kconfig | 13 +
> > > > > drivers/media/i2c/Makefile | 1 +
> > > > > drivers/media/i2c/ov02a10.c | 1025 +++++++++++++++++++++++++++++++++++++++++++
> > > > > 4 files changed, 1040 insertions(+)
> > > > > create mode 100644 drivers/media/i2c/ov02a10.c
> > > > >
> > > >
> > > > Thank you for the patch. Please see my comments inline.
> > > >
> > > > [snip]
> > > > > diff --git a/drivers/media/i2c/ov02a10.c b/drivers/media/i2c/ov02a10.c
> > > > > new file mode 100644
> > > > > index 0000000..160a0b5
> > > > > --- /dev/null
> > > > > +++ b/drivers/media/i2c/ov02a10.c
> > > > [snip]
> > > > > +static const char * const ov02a10_test_pattern_menu[] = {
> > > > > + "Disabled",
> > > > > + "Color Bar",
> > > >
> > > > nit: We should normalize this to one of the standard names. What is the
> > > > pattern on this sensor? Is it perhaps "Eight Vertical Colour Bars"?
> > > >
> > > > > +};
> > > > [snip]
> > > > > +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);
> > > > > +
> > > >
> > > >
> > > > Don't we need to handle the case when fmt->which is V4L2_SUBDEV_FORMAT_TRY,
> > > > which is used for trying the format, but not applying it to the hardware?
> > >
> > > Yes.
> > >
> > > >
> > > > > + 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;
> > > > > +
> > > > > + mutex_unlock(&ov02a10->mutex);
> > > > > +
> > > > > + return 0;
> > > > > +}
> > > > > +
> > > > > +static int ov02a10_get_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);
> > > > > +
> > > > > + fmt->format = ov02a10->fmt;
> > > >
> > > > Ditto.
> > > >
> > > > > + mbus_fmt->code = ov02a10->fmt.code;
> > > > > + ov02a10_fill_fmt(ov02a10->cur_mode, mbus_fmt);
> > > > > +
> > > > > + mutex_unlock(&ov02a10->mutex);
> > > > > +
> > > > > + return 0;
> > > > > +}
> > > > > +
> > > > > +static int ov02a10_enum_mbus_code(struct v4l2_subdev *sd,
> > > > > + struct v4l2_subdev_pad_config *cfg,
> > > > > + struct v4l2_subdev_mbus_code_enum *code)
> > > > > +{
> > > > > + struct ov02a10 *ov02a10 = to_ov02a10(sd);
> > > > > +
> > > > > + if (code->index >= ARRAY_SIZE(supported_modes))
> > > > > + return -EINVAL;
> > > >
> > > > Hmm, supported_modes[] doesn't seem to hold the information about mbus
> > > > codes. Should this just perhaps be "!= 0"?
> > > >
> > > > > +
> > > > > + code->code = ov02a10->fmt.code;
> > > > > +
> > > > > + return 0;
> > > > > +}
> > > > [snip]
> > > > > +static int ov02a10_entity_init_cfg(struct v4l2_subdev *sd,
> > > > > + struct v4l2_subdev_pad_config *cfg)
> > > > > +{
> > > > > + struct v4l2_subdev_format fmt = {
> > > > > + .which = cfg ? V4L2_SUBDEV_FORMAT_TRY : V4L2_SUBDEV_FORMAT_ACTIVE,
> > > > > + .format = {
> > > > > + .width = 1600,
> > > > > + .height = 1200,
> > > > > + }
> > > > > + };
> > > > > +
> > > > > + ov02a10_set_fmt(sd, cfg, &fmt);
> > > > > +
> > > > > + return 0;
> > > > > +}
> > > > > +
> > > >
> > > > I'm not familiar with this init_cfg operation and the documentation is very
> > > > sparse about it. Sakari, is this a correct implementation?
> > >
> > > The purpose is to initialise a pad configuration (format and selection
> > > rectangles) to the device defaults. As there seem to be no selection
> > > rectangles, this seems fine to me.
> >
> > Thanks. I traced the code and could only see one place where the
> > callback is being called and that was with cfg != NULL. Still, the
> > code above uses "cfg ?" as a check to determine whether TRY or ACTIVE
> > should be passed to which. Is that also correct?
>
> It could be used in setting the active format in probe. That would probably
> be cleaner than what it currently does.
>
Sakari, did you mean that we need to update _probe API?
Like this:
struct v4l2_subdev_format fmt = {
.which = V4L2_SUBDEV_FORMAT_ACTIVE,
};
> But apart from that, the framework always calls init_cfg with cfg non-NULL.
>
