Hi,
Am Sonntag, 17. Juli 2022, 16:22:01 CEST schrieb Sakari Ailus:
> Hi Alexander,
>
> On Fri, Jul 15, 2022 at 09:48:58AM +0200, Alexander Stein wrote:
> > Apparently the Vision Components model (VC MIPI OV9281) does not support
> > address auto-increment, so probe fails with:
> > ov9282 2-0060: chip id mismatch: 9281!=92ff
> > Instead do two 1 byte reads and combine the result.
> >
> > Signed-off-by: Alexander Stein <alexander.stein@xxxxxxxxxxxxxxx>
> > ---
> > Changes in v2:
> > * Fix commit message
> > * Add comment about prevented auto-increment
> > * Return early if reading ID register failed
> > * Reorder ID registers, smaller register number first
> >
> > drivers/media/i2c/ov9282.c | 15 ++++++++++++++-
> > 1 file changed, 14 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/media/i2c/ov9282.c b/drivers/media/i2c/ov9282.c
> > index 263cdffc558f..532791304c3d 100644
> > --- a/drivers/media/i2c/ov9282.c
> > +++ b/drivers/media/i2c/ov9282.c
> > @@ -761,11 +761,24 @@ static int ov9282_set_stream(struct v4l2_subdev *sd,
> > int enable)>
> > static int ov9282_detect(struct ov9282 *ov9282)
> > {
> >
> > int ret;
> >
> > + u32 id[2];
> >
> > u32 val;
> >
> > - ret = ov9282_read_reg(ov9282, OV9282_REG_ID, 2, &val);
> > + /*
> > + * Some vendors prevent auto-increment, so each register has to
> > + * be read separately
> > + */
>
> I suppose it still works for writes I guess? Would be nice to have this in
> the comment.
>
> > + ret = ov9282_read_reg(ov9282, OV9282_REG_ID,
> > + 1, &id[0]);
>
> Fits on one line. Same below.
>
> > if (ret)
> >
> > return ret;
> >
> > + ret = ov9282_read_reg(ov9282, OV9282_REG_ID + 1,
> > + 1, &id[1]);
> > + if (ret)
> > + return ret;
> > +
> > + val = id[1];
> > + val |= (id[0] << 8);
> >
> > if (val != OV9282_ID) {
> >
> > dev_err(ov9282->dev, "chip id mismatch: %x!=%x",
imx290 is affected by the same problem. This can be handles by using regmap's
config option use_single_read=true.
Will convert to regmap to address this.
Best regards,
Alexander
