Re: [PATCH 2/2] media: ov9282: enable single-read I2C transactions

[Laurent Pinchart]

On Tue, Jul 21, 2026 at 03:38:26PM +0200, Alexander Stein wrote:
> Hi Richard,
> 
> thanks for addressing this long-standing issue.
> 
> Am Dienstag, 21. Juli 2026, 15:25:29 CEST schrieb Richard Leitner:
> > Some OV9282 camera modules, such as those from Vision Components, fail
> > multi-byte register reads with the default CCI I2C regmap access pattern
> > and only work when single-register read transactions are used. This
> > results in the driver being unable to probe due to a chip id mismatch.
> > 
> > As the driver has no reliable way to identify affected modules enable
> > use_single_read for OV9282 unconditionally when creating the CCI regmap.
> 
> What about a property in the DT instead? In DT it should be clear if a
> Vision Components camera is used.

Yes, this should not be done by default, or we'll have to do the same
for all sensors used in any module from Vision Components.

> > Tested on an i.M8MP system with OV9282 modules from Vision Components.
> > 
> > Signed-off-by: Richard Leitner <richard.leitner@xxxxxxxxx>
> > ---
> >  drivers/media/i2c/ov9282.c | 7 ++++++-
> >  1 file changed, 6 insertions(+), 1 deletion(-)
> > 
> > diff --git a/drivers/media/i2c/ov9282.c b/drivers/media/i2c/ov9282.c
> > index 5b6f897a74fcd..8267a0a9c6f2d 100644
> > --- a/drivers/media/i2c/ov9282.c
> > +++ b/drivers/media/i2c/ov9282.c
> > @@ -1283,6 +1283,11 @@ static int ov9282_probe(struct i2c_client *client)
> >  	struct ov9282 *ov9282;
> >  	int ret;
> >  
> > +	const struct cci_regmap_config config = {
> > +		.reg_addr_bits = 16,
> > +		.use_single_read = true,
> > +	};
> > +
> >  	ov9282 = devm_kzalloc(&client->dev, sizeof(*ov9282), GFP_KERNEL);
> >  	if (!ov9282)
> >  		return -ENOMEM;
> > @@ -1301,7 +1306,7 @@ static int ov9282_probe(struct i2c_client *client)
> >  		return ret;
> >  	}
> >  
> > -	ov9282->regmap = devm_cci_regmap_init_i2c(client, 16);
> > +	ov9282->regmap = devm_cci_regmap_init_i2c_cfg(client, &config);
> >  	if (IS_ERR(ov9282->regmap))
> >  		return dev_err_probe(ov9282->dev, PTR_ERR(ov9282->regmap),
> >  				     "Failed to init CCI\n");

-- 
Regards,

Laurent Pinchart