Hi Alexander, On Wed, 7 Aug 2024 at 10:33, Alexander Stein <alexander.stein@xxxxxxxxxxxxxxx> wrote: > Hi Benjamin, > > Am Mittwoch, 7. August 2024, 10:10:28 CEST schrieb Benjamin Bara: > > Currently, the V4L2 subdevice is also created when the device is not > > available/connected. In this case, dmesg shows the following: > > > > [ 10.419510] imx290 7-001a: Error writing reg 0x301c: -6 > > [ 10.428981] imx290 7-001a: Error writing reg 0x3020: -6 > > [ 10.442712] imx290 7-001a: Error writing reg 0x3018: -6 > > [ 10.454018] imx290 7-001a: Error writing reg 0x3020: -6 > > > > which seems to come from imx290_ctrl_update() after the subdev init is > > finished. However, as the errors are ignored, the subdev is initialized > > but simply does not work. From userspace perspective, there is no > > visible difference between a working and not-working subdevice (except > > when trying it out or watching for the error message). > > > > This commit adds a simple availability check before starting with the > > subdev initialization to error out instead. > > There is already a patch reading the ID register at [1]. This also reads the > ID register. But I don't have any documentation regarding that register, > neither address nor values definitions. If there is known information about > that I would prefer reading the ID and compare it to expected values. Thanks for the link - it seems like Laurent has dropped the patch for the more recent kernel versions on their GitLab. This was also my initial intention, but similar to you, I don't have a docu describing this register, so I am not sure where the info is coming from and if it really contains the identification/type info. Probably Laurent has more infos on that. Best regards Benjamin > Best regards, > Alexander > > [1] https://gitlab.com/ideasonboard/nxp/linux/-/commit/85ce725f1de7c16133bfb92b2ab0d3d84efcdb47 > > > Signed-off-by: Benjamin Bara <benjamin.bara@xxxxxxxxxxx> > > --- > > drivers/media/i2c/imx290.c | 5 +++++ > > 1 file changed, 5 insertions(+) > > > > diff --git a/drivers/media/i2c/imx290.c b/drivers/media/i2c/imx290.c > > index 4150e6e4b9a6..a86076e42a36 100644 > > --- a/drivers/media/i2c/imx290.c > > +++ b/drivers/media/i2c/imx290.c > > @@ -1580,6 +1580,11 @@ static int imx290_probe(struct i2c_client *client) > > pm_runtime_set_autosuspend_delay(dev, 1000); > > pm_runtime_use_autosuspend(dev); > > > > + /* Make sure the sensor is available before V4L2 subdev init. */ > > + ret = cci_read(imx290->regmap, IMX290_STANDBY, NULL, NULL); > > + if (ret) > > + goto err_pm; > > + > > /* Initialize the V4L2 subdev. */ > > ret = imx290_subdev_init(imx290); > > if (ret) > > > > > > > -- > TQ-Systems GmbH | Mühlstraße 2, Gut Delling | 82229 Seefeld, Germany > Amtsgericht München, HRB 105018 > Geschäftsführer: Detlef Schneider, Rüdiger Stahl, Stefan Schneider > http://www.tq-group.com/ > >
