Re: [PATCH v2 2/2] media: i2c: mt9m114: add support for Aptina MI1040

[Svyatoslav Ryhel]

ср, 4 бер. 2026 р. о 10:32 Sakari Ailus <sakari.ailus@xxxxxxxxxxxxxxx> пише:
>
> Hi Svyatoslav, Hans,
>
> On Thu, Feb 12, 2026 at 06:44:06PM +0200, Svyatoslav Ryhel wrote:
> > чт, 12 лют. 2026 р. о 17:53 <johannes.goede@xxxxxxxxxxxxxxxx> пише:
> > >
> > > Hi,
> > >
> > > On 12-Feb-26 13:23, Svyatoslav Ryhel wrote:
> > > > Slightly different version of MT9M114 camera module is used in a several
> > > > devices like ASUS Nexus 7 (2012) or ASUS Transformer Prime TF201 and is
> > > > called Aptina MI1040. The only difference found so far is lacking ability
> > > > to poll STATE register during power on sequence, which causes driver to
> > > > fail with time out error. Add state_polling flag to diverge models and
> > > > address quirk found in MI1040.
> > > >
> > > > Signed-off-by: Svyatoslav Ryhel <clamor95@xxxxxxxxx>
> > > > ---
> > > >  drivers/media/i2c/mt9m114.c | 29 ++++++++++++++++++++++++-----
> > > >  1 file changed, 24 insertions(+), 5 deletions(-)
> > > >
> > > > diff --git a/drivers/media/i2c/mt9m114.c b/drivers/media/i2c/mt9m114.c
> > > > index d5b142fe68a9..a4b021702a1f 100644
> > > > --- a/drivers/media/i2c/mt9m114.c
> > > > +++ b/drivers/media/i2c/mt9m114.c
> > > > @@ -373,6 +373,10 @@ enum {
> > > >   * Data Structures
> > > >   */
> > > >
> > > > +struct mt9m114_model_info {
> > > > +     bool state_polling;
> > > > +};
> > > > +
> > > >  enum mt9m114_format_flag {
> > > >       MT9M114_FMT_FLAG_PARALLEL = BIT(0),
> > > >       MT9M114_FMT_FLAG_CSI2 = BIT(1),
> > > > @@ -422,6 +426,8 @@ struct mt9m114 {
> > > >
> > > >               struct v4l2_ctrl *tpg[4];
> > > >       } ifp;
> > > > +
> > > > +     const struct mt9m114_model_info *info;
> > > >  };
> > > >
> > > >  /* -----------------------------------------------------------------------------
> > > > @@ -2279,9 +2285,11 @@ static int mt9m114_power_on(struct mt9m114 *sensor)
> > > >        * reaches the standby mode (either initiated manually above in
> > > >        * parallel mode, or automatically after reset in MIPI mode).
> > > >        */
> > > > -     ret = mt9m114_poll_state(sensor, MT9M114_SYS_STATE_STANDBY);
> > > > -     if (ret < 0)
> > > > -             goto error_clock;
> > > > +     if (sensor->info->state_polling) {
> > > > +             ret = mt9m114_poll_state(sensor, MT9M114_SYS_STATE_STANDBY);
> > > > +             if (ret < 0)
> > > > +                     goto error_clock;
> > > > +     }
> > >
> > > So I would expect a flag called state_polling to be checked
> > > in mt9m114_poll_state(). It looks like you are only disabling
> > > one specific case of state polling, not all of them.
>
> There's a single user for mt9m114_poll_state()... I think the current name
> is fine.
>

I will name the flag `state_standby_polling` if everyone is fine with
it since the case below requires resending anyway.

> > >
> > > Please rename the flag to reflect this.
> > >
> >
> > And which name you see fitting? There is only one instance of using
> > mt9m114_poll_state in this driver, I see no controversy in naming.
> >
> > > >
> > > >       return 0;
> > > >
> > > > @@ -2527,6 +2535,8 @@ static int mt9m114_probe(struct i2c_client *client)
> > > >       if (ret < 0)
> > > >               return ret;
> > > >
> > > > +     sensor->info = device_get_match_data(dev);
> > > > +
> > >
> > > This can return NULL when the driver is manually bound through
> > > sysfs, which will result in a crash later on when checked in
> > > mt9m114_power_on()
>
> Svyatoslav, can you add a check for this?
>
> I guess a few other drivers also suffer from this...
>

Yes, sure. Should I set it to return neg error or fallback to default entry?

> --
> Regards,
>
> Sakari Ailus