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

[Sakari Ailus <sakari.ailus@linux.intel.com>]

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@oss.qualcomm.com> 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@gmail.com>
> > > ---
> > >  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.

> >
> > 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...

-- 
Regards,

Sakari Ailus