linux-kernel - Re: [PATCH v1 2/2] media: i2c: mt9m114: add support for Aptina MI1040

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Message-ID: <CAPVz0n3=JPyjm3RypcSec=FZ66W2cq4Mwu2yodR03Ng2jDbxEw@mail.gmail.com>
Date: Mon, 26 Jan 2026 11:50:05 +0200
From: Svyatoslav Ryhel <clamor95@...il.com>
To: Sakari Ailus <sakari.ailus@...ux.intel.com>
Cc: Laurent Pinchart <laurent.pinchart@...asonboard.com>, 
	Mauro Carvalho Chehab <mchehab@...nel.org>, Rob Herring <robh@...nel.org>, 
	Krzysztof Kozlowski <krzk+dt@...nel.org>, Conor Dooley <conor+dt@...nel.org>, linux-media@...r.kernel.org, 
	devicetree@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v1 2/2] media: i2c: mt9m114: add support for Aptina MI1040

пн, 26 січ. 2026 р. о 11:35 Sakari Ailus <sakari.ailus@...ux.intel.com> пише:
>
> Hi Svyatoslav,
>
> Thanks for the patchset.
>
> On Mon, Jan 26, 2026 at 10:34:30AM +0200, 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. Only difference found so far is lacking ability to
>
> s/Only/The only/
>
> > poll STATUS and COMMAND registers during power on sequence, which causes
> > driver to fail with time out error. Add polling flag to diverge models and
> > address quirk found in MI1040.
> >
> > Signed-off-by: Svyatoslav Ryhel <clamor95@...il.com>
> > ---
> >  drivers/media/i2c/mt9m114.c | 35 ++++++++++++++++++++++++++++-------
> >  1 file changed, 28 insertions(+), 7 deletions(-)
> >
> > diff --git a/drivers/media/i2c/mt9m114.c b/drivers/media/i2c/mt9m114.c
> > index 4ec033c0ee84..d96a57ebcad4 100644
> > --- a/drivers/media/i2c/mt9m114.c
> > +++ b/drivers/media/i2c/mt9m114.c
> > @@ -368,6 +368,10 @@ enum {
> >   * Data Structures
> >   */
> >
> > +struct mt9m114_model_info {
> > +     bool polling;
> > +};
> > +
> >  enum mt9m114_format_flag {
> >       MT9M114_FMT_FLAG_PARALLEL = BIT(0),
> >       MT9M114_FMT_FLAG_CSI2 = BIT(1),
> > @@ -421,6 +425,8 @@ struct mt9m114 {
> >
> >               struct v4l2_ctrl *tpg[4];
> >       } ifp;
> > +
> > +     const struct mt9m114_model_info *info;
> >  };
> >
> >  /* -----------------------------------------------------------------------------
> > @@ -2186,9 +2192,11 @@ static int mt9m114_power_on(struct mt9m114 *sensor)
> >        */
> >       usleep_range(44500, 50000);
> >
> > -     ret = mt9m114_poll_command(sensor, MT9M114_COMMAND_REGISTER_SET_STATE);
> > -     if (ret < 0)
> > -             goto error_clock;
> > +     if (sensor->info->polling) {
> > +             ret = mt9m114_poll_command(sensor, MT9M114_COMMAND_REGISTER_SET_STATE);
> > +             if (ret < 0)
> > +                     goto error_clock;
> > +     }
>
> What does the datasheet say, is there a need to do something else instead?
> As the polling is there to ensure firmware has done its job, the need
> appears to still be there.
>

MI1040 has no datasheet available and downstream code does not do this
polling. I have tested on Nexus 7 which has this camera and it seems
to be fully operational without this poling, but as soon it is enabled
camera fails will timeout. I suspect that this camera version has some
quirk regarding early access, but I cannot back it up by any
documentation or additional data.

I have a device with proper version of mt9m114 too and it works with
his driver without any major issues.

> >
> >       if (sensor->bus_cfg.bus_type == V4L2_MBUS_PARALLEL) {
> >               /*
> > @@ -2207,9 +2215,11 @@ 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->polling) {
> > +             ret = mt9m114_poll_state(sensor, MT9M114_SYS_STATE_STANDBY);
>
> Ditto.
>
> > +             if (ret < 0)
> > +                     goto error_clock;
> > +     }
> >
> >       return 0;
> >
> > @@ -2421,6 +2431,8 @@ static int mt9m114_probe(struct i2c_client *client)
> >       if (ret < 0)
> >               return ret;
> >
> > +     sensor->info = of_device_get_match_data(dev);
>
> You can use device_get_match_data() here.
>

noted

> > +
> >       /* Acquire clocks, GPIOs and regulators. */
> >       sensor->clk = devm_v4l2_sensor_clk_get(dev, NULL);
> >       if (IS_ERR(sensor->clk)) {
> > @@ -2539,8 +2551,17 @@ static void mt9m114_remove(struct i2c_client *client)
> >       pm_runtime_set_suspended(dev);
> >  }
> >
> > +static const struct mt9m114_model_info mt9m114_models_default = {
> > +     .polling = true,
> > +};
> > +
> > +static const struct mt9m114_model_info mt9m114_models_aptina = {
> > +     .polling = false,
> > +};
> > +
> >  static const struct of_device_id mt9m114_of_ids[] = {
> > -     { .compatible = "onnn,mt9m114" },
> > +     { .compatible = "onnn,mt9m114", .data = &mt9m114_models_default },
> > +     { .compatible = "aptina,mi1040", .data = &mt9m114_models_aptina },
> >       { /* sentinel */ },
>
> The sentinel entry shouldn't have a comma. Feel free to fix that while at
> it.
>

noted

> >  };
> >  MODULE_DEVICE_TABLE(of, mt9m114_of_ids);
>
> --
> Kind regards,
>
> Sakari Ailus