linux-kernel - Re: [PATCH v2 1/3] media: i2c: imx219: Fix power sequence

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Message-ID: <CA+V-a8s-7FYJdLnG5y4i6SvcpJR16iXd35GfFPgesdkO9Z7Ong@mail.gmail.com>
Date:   Fri, 6 Mar 2020 15:01:57 +0000
From:   "Lad, Prabhakar" <prabhakar.csengg@...il.com>
To:     Dave Stevenson <dave.stevenson@...pberrypi.com>
Cc:     Mauro Carvalho Chehab <mchehab@...nel.org>,
        Sakari Ailus <sakari.ailus@...ux.intel.com>,
        Linux Media Mailing List <linux-media@...r.kernel.org>,
        LKML <linux-kernel@...r.kernel.org>,
        Lad Prabhakar <prabhakar.mahadev-lad.rj@...renesas.com>
Subject: Re: [PATCH v2 1/3] media: i2c: imx219: Fix power sequence

Hi Dave,

On Fri, Mar 6, 2020 at 1:01 PM Dave Stevenson
<dave.stevenson@...pberrypi.com> wrote:
>
> Hi Prabhakar.
>
> Thanks for the update.
>
> On Fri, 6 Mar 2020 at 10:32, Lad Prabhakar <prabhakar.csengg@...il.com> wrote:
> >
> > When supporting Rpi Camera v2 Module on the RZ/G2E, found the driver had
> > some issues with rcar mipi-csi driver. The sensor never entered into LP-11
> > state.
> >
> > The powerup sequence in the datasheet[1] shows the sensor entering into
> > LP-11 in streaming mode, so to fix this issue transitions are performed
> > from "streaming -> standby" in the probe() after power up.
> >
> > With this commit the sensor is able to enter LP-11 mode during power up,
> > as expected by some CSI-2 controllers.
> >
> > [1] https://publiclab.org/system/images/photos/000/023/294/original/
> > RASPBERRY_PI_CAMERA_V2_DATASHEET_IMX219PQH5_7.0.0_Datasheet_XXX.PDF
> >
> > Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@...renesas.com>
>
> Acked-by: Dave Stevenson <dave.stevenson@...pberrypi.com>
>
Thank you for the Ack.

Cheers,
--Prabhakar

>
> > ---
> >  drivers/media/i2c/imx219.c | 17 +++++++++++++++++
> >  1 file changed, 17 insertions(+)
> >
> > diff --git a/drivers/media/i2c/imx219.c b/drivers/media/i2c/imx219.c
> > index f1effb5a5f66..16010ca1781a 100644
> > --- a/drivers/media/i2c/imx219.c
> > +++ b/drivers/media/i2c/imx219.c
> > @@ -1224,6 +1224,23 @@ static int imx219_probe(struct i2c_client *client)
> >         /* Set default mode to max resolution */
> >         imx219->mode = &supported_modes[0];
> >
> > +       /* sensor doesn't enter LP-11 state upon power up until and unless
> > +        * streaming is started, so upon power up switch the modes to:
> > +        * streaming -> standby
> > +        */
> > +       ret = imx219_write_reg(imx219, IMX219_REG_MODE_SELECT,
> > +                              IMX219_REG_VALUE_08BIT, IMX219_MODE_STREAMING);
> > +       if (ret < 0)
> > +               goto error_power_off;
> > +       usleep_range(100, 110);
> > +
> > +       /* put sensor back to standby mode */
> > +       ret = imx219_write_reg(imx219, IMX219_REG_MODE_SELECT,
> > +                              IMX219_REG_VALUE_08BIT, IMX219_MODE_STANDBY);
> > +       if (ret < 0)
> > +               goto error_power_off;
> > +       usleep_range(100, 110);
> > +
> >         ret = imx219_init_controls(imx219);
> >         if (ret)
> >                 goto error_power_off;
> > --
> > 2.20.1
> >