linux-kernel - Re: [PATCH v7 3/3] media: ov8856: Implement sensor module revision identification

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Message-ID: <CAG3jFyvvzk8n1+fkfS5h6TPpqMQ3sGXuJ1_yot1MKFRTcDkhnQ@mail.gmail.com>
Date:   Wed, 6 May 2020 16:48:06 +0200
From:   Robert Foss <robert.foss@...aro.org>
To:     Marco Felsch <m.felsch@...gutronix.de>
Cc:     Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
        Sakari Ailus <sakari.ailus@....fi>,
        Maxime Ripard <maxime@...no.tech>,
        linux-media <linux-media@...r.kernel.org>,
        "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" 
        <devicetree@...r.kernel.org>,
        linux-kernel <linux-kernel@...r.kernel.org>,
        "moderated list:ARM/FREESCALE IMX / MXC ARM ARCHITECTURE" 
        <linux-arm-kernel@...ts.infradead.org>,
        Dongchun Zhu <dongchun.zhu@...iatek.com>,
        Fabio Estevam <festevam@...il.com>,
        Tomasz Figa <tfiga@...omium.org>, Ben Kao <ben.kao@...el.com>
Subject: Re: [PATCH v7 3/3] media: ov8856: Implement sensor module revision identification

Hey Marco,

On Tue, 5 May 2020 at 12:17, Marco Felsch <m.felsch@...gutronix.de> wrote:
>
> Hi Robert,
>
> On 20-05-05 12:01, Robert Foss wrote:
> > Query the sensor for its module revision, and compare it
> > to known revisions.
> >
> > Currently 2A and 1B revision indentification is supported.
> >
> > Signed-off-by: Robert Foss <robert.foss@...aro.org>
> > ---
> >
> > - Changes since v3:
> >   * Actually add module revision 2A
> >
> > - Changes since v2:
> >   * Add module revision 2A
> >   * Sakari: Remove ov8856_check_revision()
> >   * Sakari: Stop EEPROM streaming mode
> >
> >  drivers/media/i2c/ov8856.c | 53 ++++++++++++++++++++++++++++++++++++++
> >  1 file changed, 53 insertions(+)
> >
> > diff --git a/drivers/media/i2c/ov8856.c b/drivers/media/i2c/ov8856.c
> > index e6418a79801e..3c82c3e588d7 100644
> > --- a/drivers/media/i2c/ov8856.c
> > +++ b/drivers/media/i2c/ov8856.c
> > @@ -32,6 +32,19 @@
> >  #define OV8856_MODE_STANDBY          0x00
> >  #define OV8856_MODE_STREAMING                0x01
> >
> > +/* module revisions */
> > +#define OV8856_2A_MODULE             0x01
> > +#define OV8856_1B_MODULE             0x02
> > +
> > +/* the OTP read-out buffer is at 0x7000 and 0xf is the offset
> > + * of the byte in the OTP that means the module revision
> > + */
> > +#define OV8856_MODULE_REVISION               0x700f
> > +#define OV8856_OTP_MODE_CTRL         0x3d84
> > +#define OV8856_OTP_LOAD_CTRL         0x3d81
> > +#define OV8856_OTP_MODE_AUTO         0x00
> > +#define OV8856_OTP_LOAD_CTRL_ENABLE  BIT(0)
> > +
> >  /* vertical-timings from sensor */
> >  #define OV8856_REG_VTS                       0x380e
> >  #define OV8856_VTS_MAX                       0x7fff
> > @@ -1152,6 +1165,46 @@ static int ov8856_identify_module(struct ov8856 *ov8856)
> >               return -ENXIO;
> >       }
> >
> > +     ret = ov8856_write_reg(ov8856, OV8856_REG_MODE_SELECT,
> > +                            OV8856_REG_VALUE_08BIT, OV8856_MODE_STREAMING);
> > +     if (ret)
> > +             return ret;
> > +
> > +     ret = ov8856_write_reg(ov8856, OV8856_OTP_MODE_CTRL,
> > +                            OV8856_REG_VALUE_08BIT, OV8856_OTP_MODE_AUTO);
> > +     if (ret) {
> > +             dev_err(&client->dev, "failed to set otp mode");
> > +             return ret;
> > +     }
> > +
> > +     ret = ov8856_write_reg(ov8856, OV8856_OTP_LOAD_CTRL,
> > +                            OV8856_REG_VALUE_08BIT,
> > +                            OV8856_OTP_LOAD_CTRL_ENABLE);
> > +     if (ret) {
> > +             dev_err(&client->dev, "failed to enable load control");
> > +             return ret;
> > +     }
> > +
> > +     ret = ov8856_read_reg(ov8856, OV8856_MODULE_REVISION,
> > +                           OV8856_REG_VALUE_08BIT, &val);
> > +     if (ret) {
> > +             dev_err(&client->dev, "failed to read module revision");
> > +             return ret;
> > +     }
> > +
> > +     dev_info(&client->dev, "OV8856 revision %x (%s) at address 0x%02x\n",
> > +             val,
> > +             val == OV8856_2A_MODULE ? "2A" :
> > +             val == OV8856_1B_MODULE ? "1B" : "unknown revision",
> > +             client->addr);
>
> Pls check the alignment here too.

Ack.

>
> Regards,
>   Marco
>
> > +
> > +     ret = ov8856_write_reg(ov8856, OV8856_REG_MODE_SELECT,
> > +                            OV8856_REG_VALUE_08BIT, OV8856_MODE_STANDBY);
> > +     if (ret) {
> > +             dev_err(&client->dev, "failed to exit streaming mode");
> > +             return ret;
> > +     }
> > +
> >       return 0;
> >  }
> >
> > --
> > 2.25.1