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

Robert Foss
2020-05-06T14:48:20Z

Hey Marco,

On Tue, 5 May 2020 at 12:17, Marco Felsch <m.felsch@pengutronix.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@linaro.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