Re: [PATCH v3 1/2] media: ov5640: Re-work MIPI startup sequence

[jacopo mondi <jacopo@jmondi.org>]

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Hello Loic,
   thanks for looking into this

On Tue, Sep 04, 2018 at 07:22:50PM +0200, Loic Poulain wrote:
> Hi Jacopo,
>
> > -       ret = ov5640_mod_reg(sensor, OV5640_REG_MIPI_CTRL00, BIT(5),
> > -                            on ? 0 : BIT(5));
> > -       if (ret)
> > -               return ret;
> > -       ret = ov5640_write_reg(sensor, OV5640_REG_PAD_OUTPUT00,
> > -                              on ? 0x00 : 0x70);
> > +       /*
> > +        * Enable/disable the MIPI interface
> > +        *
> > +        * 0x300e = on ? 0x45 : 0x40
> > +        * [7:5] = 001  : 2 data lanes mode
>
> Does 2-Lanes work with this config?
> AFAIU, if 2-Lanes is bit 5, value should be 0x25 and 0x20.
>

Yes, confusing.

The sensor manual reports
0x300e[7:5] = 000 one lane mode
0x300e[7:5] = 001 two lanes mode

Although this configuration works with 2 lanes, and the application
note I have, with the suggested settings for MIPI CSI-2 2 lanes
reports 0x40 to be the 2 lanes mode...

I used that one, also because the removed entry from the settings blob
is:
-       {0x300e, 0x45, 0, 0}, {0x302e, 0x08, 0, 0}, {0x4300, 0x3f, 0, 0},
+       {0x302e, 0x08, 0, 0}, {0x4300, 0x3f, 0, 0},

So it was using BIT(6) already.

I do not remember if I tested BIT(5) or not, it would be interesting
if someone using a 1-lane interface could try '000' and '001' maybe.

Anyway, it works for me with 2 lanes (and I assume Steve), you have tested
too, with how many lanes are you working with?

Anyway, a comment there might be nice to have... Will add in next
version

Thanks
   j

> > +        * [4] = 0      : Power up MIPI HS Tx
> > +        * [3] = 0      : Power up MIPI LS Rx
> > +        * [2] = 1/0    : MIPI interface enable/disable
> > +        * [1:0] = 01/00: FIXME: 'debug'
> > +        */
> > +       ret = ov5640_write_reg(sensor, OV5640_REG_IO_MIPI_CTRL00,
> > +                              on ? 0x45 : 0x40);
>
> Regards,
> Loic

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