Re: Nokia N900 - audio TPA6130A2 problems

Tony Lindgren
2016-03-17T13:33:22Z

* Ivaylo Dimitrov <ivo.g.dimitrov.75@gmail.com> [160317 06:11]:
> Hi,
>
> On 17.03.2016 15:01, Pali Rohár wrote:
> >On Thursday 17 March 2016 09:56:22 Ivaylo Dimitrov wrote:
> >>Hi,
> >>
> >
> >Is camera on same bus as tpa? Maybe this is reason why camera is
> >non-functional too?
> >
>
> It doesn't matter, all the i2c busses are missing the pullups.
>
> >>Will fix the board DTS file later on an will report
> >
> >Thanks for investigation! Is that problem in both DTS and also legacy
> >board code?
> >
>
> I guess legacy board code does not set i2c pull-ups either, as we
> have that problem since the beginning of time. Anyway, let me first
> check if enabling pullups really solves the issue, I hope to test that in a
> couple of hours when I am back home.
>
> Or you can do it yourself, it is just a matter of replacing PIN_INPUT with
> PIN_INPUT_PULLUP in https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/arch/arm/boot/dts/omap3-n900.dts?id=refs/tags/v4.5#n199
> for all the 3 ic2 busses

Check the schematics. If the hardware has external pull-ups on a
line then don't enable the internal pull-ups. Otherwise both the
external and intenal pulls are parallel the pull value will be
wrong. My guess is that on n900 all the i2c lines have external
pulls.

Regards,

Tony