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Re: Nokia N900 - audio TPA6130A2 problems

From Tony Lindgren <tony@atomide.com>
Newsgroups linux.kernel
Subject Re: Nokia N900 - audio TPA6130A2 problems
Date 2016-03-17 15:40 +0100
Message-ID <rdHfI-9X-7@gated-at.bofh.it> (permalink)
References (5 earlier) <rdB0C-4pn-15@gated-at.bofh.it> <rdFQD-7QE-31@gated-at.bofh.it> <rdG0i-7TR-9@gated-at.bofh.it> <rdGjE-80w-19@gated-at.bofh.it> <rdGD0-87J-1@gated-at.bofh.it>
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* Ivaylo Dimitrov <ivo.g.dimitrov.75@gmail.com> [160317 06:51]:
> Hi,
> 
> On 17.03.2016 15:33, Tony Lindgren wrote:
> >
> >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.
> 
> There are, 1k connected to VIO_18, but still, stock Nokia kernel enables the
> internal pull-ups as well. I doubt Nokia devs did that by mistake. Could it
> be that VIO_18 is disabled by the time  TPA6130A2 is probed?

Seems like a bug to me. My bets are on the deferred probe related
Peter posted.

> Also, what is the problem to have both internal and external pull-ups in
> parallel?

You can calculate the parallel resistor value of the weak internal
pull with the 1k external pull :) If the i2c line pulls are wrong
the signal quality won't match the spec and you will be getting
i2c bus errors. If you can read and write to the i2c chip, this
is not the issue.

Regards,

Tony

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Thread

Re: Nokia N900 - audio TPA6130A2 problems Sebastian Reichel <sre@kernel.org> - 2016-03-06 16:30 +0100
  Re: Nokia N900 - audio TPA6130A2 problems Pali Rohár <pali.rohar@gmail.com> - 2016-03-07 13:00 +0100
    Re: Nokia N900 - audio TPA6130A2 problems Ivaylo Dimitrov <ivo.g.dimitrov.75@gmail.com> - 2016-03-08 07:50 +0100
      Re: Nokia N900 - audio TPA6130A2 problems Pali Rohár <pali.rohar@gmail.com> - 2016-03-12 13:50 +0100
  Re: Nokia N900 - audio TPA6130A2 problems Pali Rohár <pali.rohar@gmail.com> - 2016-03-12 13:50 +0100
    Re: Nokia N900 - audio TPA6130A2 problems Peter Ujfalusi <peter.ujfalusi@ti.com> - 2016-03-14 11:10 +0100
      Re: Nokia N900 - audio TPA6130A2 problems Ivaylo Dimitrov <ivo.g.dimitrov.75@gmail.com> - 2016-03-14 18:10 +0100
      Re: Nokia N900 - audio TPA6130A2 problems Pali Rohár <pali.rohar@gmail.com> - 2016-03-16 14:40 +0100
        Re: Nokia N900 - audio TPA6130A2 problems Sebastian Reichel <sre@kernel.org> - 2016-03-16 15:50 +0100
          Re: Nokia N900 - audio TPA6130A2 problems Ivaylo Dimitrov <ivo.g.dimitrov.75@gmail.com> - 2016-03-16 19:30 +0100
            Re: Nokia N900 - audio TPA6130A2 problems Grygorii Strashko <grygorii.strashko@ti.com> - 2016-03-16 19:40 +0100
              Re: Nokia N900 - audio TPA6130A2 problems Ivaylo Dimitrov <ivo.g.dimitrov.75@gmail.com> - 2016-03-16 21:00 +0100
                Re: Nokia N900 - audio TPA6130A2 problems Sebastian Reichel <sre@kernel.org> - 2016-03-17 01:50 +0100
                Re: Nokia N900 - audio TPA6130A2 problems Ivaylo Dimitrov <ivo.g.dimitrov.75@gmail.com> - 2016-03-17 09:00 +0100
                Re: Nokia N900 - audio TPA6130A2 problems Pali Rohár <pali.rohar@gmail.com> - 2016-03-17 14:10 +0100
                Re: Nokia N900 - audio TPA6130A2 problems Ivaylo Dimitrov <ivo.g.dimitrov.75@gmail.com> - 2016-03-17 14:20 +0100
                Re: Nokia N900 - audio TPA6130A2 problems Tony Lindgren <tony@atomide.com> - 2016-03-17 14:40 +0100
                Re: Nokia N900 - audio TPA6130A2 problems Ivaylo Dimitrov <ivo.g.dimitrov.75@gmail.com> - 2016-03-17 15:00 +0100
                Re: Nokia N900 - audio TPA6130A2 problems Tony Lindgren <tony@atomide.com> - 2016-03-17 15:40 +0100
                Re: Nokia N900 - audio TPA6130A2 problems Ivaylo Dimitrov <ivo.g.dimitrov.75@gmail.com> - 2016-03-17 16:00 +0100
                Re: Nokia N900 - audio TPA6130A2 problems Peter Ujfalusi <peter.ujfalusi@ti.com> - 2016-03-17 09:00 +0100
                Re: Nokia N900 - audio TPA6130A2 problems Ivaylo Dimitrov <ivo.g.dimitrov.75@gmail.com> - 2016-03-17 18:30 +0100
                Re: Nokia N900 - audio TPA6130A2 problems Peter Ujfalusi <peter.ujfalusi@ti.com> - 2016-03-18 11:40 +0100
                Re: Nokia N900 - audio TPA6130A2 problems Ивайло Димитров   <ivo.g.dimitrov.75@gmail.com> - 2016-03-18 14:20 +0100
                Re: Nokia N900 - audio TPA6130A2 problems Sebastian Reichel <sre@kernel.org> - 2016-03-18 14:40 +0100
                Re: Nokia N900 - audio TPA6130A2 problems Ivaylo Dimitrov <ivo.g.dimitrov.75@gmail.com> - 2016-03-18 14:50 +0100
                Re: Nokia N900 - audio TPA6130A2 problems Sebastian Reichel <sre@kernel.org> - 2016-03-18 16:10 +0100
                Re: Nokia N900 - audio TPA6130A2 problems Ivaylo Dimitrov <ivo.g.dimitrov.75@gmail.com> - 2016-03-18 17:00 +0100
                Re: Nokia N900 - audio TPA6130A2 problems Ivaylo Dimitrov <ivo.g.dimitrov.75@gmail.com> - 2016-03-19 10:00 +0100
                Re: Nokia N900 - audio TPA6130A2 problems Sebastian Reichel <sre@kernel.org> - 2016-03-20 06:20 +0100
                Re: Nokia N900 - audio TPA6130A2 problems Ivaylo Dimitrov <ivo.g.dimitrov.75@gmail.com> - 2016-03-20 20:50 +0100
                Re: Nokia N900 - audio TPA6130A2 problems Sebastian Reichel <sre@kernel.org> - 2016-03-21 01:10 +0100
                Re: Nokia N900 - audio TPA6130A2 problems Sebastian Reichel <sre@kernel.org> - 2016-03-21 02:50 +0100
                Re: Nokia N900 - audio TPA6130A2 problems Mark Brown <broonie@kernel.org> - 2016-03-21 13:10 +0100
                Re: Nokia N900 - audio TPA6130A2 problems Mark Brown <broonie@kernel.org> - 2016-03-21 12:50 +0100
                Re: Nokia N900 - audio TPA6130A2 problems Ivaylo Dimitrov <ivo.g.dimitrov.75@gmail.com> - 2016-03-21 14:40 +0100
                Re: Nokia N900 - audio TPA6130A2 problems Mark Brown <broonie@kernel.org> - 2016-03-21 14:50 +0100
                Re: Nokia N900 - audio TPA6130A2 problems Sebastian Reichel <sre@kernel.org> - 2016-03-21 16:00 +0100
                Re: Nokia N900 - audio TPA6130A2 problems Ivaylo Dimitrov <ivo.g.dimitrov.75@gmail.com> - 2016-03-21 20:40 +0100
                Re: Nokia N900 - audio TPA6130A2 problems Ivaylo Dimitrov <ivo.g.dimitrov.75@gmail.com> - 2016-03-22 09:10 +0100
          Race condition in TPA6130A2 (Was: Re: Nokia N900 - audio TPA6130A2  problems) Pali Rohár <pali.rohar@gmail.com> - 2016-04-01 12:50 +0200

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