Re: [PATCH 27/32] gpio: Add support for the FXL6408 GPIO expander.

From	Eric Anholt <eric@anholt.net>
Newsgroups	linux.kernel
Subject	Re: [PATCH 27/32] gpio: Add support for the FXL6408 GPIO expander.
Date	2016-06-09 19:30 +0200
Message-ID	<rIbWh-10d-5@gated-at.bofh.it> (permalink)
References	<rFmbv-5DL-15@gated-at.bofh.it> <rFmbv-5DL-13@gated-at.bofh.it> <rHHOy-6Iz-27@gated-at.bofh.it>
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Linus Walleij <linus.walleij@linaro.org> writes:

> On Wed, Jun 1, 2016 at 11:43 PM, Gerd Hoffmann <kraxel@redhat.com> wrote:
>
>> +#define FXL6408_OUTPUT                 0x05
>> +/* Bits here make the output High-Z, instead of the OUTPUT value. */
>> +#define FXL6408_OUTPUT_HIGH_Z          0x07
> (...)
>> +       /* Disable High-Z of outputs, so that our OUTPUT updates
>> +        * actually take effect.
>> +        */
>> +       i2c_smbus_write_byte_data(client, FXL6408_OUTPUT_HIGH_Z, 0);
>
> High-Z is probably the same as open drain right? And if not open drain,
> it is push-pull.
>
> So you want to implement .set_single_ended() for configuring the lines in
> "high-z", i.e. open drain output mode.

I'll keep this in mind for whenever I end up writing my next GPIO
driver, but this one is dead for now (not actually usable because of the
closed firmware).

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[PATCH 27/32] gpio: Add support for the FXL6408 GPIO expander. Gerd Hoffmann <kraxel@redhat.com> - 2016-06-01 23:50 +0200
  Re: [PATCH 27/32] gpio: Add support for the FXL6408 GPIO expander. Eric Anholt <eric@anholt.net> - 2016-06-07 02:00 +0200
  Re: [PATCH 27/32] gpio: Add support for the FXL6408 GPIO expander. Florian Fainelli <f.fainelli@gmail.com> - 2016-06-07 02:10 +0200
  Re: [PATCH 27/32] gpio: Add support for the FXL6408 GPIO expander. Linus Walleij <linus.walleij@linaro.org> - 2016-06-08 11:20 +0200
    Re: [PATCH 27/32] gpio: Add support for the FXL6408 GPIO expander. Eric Anholt <eric@anholt.net> - 2016-06-09 19:30 +0200

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