Re: [RFC PATCH 1/2] pinctrl: Add output-disable

[Linus Walleij]

On Tue, Oct 28, 2014 at 9:57 PM, Doug Anderson <dianders@xxxxxxxxxxxx> wrote:
> The pinctrl bindings / API allow you to specify that:
> - a pin should be an output
> - a pin should have its input path enabled / disabled
>
> ...but they don't allow you to tell a pin to stop outputting.  Lets
> add a new setting for that just in case the bootloader (or the default
> state) left a pin as an output and we don't want it that way anymore.
>
> Signed-off-by: Doug Anderson <dianders@xxxxxxxxxxxx>
(...)
> + * @PIN_CONFIG_OUTPUT_DISABLE: this will configure the pin _not_ to output.
> + *     Parameter should be 1.

This doesn't make sense. The pin is either low, high, some analog mode
or tristate/high impedance.

It does *not* stop existing.

Figure out the exact electronic meaning of what happens when you do
"output disable" in your hardware, I think it is very likely that
PIN_CONFIG_BIAS_HIGH_IMPEDANCE is what you are really
after here.

Yours,
Linus Walleij
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