Messages in this thread | | | Date | Wed, 19 Jun 2013 16:03:01 -0600 | From | Stephen Warren <> | Subject | Re: [PATCH] pinctrl: establish pull-up/pull-down terminology |
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On 06/16/2013 04:45 AM, Linus Walleij wrote: > From: Linus Walleij <linus.walleij@linaro.org> > > It is counter-intuitive to have "0" mean disable in a boolean > manner for electronic properties of pins such as pull-up and > pull-down. Therefore, define that a pull-up/pull-down argument > of 0 to such a generic option means that the pin is > short-circuited to VDD or GROUND. Pull disablement shall be > done using PIN_CONFIG_BIAS_DISABLE. > > Cc: Heiko St�bner <heiko@sntech.de> > Cc: James Hogan <james.hogan@imgtec.com> > Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com> > Signed-off-by: Linus Walleij <linus.walleij@linaro.org> > --- > include/linux/pinctrl/pinconf-generic.h | 13 +++++++------ > 1 file changed, 7 insertions(+), 6 deletions(-) > > diff --git a/include/linux/pinctrl/pinconf-generic.h b/include/linux/pinctrl/pinconf-generic.h > index d414a77..67780f5 100644 > --- a/include/linux/pinctrl/pinconf-generic.h > +++ b/include/linux/pinctrl/pinconf-generic.h > @@ -36,14 +36,15 @@ > * tristate. The argument is ignored. > * @PIN_CONFIG_BIAS_PULL_UP: the pin will be pulled up (usually with high > * impedance to VDD). If the argument is != 0 pull-up is enabled, > - * if it is 0, pull-up is disabled. > + * if it is 0, pull-up it total, i.e. the pin is connected to VDD. > * @PIN_CONFIG_BIAS_PULL_DOWN: the pin will be pulled down (usually with high > * impedance to GROUND). If the argument is != 0 pull-down is enabled, > - * if it is 0, pull-down is disabled. > + * if it is 0, pull-down is total, i.e. the pin is connected to GROUND. > * @PIN_CONFIG_BIAS_PULL_PIN_DEFAULT: the pin will be pulled up or down based > * on embedded knowledge of the controller, like current mux function. > - * If the argument is != 0 pull up/down is enabled, if it is 0, > - * the pull is disabled. > + * If the argument is != 0 pull up/down is enabled, if it is 0, the > + * configuration is ignored. The proper way to disable it is to use > + * @PIN_CONFIG_BIAS_DISABLE.
Why treat PULL_UP/PULL_DOWN differently from PULL_PIN_DEFAULT? PULL_PIN_DEFAULT is logically simply a macro that selects PULL_UP/DOWN based on what's "normal" for the pin's expected usage, so surely the value associated with that option should behave identically?
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