diff options
| author | Linus Walleij <linus.walleij@linaro.org> | 2013-06-16 12:43:06 +0200 |
|---|---|---|
| committer | Linus Walleij <linus.walleij@linaro.org> | 2013-06-17 18:18:32 +0200 |
| commit | 5ca3353bcee929c3b7bbf39f79038842f443f01a (patch) | |
| tree | b9ca8539bef9bf05e6a170e25f5b243c49201d96 /include/linux/pinctrl | |
| parent | 6abab2d4bec982bcefbe99201ddee5f25227daf4 (diff) | |
pinctrl: establish pull-up/pull-down terminology
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: James Hogan <james.hogan@imgtec.com>
Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by Heiko Stuebner <heiko@sntech.de>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Diffstat (limited to 'include/linux/pinctrl')
| -rw-r--r-- | include/linux/pinctrl/pinconf-generic.h | 13 |
1 files changed, 7 insertions, 6 deletions
diff --git a/include/linux/pinctrl/pinconf-generic.h b/include/linux/pinctrl/pinconf-generic.h index d414a772942..10ad996afee 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 is 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. * @PIN_CONFIG_DRIVE_PUSH_PULL: the pin will be driven actively high and * low, this is the most typical case and is typically achieved with two * active transistors on the output. Setting this config will enable @@ -72,8 +73,8 @@ * supplies, the argument to this parameter (on a custom format) tells * the driver which alternative power source to use. * @PIN_CONFIG_SLEW_RATE: if the pin can select slew rate, the argument to - * this parameter (on a custom format) tells the driver which alternative - * slew rate to use. + * this parameter (on a custom format) tells the driver which alternative + * slew rate to use. * @PIN_CONFIG_LOW_POWER_MODE: this will configure the pin for low power * operation, if several modes of operation are supported these can be * passed in the argument on a custom form, else just use argument 1 |