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authorLinus Walleij <linus.walleij@linaro.org>2013-06-16 12:43:06 +0200
committerLinus Walleij <linus.walleij@linaro.org>2013-06-17 18:18:32 +0200
commit5ca3353bcee929c3b7bbf39f79038842f443f01a (patch)
treeb9ca8539bef9bf05e6a170e25f5b243c49201d96
parent6abab2d4bec982bcefbe99201ddee5f25227daf4 (diff)
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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>
-rw-r--r--include/linux/pinctrl/pinconf-generic.h13
1 files changed, 7 insertions, 6 deletions
diff --git a/include/linux/pinctrl/pinconf-generic.h b/include/linux/pinctrl/pinconf-generic.h
index d414a7729424..10ad996afee4 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