pinctrl: more clarifications for generic pull configs
From: Heiko Stuebner <heiko@...> Date: Mon, 24 Jun 2013 21:54:16 +0200
Commit-Message
PULL_PIN_DEFAULT is meant for hardware completely hiding any pull settings from the driver, so that it's really only possible to turn the pull on or off, but it not being possible to determine any pull settings from software. Also the binding-documentation for the pull arguments did not match the changes to the expected values. Signed-off-by: Heiko Stuebner <heiko@...>
Patch-Comment
Documentation/devicetree/bindings/pinctrl/pinctrl-bindings.txt | 5 ++--- include/linux/pinctrl/pinconf-generic.h | 5 ++++- 2 files changed, 6 insertions(+), 4 deletions(-)
Statistics
- 6 lines added
- 4 lines removed
Changes
-------- Documentation/devicetree/bindings/pinctrl/pinctrl-bindings.txt --------
index 2d730e3..7498bdc 100644
@@ -165,9 +165,8 @@ output-high - set the pin to output mode with high level
Arguments for parameters:
+- bias-pull-up, -down and -pin-default take as optional argument on hardware
+ supporting it the pull strength in Ohm. bias-disable will disable the pull.
- drive-strength takes as argument the target strength in mA.
------------------- include/linux/pinctrl/pinconf-generic.h --------------------
index 10ad996..48aa4ba 100644
@@ -41,7 +41,10 @@
* impedance to GROUND). If the argument is != 0 pull-down is enabled,
* 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 hardware, like current mux
+ * function. The pull direction and possibly strength too will normally
+ * be decided completely inside the hardware block and not be readable
+ * from the kernel side.
* 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.