pinctrl: clarify some dt pinconfig options

The bias-pull-* options use values > 0 to indicate that the pull should
be activated and optionally also indicate the strength of the pull.
Therefore use an default value of 1 for these options.

Split the low-power-mode option into low-power-enable and -disable.

Update the documentation to describe the param arguments better.

Reported-by: James Hogan <james.hogan@imgtec.com>
Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

Documentation/devicetree/bindings/pinctrl/pinctrl-bindings.txt

@@ -158,9 +158,29 @@ input-schmitt		- run in schmitt-trigger mode with hysteresis X
 input-debounce		- debounce mode with debound time X
 power-source		- select power source X
 slew-rate		- use slew-rate X
-low-power-mode		- low power mode
+low-power-enable	- enable low power mode
+low-power-disable	- disable low power mode
 output-low		- set the pin to output mode with low level
 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 0 to disable
+  the pull, on hardware supporting it the pull strength in Ohm. bias-disable
+  will also disable any active pull.
+
+- drive-strength takes as argument the target strength in mA.
+
+- input-schmitt takes as argument the adjustable hysteresis in a
+  driver-specific format
+
+- input-debounce takes the debounce time as argument or 0 to disable debouncing
+
+- power-source argument is the custom value describing the source to select
+
+- slew-rate takes as argument the target rate in a driver-specific format
+
+All parameters not listed here, do not take an argument.
+
 More in-depth documentation on these parameters can be found in
 <include/linux/pinctrl/pinconfig-generic.h>

drivers/pinctrl/pinconf-generic.c

@@ -152,9 +152,9 @@ static struct pinconf_generic_dt_params dt_params[] = {
 	{ "bias-disable", PIN_CONFIG_BIAS_DISABLE, 0 },
 	{ "bias-high-impedance", PIN_CONFIG_BIAS_HIGH_IMPEDANCE, 0 },
 	{ "bias-bus-hold", PIN_CONFIG_BIAS_BUS_HOLD, 0 },
-	{ "bias-pull-up", PIN_CONFIG_BIAS_PULL_UP, 0 },
-	{ "bias-pull-down", PIN_CONFIG_BIAS_PULL_DOWN, 0 },
-	{ "bias-pull-pin-default", PIN_CONFIG_BIAS_PULL_PIN_DEFAULT, 0 },
+	{ "bias-pull-up", PIN_CONFIG_BIAS_PULL_UP, 1 },
+	{ "bias-pull-down", PIN_CONFIG_BIAS_PULL_DOWN, 1 },
+	{ "bias-pull-pin-default", PIN_CONFIG_BIAS_PULL_PIN_DEFAULT, 1 },
 	{ "drive-push-pull", PIN_CONFIG_DRIVE_PUSH_PULL, 0 },
 	{ "drive-open-drain", PIN_CONFIG_DRIVE_OPEN_DRAIN, 0 },
 	{ "drive-open-source", PIN_CONFIG_DRIVE_OPEN_SOURCE, 0 },
@@ -165,7 +165,8 @@ static struct pinconf_generic_dt_params dt_params[] = {
 	{ "input-debounce", PIN_CONFIG_INPUT_DEBOUNCE, 0 },
 	{ "power-source", PIN_CONFIG_POWER_SOURCE, 0 },
 	{ "slew-rate", PIN_CONFIG_SLEW_RATE, 0 },
-	{ "low-power-mode", PIN_CONFIG_LOW_POWER_MODE, 0 },
+	{ "low-power-enable", PIN_CONFIG_LOW_POWER_MODE, 1 },
+	{ "low-power-disable", PIN_CONFIG_LOW_POWER_MODE, 0 },
 	{ "output-low", PIN_CONFIG_OUTPUT, 0, },
 	{ "output-high", PIN_CONFIG_OUTPUT, 1, },
 };