Add output-enable generic pin configuration property.
This properties allows enabling/disabling pin's output capabilities
without actually driving any value on the line.

Signed-off-by: Jacopo Mondi <redacted>
---

So, after that many discussions I'm now sending this, that only adds a new
flag used to enable or disable a pin's output capabilities.
I intentionally avoided naming the output buffer explicitly because if and
how it has to be enabled/disabled is a platform specific details each
driver has to take care of.

Dong: this is similar to what you recently proposed, without mentioning the
output buffer directly. Can I have your Reviewed-by or your Acked-by here?

Linus, Andy: I initially proposed to add "output-buffer-enable" in place of
this one, so not to confuse the property's semantic with its real world
effect. While I'm still partially convinced output-enable is not the most
accurate choice possible, it certainly is the best balance with bindings
clearness, and the one where more consensus has been collected on. Hope
this flies for you too and we can have this merged so me and Dong can send
our updated series on top of this.

Thanks
   j

 Documentation/devicetree/bindings/pinctrl/pinctrl-bindings.txt | 2 ++
 drivers/pinctrl/pinconf-generic.c                              | 3 +++
 include/linux/pinctrl/pinconf-generic.h                        | 3 +++
 3 files changed, 8 insertions(+)

diff --git a/Documentation/devicetree/bindings/pinctrl/pinctrl-bindings.txt

b/Documentation/devicetree/bindings/pinctrl/pinctrl-bindings.txt index
f01d154..f8af190 100644

--- a/Documentation/devicetree/bindings/pinctrl/pinctrl-bindings.txt
+++ b/Documentation/devicetree/bindings/pinctrl/pinctrl-bindings.txt

@@ -259,6 +259,8 @@ input-debounce		- debounce mode with debound 

 power-source		- select between different power supplies
 low-power-enable	- enable low power mode
 low-power-disable	- disable low power mode
+output-disable		- disable output on a pin
+output-enable		- enable output on a pin
 output-low		- set the pin to output mode with low level
 output-high		- set the pin to output mode with high level
 slew-rate		- set the slew rate

diff --git a/drivers/pinctrl/pinconf-generic.c

b/drivers/pinctrl/pinconf-generic.c index 720a19f..fc0c230 100644

--- a/drivers/pinctrl/pinconf-generic.c
+++ b/drivers/pinctrl/pinconf-generic.c

@@ -44,6 +44,7 @@ static const struct pin_config_item conf_items[] = {
 	PCONFDUMP(PIN_CONFIG_INPUT_SCHMITT, "input schmitt trigger", NULL, 

 	PCONFDUMP(PIN_CONFIG_SLEW_RATE, "slew rate", NULL, true),

@@ -172,6 +173,8 @@ static const struct pinconf_generic_params dt_params[] =

{ { "input-schmitt-enable", PIN_CONFIG_INPUT_SCHMITT_ENABLE, 1 },
 	{ "low-power-disable", PIN_CONFIG_LOW_POWER_MODE, 0 },
 	{ "low-power-enable", PIN_CONFIG_LOW_POWER_MODE, 1 },
+	{ "output-disable", PIN_CONFIG_OUTPUT_ENABLE, 0 },
+	{ "output-enable", PIN_CONFIG_OUTPUT_ENABLE, 1 },
 	{ "output-high", PIN_CONFIG_OUTPUT, 1, },
 	{ "output-low", PIN_CONFIG_OUTPUT, 0, },
 	{ "power-source", PIN_CONFIG_POWER_SOURCE, 0 },

diff --git a/include/linux/pinctrl/pinconf-generic.h

b/include/linux/pinctrl/pinconf-generic.h index 7620eb1..5761958 100644

--- a/include/linux/pinctrl/pinconf-generic.h
+++ b/include/linux/pinctrl/pinconf-generic.h

@@ -73,6 +73,8 @@
  *	operation, if several modes of operation are supported these can be
  *	passed in the argument on a custom form, else just use argument 1
  *	to indicate low power mode, argument 0 turns low power mode off.
+ * @PIN_CONFIG_OUTPUT_ENABLE: this will enable the pin's output mode
+ * 	without driving a value there. 1 enables output mode, 0 disables it.

  * @PIN_CONFIG_OUTPUT: this will configure the pin as an output. Use
argument
  *	1 to indicate high level, argument 0 to indicate low level. (Please
  *	see Documentation/pinctrl.txt, section "GPIO mode pitfalls" for a

@@ -105,6 +107,7 @@ enum pin_config_param {
 	PIN_CONFIG_INPUT_SCHMITT,
 	PIN_CONFIG_INPUT_SCHMITT_ENABLE,
 	PIN_CONFIG_LOW_POWER_MODE,
+	PIN_CONFIG_OUTPUT_ENABLE,
 	PIN_CONFIG_OUTPUT,
 	PIN_CONFIG_POWER_SOURCE,
 	PIN_CONFIG_SLEW_RATE,
--

2.7.4