[v4,2/2] gpio: Document GPIO hogging mechanism
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Message ID 1418422051-9471-3-git-send-email-bparrot@ti.com
State Changes Requested
Headers show

Commit Message

Benoit Parrot Dec. 12, 2014, 10:07 p.m. UTC
Add GPIO hogging documentation to gpio.txt

Signed-off-by: Benoit Parrot <bparrot@ti.com>
---
Changes since v3:
 * Renamed the "direction" DT properties to "state".

 Documentation/devicetree/bindings/gpio/gpio.txt | 23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)

Comments

Alexandre Courbot Dec. 17, 2014, 8:43 a.m. UTC | #1
A few nits:

On Sat, Dec 13, 2014 at 7:07 AM, Benoit Parrot <bparrot@ti.com> wrote:
> Add GPIO hogging documentation to gpio.txt
>
> Signed-off-by: Benoit Parrot <bparrot@ti.com>
> ---
> Changes since v3:
>  * Renamed the "direction" DT properties to "state".
>
>  Documentation/devicetree/bindings/gpio/gpio.txt | 23 +++++++++++++++++++++++
>  1 file changed, 23 insertions(+)
>
> diff --git a/Documentation/devicetree/bindings/gpio/gpio.txt b/Documentation/devicetree/bindings/gpio/gpio.txt
> index 3fb8f53..a38da91 100644
> --- a/Documentation/devicetree/bindings/gpio/gpio.txt
> +++ b/Documentation/devicetree/bindings/gpio/gpio.txt
> @@ -103,6 +103,22 @@ Every GPIO controller node must contain both an empty "gpio-controller"
>  property, and a #gpio-cells integer property, which indicates the number of
>  cells in a gpio-specifier.
>
> +The GPIO chip may contain GPIO hog definitions. GPIO hogging is a mechanism
> +providing automatic GPIO request and configuration as part of the
> +gpio-controller's driver probe function.
> +
> +Each GPIO hog definition is represented as a child node of the GPIO controller.
> +Required properties:
> +- gpio-hog:  A property specifying that this child node represent a gpio-hog.

... represent a GPIO hog.

> +- gpios:     Store the gpio information (id, flags, ...). Shall contain the
> +            number of cells specified in its parent node (GPIO controller
> +            node).
> +- state:     A property specifying the direction/value needed. This property
> +            can take the folowing values: input, output-high, output-low.

s/folowing/following

This aside,

Reviewed-by: Alexandre Courbot <acourbot@nvidia.com>
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Patch
diff mbox

diff --git a/Documentation/devicetree/bindings/gpio/gpio.txt b/Documentation/devicetree/bindings/gpio/gpio.txt
index 3fb8f53..a38da91 100644
--- a/Documentation/devicetree/bindings/gpio/gpio.txt
+++ b/Documentation/devicetree/bindings/gpio/gpio.txt
@@ -103,6 +103,22 @@  Every GPIO controller node must contain both an empty "gpio-controller"
 property, and a #gpio-cells integer property, which indicates the number of
 cells in a gpio-specifier.
 
+The GPIO chip may contain GPIO hog definitions. GPIO hogging is a mechanism
+providing automatic GPIO request and configuration as part of the
+gpio-controller's driver probe function.
+
+Each GPIO hog definition is represented as a child node of the GPIO controller.
+Required properties:
+- gpio-hog:  A property specifying that this child node represent a gpio-hog.
+- gpios:     Store the gpio information (id, flags, ...). Shall contain the
+	     number of cells specified in its parent node (GPIO controller
+	     node).
+- state:     A property specifying the direction/value needed. This property
+	     can take the folowing values: input, output-high, output-low.
+
+Optional properties:
+- line-name: The GPIO label name. If not present the node name is used.
+
 Example of two SOC GPIO banks defined as gpio-controller nodes:
 
 	qe_pio_a: gpio-controller@1400 {
@@ -110,6 +126,13 @@  Example of two SOC GPIO banks defined as gpio-controller nodes:
 		reg = <0x1400 0x18>;
 		gpio-controller;
 		#gpio-cells = <2>;
+
+		line_b {
+			gpio-hog;
+			gpios = <6 0>;
+			state = "output-low";
+			line-name = "foo-bar-gpio";
+		};
 	};
 
 	qe_pio_e: gpio-controller@1460 {