[1/2] devicetree: add a binding for GPIOs going though a level shifter

Signed-off-by: Alban Bedel <alban.bedel@avionic-design.de>
---
 .../devicetree/bindings/gpio/gpio-level-shifter.txt       | 15 +++++++++++++++
 1 file changed, 15 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/gpio/gpio-level-shifter.txt

On Mon, Nov 24, 2014 at 8:01 AM, Alban Bedel
<alban.bedel@avionic-design.de> wrote:
> Signed-off-by: Alban Bedel <alban.bedel@avionic-design.de>
> ---
>  .../devicetree/bindings/gpio/gpio-level-shifter.txt       | 15 +++++++++++++++
>  1 file changed, 15 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/gpio/gpio-level-shifter.txt
>
> diff --git a/Documentation/devicetree/bindings/gpio/gpio-level-shifter.txt b/Documentation/devicetree/bindings/gpio/gpio-level-shifter.txt
> new file mode 100644
> index 0000000..e108c43
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/gpio/gpio-level-shifter.txt
> @@ -0,0 +1,15 @@
> +GPIO level shifter
> +
> +This binding allow supporting GPIOs going though a level shifter.
> +
> +Required properties:
> +- compatible : should be "gpio-level-shifter"
> +- data-gpios : list of the data GPIO phandles
> +- #gpio-cells : should be 2
> +- gpio-controller : marks the device node as a GPIO controller
> +
> +Optional properties:
> +- enable-gpio : phandle of the GPIO that control the level shifter enable pin
> +- direction-gpio : phandle of the GPIO that control the level shifter direction

What if you had 2 level shifters with a common enable, but with
different directions? We'd have to support an ORing of the enable
state. That's largely a gpio subsystem problem I guess.

Otherwise, this looks pretty good to me:

Acked-by: Rob Herring <robh@kernel.org>

Rob

> +- vcca-supply : phandle of the regulator for side A of the level shifter
> +- vccb-supply : phandle of the regulator for side B of the level shifter
> --
> 2.1.3
>
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On Mon, Nov 24, 2014 at 3:01 PM, Alban Bedel
<alban.bedel@avionic-design.de> wrote:

> Signed-off-by: Alban Bedel <alban.bedel@avionic-design.de>
> ---
>  .../devicetree/bindings/gpio/gpio-level-shifter.txt       | 15 +++++++++++++++
>  1 file changed, 15 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/gpio/gpio-level-shifter.txt
>
> diff --git a/Documentation/devicetree/bindings/gpio/gpio-level-shifter.txt b/Documentation/devicetree/bindings/gpio/gpio-level-shifter.txt
> new file mode 100644
> index 0000000..e108c43
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/gpio/gpio-level-shifter.txt
> @@ -0,0 +1,15 @@
> +GPIO level shifter
> +
> +This binding allow supporting GPIOs going though a level shifter.
> +
> +Required properties:
> +- compatible : should be "gpio-level-shifter"
> +- data-gpios : list of the data GPIO phandles
> +- #gpio-cells : should be 2
> +- gpio-controller : marks the device node as a GPIO controller
> +
> +Optional properties:
> +- enable-gpio : phandle of the GPIO that control the level shifter enable pin
> +- direction-gpio : phandle of the GPIO that control the level shifter direction
> +- vcca-supply : phandle of the regulator for side A of the level shifter
> +- vccb-supply : phandle of the regulator for side B of the level shifter

It must be clear which side is facing the parent GPIO controller,
A or B.

It must be clear which one of these two should be used if the level shifter
has ony VCC.

And isn't the proper terminology VCC+VDD?

An example must be provided.

Yours,
Linus Walleij
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