Subject: [PATCH 4/7] drivers/gpio: gpio-nomadik: Provide documentation for Device Tree bindings

From: [email-masked] (Grant Likely)
Date: Thu, 05 Apr 2012 21:20:54 -0700

On Thu,  5 Apr 2012 10:55:45 +0100, Lee Jones <[email-masked]> wrote:
> Add required documentation for specific gpio-nomadik DT bindings.
> 
> Signed-off-by: Lee Jones <[email-masked]>
> ---
>  .../devicetree/bindings/gpio/gpio-nmk.txt          |   29 ++++++++++++++++++++
>  1 files changed, 29 insertions(+), 0 deletions(-)
>  create mode 100644 Documentation/devicetree/bindings/gpio/gpio-nmk.txt
> 
> diff --git a/Documentation/devicetree/bindings/gpio/gpio-nmk.txt b/Documentation/devicetree/bindings/gpio/gpio-nmk.txt
> new file mode 100644
> index 0000000..1555029
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/gpio/gpio-nmk.txt
> @@ -0,0 +1,29 @@
> +Nomadik GPIO controller
> +
> +Required properties:
> +- compatible           : Should be "stmicroelectronics,nomadik-gpio".

"stmicroelectronics," is a really long prefix.  You can use simply
"st," here since it has already been defined and documented in
Documentation/devicetree/bindings/vendor-prefixes.txt

> +- reg                  : Physical base address and length of the controller's registers.
> +- interrupts           : The interrupt outputs from the controller.
> +- #gpio-cells          : Should be two:
> +                           The first cell is the pin number.
> +                           The second cell is used to specify optional parameters:
> +                             - bits[3:0] trigger type and level flags:
> +                                 1 = low-to-high edge triggered.
> +                                 2 = high-to-low edge triggered.
> +                                 4 = active high level-sensitive.
> +                                 8 = active low level-sensitive.

Those look like interrupt flags, not gpio flags.  If the gpio lines
can be used as generic irq input lines, then this node should also
declare itself as an interrupt controller.

> +- gpio-controller      : Marks the device node as a GPIO controller.
> +- supports-sleepmode   : Specifies whether controller can sleep or not

Typically, custom properites that are for a specific device should be
prefixed with the manufacturer name.  So, something like:
"st,has-sleepmode".

> +- gpio-bank            : Specifies which bank a controller owns.

What is this for (how is it used)?  It shouldn't be needed to specify
a bank number.

> +
> +Example:
> +
> +                gpio1: gpio at 8012e080 {
> +                        compatible = "stmicroelectronics,nomadik-gpio";
> +                        reg =  <0x8012e080 0x80>;
> +                        interrupts = <0 120 0x4>;
> +                        #gpio-cells = <2>;
> +                        gpio-controller;
> +                        supports-sleepmode;
> +                        gpio-bank = <1>;
> +                };
> -- 
> 1.7.9.1
> 

-- 
Grant Likely, B.Sc, P.Eng.
Secret Lab Technologies,Ltd.