Re: [PATCH v8 1/2] drivers/gpio: Altera soft IP GPIO driver device tree binding

[Linus Walleij <linus.walleij@xxxxxxxxxx>]

On Wed, Dec 24, 2014 at 9:22 AM,  <thloh@xxxxxxxxxx> wrote:

> From: Tien Hock Loh <thloh@xxxxxxxxxx>
>
> Adds a new driver device tree binding for Altera soft GPIO IP
>
> Signed-off-by: Tien Hock Loh <thloh@xxxxxxxxxx>
> ---
>  .../devicetree/bindings/gpio/gpio-altera.txt       |   43 ++++++++++++++++++++
>  1 files changed, 43 insertions(+), 0 deletions(-)
>  create mode 100644 Documentation/devicetree/bindings/gpio/gpio-altera.txt
>
> diff --git a/Documentation/devicetree/bindings/gpio/gpio-altera.txt b/Documentation/devicetree/bindings/gpio/gpio-altera.txt
> new file mode 100644
> index 0000000..649fa02
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/gpio/gpio-altera.txt
> @@ -0,0 +1,43 @@
> +Altera GPIO controller bindings
> +
> +Required properties:
> +- compatible:
> +  - "altr,pio-1.0"
> +- reg: Physical base address and length of the controller's registers.
> +- #gpio-cells : Should be 2

Yeah.

> +  - The first cell is the gpio offset number.
> +  - The second cell is reserved and is currently unused.
> +- gpio-controller : Marks the device node as a GPIO controller.
> +- interrupt-controller: Mark the device node as an interrupt controller
> +- #interrupt-cells : Should be 1. The interrupt type is fixed in the hardware.
> +  - The first cell is the GPIO offset number within the GPIO controller.
> +- interrupts: Specify the interrupt.
> +- altr,interrupt-trigger: Specifies the interrupt trigger type the GPIO
> +  hardware is synthesized. This field is required if the Altera GPIO controller
> +  used has IRQ enabled as the interrupt type is not software controlled,
> +  but hardware synthesized. Required if GPIO is used as an interrupt
> +  controller. The value is defined in <dt-bindings/interrupt-controller/irq.h>
> +  Only the following flags are supported:
> +    IRQ_TYPE_EDGE_RISING
> +    IRQ_TYPE_EDGE_FALLING
> +    IRQ_TYPE_EDGE_BOTH
> +    IRQ_TYPE_LEVEL_HIGH
> +
> +Optional properties:
> +- altr,ngpio: Width of the GPIO bank. This defines how many pins the
> +  GPIO device has. Ranges between 1-32. Optional and defaults to 32 is not
> +  specified.
> +
> +Example:
> +
> +gpio_altr: gpio@0xff200000 {
> +       compatible = "altr,pio-1.0";
> +       reg = <0xff200000 0x10>;
> +       interrupts = <0 45 4>;
> +       altr,ngpio = <32>;
> +       altr,interrupt_trigger = <IRQ_TYPE_EDGE_RISING>;
> +       #gpio-cells = <1>;

So why is there one cell in the example?

I know the second cell will describe the interrupt type that is
anyway hardcoded but yeah, I guess it is best to work
like all other controllers.

If you actually want it onecell that is fine too.

Yours,
Linus Walleij
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