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SubjectRe: [PATCH 1/4] Make non-linear GPIO ranges accesible from gpiolib
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On Tue, Jun 18, 2013 at 11:29 AM, Christian Ruppert
<christian.ruppert@abilis.com> wrote:

> This patch adds the infrastructure required to register non-linear gpio
> ranges through gpiolib and the standard GPIO device tree bindings.
>
> Signed-off-by: Christian Ruppert <christian.ruppert@abilis.com>

I'm basically fine with this, but would like Stephen's ACK if possible.

> +In addition, named groups of pins can be mapped to pin groups of a given
> +pin controller:
> +
> + gpio_pio_g: gpio-controller@1480 {
> + #gpio-cells = <2>;
> + compatible = "fsl,qe-pario-bank-e", "fsl,qe-pario-bank";
> + reg = <0x1480 0x18>;
> + gpio-controller;
> + gpio-ranges = <&pinctrl1 0 0 0>, <&pinctrl2 3 0 0>;
> + gpio-ranges-group-names = "foo", "bar";
> + };
> +
> +where,
> + &pinctrl1 and &pinctrl2 is the phandle to the pinctrl DT node.
> +
> + The following value specifies the base GPIO offset of the pin range with
> + respect to the GPIO controller's base. The remaining two values must be
> + 0 to indicate that a named pin group should be used for the respective
> + range. The number of pins in the range is the number of pins in the pin
> + group.

So while this works, these zeroes seem a bit awkward, but maybe
it's the only way?

I'm not good enough on device tree conventions, but isn't this possible:

gpio-ranges = <&pinctrl1 0>, <&pinctrl2 3>;
gpio-ranges-group-names = "foo", "bar";

Since we don't have any #gpio-ranges-cells or anything like that I
guess we can define this to have a flexible number of cells
depending on use case?

In the mixed case the blank groups does not look
good eitherm, wouldn't this be possible:


gpio-ranges = <&pinctrl1 0 20 10>,
<&pinctrl2 10>,
<&pinctrl1 15 0 10>,
<&pinctrl2 25>;
// Matches the two ranges without pins
gpio-ranges-group-names = "foo", "bar";

Or is this just making things complicated?

Yours,
Linus Walleij


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