Re: [PATCH] pinctrl: update GPIO range doc

From: Christian Ruppert
Date: Mon Jun 17 2013 - 04:12:54 EST


On Sun, Jun 16, 2013 at 12:18:29PM +0200, Linus Walleij wrote:
> From: Linus Walleij <linus.walleij@xxxxxxxxxx>
>
> This updates the GPIO range documentation with the API changes
> for sparse/random/arbitrary pin-to-GPIO mappings.

Oops, sorry, I should have thought of updating this with my previous
patch. Thanks for stepping in.

Reviewed-by: Christian Ruppert <christian.ruppert@xxxxxxxxxx>

> Cc: Christian Ruppert <christian.ruppert@xxxxxxxxxx>
> Signed-off-by: Linus Walleij <linus.walleij@xxxxxxxxxx>
> ---
> Documentation/pinctrl.txt | 24 +++++++++++++++++++++---
> 1 file changed, 21 insertions(+), 3 deletions(-)
>
> diff --git a/Documentation/pinctrl.txt b/Documentation/pinctrl.txt
> index f6e664b..4548743 100644
> --- a/Documentation/pinctrl.txt
> +++ b/Documentation/pinctrl.txt
> @@ -350,6 +350,23 @@ chip b:
> - GPIO range : [48 .. 55]
> - pin range : [64 .. 71]
>
> +The above examples assume the mapping between the GPIOs and pins is
> +linear. If the mapping is sparse or haphazard, an array of arbitrary pin
> +numbers can be encoded in the range like this:
> +
> +static const unsigned range_pins[] = { 14, 1, 22, 17, 10, 8, 6, 2 };
> +
> +static struct pinctrl_gpio_range gpio_range = {
> + .name = "chip",
> + .id = 0,
> + .base = 32,
> + .pins = &range_pins,
> + .npins = ARRAY_SIZE(range_pins),
> + .gc = &chip;
> +};
> +
> +In this case the pin_base property will be ignored.
> +
> When GPIO-specific functions in the pin control subsystem are called, these
> ranges will be used to look up the appropriate pin controller by inspecting
> and matching the pin to the pin ranges across all controllers. When a
> @@ -357,9 +374,9 @@ pin controller handling the matching range is found, GPIO-specific functions
> will be called on that specific pin controller.
>
> For all functionalities dealing with pin biasing, pin muxing etc, the pin
> -controller subsystem will subtract the range's .base offset from the passed
> -in gpio number, and add the ranges's .pin_base offset to retrive a pin number.
> -After that, the subsystem passes it on to the pin control driver, so the driver
> +controller subsystem will look up the corresponding pin number from the passed
> +in gpio number, and use the ranges internals to retrive a pin number. After
> +that, the subsystem passes it on to the pin control driver, so the driver
> will get an pin number into its handled number range. Further it is also passed
> the range ID value, so that the pin controller knows which range it should
> deal with.
> @@ -368,6 +385,7 @@ Calling pinctrl_add_gpio_range from pinctrl driver is DEPRECATED. Please see
> section 2.1 of Documentation/devicetree/bindings/gpio/gpio.txt on how to bind
> pinctrl and gpio drivers.
>
> +
> PINMUX interfaces
> =================
>
> --
> 1.7.11.3
>

--
Christian Ruppert , <christian.ruppert@xxxxxxxxxx>
/|
Tel: +41/(0)22 816 19-42 //| 3, Chemin du Pré-Fleuri
_// | bilis Systems CH-1228 Plan-les-Ouates
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