• Stephen Warren's avatar
    gpio: clean up gpio-ranges documentation · a1bc260b
    Stephen Warren authored
    This change makes documentation of the the gpio-ranges property shorter
    and more succinct, more consistent with the style of the rest of the
    document, and not mention Linux-specifics such as the API
    pinctrl_request_gpio(); DT binding documents should be OS independant
    where at all possible. As part of this, the gpio-ranges property's format
    is described in BNF form, in order to match the rest of the document.
    
    This change also deprecates the #gpio-range-cells property. Such
    properties are useful when one node references a second node, and that
    second node dictates the format of the reference. However, that is not
    the case here; the definition of gpio-ranges itself always dictates its
    format entirely, and hence the value #gpio-range-cells must always be 3,
    and hence there is no point requiring any referenced node to include
    this property. The only remaining need for this property is to ensure
    compatibility of DTs with older SW that was written to support the
    previous version of the binding.
    
    v4:
    * Mention #gpio-range-cells as being deprecated, rather than removing all
      documentation of that property. This allows DTs to be written in a
      backwards-compatible way if desired, and also allows older DTs to be
      interpreted fully using the latest documentation.
    v3:
    * Mention BNF in commit description.
    * Fixed typo.
    * Dropped patch that removed the deprecated property from *.dts, since
      it's required to boot older kernels.
    Signed-off-by: default avatarStephen Warren <swarren@nvidia.com>
    Acked-by: default avatarMark Rutland <mark.rutland@arm.com>
    Signed-off-by: default avatarLinus Walleij <linus.walleij@linaro.org>
    a1bc260b
gpio.txt 3.84 KB