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    SubjectRe: [RFC PATCH v2 00/13] arm/tegra: Initialize GPIO & pinmux from DT
    On Tue, Aug 16, 2011 at 4:37 PM, Arnd Bergmann <> wrote:
    > On Tuesday 16 August 2011, Linus Walleij wrote:
    >> Say mmc instance 0 need pingroup foo on pincontroller bar
    >> means that there must be a specific reference from mmc.0:s
    >> struct device * to pinctrl bar:s struct device *. Maybe this is
    >> peanuts in DT, sorry not enough insight.
    > I think what you are looking for is the equivalent of the
    > interrupt-parent property for pinmux. The idea is that each
    > node in the device tree can point to a device managing the
    > pinmux, so reference would point to a local number in that
    > space. We have discussed this for the GPIO case already, and
    > I suspect that the two should be identical (gpio-controller
    > and pinmux-controller using the same device node and same
    > property to refer to them).

    Yes. I discussed with Grant and his idea is for e.g.
    advanced combined pincontrol + GPIO blocks that handle
    a lot of stuff like muxing, biasing and GPIO, to expose
    a single pinctrl device that in turn provide also a gpio_chip
    in addition to the pinctrl interfaces so tehy should be
    all on the same struct device *

    > Since the pinmux-parent
    > (gpio-parent, ...) property gets inherited by all child
    > devices, you only need to set it once at the root of the
    > device tree for the simple case where there is only one
    > controller.

    This will likely be the case for most of the advanced muxes
    I know of, OMAP, Tegra and Nomadik.

    Linus Walleij

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