On Tue, Sep 6, 2016 at 4:15 PM, Linus Walleij <linus.walleij@xxxxxxxxxx> wrote: > pa: pinctrla { > compatible = "parent-device-compat"; > (...) > }; > > pb: pinctrlb { > compatible = "child-device-compat"; > pinctrl-parent = &pinctrla; > (...) > }; After thinking some more I kind of fancy the GPIO ranges approach to be reused: pa: pinctrla { compatible = "parent-device-compat"; (...) }; pb: pinctrlb { compatible = "child-device-compat"; pinctrl-ranges = <&pa 0 31 0>; (...) }; The definition and use would be similar to gpio-ranges, see: Documentation/devicetree/bindings/gpio/gpio.txt, but these bindings are specified in BNF which IMO is just confusing. Anyways its <phandle local-offset count remote-offset> Also group names are supported for GPIO ranges. In the Linux implementation this facilitates reuse of the existing GPIO ranges parsing and resolution. To make cross-calls we need an abstract call akin to the existing pinctrl_request_gpio() and pinctrl_free_gpio() just named pinctrl_request_hierarchical() pinctrl_free_hierarchical() or so so it is chrystal clear what is going on when reading the code. As this passes through the pinctrl driver core, new callbacks are needed in struct pinmux_ops such as .hierarchical_request(), .hierarchical_free(). This is going to be complex, but a way more maintainable solution than doing the hack in patch 1/3 where we totally loose control and definition of what happens. Yours, Linus Walleij -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html