Hi Marek,
On Sun, Feb 17, 2019 at 8:00 AM <[email protected]> wrote:
> From: Marek Vasut <[email protected]>
> Reword the binding document to make it clear how the propeties work
> and which properties affect which other properties.
>
> Signed-off-by: Marek Vasut <[email protected]>
> Cc: Harald Geyer <[email protected]>
> Cc: Kuninori Morimoto <[email protected]>
> Cc: Linus Walleij <[email protected]>
> Cc: Mark Brown <[email protected]>
> Cc: Rob Herring <[email protected]>
> Cc: [email protected]
> To: [email protected]
> ---
> Note: The recent gpio-regulator rework caused breakage. While the
> changes in the gpio-regulator code were according to the DT
> binding document, they stopped working with older DTs. Make
> the binding document clearer to prevent such breakage in the
> future.
Thanks, adding more worms to the can, below...
> --- a/Documentation/devicetree/bindings/regulator/gpio-regulator.txt
> +++ b/Documentation/devicetree/bindings/regulator/gpio-regulator.txt
> @@ -4,16 +4,25 @@ Required properties:
> - compatible : Must be "regulator-gpio".
> - regulator-name : Defined in regulator.txt as optional, but required
> here.
> -- states : Selection of available voltages and GPIO configs.
> - if there are no states, then use a fixed regulator
> +- states : Selection of available voltages/currents provided by
> + this regulator and matching GPIO configurations to
> + achieve them. If there are no states in the "states"
> + array, use a fixed regulator instead.
>
> Optional properties:
> -- enable-gpio : GPIO to use to enable/disable the regulator.
> -- gpios : GPIO group used to control voltage.
> -- gpios-states : gpios pin's initial states array. 0: LOW, 1: HIGH.
> - defualt is LOW if nothing is specified.
> +- enable-gpio : GPIO used to enable/disable the regulator.
According to modern GPIO rules, that should be "enable-gpios" (plural) ...
> + Warning, the GPIO phandle flags are ignored and the
> + GPIO polarity is controlled solely by the presence
> + of "enable-active-high" DT property. This is due to
> + compatibility with old DTs.
Wasn't the purpose of the various *active-* flags to accommodate GPIOs
lacking a flags cell (i.e. typically #gpio-cells = <1>)?
When the flags cell is present, there's indeed opportunity for confusion
(and breakage), combined with the presence/lack of *active-* below...
> +- enable-active-high : Polarity of "enable-gpio" GPIO is active HIGH.
> + Default is active LOW.
> +- gpios : Array of one or more GPIO pins used to
> select the
> + regulator voltage/current listed in "states".
> +- gpios-states : Initial state of GPIO pins in "gpios" array.
> + 0: LOW, 1: HIGH.
> + Default is LOW if nothing else is specified.
> - startup-delay-us : Startup time in microseconds.
> -- enable-active-high : Polarity of GPIO is active high (default is low).
> - regulator-type : Specifies what is being regulated, must be either
> "voltage" or "current", defaults to voltage.
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- [email protected]
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
