Hi Marek,
On Mon, Feb 18, 2019 at 8:04 PM Marek Vasut <[email protected]> wrote:
> On 2/18/19 10:30 AM, Geert Uytterhoeven wrote:
> > 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]>
> >> --- 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) ...
>
> Isn't that changing the ABI spec then ?
of_find_gpio() supports both anyway, through gpio_suffixes[].
> >> + 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>)?
>
> Yes
>
> > When the flags cell is present, there's indeed opportunity for confusion
> > (and breakage), combined with the presence/lack of *active-* below...
>
> The code is rather clear that the flags cell is ignored.
>
> drivers/gpio/gpiolib-of.c:
> 91 /*
> 92 * The regulator GPIO handles are specified such that the
> 93 * presence or absence of "enable-active-high" solely controls
> 94 * the polarity of the GPIO line. Any phandle flags must
> 95 * be actively ignored.
> 96 */
Yeah, the code is the binding doc...
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
