Marek Vasut writes: > On 3/5/19 5:10 PM, Harald Geyer wrote: > > Marek Vasut writes: > >> On 3/5/19 11:07 AM, Harald Geyer wrote: > >>> marek.vasut@xxxxxxxxx writes: > >>>> From: Marek Vasut <marek.vasut+renesas@xxxxxxxxx> > >>>> > >>>> Reword the binding document to make it clear how the propeties work > >>>> and which properties affect which other properties. > >>>> > >>>> Signed-off-by: Marek Vasut <marek.vasut+renesas@xxxxxxxxx> > >>>> Cc: Harald Geyer <harald@xxxxxxxxx> > >>>> Cc: Kuninori Morimoto <kuninori.morimoto.gx@xxxxxxxxxxx> > >>>> Cc: Linus Walleij <linus.walleij@xxxxxxxxxx> > >>>> Cc: Mark Brown <broonie@xxxxxxxxxx> > >>>> Cc: Rob Herring <robh@xxxxxxxxxx> > >>>> Cc: linux-renesas-soc@xxxxxxxxxxxxxxx > >>>> To: devicetree@xxxxxxxxxxxxxxx > >>>> --- > >>>> V2: - Make "gpios" a mandatory property > >>>> - Reword "gpio-states" property description > >>>> - Change "enable-gpio" to "enable-gpios" to match modern DT rules > >>>> 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 for the update. I think it addresses all my concerns except for > >>> one: > >>> > >>>> +- gpios-states : State of GPIO pins in "gpios" array that is set until > >>>> + changed by the first consumer. 0: LOW, 1: HIGH. > >>>> + Default is LOW if nothing else is specified. > >>> > >>> I still believe this not true: There is no guarantee that the regulator > >>> core won't change the state of GPIO pins before the first consumer comes > >>> up. > >> > >> Why would it do that ? > > > > Because the regulator core doesn't know about this driver specific > > property at all. And without any constraints placed by consumers, the > > core is free to choose any state whatsoever at any point in time. > > But git grep seems to disagree, see drivers/regulator/gpio-regulator.c: > ret = of_property_read_u32_index(np, "gpios-states", i, > > The core sets the pins to such a value until the consumer takes over. I think we have a misunderstanding of terminology. When I write "regulator core", I mean the driver independent regulator code. The line you quote above is part of the gpio-regulator driver and thus not part of what I call the "regulator core". AFAICS the data from the property is only stored in a driver specific data structure (and not used at all outside of probe) but never passed to what I call the regulator core. Why do you believe there is a guarantee that the value set during probeing is preserved until a consumer takes over? Harald
