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SubjectRe: [PATCH v3 3/6] dt-bindings: mfd: da9062: add regulator voltage selection documentation
On 19-12-17 10:00, Marco Felsch wrote:
> On 19-12-16 16:32, Adam Thomson wrote:
> > On 16 December 2019 08:55, Marco Felsch wrote:
> >
> > > On 19-12-12 16:51, Mark Brown wrote:
> > > > On Thu, Dec 12, 2019 at 05:21:53PM +0100, Marco Felsch wrote:
> > > >
> > > > > "... what's driving the input ..":
> > > > > Sorry I didn't get you here. What did you mean? The input is driven by
> > > > > the host. This can be any gpio line and in my case it is a gpio line
> > > > > driven by the soc-hw during a suspend operation.
> > > >
> > > > Something needs to say what that thing is, especially if it's runtime
> > > > controllable. In your case from the point of view of software there is
> > > > actually no enable control so we shouldn't be providing an enable
> > > > operation to the framework.
> > >
> > > The enabel control signal is always available, please check [1] table
> > > 63. There is a mux in front of the enable pin so:
> > >
> > > +-------------
> > > Seq. |\ | Regulator
> > > GPI1 | \ |
> > > GPI2 | | -- > Enable
> > > GPI3 | / |
> > > |/ .
> > > .
> > > .
> > >
> > > Adam please correct me if this is wrong.
> >
> > Yes the register can always be configured regardless of the associated pin
> > configuration, but if say GPIO1 was configured as a GPO but a regulator was
> > configured to use GPIO1 as its GPI control mechanism, the output signal from
> > GPIO1 would be ignored, the sequencer control would not have any effect and
> > you're simply left with manual I2C control. Really we shouldn't be getting into
> > that situation though. If a GPIO is to be used as a regulator control signal
> > then it should be marked as such and I don't think we should be able to use that
> > pin for anything other than regulator control.
>
> I see, so we have to guarantee that the requested gpio is configured as
> input. This can be done by:
>
> if (gpi->flags & FLAG_IS_OUT)
> return -EINVAL;

Sorry didn't noticed that the flags are only used internally. The
correct check must be:

/* GPIO must be configured as input */
if (!gpiod_get_direction(gpi)) {
ret = -EINVAL;
goto free;
}

>
> Regards,
> Marco
>
> > >
> > > [1] https://www.dialog-
> > > semiconductor.com/sites/default/files/da9062_datasheet_3v6.pdf
> > >
> > > Regards,
> > > Marco
> > >
> > > > _______________________________________________
> > > > linux-arm-kernel mailing list
> > > > linux-arm-kernel@lists.infradead.org
> > > > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
> >
> > _______________________________________________
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> > linux-arm-kernel@lists.infradead.org
> > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
> >
>
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