Re: [PATCH] Make EN2 pin optional in the TRF7970A driver

[Heiko Schocher]

Hello Rob,

Am 10.02.2017 um 16:51 schrieb Rob Herring:
> On Tue, Feb 07, 2017 at 06:22:04AM +0100, Heiko Schocher wrote:
> > From: Guan Ben <ben.guan@xxxxxxxxxxxx>
> >
> > Make the EN2 pin optional. This is useful for boards,
> > which have this pin fix wired, for example to ground.
> >
> > Signed-off-by: Guan Ben <ben.guan@xxxxxxxxxxxx>
> > Signed-off-by: Mark Jonas <mark.jonas@xxxxxxxxxxxx>
> > Signed-off-by: Heiko Schocher <hs@xxxxxxx>
> >
> > ---
> >
> >   .../devicetree/bindings/net/nfc/trf7970a.txt       |  4 ++--
> >   drivers/nfc/trf7970a.c                             | 26 ++++++++++++----------
> >   2 files changed, 16 insertions(+), 14 deletions(-)
> >
> > diff --git a/Documentation/devicetree/bindings/net/nfc/trf7970a.txt b/Documentation/devicetree/bindings/net/nfc/trf7970a.txt
> > index 32b35a0..5889a3d 100644
> > --- a/Documentation/devicetree/bindings/net/nfc/trf7970a.txt
> > +++ b/Documentation/devicetree/bindings/net/nfc/trf7970a.txt
> > @@ -5,8 +5,8 @@ Required properties:
> >   - spi-max-frequency: Maximum SPI frequency (<= 2000000).
> >   - interrupt-parent: phandle of parent interrupt handler.
> >   - interrupts: A single interrupt specifier.
> > -- ti,enable-gpios: Two GPIO entries used for 'EN' and 'EN2' pins on the
> > -  TRF7970A.
> > +- ti,enable-gpios: One or two GPIO entries used for 'EN' and 'EN2' pins on the
> > +  TRF7970A. EN2 is optional.
>
> Could EN ever be optional/fixed? If so, perhaps deprecate this property
> and do 2 properties, one for each pin.

The hardware I have has the EN2 pin fix connected to ground. Looking
into http://www.ti.com/lit/ds/slos743k/slos743k.pdf page 19 table 6-3
and 6-4 the EN2 pin is a don;t core if EN = 1. If EN = 0 EN2 pin
selects between Power Down and Sleep Mode ... I see no reason why
this is not possible/allowed ...

Hmm.. I do not like the idea of deprecating the "ti,enable-gpios"
property into 2 seperate properties ... but if this would be a reason
for not accepting this patch, I can do this ... How should I name
the 2 new properties?

"ti,pin-enable"  and "ti,pin-enable2" ?

bye,
Heiko
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