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

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Message-ID: <CAL_JsqKM4fEcfPekYkt-+TVNXE3nMF1AEfSHWW+3wAgdYDMXEg@mail.gmail.com>
Date:   Mon, 13 Feb 2017 15:31:57 -0600
From:   Rob Herring <robh@...nel.org>
To:     Heiko Schocher <hs@...x.de>
Cc:     netdev <netdev@...r.kernel.org>, Guan Ben <ben.guan@...bosch.com>,
        Mark Jonas <mark.jonas@...bosch.com>,
        "devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
        linux-wireless <linux-wireless@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        Samuel Ortiz <sameo@...ux.intel.com>,
        Lauro Ramos Venancio <lauro.venancio@...nbossa.org>,
        Aloisio Almeida Jr <aloisio.almeida@...nbossa.org>,
        Mark Rutland <mark.rutland@....com>
Subject: Re: [PATCH] Make EN2 pin optional in the TRF7970A driver

On Mon, Feb 13, 2017 at 12:38 AM, Heiko Schocher <hs@...x.de> wrote:
> 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@...bosch.com>
>>>
>>> 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@...bosch.com>
>>> Signed-off-by: Mark Jonas <mark.jonas@...bosch.com>
>>> Signed-off-by: Heiko Schocher <hs@...x.de>
>>>
>>> ---
>>>
>>>   .../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?

I guess if this ever happens, then we just add "ti,enable2-gpios" and
ti,enable-gpios continues to point to EN. We don't need to deprecate
anything (or maybe just deprecate having both GPIOs on single
property).

In that case,

Acked-by: Rob Herring <robh@...nel.org>

>
> "ti,pin-enable"  and "ti,pin-enable2" ?
>
> bye,
> Heiko
> --
> DENX Software Engineering GmbH,      Managing Director: Wolfgang Denk
> HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany