Date:   Wed, 1 Feb 2023 11:02:39 -0800
From:   Dmitry Torokhov <dmitry.torokhov@gmail.com>
To:     Rob Herring <robh@kernel.org>
Cc:     Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>,
        Alessandro Zummo <a.zummo@towertech.it>,
        Alexandre Belloni <alexandre.belloni@bootlin.com>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        Arnd Bergmann <arnd@arndb.de>, linux-rtc@vger.kernel.org,
        linux-kernel@vger.kernel.org, devicetree@vger.kernel.org
Subject: Re: [PATCH 2/3] dt-bindings: rtc: moxart: use proper names for gpio
 properties
Message-ID: <Y9q3T17r5G2PD9Gk@google.com>
References: <20230201054815.4112632-1-dmitry.torokhov@gmail.com>
 <20230201054815.4112632-2-dmitry.torokhov@gmail.com>
 <31e979dd-f4e9-081e-1bf2-e44dffc4e70f@linaro.org>
 <Y9qQHj70SN/3fZCc@google.com>
 <20230201175504.GA4075318-robh@kernel.org>
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On Wed, Feb 01, 2023 at 11:55:04AM -0600, Rob Herring wrote:
> On Wed, Feb 01, 2023 at 08:15:26AM -0800, Dmitry Torokhov wrote:
> > On Wed, Feb 01, 2023 at 08:38:48AM +0100, Krzysztof Kozlowski wrote:
> > > On 01/02/2023 06:48, Dmitry Torokhov wrote:
> > > > MOXA ART RTC driver has been switched to gpiod API and is now using
> > > > properly named properties for its gpios (with gpiolib implementing a
> > > > quirk to recognize legacy names). Change binding document to use
> > > > proper names as well.
> > > > 
> > > > Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
> > > > ---
> > > >  .../devicetree/bindings/rtc/moxa,moxart-rtc.txt      | 12 ++++++------
> > > >  1 file changed, 6 insertions(+), 6 deletions(-)
> > > > 
> > > > diff --git a/Documentation/devicetree/bindings/rtc/moxa,moxart-rtc.txt b/Documentation/devicetree/bindings/rtc/moxa,moxart-rtc.txt
> > > > index c9d3ac1477fe..1374df7bf9d6 100644
> > > > --- a/Documentation/devicetree/bindings/rtc/moxa,moxart-rtc.txt
> > > > +++ b/Documentation/devicetree/bindings/rtc/moxa,moxart-rtc.txt
> > > > @@ -3,15 +3,15 @@ MOXA ART real-time clock
> > > >  Required properties:
> > > >  
> > > >  - compatible : Should be "moxa,moxart-rtc"
> > > > -- gpio-rtc-sclk : RTC sclk gpio, with zero flags
> > > > -- gpio-rtc-data : RTC data gpio, with zero flags
> > > > -- gpio-rtc-reset : RTC reset gpio, with zero flags
> > > > +- rtc-sclk-gpios : RTC sclk gpio, with zero flags
> > > > +- rtc-data-gpios : RTC data gpio, with zero flags
> > > > +- rtc-reset-gpios : RTC reset gpio, with zero flags
> > > 
> > > Your driver breaks the ABI, doesn't it? If not, how are the old
> > > properties parsed?
> > 
> > It does not. As I mentioned in the driver code patch, commit
> > eaf1a29665cd ("gpiolib: of: add a quirk for legacy names in MOXA ART
> > RTC") makes sure gpiolib falls back to trying old variants if it can't
> > locate properly formatted names.
> 
> A dtb with the new names and a kernel without the gpiod conversion would 
> be broken. Up to the platform whether they care really.

Seriously? And I guess devices with DTS do not work with kernels v2.0 so
we should never have introduced it...

I understand wanting backward compatibility, but asking for both
backward and forward is a bit too much IMO.

Thanks.

-- 
Dmitry