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Date:   Wed, 30 Jan 2019 21:23:31 +0100 (CET)
From:   Stefan Wahren <stefan.wahren@i2se.com>
To:     Guenter Roeck <linux@roeck-us.net>
Cc:     Kamil Debski <kamil@wypas.org>,
        Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>,
        Jean Delvare <jdelvare@suse.com>,
        Rob Herring <robh+dt@kernel.org>,
        Mark Rutland <mark.rutland@arm.com>,
        linux-hwmon@vger.kernel.org, devicetree@vger.kernel.org,
        linux-kernel@vger.kernel.org
Message-ID: <625436113.118199.1548879811777@email.ionos.de>
In-Reply-To: <20190130172815.GC14781@roeck-us.net>
References: <1548860827-29796-1-git-send-email-stefan.wahren@i2se.com>
 <1548860827-29796-2-git-send-email-stefan.wahren@i2se.com>
 <20190130172815.GC14781@roeck-us.net>
Subject: Re: [PATCH RFC 1/3] dt-bindings: hwmon: Add tachometer interrupt to
 pwm-fan
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Hi Guenter,

> Guenter Roeck <linux@roeck-us.net> hat am 30. Januar 2019 um 18:28 geschrieben:
> 
> 
> On Wed, Jan 30, 2019 at 04:07:05PM +0100, Stefan Wahren wrote:
> > This adds the tachometer interrupt to the pwm-fan binding, which is
> > necessary for RPM support.
> > 
> > Signed-off-by: Stefan Wahren <stefan.wahren@i2se.com>
> > ---
> >  Documentation/devicetree/bindings/hwmon/pwm-fan.txt | 3 +++
> >  1 file changed, 3 insertions(+)
> > 
> > diff --git a/Documentation/devicetree/bindings/hwmon/pwm-fan.txt b/Documentation/devicetree/bindings/hwmon/pwm-fan.txt
> > index 49ca5d8..7f69b0b 100644
> > --- a/Documentation/devicetree/bindings/hwmon/pwm-fan.txt
> > +++ b/Documentation/devicetree/bindings/hwmon/pwm-fan.txt
> > @@ -8,6 +8,9 @@ Required properties:
> >  
> >  Optional properties:
> >  - fan-supply    : phandle to the regulator that provides power to the fan
> > +- interrupts    : contains a single interrupt specifier which describes the
> > +                  tachometer pin output of a 2 pulse-per-revolution fan.
> > +                  See interrupt-controller/interrupts.txt for the format.
> 
> So a hypothetical {1,4} pulse-per-revolution fan would explicitly not be
> supported ? Why ?

i could add an additional property to specify the pulse per revolution and use the 2 as default (according to the Intel spec for 4 pin pwm fan) which should fit in most cases.

> 
> Guenter