From: Jonathan Cameron <jic23@jic23.retrosnub.co.uk>
To: Song Qiang <songqiang1304521@gmail.com>
Cc: knaack.h@gmx.de, lars@metafoo.de, pmeerw@pmeerw.net,
robh+dt@kernel.org, mark.rutland@arm.com,
himanshujha199640@gmail.com, linux-iio@vger.kernel.org,
devicetree@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v3 2/3] dt-bindings: Add PNI RM3100 device tree binding.
Date: Sun, 7 Oct 2018 16:20:20 +0100 [thread overview]
Message-ID: <20181007162020.6535767e@archlinux> (raw)
In-Reply-To: <20181007161808.44a61d45@archlinux>
On Sun, 7 Oct 2018 16:18:08 +0100
Jonathan Cameron <jic23@kernel.org> wrote:
> On Tue, 2 Oct 2018 22:38:11 +0800
> Song Qiang <songqiang1304521@gmail.com> wrote:
>
> > Signed-off-by: Song Qiang <songqiang1304521@gmail.com>
> > ---
> > .../bindings/iio/magnetometer/pni,rm3100.txt | 20 +++++++++++++++++++
> > 1 file changed, 20 insertions(+)
> > create mode 100644 Documentation/devicetree/bindings/iio/magnetometer/pni,rm3100.txt
> >
> > diff --git a/Documentation/devicetree/bindings/iio/magnetometer/pni,rm3100.txt b/Documentation/devicetree/bindings/iio/magnetometer/pni,rm3100.txt
> > new file mode 100644
> > index 000000000000..4677690fc5d0
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/iio/magnetometer/pni,rm3100.txt
> > @@ -0,0 +1,20 @@
> > +* PNI RM3100 3-axis magnetometer sensor
> > +
> > +Required properties:
> > +
> > +- compatible : should be "pni,rm3100"
> > +- reg : the I2C address or SPI chip select number of the sensor.
> > +
> > +Optional properties:
> > +
> > +- interrupts: data ready (DRDY) from the chip.
> > + The interrupts can be triggered on rising edges.
> From Phil's response this appears to be incorrect and
> it's actually a level sensitive interrupt.
> I haven't checked the data sheet to confirm this.
>
> That'll bring all sorts of pain if you have a host that can only
> do edge sensitive so I'm hoping that's not true for you
> (edge sensitive only interrupts on hosts are pretty unusual
> though it cause me a lot of problems when I started out
> with IIO years ago :(
>
> The docs aren't super clear on this. The subtlety is
> whether there is a guaranteed 'low' time between reading the
> data and it going high again due to another reading. This usually
> only matters if you are running very quickly though so may be
> fine here.
>
> This will only become relevant with continuous mode if you
> add support for that later (I think!)
I realised just after I sent this that I was being unclear.
If you aren't doing continuous mode and hence have a fairly
strong guarantee of a decent gap between reads, you may be
able to get away with supporting either LEVEL or EDGE
interrupts. In continuous mode, it is necessary to have
a minimum low time for EDGE interrupts to work.
Jonathan
>
> Jonathan
>
> > +
> > +Example:
> > +
> > +rm3100: rm3100@20 {
> > + compatible = "pni,rm3100";
> > + reg = <0x20>;
> > + interrupt-parent = <&gpio0>;
> > + interrupts = <4 IRQ_TYPE_EDGE_RISING>;
> > +};
>
next prev parent reply other threads:[~2018-10-07 15:20 UTC|newest]
Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-09-25 3:17 [PATCH 1/2] iio: magnetometer: Add DT support for PNI RM3100 Song Qiang
2018-09-25 3:17 ` [PATCH 2/2] iio: magnetometer: Add driver " Song Qiang
2018-09-25 13:30 ` Jonathan Cameron
2018-09-25 14:36 ` Phil Reid
2018-09-26 1:49 ` Song Qiang
2018-09-26 2:30 ` Phil Reid
2018-09-26 8:09 ` Song Qiang
2018-09-27 1:57 ` Phil Reid
2018-09-29 11:37 ` Jonathan Cameron
2018-09-26 1:33 ` Song Qiang
2018-09-29 11:45 ` Jonathan Cameron
2018-09-25 17:50 ` Himanshu Jha
2018-09-26 2:24 ` Song Qiang
2018-09-25 13:05 ` [PATCH 1/2] iio: magnetometer: Add DT " Jonathan Cameron
2018-10-02 14:38 ` [PATCH v3 0/3] Add support for PNI RM3100 magnetometer Song Qiang
2018-10-02 14:38 ` [PATCH v3 1/3] dt-bindings: Add PNI to the vendor prefixes Song Qiang
2018-10-02 14:38 ` [PATCH v3 2/3] dt-bindings: Add PNI RM3100 device tree binding Song Qiang
2018-10-07 15:18 ` Jonathan Cameron
2018-10-07 15:20 ` Jonathan Cameron [this message]
2018-10-02 14:38 ` [PATCH v3 3/3] iio: magnetometer: Add driver support for PNI RM3100 Song Qiang
2018-10-03 1:42 ` Phil Reid
2018-10-07 15:07 ` Jonathan Cameron
2018-10-07 15:44 ` Jonathan Cameron
2018-10-11 4:35 ` Song Qiang
2018-10-13 9:24 ` Jonathan Cameron
2018-10-12 7:35 ` [PATCH v4 0/3] Add support for PNI RM3100 magnetometer Song Qiang
2018-10-12 7:35 ` [PATCH v4 1/3] dt-bindings: Add PNI to the vendor prefixes Song Qiang
2018-10-12 11:36 ` Rob Herring
2018-10-12 7:35 ` [PATCH v4 2/3] iio: magnetometer: Add DT support for PNI RM3100 Song Qiang
2018-10-12 11:37 ` Rob Herring
2018-10-12 7:35 ` [PATCH v4 3/3] iio: magnetometer: Add driver " Song Qiang
2018-10-12 8:36 ` Song Qiang
2018-10-12 12:53 ` Himanshu Jha
2018-10-17 8:00 ` Song Qiang
2018-10-21 14:08 ` Jonathan Cameron
2018-10-13 10:19 ` Jonathan Cameron
2018-10-18 8:24 ` Song Qiang
2018-10-21 14:14 ` Jonathan Cameron
2018-11-02 7:55 ` Song Qiang
2018-11-02 9:24 ` Jonathan Cameron
2018-11-05 0:39 ` Song Qiang
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