From: Kamel Bouhara <kamel.bouhara@bootlin.com>
To: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Cc: Mark Rutland <mark.rutland@arm.com>,
devicetree@vger.kernel.org,
Alexandre Belloni <alexandre.belloni@bootlin.com>,
linux-iio@vger.kernel.org, linux-kernel@vger.kernel.org,
William Breathitt Gray <vilhelm.gray@gmail.com>,
Ludovic Desroches <ludovic.desroches@microchip.com>,
Rob Herring <robh+dt@kernel.org>,
Thomas Petazzoni <thomas.petazzoni@bootlin.com>,
linux-input@vger.kernel.org,
linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH 2/3] Input: rotary-encoder-counter: add DT bindings
Date: Sat, 11 Apr 2020 12:43:53 +0200 [thread overview]
Message-ID: <20200411104353.GB161090@kb-xps> (raw)
In-Reply-To: <20200409234623.GU75430@dtor-ws>
On Thu, Apr 09, 2020 at 04:46:23PM -0700, Dmitry Torokhov wrote:
> On Fri, Apr 10, 2020 at 12:39:07AM +0200, Alexandre Belloni wrote:
> > Hi Dmitry,
> >
> > On 09/04/2020 15:21:15-0700, Dmitry Torokhov wrote:
> > > On Mon, Apr 06, 2020 at 05:58:05PM +0200, Kamel Bouhara wrote:
> > > > Add dt binding for the counter variant of the rotary encoder driver.
> > > >
> > > > Signed-off-by: Kamel Bouhara <kamel.bouhara@bootlin.com>
> > > > ---
> > > > .../input/rotary-encoder-counter.yaml | 67 +++++++++++++++++++
> > > > 1 file changed, 67 insertions(+)
> > > > create mode 100644 Documentation/devicetree/bindings/input/rotary-encoder-counter.yaml
> > > >
> > > > diff --git a/Documentation/devicetree/bindings/input/rotary-encoder-counter.yaml b/Documentation/devicetree/bindings/input/rotary-encoder-counter.yaml
> > > > new file mode 100644
> > > > index 000000000000..a59f7c1faf0c
> > > > --- /dev/null
> > > > +++ b/Documentation/devicetree/bindings/input/rotary-encoder-counter.yaml
> > > > @@ -0,0 +1,67 @@
> > > > +# SPDX-License-Identifier: GPL-2.0
> > > > +%YAML 1.2
> > > > +---
> > > > +$id: http://devicetree.org/schemas/input/rotary-encoder-counter.yaml#
> > > > +$schema: http://devicetree.org/meta-schemas/core.yaml#
> > > > +
> > > > +title: Rotary Encoder Counter
> > > > +
> > > > +maintainers:
> > > > + - Kamel Bouhara <kamel.bouhara@bootlin.com>
> > > > +
> > > > +description:
> > > > + Registers a Rotary encoder connected through a counter device.
> > > > +
> > > > +properties:
> > > > + compatible:
> > > > + const: rotary-encoder-counter
> > >
> > > I wonder if a separate driver is really needed. The original driver be
> > > taught to use counter device when available?
> > >
> >
> > By the original driver, do you mean drivers/input/misc/rotary_encoder.c
> > that is using gpios ?
>
> Yes.
>
Well, it could be the case if the counter device could provide such a
way to signal interrupts.
> >
> > > > +
> > > > + counter:
> > > > + description: Phandle for the counter device providing rotary position.
> > > > +
> > > > + linux-axis:
> > > > + description: The input subsystem axis to map to this rotary encoder.
> > > > + type: boolean
> > > > +
> > > > + qdec-mode:
> > > > + description: |
> > > > + Quadrature decoder function to set in the counter device.
> > > > + 3: x1-PHA
> > > > + 4: x1-PHB
> > > > + 5: x2-PHA
> > > > + 6: x2-PHB
> > > > + 7: x4-PHA and PHB
> > >
> > > Is it really property of the rotary encoder itself or property of the
> > > counter device?
> > >
> >
> > The mode the quadrature decoder has to be put in depends on both the
> > rotary encoder and the qdec.
>
> OK.
>
> >
> > > > +
> > > > + steps:
> > > > + description: Number of steps in a full turnaround of the encoder.
> > > > + Only relevant for absolute axis. Defaults to 24 which is a typical
> > > > + value for such devices.
> > > > +
> > > > + relative-axis:
> > > > + description: Register a relative axis rather than an absolute one.
> > > > + type: boolean
> > > > +
> > > > + rollover:
> > > > + description: Automatic rollover when the rotary value becomes greater
> > > > + than the specified steps or smaller than 0. For absolute axis only.
> > > > + type: boolean
> > > > +
> > > > + poll-interval:
> > > > + description: Poll interval at which the position is read from the counter
> > > > + device (default 500ms).
> > >
> > > Is there a way found counters to signal an interrupt?
> > >
> >
> > For some counters, there are interrupts available, this is not trivial
> > with the counter that is the target of this work but this is on the TODO
> > list. Of course, this will also require adding a bit more to the
> > in-kernel counter API to allow registering a callback that would be
> > called when an interrupt happens.
>
> Should it be a callback, or can counter create an irqchip so that users
> do not need to know how exactly it is wired up?
>
Maybe for some of them yes but for others the polling is still required.
> Thanks.
>
> --
> Dmitry
--
Kamel Bouhara, Bootlin
Embedded Linux and kernel engineering
https://bootlin.com
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2020-04-11 10:44 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-06 15:58 [PATCH 0/3] Introduce a counter inkernel API Kamel Bouhara
2020-04-06 15:58 ` [PATCH 1/3] counter: add an " Kamel Bouhara
2020-04-10 17:34 ` Randy Dunlap
2020-04-11 9:58 ` Kamel Bouhara
2020-04-06 15:58 ` [PATCH 2/3] Input: rotary-encoder-counter: add DT bindings Kamel Bouhara
2020-04-07 9:41 ` Maxime Ripard
2020-04-07 11:03 ` Kamel Bouhara
2020-04-07 14:22 ` Maxime Ripard
2020-04-07 14:55 ` Kamel Bouhara
2020-04-09 22:21 ` Dmitry Torokhov
2020-04-09 22:39 ` Alexandre Belloni
2020-04-09 23:46 ` Dmitry Torokhov
2020-04-11 10:43 ` Kamel Bouhara [this message]
2020-04-06 15:58 ` [PATCH 3/3] Input: add a rotary encoders based on counter devices Kamel Bouhara
2020-04-11 17:22 ` [PATCH 0/3] Introduce a counter inkernel API William Breathitt Gray
2020-04-11 23:31 ` Alexandre Belloni
2020-04-12 1:48 ` William Breathitt Gray
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20200411104353.GB161090@kb-xps \
--to=kamel.bouhara@bootlin.com \
--cc=alexandre.belloni@bootlin.com \
--cc=devicetree@vger.kernel.org \
--cc=dmitry.torokhov@gmail.com \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-iio@vger.kernel.org \
--cc=linux-input@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=ludovic.desroches@microchip.com \
--cc=mark.rutland@arm.com \
--cc=robh+dt@kernel.org \
--cc=thomas.petazzoni@bootlin.com \
--cc=vilhelm.gray@gmail.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).