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@xxxxxxxxxxx> > > > > --- > > > > .../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@xxxxxxxxxxx> > > > > + > > > > +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
