On Thu, Mar 24, 2016 at 08:57:12AM +0100, Uwe Kleine-König wrote:
> It's not advisable to use this encoding, but to support existing devices
> add support for this to the driver.
>
> Signed-off-by: Uwe Kleine-König <u.kleine-koenig@xxxxxxxxxxxxxx>
> ---
>
> Notes:
> Changes since (implicit) v1, sent with
> Message-Id: 1458680914-4533-1-git-send-email-u.kleine-koenig@xxxxxxxxxxxxxx
>
> - switch format of dt properties to use strings
>
> .../devicetree/bindings/input/rotary-encoder.txt | 4 ++++
> drivers/input/misc/rotary_encoder.c | 22 +++++++++++++++++++---
> 2 files changed, 23 insertions(+), 3 deletions(-)
>
> diff --git a/Documentation/devicetree/bindings/input/rotary-encoder.txt b/Documentation/devicetree/bindings/input/rotary-encoder.txt
> index 6c9f0c8a846c..e85ce3dea480 100644
> --- a/Documentation/devicetree/bindings/input/rotary-encoder.txt
> +++ b/Documentation/devicetree/bindings/input/rotary-encoder.txt
> @@ -20,6 +20,8 @@ Optional properties:
> 2: Half-period mode
> 4: Quarter-period mode
> - wakeup-source: Boolean, rotary encoder can wake up the system.
> +- rotary-encoder,encoding: String, the method used to encode steps.
> + Supported are "gray" (the default and more common) and "binary".
>
> Deprecated properties:
> - rotary-encoder,half-period: Makes the driver work on half-period mode.
> @@ -34,6 +36,7 @@ Example:
> compatible = "rotary-encoder";
> gpios = <&gpio 19 1>, <&gpio 20 0>; /* GPIO19 is inverted */
> linux,axis = <0>; /* REL_X */
> + rotary-encoder,encoding = "gray";
> rotary-encoder,relative-axis;
> };
>
> @@ -42,5 +45,6 @@ Example:
> gpios = <&gpio 21 0>, <&gpio 22 0>;
> linux,axis = <1>; /* ABS_Y */
> rotary-encoder,steps = <24>;
> + rotary-encoder,encoding = "binary";
> rotary-encoder,rollover;
> };
> diff --git a/drivers/input/misc/rotary_encoder.c b/drivers/input/misc/rotary_encoder.c
> index 96c486de49e0..d226d69a174a 100644
> --- a/drivers/input/misc/rotary_encoder.c
> +++ b/drivers/input/misc/rotary_encoder.c
> @@ -28,6 +28,11 @@
>
> #define DRV_NAME "rotary-encoder"
>
> +enum rotary_encoder_encoding {
> + ROTENC_GRAY,
> + ROTENC_BINARY,
> +};
> +
> struct rotary_encoder {
> struct input_dev *input;
>
> @@ -37,6 +42,7 @@ struct rotary_encoder {
> u32 axis;
> bool relative_axis;
> bool rollover;
> + enum rotary_encoder_encoding encoding;
>
> unsigned int pos;
>
> @@ -57,9 +63,11 @@ static unsigned rotary_encoder_get_state(struct rotary_encoder *encoder)
>
> for (i = 0; i < encoder->gpios->ndescs; ++i) {
> int val = gpiod_get_value_cansleep(encoder->gpios->desc[i]);
> - /* convert from gray encoding to normal */
> - if (ret & 1)
> - val = !val;
> +
> + if (encoder->encoding == ROTENC_GRAY)
> + /* convert from gray encoding to binary */
> + if (ret & 1)
> + val = !val;
>
> ret = ret << 1 | val;
> }
> @@ -183,6 +191,7 @@ static int rotary_encoder_probe(struct platform_device *pdev)
> struct device *dev = &pdev->dev;
> struct rotary_encoder *encoder;
> struct input_dev *input;
> + const char *encoding;
> irq_handler_t handler;
> u32 steps_per_period;
> unsigned int i;
> @@ -213,6 +222,13 @@ static int rotary_encoder_probe(struct platform_device *pdev)
> encoder->rollover =
> device_property_read_bool(dev, "rotary-encoder,rollover");
>
> + err = device_property_read_string(dev, "rotary-encoder,encoding",
> + &encoding);
> + if (!err && encoding[0] == 'b')
Why do we only match on first letter? I'd prefer we did better parsing
(i.e. only accepted valid encodings or no encoding property.
> + encoder->encoding = ROTENC_BINARY;
> + else
> + encoder->encoding = ROTENC_GRAY;
> +
> device_property_read_u32(dev, "linux,axis", &encoder->axis);
> encoder->relative_axis =
> device_property_read_bool(dev, "rotary-encoder,relative-axis");
> --
> 2.7.0
>
Thanks.
--
Dmitry
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