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Commit d205a218 authored by Uwe Kleine-König's avatar Uwe Kleine-König Committed by Dmitry Torokhov
Browse files

Input: rotary_encoder - support binary encoding of states 



It's not advisable to use this encoding, but to support existing devices
add support for this to the driver.

Signed-off-by: default avatarUwe Kleine-König <u.kleine-koenig@pengutronix.de>
Acked-by: default avatarRob Herring <robh@kernel.org>
Signed-off-by: default avatarDmitry Torokhov <dmitry.torokhov@gmail.com>
parent f712a5a0

Documentation/devicetree/bindings/input/rotary-encoder.txt

+4 −0
Original line number Diff line number Diff line
@@ -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;

		};

drivers/input/misc/rotary_encoder.c

+22 −1
Original line number Diff line number Diff line
@@ -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;
@@ -57,8 +63,9 @@ static unsigned int 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)

		if (encoder->encoding == ROTENC_GRAY && ret & 1)

			val = !val;



		ret = ret << 1 | val;
@@ -213,6 +220,20 @@ static int rotary_encoder_probe(struct platform_device *pdev) 
	encoder->rollover =

		device_property_read_bool(dev, "rotary-encoder,rollover");



	if (!device_property_present(dev, "rotary-encoder,encoding") ||

	    !device_property_match_string(dev, "rotary-encoder,encoding",

					  "gray")) {

		dev_info(dev, "gray");

		encoder->encoding = ROTENC_GRAY;

	} else if (!device_property_match_string(dev, "rotary-encoder,encoding",

						 "binary")) {

		dev_info(dev, "binary");

		encoder->encoding = ROTENC_BINARY;

	} else {

		dev_err(dev, "unknown encoding setting\n");

		return -EINVAL;

	}



	device_property_read_u32(dev, "linux,axis", &encoder->axis);

	encoder->relative_axis =

		device_property_read_bool(dev, "rotary-encoder,relative-axis");