[RFC][Draft][DNM] Input Subsystem proof-of-concept

boards/arm/nrf52dk_nrf52832/nrf52dk_nrf52832-pinctrl.dtsi

@@ -25,15 +25,15 @@
 
 	i2c0_default: i2c0_default {
 		group1 {
-			psels = <NRF_PSEL(TWIM_SDA, 0, 26)>,
-				<NRF_PSEL(TWIM_SCL, 0, 27)>;
+			psels = <NRF_PSEL(TWIM_SDA, 0, 27)>,
+				<NRF_PSEL(TWIM_SCL, 0, 26)>;
 		};
 	};
 
 	i2c0_sleep: i2c0_sleep {
 		group1 {
-			psels = <NRF_PSEL(TWIM_SDA, 0, 26)>,
-				<NRF_PSEL(TWIM_SCL, 0, 27)>;
+			psels = <NRF_PSEL(TWIM_SDA, 0, 27)>,
+				<NRF_PSEL(TWIM_SCL, 0, 26)>;
 			low-power-enable;
 		};
 	};

boards/arm/nrf52dk_nrf52832/nrf52dk_nrf52832.dts

@@ -7,6 +7,7 @@
 
 /dts-v1/;
 #include <nordic/nrf52832_qfaa.dtsi>
+#include <dt-bindings/input/input-event-codes.h>
 #include "nrf52dk_nrf52832-pinctrl.dtsi"
 
 / {
@@ -22,6 +23,26 @@
 		zephyr,sram = &sram0;
 		zephyr,flash = &flash0;
 		zephyr,code-partition = &slot0_partition;
+		zephyr,keyboard-scan = &kscan_adapter;
+	};
+
+	kscan_adapter: kscan-adapter {
+		compatible = "zephyr,kscan-adapter";
+		input = <&ft5336>;
+	};
+
+	abs-to-rel {
+		compatible = "zephyr,input-abs-to-rel";
+		input = <&qdec>;
+	};
+
+	longpress {
+		compatible = "zephyr,input-longpress";
+		input = <&buttons>;
+		input-code = <INPUT_KEY_3>;
+		short-code = <INPUT_KEY_A>;
+		long-codes = <INPUT_KEY_B>, <INPUT_KEY_C>, <INPUT_KEY_D>;
+		long-delays-ms = <500>, <1000>, <2000>;
 	};
 
 	leds {
@@ -51,23 +72,27 @@
 		};
 	};
 
-	buttons {
-		compatible = "gpio-keys";
+	buttons: buttons {
+		compatible = "zephyr,gpio-keys";
 		button0: button_0 {
 			gpios = <&gpio0 13 (GPIO_PULL_UP | GPIO_ACTIVE_LOW)>;
 			label = "Push button switch 0";
+			zephyr,code = <INPUT_KEY_0>;
 		};
 		button1: button_1 {
 			gpios = <&gpio0 14 (GPIO_PULL_UP | GPIO_ACTIVE_LOW)>;
 			label = "Push button switch 1";
+			zephyr,code = <INPUT_KEY_1>;
 		};
 		button2: button_2 {
 			gpios = <&gpio0 15 (GPIO_PULL_UP | GPIO_ACTIVE_LOW)>;
 			label = "Push button switch 2";
+			zephyr,code = <INPUT_KEY_2>;
 		};
 		button3: button_3 {
 			gpios = <&gpio0 16 (GPIO_PULL_UP | GPIO_ACTIVE_LOW)>;
 			label = "Push button switch 3";
+			zephyr,code = <INPUT_KEY_3>;
 		};
 	};
 
@@ -128,6 +153,31 @@
 		watchdog0 = &wdt0;
 	};
 };
+&pinctrl {
+	qdec_default: qdec_default {
+		group1 {
+			psels = <NRF_PSEL(QDEC_A, 0, 29)>,
+			        <NRF_PSEL(QDEC_B, 0, 31)>;
+		};
+	};
+
+	qdec_sleep: qdec_sleep {
+		group1 {
+			psels = <NRF_PSEL(QDEC_A, 0, 29)>,
+				<NRF_PSEL(QDEC_B, 0, 31)>;
+			low-power-enable;
+		};
+	};
+};
+
+&qdec {
+	status = "okay";
+	led-pre = <0>;
+	steps = <360>;
+	pinctrl-0 = <&qdec_default>;
+	pinctrl-1 = <&qdec_sleep>;
+	pinctrl-names = "default", "sleep";
+};
 
 &adc {
 	status = "okay";
@@ -156,6 +206,12 @@ arduino_i2c: &i2c0 {
 	pinctrl-0 = <&i2c0_default>;
 	pinctrl-1 = <&i2c0_sleep>;
 	pinctrl-names = "default", "sleep";
+
+	ft5336: ft5336@38 {
+		compatible = "focaltech,ft5336";
+		reg = <0x38>;
+		int-gpios = <&gpio0 2 GPIO_ACTIVE_LOW>;
+	};
 };
 
 &i2c1 {

doc/services/index.rst

@@ -14,6 +14,7 @@ OS Services
    file_system/index.rst
    formatted_output.rst
    ipc/index.rst
+   input/index.rst
    logging/index.rst
    tracing/index.rst
    resource_management/index.rst

doc/services/input/index.rst

@@ -0,0 +1,73 @@
+.. _input:
+
+Input
+#####
+
+The input subsystem provides an API for dispatching input events from input
+devices to the application.
+
+Input Events
+************
+
+The subsystem is built around the :c:struct:`input_event` structure. An input
+event represents a change in an individual event entity, for example the state
+of a single button, or a movement in a single axis.
+
+The :c:struct:`input_event` structure describes the specific event, and
+includes a synchronization bit to indicate that the device reached a stable
+state, for example when the events corresponding to multiple axes of a
+multi-axis device have been reported.
+
+Input Drivers
+*************
+
+An input device can report input events directly using any of the
+:c:func:`input_report` functions, for example buttons or other on-off input
+devices would use :c:func:`input_report_key`.
+
+Complex devices may use a combination of multiple events, and set the ``sync``
+bit once the output is stable.
+
+The :c:func:`input_report` functions take a :c:struct:`device` pointer, which
+is used to indicate which device reported the event and can be used by
+subscribers to only receive events from a specific device. If there's no actual
+device associated with the event, it can be set to ``NULL``, in which case only
+subscribers with no device filter will receive the event.
+
+Application API
+***************
+
+An application can register a callback using the
+:c:func:`INPUT_LISTENER_CB_DEFINE` macro. If a device node is specified, the
+callback is only invoked for events from the specific device, otherwise the
+callback will receive all the events in the system. This is the only type of
+filtering supported, any more complex filtering logic has to be implemented in
+the callback itself.
+
+The subsystem can operate synchronously or by using an event queue, depending
+on the :kconfig:option:`CONFIG_INPUT_THREAD` option. If the input thread is
+used, all the events are added to a queue and executed in a common ``input``
+thread. If the thread is not used, the callback are invoked directly in the
+input driver context.
+
+The synchronous mode can be used in a simple application to keep a minimal
+footprint, or in a complex application with an existing event model, where the
+callback is just a wrapper to pipe back the event in a more complex application
+specific event system.
+
+Kscan Compatibility
+*******************
+
+Input devices generating X/Y/Touch events can be used in existing applications
+based on the :ref:`kscan_api` API by defining a
+:dtcompatible:`zephyr,kscan-adapter` node.
+
+API Reference
+*************
+
+.. doxygengroup:: input_interface
+
+Driver API Reference
+********************
+
+.. doxygengroup:: input_driver_interface

drivers/gpio/Kconfig.zephyr

@@ -5,5 +5,6 @@ config GPIO_KEYS_ZEPHYR
 	bool "Zephyr GPIO Keys"
 	default y
 	depends on DT_HAS_ZEPHYR_GPIO_KEYS_ENABLED
+	select INPUT
 	help
 	  Enable support for Zephyr GPIO Keys.

drivers/gpio/gpio_keys_zephyr.c

@@ -5,10 +5,11 @@
  */
 
 #include <zephyr/device.h>
-#include <zephyr/drivers/gpio.h>
+#include <zephyr/drivers/input.h>
 #include <zephyr/drivers/gpio_keys.h>
 #include <zephyr/kernel.h>
 #include <zephyr/logging/log.h>
+#include <zephyr/input/input.h>
 
 LOG_MODULE_REGISTER(zephyr_gpio_keys, CONFIG_GPIO_LOG_LEVEL);
 
@@ -61,7 +62,7 @@ static void gpio_keys_change_deferred(struct k_work *work)
 		pin_data->cb_data.pin_state = new_pressed;
 		LOG_DBG("Calling callback %s %d, code=%d", dev->name, new_pressed,
 			pin_cfg->zephyr_code);
-		data->callback(dev, &pin_data->cb_data, BIT(pin_cfg->spec.pin));
+		input_report_key(dev, pin_cfg->zephyr_code, new_pressed, true, K_FOREVER);
 	}
 }
 
@@ -211,13 +212,12 @@ static int gpio_keys_init(const struct device *dev)
 		k_work_init_delayable(&data->pin_data[i].work, gpio_keys_change_deferred);
 	}
 
+	gpio_keys_zephyr_enable_interrupt(dev, NULL);
+
 	return 0;
 }
 
-static const struct gpio_keys_api gpio_keys_zephyr_api = {
-	.enable_interrupt = gpio_keys_zephyr_enable_interrupt,
-	.disable_interrupt = gpio_keys_zephyr_disable_interrupt,
-	.get_pin = gpio_keys_zephyr_get_pin,
+static const struct input_driver_api gpio_keys_api = {
 };
 
 #define GPIO_KEYS_CFG_DEF(node_id)                                                                 \
@@ -241,6 +241,6 @@ static const struct gpio_keys_api gpio_keys_zephyr_api = {
 	};                                                                                         \
 	DEVICE_DT_INST_DEFINE(i, &gpio_keys_init, NULL, &gpio_keys_data_##i,                       \
 			      &gpio_keys_config_##i, POST_KERNEL, CONFIG_GPIO_INIT_PRIORITY,       \
-			      &gpio_keys_zephyr_api);
+			      &gpio_keys_api);
 
 DT_INST_FOREACH_STATUS_OKAY(GPIO_KEYS_INIT)

drivers/kscan/CMakeLists.txt

@@ -11,5 +11,6 @@ zephyr_library_sources_ifdef(CONFIG_KSCAN_HT16K33	kscan_ht16k33.c)
 zephyr_library_sources_ifdef(CONFIG_KSCAN_CST816S	kscan_cst816s.c)
 zephyr_library_sources_ifdef(CONFIG_KSCAN_CAP1203	kscan_cap1203.c)
 zephyr_library_sources_ifdef(CONFIG_KSCAN_NPCX		kscan_npcx.c)
+zephyr_library_sources_ifdef(CONFIG_KSCAN_ADAPTER	kscan_adapter.c)
 
 zephyr_library_sources_ifdef(CONFIG_USERSPACE	    kscan_handlers.c)

drivers/kscan/Kconfig

@@ -30,4 +30,9 @@ config KSCAN_INIT_PRIORITY
 	help
 	  Keyboard scan device driver initialization priority.
 
+config KSCAN_ADAPTER
+        bool "Input subsystem to kscan adapter driver"
+        default y
+        depends on DT_HAS_ZEPHYR_KSCAN_ADAPTER_ENABLED
+
 endif # KSCAN

drivers/kscan/Kconfig.ft5336

@@ -7,6 +7,7 @@ menuconfig KSCAN_FT5336
 	default y
 	depends on DT_HAS_FOCALTECH_FT5336_ENABLED
 	select I2C
+	select INPUT
 	help
 	  Enable driver for multiple Focaltech capacitive touch panel
 	  controllers. This driver should support FT5x06, FT5606, FT5x16,