API: kscan: Add API for Keyboard scan matrix

    -kscan_config
    -kscan_enable_callback
    -kscan_disable_callback

Signed-off-by: Francisco Munoz <[email protected]>

Author: franciscomunoz

include/drivers/kscan.h

@@ -0,0 +1,141 @@
+/*
+ * Copyright (c) 2019 Intel Corporation
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+/**
+ * @file
+ * @brief Public API for Keyboard scan matrix devices.
+ * The scope of this API is simply to report which key event was triggered
+ * and users can later decode keys using their desired scan code tables in
+ * their application. In additon, typematic rate and delay can easily be
+ * implemented using a timer if desired.
+ */
+
+#ifndef ZEPHYR_INCLUDE_DRIVERS_KB_SCAN_H_
+#define ZEPHYR_INCLUDE_DRIVERS_KB_SCAN_H_
+
+#include <zephyr/types.h>
+#include <stddef.h>
+#include <device.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/**
+ * @brief KSCAN APIs
+ * @defgroup kscan_interface Keyboard Scan Driver APIs
+ * @ingroup io_interfaces
+ * @{
+ */
+
+/**
+ * @brief Keyboard scan callback called when user press/release
+ * a key on a matrix keyboard.
+ *
+ * @param dev   Pointer to the device structure for the driver instance.
+ * @param data  Data byte passed pack to the user.
+ * @param col	Describes column change.
+ * @param row	Describes row change.
+ * @param pressed Describes the kind of key event.
+ */
+typedef void (*kscan_callback_t)(struct device *dev, u8_t row, u8_t column,
+				 bool pressed);
+
+/**
+ * @cond INTERNAL_HIDDEN
+ *
+ * Keyboard scan driver API definition and system call entry points.
+ *
+ * (Internal use only.)
+ */
+typedef int (*kscan_config_t)(struct device *dev,
+			    kscan_callback_t callback);
+typedef int (*kscan_disable_callback_t)(struct device *dev);
+typedef int (*kscan_enable_callback_t)(struct device *dev);
+
+struct kscan_driver_api {
+	kscan_config_t config;
+	kscan_disable_callback_t disable_callback;
+	kscan_enable_callback_t enable_callback;
+};
+/**
+ * @endcond
+ */
+
+/**
+ * @brief Configure a Keyboard scan instance.
+ *
+ * @param dev Pointer to the device structure for the driver instance.
+ * @param callback called when keyboard devices reply to to a keyboard
+ * event susch as key pressed/released.
+ *
+ * @retval 0 If successful.
+ * @retval Negative errno code if failure.
+ */
+__syscall int kscan_config(struct device *dev,
+			     kscan_callback_t callback);
+
+static inline int z_impl_kscan_config(struct device *dev,
+					kscan_callback_t callback)
+{
+	const struct kscan_driver_api *api =
+				(struct kscan_driver_api *)dev->driver_api;
+
+	return api->config(dev, callback);
+}
+/**
+ * @brief Enables callback.
+ * @param dev Pointer to the device structure for the driver instance.
+ *
+ * @retval 0 If successful.
+ * @retval Negative errno code if failure.
+ */
+__syscall int kscan_enable_callback(struct device *dev);
+
+static inline int z_impl_kscan_enable_callback(struct device *dev)
+{
+	const struct kscan_driver_api *api =
+			(const struct kscan_driver_api *)dev->driver_api;
+
+	if (api->enable_callback == NULL) {
+		return -ENOTSUP;
+	}
+
+	return api->enable_callback(dev);
+}
+
+/**
+ * @brief Disables callback.
+ * @param dev Pointer to the device structure for the driver instance.
+ *
+ * @retval 0 If successful.
+ * @retval Negative errno code if failure.
+ */
+__syscall int kscan_disable_callback(struct device *dev);
+
+static inline int z_impl_kscan_disable_callback(struct device *dev)
+{
+	const struct kscan_driver_api *api =
+			(const struct kscan_driver_api *)dev->driver_api;
+
+	if (api->disable_callback == NULL) {
+		return -ENOTSUP;
+	}
+
+	return api->disable_callback(dev);
+}
+
+#ifdef __cplusplus
+}
+#endif
+
+/**
+ * @}
+ */
+
+#include <syscalls/kscan.h>
+
+#endif /* ZEPHYR_INCLUDE_DRIVERS_KB_SCAN_H_ */