input SDL: Split in top and bottom

Split the SDL input driver in a top and bottom
to enable using it with embedded libCs.

Signed-off-by: Alberto Escolar Piedras <alberto.escolar.piedras@nordicsemi.no>

drivers/input/CMakeLists.txt

@@ -7,5 +7,13 @@ zephyr_library_sources_ifdef(CONFIG_INPUT_FT5336 input_ft5336.c)
 zephyr_library_sources_ifdef(CONFIG_INPUT_GPIO_KEYS input_gpio_keys.c)
 zephyr_library_sources_ifdef(CONFIG_INPUT_GPIO_QDEC input_gpio_qdec.c)
 zephyr_library_sources_ifdef(CONFIG_INPUT_NPCX_KBD input_npcx_kbd.c)
-zephyr_library_sources_ifdef(CONFIG_INPUT_SDL_TOUCH input_sdl_touch.c)
 zephyr_library_sources_ifdef(CONFIG_INPUT_XPT2046 input_xpt2046.c)
+
+if (CONFIG_INPUT_SDL_TOUCH)
+  zephyr_library_sources(input_sdl_touch.c)
+  if (CONFIG_NATIVE_APPLICATION)
+    zephyr_library_sources(input_sdl_touch_bottom.c)
+  else()
+    target_sources(native_simulator INTERFACE input_sdl_touch_bottom.c)
+  endif()
+endif()

drivers/input/input_sdl_touch.c

@@ -1,43 +1,24 @@
 /*
  * Copyright (c) 2020 Jabil Inc.
+ * Copyright (c) 2023 Nordic Semiconductor
  *
  * SPDX-License-Identifier: Apache-2.0
  */
 
 #define DT_DRV_COMPAT zephyr_input_sdl_touch
 
+#include <stdbool.h>
 #include <zephyr/input/input.h>
 #include <zephyr/logging/log.h>
-
+#include "input_sdl_touch_bottom.h"
-#include <SDL.h>
 
 LOG_MODULE_REGISTER(sdl_input, CONFIG_INPUT_LOG_LEVEL);
 
-struct sdl_data {
+static void sdl_input_callback(struct sdl_input_data *data)
-	const struct device *dev;
-	int x;
-	int y;
-	bool pressed;
-};
-
-static int sdl_filter(void *arg, SDL_Event *event)
 {
-	struct sdl_data *data = arg;
+	if (data->just_released == true) {
-
-	switch (event->type) {
-	case SDL_MOUSEBUTTONUP:
-		data->pressed = false;
 		input_report_key(data->dev, INPUT_BTN_TOUCH, 0, true, K_FOREVER);
-		break;
+		data->just_released = false;
-	case SDL_MOUSEBUTTONDOWN:
-		data->pressed = true;
-		break;
-	case SDL_MOUSEMOTION:
-		data->x = event->button.x;
-		data->y = event->button.y;
-		break;
-	default:
-		return 1;
 	}
 
 	if (data->pressed) {
@@ -45,23 +26,22 @@ static int sdl_filter(void *arg, SDL_Event *event)
 		input_report_abs(data->dev, INPUT_ABS_Y, data->y, false, K_FOREVER);
 		input_report_key(data->dev, INPUT_BTN_TOUCH, 1, true, K_FOREVER);
 	}
-
-	return 1;
 }
 
 static int sdl_init(const struct device *dev)
 {
-	struct sdl_data *data = dev->data;
+	struct sdl_input_data *data = dev->data;
-
-	data->dev = dev;
 
 	LOG_INF("Init '%s' device", dev->name);
-	SDL_AddEventWatch(sdl_filter, data);
+
+	data->dev = dev;
+	data->callback = sdl_input_callback;
+	sdl_input_init_bottom(data);
 
 	return 0;
 }
 
-static struct sdl_data sdl_data_0;
+static struct sdl_input_data sdl_data_0;
 
 DEVICE_DT_INST_DEFINE(0, sdl_init, NULL, &sdl_data_0, NULL,
 		    POST_KERNEL, CONFIG_INPUT_INIT_PRIORITY, NULL);

drivers/input/input_sdl_touch_bottom.c

@@ -0,0 +1,39 @@
+/*
+ * Copyright (c) 2020 Jabil Inc.
+ * Copyright (c) 2023 Nordic Semiconductor
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <SDL.h>
+#include "input_sdl_touch_bottom.h"
+
+static int sdl_filter(void *arg, SDL_Event *event)
+{
+	struct sdl_input_data *data = arg;
+
+	switch (event->type) {
+	case SDL_MOUSEBUTTONUP:
+		data->pressed = false;
+		data->just_released = true;
+		break;
+	case SDL_MOUSEBUTTONDOWN:
+		data->pressed = true;
+		break;
+	case SDL_MOUSEMOTION:
+		data->x = event->button.x;
+		data->y = event->button.y;
+		break;
+	default:
+		return 1;
+	}
+
+	data->callback(data);
+
+	return 1;
+}
+
+void sdl_input_init_bottom(struct sdl_input_data *data)
+{
+	SDL_AddEventWatch(sdl_filter, data);
+}

drivers/input/input_sdl_touch_bottom.h

@@ -0,0 +1,38 @@
+/*
+ * Copyright (c) 2023 Nordic Semiconductor
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * "Bottom" of the SDL input driver.
+ * When built with the native_simulator this will be built in the runner context,
+ * that is, with the host C library, and with the host include paths.
+ */
+
+#ifndef DRIVERS_INPUT_INPUT_SDL_TOUCH_BOTTOM_H
+#define DRIVERS_INPUT_INPUT_SDL_TOUCH_BOTTOM_H
+
+#include <stdint.h>
+#include <stdbool.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/* Note: None of these are public interfaces. But internal to the SDL input driver */
+
+struct sdl_input_data {
+	const void *dev; /* device structure pointer */
+	void (*callback)(struct sdl_input_data *data);
+	int x;
+	int y;
+	bool pressed;
+	bool just_released;
+};
+
+void sdl_input_init_bottom(struct sdl_input_data *data);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* DRIVERS_INPUT_INPUT_SDL_TOUCH_BOTTOM_H */