drivers gpio SDL emul: Split in top and bottom

Split the SDL GPIO emulator 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/gpio/CMakeLists.txt

@@ -45,7 +45,6 @@ zephyr_library_sources_ifdef(CONFIG_GPIO_LPC11U6X   gpio_lpc11u6x.c)
 zephyr_library_sources_ifdef(CONFIG_GPIO_XLNX_AXI   gpio_xlnx_axi.c)
 zephyr_library_sources_ifdef(CONFIG_GPIO_NPCX       gpio_npcx.c)
 zephyr_library_sources_ifdef(CONFIG_GPIO_EMUL       gpio_emul.c)
-zephyr_library_sources_ifdef(CONFIG_GPIO_EMUL_SDL   gpio_emul_sdl.c)
 zephyr_library_sources_ifdef(CONFIG_GPIO_PSOC6      gpio_psoc6.c)
 zephyr_library_sources_ifdef(CONFIG_GPIO_PCAL64XXA  gpio_pcal64xxa.c)
 zephyr_library_sources_ifdef(CONFIG_GPIO_EOS_S3     gpio_eos_s3.c)
@@ -82,6 +81,15 @@ zephyr_library_sources_ifdef(CONFIG_GPIO_HOGS       gpio_hogs.c)
 zephyr_library_sources_ifdef(CONFIG_GPIO_NUMAKER    gpio_numaker.c)
 zephyr_library_sources_ifdef(CONFIG_GPIO_EFINIX_SAPPHIRE    gpio_efinix_sapphire.c)
 
+if (CONFIG_GPIO_EMUL_SDL)
+  zephyr_library_sources(gpio_emul_sdl.c)
+  if (CONFIG_NATIVE_APPLICATION)
+    zephyr_library_sources(gpio_emul_sdl_bottom.c)
+  else()
+    target_sources(native_simulator INTERFACE gpio_emul_sdl_bottom.c)
+  endif()
+endif()
+
 if(CONFIG_GPIO_SC18IM704)
   zephyr_library_include_directories(${ZEPHYR_BASE}/drivers)
   zephyr_library_sources(gpio_sc18im704.c)

drivers/gpio/gpio_emul_sdl.c

@@ -10,37 +10,29 @@
 #include <zephyr/kernel.h>
 #include <zephyr/logging/log.h>
 
-#include <SDL.h>
+#include "gpio_emul_sdl_bottom.h"
 
 LOG_MODULE_REGISTER(gpio_emul_sdl, CONFIG_GPIO_LOG_LEVEL);
 
 struct gpio_sdl_config {
 	const struct device *emul;
 
-	const SDL_Scancode *codes;
+	const int *codes;
 	uint8_t num_codes;
+	struct gpio_sdl_data *data;
 };
 
-static int sdl_filter(void *arg, SDL_Event *event)
+static int sdl_filter_top(struct gpio_sdl_data *bottom_data)
 {
-	const struct device *port = arg;
+	const struct device *port = bottom_data->dev;
 	const struct gpio_sdl_config *config = port->config;
 	int ret;
 
 	gpio_pin_t pin = 0;
 
-	/* Only handle keyboard events */
-	switch (event->type) {
-	case SDL_KEYDOWN:
-	case SDL_KEYUP:
-		break;
-	default:
-		return 1;
-	}
-
 	/* Search for the corresponding scancode */
 	while (pin < config->num_codes) {
-		if (config->codes[pin] == event->key.keysym.scancode) {
+		if (config->codes[pin] == bottom_data->event_scan_code) {
 			break;
 		}
 		pin++;
@@ -58,7 +50,7 @@ static int sdl_filter(void *arg, SDL_Event *event)
 	k_sched_lock();
 
 	/* Update the pin state */
-	ret = gpio_emul_input_set(config->emul, pin, event->type == SDL_KEYDOWN ? 1 : 0);
+	ret = gpio_emul_input_set(config->emul, pin, bottom_data->key_down);
 
 	k_sched_unlock();
 	if (ret < 0) {
@@ -73,13 +65,14 @@ static int gpio_sdl_init(const struct device *dev)
 	const struct gpio_sdl_config *config = dev->config;
 
 	for (uint8_t pin = 0; pin < config->num_codes; ++pin) {
-		if (config->codes[pin] != SDL_SCANCODE_UNKNOWN) {
+		if (config->codes[pin] != GPIOEMULSDL_SCANCODE_UNKNOWN) {
 			LOG_INF("GPIO %s:%u = %u", dev->name, pin, config->codes[pin]);
 		}
 	}
 
-	SDL_AddEventWatch(sdl_filter, (void *)dev);
-
+	config->data->dev = (void *)dev;
+	config->data->callback = sdl_filter_top;
+	gpio_sdl_init_bottom(config->data);
 	return 0;
 }
 
@@ -88,13 +81,16 @@ static int gpio_sdl_init(const struct device *dev)
 					       zephyr_gpio_emul, okay),			\
 		     "Enabled parent zephyr,gpio-emul node is required");		\
 											\
-	static const SDL_Scancode gpio_sdl_##inst##_codes[]				\
+	static const int gpio_sdl_##inst##_codes[]					\
 		= DT_INST_PROP(inst, scancodes);					\
 											\
+	static struct gpio_sdl_data data_##inst;				\
+											\
 	static const struct gpio_sdl_config gpio_sdl_##inst##_config = {		\
 		.emul = DEVICE_DT_GET(DT_INST_PARENT(inst)),				\
 		.codes = gpio_sdl_##inst##_codes,					\
 		.num_codes = DT_INST_PROP_LEN(inst, scancodes),				\
+		.data = &data_##inst,					\
 	};										\
 												\
 	DEVICE_DT_INST_DEFINE(inst, gpio_sdl_init, NULL, NULL,				\

drivers/gpio/gpio_emul_sdl_bottom.c

@@ -0,0 +1,33 @@
+/*
+ * Copyright (c) 2022, Basalte bv
+ * Copyright (c) 2023 Nordic Semiconductor
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <SDL.h>
+#include "gpio_emul_sdl_bottom.h"
+
+static int sdl_filter_bottom(void *arg, SDL_Event *event)
+{
+	struct gpio_sdl_data *data = arg;
+
+	/* Only handle keyboard events */
+	switch (event->type) {
+	case SDL_KEYDOWN:
+	case SDL_KEYUP:
+		break;
+	default:
+		return 1;
+	}
+
+	data->event_scan_code = event->key.keysym.scancode;
+	data->key_down = event->type == SDL_KEYDOWN;
+
+	return data->callback(arg);
+}
+
+void gpio_sdl_init_bottom(struct gpio_sdl_data *data)
+{
+	SDL_AddEventWatch(sdl_filter_bottom, (void *)data);
+}

drivers/gpio/gpio_emul_sdl_bottom.h

@@ -0,0 +1,39 @@
+/*
+ * Copyright (c) 2022, Basalte bv
+ * Copyright (c) 2023 Nordic Semiconductor
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * "Bottom" of the SDL GPIO emulator.
+ * 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_GPIO_GPIO_EMUL_SDL_BOTTOM_H
+#define DRIVERS_GPIO_GPIO_EMUL_SDL_BOTTOM_H
+
+#include <stdbool.h>
+#include <stdint.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/* Note: None of these are public interfaces. But internal to the SDL GPIO emulator */
+
+#define GPIOEMULSDL_SCANCODE_UNKNOWN 0
+
+struct gpio_sdl_data {
+	void *dev;
+	int (*callback)(struct gpio_sdl_data *data);
+	int event_scan_code;
+	bool key_down;
+};
+
+void gpio_sdl_init_bottom(struct gpio_sdl_data *data);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* DRIVERS_GPIO_GPIO_EMUL_SDL_BOTTOM_H */