feat(drivers): initial implementation of a QNX screen driver (#6507)

Co-authored-by: Elad Lahav <elahav@qnx.com>

docs/integration/os/qnx.rst

@@ -0,0 +1,123 @@
+===
+QNX
+===
+
+What is QNX?
+------------
+
+QNX is a commercial operating system first released in 1980. The operating
+system is based on a micro-kernel design, with the file system(s), network
+stack, and various other drivers each running in its own process with a separate
+address space.
+
+See www.qnx.com for more details.
+
+Highlight of QNX
+~~~~~~~~~~~~~~~~
+
+- 64-bit only, runs on x86_64 and ARMv8
+- Requires an MMU as the design mandates separation among processes
+- Support for thousands of processes and millions of threads
+- Up to 64 cores, up to 16TB of RAM
+- Virtualization support (as host and guest)
+- Full POSIX compatibility
+- Safety certification to various automotive, industrial and medical standards
+
+How to run LVGL on QNX?
+-----------------------
+
+Build LVGL
+~~~~~~~~~~
+
+The top-level `qnx` directory includes a recursive make file for building LVGL,
+both as a shared library and as a static library for the supported
+architectures. To build all libraries, simply invoke `make` in this directory:
+
+.. code:: shell
+
+    # cd $(LVGL_ROOT)/qnx
+    # make
+
+If you prefer to build for a specific architecture and variant, go to the
+appropriate directory and run `make` there. For example, to build a shared
+library for ARMv8:
+
+.. code:: shell
+
+    # cd $(LVGL_ROOT)/qnx/aarch64/so.le
+    # make
+
+As a general rule, if you only want to have one LVGL application in your system
+then it is better to use a static library. If you have more than one, and
+especially if they run concurrently, it is better to use the shared library.
+
+Before building the library, you may wish to edit `$(LVGL_ROOT)/qnx/lv_conf.h`,
+e.g. to enable double-buffering.
+
+Writing a LVGL Application
+~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+To create a LVGL application for QNX, follow these steps in your code:
+
+1. Initialize the library.
+2. Create a window.
+3. Add the input devices.
+4. Create the UI.
+5. Run the event loop.
+
+Steps 2, 3 and 5 use QNX-specific calls, but the rest of the code should be
+identical to that of a LVGL application written for any other platform.
+
+The following code shows how to create a "Hello World" application:
+
+.. code:: c
+
+    #include <lvgl.h>
+
+    int
+    main(int argc, char **argv)
+    {
+        /* Initialize the library. */
+        lv_init();
+
+        /* Create a 800x480 window. */
+        lv_display_t *disp = lv_qnx_window_create(800, 480);
+        lv_qnx_window_set_title(disp, "LVGL Example");
+
+        /* Add a keyboard and mouse devices. */
+        lv_qnx_add_keyboard_device(disp);
+        lv_qnx_add_pointer_device(disp);
+
+        /* Generate the UI. */
+        lv_obj_set_style_bg_color(lv_screen_active(), lv_color_hex(0x003a57), LV_PART_MAIN);
+
+        lv_obj_t * label = lv_label_create(lv_screen_active());
+        lv_label_set_text(label, "Hello world");
+        lv_obj_set_style_text_color(lv_screen_active(), lv_color_hex(0xffffff), LV_PART_MAIN);
+        lv_obj_align(label, LV_ALIGN_CENTER, 0, 0);
+
+        /* Run the event loop until it exits. */
+        return lv_qnx_event_loop(disp);
+    }
+
+Build the Application
+~~~~~~~~~~~~~~~~~~~~~
+
+Building the application consists of compiling the source with the LVGL headers,
+and then linking against the library. This can be done in many ways, using
+different build systems. The following is a simple make file for the example
+above, which builds for ARMv8 with the shared library:
+
+.. code:: makefile
+
+    CC=qcc -Vgcc_ntoaarch64le
+
+    LVGL_DIR=$(HOME)/src/lvgl
+    CCFLAGS=-I$(LVGL_DIR)/qnx -I$(LVGL_DIR)
+    LDFLAGS=-lscreen -llvgl -L$(LVGL_DIR)/qnx/aarch64/so.le
+
+    lvgl_example: lvgl_example.c
+    	$(CC) $(CCFLAGS) -Wall -o $@ $< $(LDFLAGS)
+
+    clean:
+    	rm -f *.o *~ lvgl_example