docs: add evdev documentation (#6376)

Co-authored-by: Gabor Kiss-Vamosi <kisvegabor@gmail.com>

docs/integration/driver/touchpad/evdev.rst

@@ -0,0 +1,57 @@
+==================
+Linux Evdev Driver
+==================
+
+Overview
+--------
+
+The Linux event device (evdev) is a hardware-independent API that gives access to input events from, 
+for example, a mouse or touchscreen. It is exposed via the Linux device file system interface. 
+
+Prerequisites
+-------------
+
+Your system has an input device configured (usually under ``/dev/input/`` such as ``/dev/input/event0``).
+
+Configuring the driver
+----------------------
+
+Enable the Linux LVGL evdev driver support in ``lv_conf.h``.    
+
+.. code:: c
+
+	#define LV_USE_EVDEV 1
+
+Usage
+-----
+
+To set up an event input, first create an input device with ``lv_edev_create`` setting it to the correct Linux event device.
+Then link this to the LVGL display with ``lv_indev_set_display``.   
+
+.. code:: c
+
+	lv_indev_t *touch = lv_evdev_create(LV_INDEV_TYPE_POINTER, "/dev/input/event0");
+	lv_indev_set_display(touch, disp);
+
+Ensure that an ``lv_display_t`` object is already created for ``disp``. An example for this is shown below, using the Linux framebuffer driver. 
+
+.. code:: c
+
+	lv_display_t * disp = lv_linux_fbdev  
+	lv_linux_fbdev_set_file(disp, "/dev/fb0");_create();
+
+
+Locating your input device
+--------------------------
+
+If you can't determine your input device, first run   
+
+```$cat /proc/bus/input/devices```
+
+This should show input devices and there will be entries with the word ``event`` which give a clue as to the device to use eg. ``event1`` would be ``/dev/input/event1``.  
+
+You can use ``evtest`` to show data from that event source to see if it is actually the one you want.
+
+Try:   
+
+``$evtest /dev/input/event1`` replacing ``eventX`` with your event device from above.   

docs/integration/driver/touchpad/index.rst

@@ -6,3 +6,4 @@ Touchpad
     :maxdepth: 2
 
     ft6x36
+    evdev