Add brightness level API to OLED driver (qmk#10772)

* Add brightness level API to OLED driver

* Set default brightness to 255

drivers/oled/oled_driver.c

@@ -107,6 +107,7 @@ OLED_BLOCK_TYPE oled_dirty          = 0;
 bool            oled_initialized    = false;
 bool            oled_active         = false;
 bool            oled_scrolling      = false;
+uint8_t         oled_brightness     = OLED_BRIGHTNESS;
 uint8_t         oled_rotation       = 0;
 uint8_t         oled_rotation_width = 0;
 uint8_t         oled_scroll_speed   = 0;  // this holds the speed after being remapped to ssd1306 internal values
@@ -193,7 +194,7 @@ bool oled_init(uint8_t rotation) {
         }
     }
 
-    static const uint8_t PROGMEM display_setup2[] = {I2C_CMD, COM_PINS, OLED_COM_PINS, CONTRAST, 0x8F, PRE_CHARGE_PERIOD, 0xF1, VCOM_DETECT, 0x40, DISPLAY_ALL_ON_RESUME, NORMAL_DISPLAY, DEACTIVATE_SCROLL, DISPLAY_ON};
+    static const uint8_t PROGMEM display_setup2[] = {I2C_CMD, COM_PINS, OLED_COM_PINS, CONTRAST, OLED_BRIGHTNESS, PRE_CHARGE_PERIOD, 0xF1, VCOM_DETECT, 0x20, DISPLAY_ALL_ON_RESUME, NORMAL_DISPLAY, DEACTIVATE_SCROLL, DISPLAY_ON};
     if (I2C_TRANSMIT_P(display_setup2) != I2C_STATUS_SUCCESS) {
         print("display_setup2 failed\n");
         return false;
@@ -550,6 +551,20 @@ bool oled_off(void) {
 
 bool is_oled_on(void) { return oled_active; }
 
+uint8_t oled_set_brightness(uint8_t level) {
+    uint8_t set_contrast[] = {I2C_CMD, CONTRAST, level};
+    if (oled_brightness != level) {
+        if (I2C_TRANSMIT(set_contrast) != I2C_STATUS_SUCCESS) {
+            print("set_brightness cmd failed\n");
+            return oled_brightness;
+        }
+        oled_brightness = level;
+    }
+    return oled_brightness;
+}
+
+uint8_t oled_get_brightness(void) { return oled_brightness; }
+
 // Set the specific 8 lines rows of the screen to scroll.
 // 0 is the default for start, and 7 for end, which is the entire
 // height of the screen.  For 128x32 screens, rows 4-7 are not used.

drivers/oled/oled_driver.h

@@ -141,6 +141,10 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 #if !defined(OLED_FONT_HEIGHT)
 #    define OLED_FONT_HEIGHT 8
 #endif
+// Default brightness level
+#if !defined(OLED_BRIGHTNESS)
+#    define OLED_BRIGHTNESS 255
+#endif
 
 #if !defined(OLED_TIMEOUT)
 #    if defined(OLED_DISABLE_TIMEOUT)
@@ -261,6 +265,12 @@ bool oled_off(void);
 // not
 bool is_oled_on(void);
 
+// Sets the brightness of the display
+uint8_t oled_set_brightness(uint8_t level);
+
+// Gets the current brightness of the display
+uint8_t oled_get_brightness(void);
+
 // Basically it's oled_render, but with timeout management and oled_task_user calling!
 void oled_task(void);