Add adjustable PWM frequency to minimize buzzing noise

src/common/system/settings.h

@@ -50,6 +50,7 @@ typedef struct settings_s {
     int ingame_long_press;
     int ingame_double_press;
     bool disable_standby;
+    int pwmfrequency;
     bool enable_logging;
     int blue_light_state;
     int blue_light_level;
@@ -106,6 +107,7 @@ static settings_s __default_settings = (settings_s){
     .blue_light_rgb = 8421504,
     .blue_light_time = "20:00",
     .blue_light_time_off = "08:00",
+    .pwmfrequency = 7,
     .mainui_button_x = "",
     .mainui_button_y = ""};
 
@@ -205,6 +207,7 @@ void settings_load(void)
     config_get("display/blueLightTime", CONFIG_STR, &settings.blue_light_time);
     config_get("display/blueLightTimeOff", CONFIG_STR, &settings.blue_light_time_off);
     config_get("display/blueLightRGB", CONFIG_INT, &settings.blue_light_rgb);
+    config_get("pwmfrequency", CONFIG_INT, &settings.pwmfrequency);
 
     if (config_flag_get(".menuInverted")) { // flag is deprecated, but keep compatibility
         settings.ingame_single_press = 2;
@@ -331,6 +334,7 @@ void settings_save(void)
     config_setString("display/blueLightTime", settings.blue_light_time);
     config_setString("display/blueLightTimeOff", settings.blue_light_time_off);
 
+    config_setNumber("pwmfrequency", settings.pwmfrequency);
     // remove deprecated flags
     remove(CONFIG_PATH ".noLowBatteryAutoSave");
     remove(CONFIG_PATH ".noBatteryWarning");

src/tweaks/actions.h

@@ -353,6 +353,16 @@ void action_advancedSetFrameThrottle(void *pt)
     stored_value_frame_throttle_changed = true;
 }
 
+void action_advancedSetPWMFreqency(void *pt)
+{
+    FILE *fp;
+    int item_value = ((ListItem *)pt)->value;
+    int pwmfrequency = atoi(((ListItem *)pt)->value_labels[item_value]);
+    char *filename = "/sys/class/pwm/pwmchip0/pwm0/period";
+    file_put(fp, filename, "%d", pwmfrequency);
+    config_setNumber(".pwmfrequency", item_value);
+}
+
 void action_advancedSetSwapTriggers(void *pt)
 {
     int item_value = ((ListItem *)pt)->value;

src/tweaks/formatters.h

@@ -29,6 +29,10 @@
     {                                                                 \
         "None", "Subtle", "Moderate", "Balanced", "Strong", "Intense" \
     }
+#define PWM_FREQUENCIES                                                                                                \
+    {                                                                                                                  \
+        "100 Hz", "200 Hz", "300 Hz", "400 Hz", "500 Hz", "600 Hz", "700 Hz", "800  Hz (Default)", "900 Hz", "1000 Hz" \
+    }
 
 void formatter_timezone(void *pt, char *out_label)
 {

src/tweaks/menus.h

@@ -677,7 +677,7 @@ void menu_diagnostics(void *pt)
 void menu_advanced(void *_)
 {
     if (!_menu_advanced._created) {
-        _menu_advanced = list_createWithTitle(6, LIST_SMALL, "Advanced");
+        _menu_advanced = list_createWithTitle(7, LIST_SMALL, "Advanced");
         list_addItemWithInfoNote(&_menu_advanced,
                                  (ListItem){
                                      .label = "Swap triggers (L<>L2, R<>R2)",
@@ -707,6 +707,17 @@ void menu_advanced(void *_)
                                      .value_formatter = formatter_fastForward,
                                      .action = action_advancedSetFrameThrottle},
                                  "Set the maximum fast forward rate.");
+        list_addItemWithInfoNote(&_menu_advanced,
+                                 (ListItem){
+                                     .label = "PWM frequency",
+                                     .item_type = MULTIVALUE,
+                                     .value_max = 9,
+                                     .value_labels = PWM_FREQUENCIES,
+                                     .value = value_getPWMFrequency(),
+                                     .action = action_advancedSetPWMFreqency},
+                                 "Change the PWM frequency\n"
+                                 "Lower values for less buzzing\n"
+                                 "Experimental feature");
         if (DEVICE_ID == MIYOO354) {
             list_addItemWithInfoNote(&_menu_advanced,
                                      (ListItem){

src/tweaks/values.h

@@ -288,6 +288,13 @@ void value_setSwapTriggers(void)
                  r_btn, l2_btn, r2_btn);
 }
 
+int value_getPWMFrequency(void)
+{
+    int pwmfrequency = 0;
+    config_get(".pwmfrequency", CONFIG_INT, &pwmfrequency);
+    return pwmfrequency;
+}
+
 int value_getLcdVoltage(void)
 {
     int value = 0x0;

static/build/.tmp_update/runtime.sh

@@ -508,7 +508,14 @@ init_system() {
 
     # init backlight
     echo 0 > /sys/class/pwm/pwmchip0/export
-    echo 800 > /sys/class/pwm/pwmchip0/pwm0/period
+    pwmfile="$sysdir/config/.pwmfrequency"
+    if [ -s $pwmfile ]; then
+        # 0 - 9 = 100 - 1000 Hz
+        frequency=$((($(cat "$pwmfile") + 1) * 100))
+    else
+        frequency=800
+    fi
+    echo $frequency > /sys/class/pwm/pwmchip0/pwm0/period
     echo $brightness_raw > /sys/class/pwm/pwmchip0/pwm0/duty_cycle
     echo 1 > /sys/class/pwm/pwmchip0/pwm0/enable
 }

static/configs/.tmp_update/config/.pwmfrequency

@@ -0,0 +1 @@
+7