2 files changed, 22 insertions, 4 deletions

diff --git a/quantum/backlight/backlight_avr.c b/quantum/backlight/backlight_avr.c
index b3e882ffe..4d66da80b 100644
--- a/quantum/backlight/backlight_avr.c
+++ b/quantum/backlight/backlight_avr.c
@@ -3,6 +3,11 @@
 #include "backlight_driver_common.h"
 #include "debug.h"
 
+// Maximum duty cycle limit
+#ifndef BACKLIGHT_LIMIT_VAL
+#    define BACKLIGHT_LIMIT_VAL 255
+#endif
+
 // This logic is a bit complex, we support 3 setups:
 //
 //   1. Hardware PWM when backlight is wired to a PWM pin.
@@ -240,6 +245,9 @@ static uint16_t cie_lightness(uint16_t v) {
     }
 }
 
+// rescale the supplied backlight value to be in terms of the value limit
+static uint32_t rescale_limit_val(uint32_t val) { return (val * (BACKLIGHT_LIMIT_VAL + 1)) / 256; }
+
 // range for val is [0..TIMER_TOP]. PWM pin is high while the timer count is below val.
 static inline void set_pwm(uint16_t val) { OCRxx = val; }
 
@@ -269,7 +277,7 @@ void backlight_set(uint8_t level) {
 #endif
     }
     // Set the brightness
-    set_pwm(cie_lightness(TIMER_TOP * (uint32_t)level / BACKLIGHT_LEVELS));
+    set_pwm(cie_lightness(rescale_limit_val(TIMER_TOP * (uint32_t)level / BACKLIGHT_LEVELS)));
 }
 
 void backlight_task(void) {}
@@ -375,7 +383,7 @@ ISR(TIMERx_OVF_vect)
         breathing_interrupt_disable();
     }
 
-    set_pwm(cie_lightness(scale_backlight((uint16_t)pgm_read_byte(&breathing_table[index]) * 0x0101U)));
+    set_pwm(cie_lightness(rescale_limit_val(scale_backlight((uint16_t)pgm_read_byte(&breathing_table[index]) * 0x0101U))));
 }
 
 #endif  // BACKLIGHT_BREATHING
diff --git a/quantum/backlight/backlight_chibios.c b/quantum/backlight/backlight_chibios.c
index 0fe812bf2..4d5a69e14 100644
--- a/quantum/backlight/backlight_chibios.c
+++ b/quantum/backlight/backlight_chibios.c
@@ -3,6 +3,11 @@
 #include <hal.h>
 #include "debug.h"
 
+// Maximum duty cycle limit
+#ifndef BACKLIGHT_LIMIT_VAL
+#    define BACKLIGHT_LIMIT_VAL 255
+#endif
+
 // GPIOV2 && GPIOV3
 #ifndef BACKLIGHT_PAL_MODE
 #    define BACKLIGHT_PAL_MODE 2
@@ -58,6 +63,11 @@ static uint16_t cie_lightness(uint16_t v) {
     }
 }
 
+static uint32_t rescale_limit_val(uint32_t val) {
+    // rescale the supplied backlight value to be in terms of the value limit
+    return (val * (BACKLIGHT_LIMIT_VAL + 1)) / 256;
+}
+
 void backlight_init_ports(void) {
 #ifdef USE_GPIOV1
     palSetPadMode(PAL_PORT(BACKLIGHT_PIN), PAL_PAD(BACKLIGHT_PIN), PAL_MODE_STM32_ALTERNATE_PUSHPULL);
@@ -85,7 +95,7 @@ void backlight_set(uint8_t level) {
         pwmDisableChannel(&BACKLIGHT_PWM_DRIVER, BACKLIGHT_PWM_CHANNEL - 1);
     } else {
         // Turn backlight on
-        uint32_t duty = (uint32_t)(cie_lightness(0xFFFF * (uint32_t)level / BACKLIGHT_LEVELS));
+        uint32_t duty = (uint32_t)(cie_lightness(rescale_limit_val(0xFFFF * (uint32_t)level / BACKLIGHT_LEVELS)));
         pwmEnableChannel(&BACKLIGHT_PWM_DRIVER, BACKLIGHT_PWM_CHANNEL - 1, PWM_FRACTION_TO_WIDTH(&BACKLIGHT_PWM_DRIVER, 0xFFFF, duty));
     }
 }
@@ -129,7 +139,7 @@ void breathing_callback(PWMDriver *pwmp) {
     static uint16_t breathing_counter = 0;
     breathing_counter                 = (breathing_counter + 1) % (breathing_period * 256);
     uint8_t  index                    = breathing_counter / interval % BREATHING_STEPS;
-    uint32_t duty                     = cie_lightness(scale_backlight(breathing_table[index] * 256));
+    uint32_t duty                     = cie_lightness(rescale_limit_val(scale_backlight(breathing_table[index] * 256)));
 
     chSysLockFromISR();
     pwmEnableChannelI(pwmp, BACKLIGHT_PWM_CHANNEL - 1, PWM_FRACTION_TO_WIDTH(&BACKLIGHT_PWM_DRIVER, 0xFFFF, duty));