nrfconnect · rlubos · Jul 11, 2025 · May 29, 2025 · May 29, 2025
diff --git a/drivers/pwm/Kconfig.nrfx b/drivers/pwm/Kconfig.nrfx
@@ -20,3 +20,13 @@ config PWM_NRFX
 	select PINCTRL
 	help
 	  Enable support for nrfx Hardware PWM driver for nRF52 MCU series.
+
+config PWM_NRFX_NO_GLITCH_DUTY_100
+	bool "No glitches when using 100% duty"
+	depends on $(dt_compat_any_has_prop,$(DT_COMPAT_NORDIC_NRF_PWM),idleout-supported,True)
+	default y
+	help
+	  Due to how IDLEOUT feature in PWM works it is possible to see a glitch on a channel
+	  with 100% duty cycle when all other channels switches to 0% or 100%. Enabling this
+	  option ensures that there are no glitches but it also means that 100% duty cycle
+	  on any channels requires PWM peripheral to be active.
diff --git a/drivers/pwm/pwm_nrfx.c b/drivers/pwm/pwm_nrfx.c
@@ -240,7 +240,10 @@
 		/* Constantly active (duty 100%). */
 		/* This value is always greater than or equal to COUNTERTOP. */
 		compare_value = PWM_NRFX_CH_COMPARE_MASK;
+		needs_pwm = pwm_is_fast(config) ||
+			(IS_ENABLED(NRF_PWM_HAS_IDLEOUT) &&
+			 IS_ENABLED(CONFIG_PWM_NRFX_NO_GLITCH_DUTY_100));
 	} else {
 		/* PWM generation needed. Check if the requested period matches
 		 * the one that is currently set, or the PWM peripheral can be
 		 * reconfigured accordingly.
@@ -279,20 +282,8 @@
 			if (inverted) {
 				out_level ^= 1;
 			}
-			/* Output of fast PWM instance is directly connected to GPIO pads,
-			 * thus it cannot controlled by GPIO. Use regular 0%/100% duty cycle
-			 * playback instead.
-			 */
-#ifdef PWM_NRFX_FAST_PRESENT
-			if (pwm_is_fast(config)) {
-				nrfx_pwm_simple_playback(&config->pwm, &config->seq, 1,
-							 NRFX_PWM_FLAG_NO_EVT_FINISHED);
-			} else {
-#else
-			{
-#endif
-				nrf_gpio_pin_write(psel, out_level);
-			}
+
+			nrf_gpio_pin_write(psel, out_level);
 		}
 
 		data->pwm_needed &= ~BIT(channel);

diff --git a/dts/bindings/pwm/nordic,nrf-pwm.yaml b/dts/bindings/pwm/nordic,nrf-pwm.yaml
@@ -18,6 +18,11 @@ properties:
     type: boolean
     description: Set this to use center-aligned (up and down) counter mode.
 
+  idleout-supported:
+    type: boolean
+    description: |
+      Indicates if the PWM instance has the IDLEOUT register.
+
   "#pwm-cells":
     const: 3
 

diff --git a/dts/vendor/nordic/nrf54h20.dtsi b/dts/vendor/nordic/nrf54h20.dtsi
@@ -656,6 +656,7 @@
 				clocks = <&hsfll120>;
 				power-domains = <&gpd NRF_GPD_FAST_ACTIVE1>;
 				#pwm-cells = <3>;
+				idleout-supported;
 			};
 
 			spis120: spi@8e5000 {
@@ -1008,6 +1009,7 @@
 				clocks = <&fll16m>;
 				power-domains = <&gpd NRF_GPD_SLOW_ACTIVE>;
 				#pwm-cells = <3>;
+				idleout-supported;
 			};
 
 			i2c130: i2c@9a5000 {
@@ -1141,6 +1143,7 @@
 				clocks = <&fll16m>;
 				power-domains = <&gpd NRF_GPD_SLOW_ACTIVE>;
 				#pwm-cells = <3>;
+				idleout-supported;
 			};
 
 			i2c132: i2c@9b5000 {
@@ -1274,6 +1277,7 @@
 				clocks = <&fll16m>;
 				#pwm-cells = <3>;
 				power-domains = <&gpd NRF_GPD_SLOW_ACTIVE>;
+				idleout-supported;
 			};
 
 			i2c134: i2c@9c5000 {
@@ -1407,6 +1411,7 @@
 				clocks = <&fll16m>;
 				#pwm-cells = <3>;
 				power-domains = <&gpd NRF_GPD_SLOW_ACTIVE>;
+				idleout-supported;
 			};
 
 			i2c136: i2c@9d5000 {

diff --git a/dts/vendor/nordic/nrf54l20.dtsi b/dts/vendor/nordic/nrf54l20.dtsi
@@ -489,6 +489,7 @@
 				reg = <0xd2000 0x1000>;
 				interrupts = <210 NRF_DEFAULT_IRQ_PRIORITY>;
 				#pwm-cells = <3>;
+				idleout-supported;
 			};
 
 			pwm21: pwm@d3000 {
@@ -497,6 +498,7 @@
 				reg = <0xd3000 0x1000>;
 				interrupts = <211 NRF_DEFAULT_IRQ_PRIORITY>;
 				#pwm-cells = <3>;
+				idleout-supported;
 			};
 
 			pwm22: pwm@d4000 {
@@ -505,6 +507,7 @@
 				reg = <0xd4000 0x1000>;
 				interrupts = <212 NRF_DEFAULT_IRQ_PRIORITY>;
 				#pwm-cells = <3>;
+				idleout-supported;
 			};
 
 			adc: adc@d5000 {

diff --git a/dts/vendor/nordic/nrf54l_05_10_15.dtsi b/dts/vendor/nordic/nrf54l_05_10_15.dtsi
@@ -479,6 +479,7 @@
 				reg = <0xd2000 0x1000>;
 				interrupts = <210 NRF_DEFAULT_IRQ_PRIORITY>;
 				#pwm-cells = <3>;
+				idleout-supported;
 			};
 
 			pwm21: pwm@d3000 {
@@ -487,6 +488,7 @@
 				reg = <0xd3000 0x1000>;
 				interrupts = <211 NRF_DEFAULT_IRQ_PRIORITY>;
 				#pwm-cells = <3>;
+				idleout-supported;
 			};
 
 			pwm22: pwm@d4000 {
@@ -495,6 +497,7 @@
 				reg = <0xd4000 0x1000>;
 				interrupts = <212 NRF_DEFAULT_IRQ_PRIORITY>;
 				#pwm-cells = <3>;
+				idleout-supported;
 			};
 
 			adc: adc@d5000 {

diff --git a/dts/vendor/nordic/nrf9280.dtsi b/dts/vendor/nordic/nrf9280.dtsi
@@ -479,6 +479,7 @@
 				status = "disabled";
 				interrupts = <228 NRF_DEFAULT_IRQ_PRIORITY>;
 				#pwm-cells = <3>;
+				idleout-supported;
 			};
 
 			spi120: spi@8e6000 {
@@ -767,6 +768,7 @@
 				status = "disabled";
 				interrupts = <420 NRF_DEFAULT_IRQ_PRIORITY>;
 				#pwm-cells = <3>;
+				idleout-supported;
 			};
 
 			i2c130: i2c@9a5000 {
@@ -881,6 +883,7 @@
 				status = "disabled";
 				interrupts = <436 NRF_DEFAULT_IRQ_PRIORITY>;
 				#pwm-cells = <3>;
+				idleout-supported;
 			};
 
 			i2c132: i2c@9b5000 {
@@ -995,6 +998,7 @@
 				status = "disabled";
 				interrupts = <452 NRF_DEFAULT_IRQ_PRIORITY>;
 				#pwm-cells = <3>;
+				idleout-supported;
 			};
 
 			i2c134: i2c@9c5000 {
@@ -1109,6 +1113,7 @@
 				status = "disabled";
 				interrupts = <468 NRF_DEFAULT_IRQ_PRIORITY>;
 				#pwm-cells = <3>;
+				idleout-supported;
 			};
 
 			i2c136: i2c@9d5000 {