ARM: dts: stm32: Add TIMERS inverted PWM channel 3 on STM32MP135F-DK

The pwm source TIM1_CH3N channel (on PE12) in inverted polarity mode
will be used to manage the brightness of the panel backlight on
STM32MP135F-DK.

Signed-off-by: Cheick Traore <cheick.traore@foss.st.com>
Reviewed-by: Fabrice Gasnier <fabrice.gasnier@foss.st.com>
Reviewed-by: Patrice Chotard <patrice.chotard@foss.st.com>
diff --git a/arch/arm/dts/stm32mp135f-dk.dts b/arch/arm/dts/stm32mp135f-dk.dts
index eea740d..275823d 100644
--- a/arch/arm/dts/stm32mp135f-dk.dts
+++ b/arch/arm/dts/stm32mp135f-dk.dts
@@ -9,6 +9,7 @@
 #include <dt-bindings/gpio/gpio.h>
 #include <dt-bindings/input/input.h>
 #include <dt-bindings/leds/common.h>
+#include <dt-bindings/pwm/pwm.h>
 #include <dt-bindings/regulator/st,stm32mp13-regulator.h>
 #include "stm32mp135.dtsi"
 #include "stm32mp13xf.dtsi"
@@ -207,6 +208,19 @@
 	status = "disabled";
 };
 
+&timers1 {
+	/* spare dmas for other usage */
+	/delete-property/dmas;
+	/delete-property/dma-names;
+	status = "okay";
+	pwm1: pwm {
+		pinctrl-0 = <&pwm1_ch3n_pins_a>;
+		pinctrl-1 = <&pwm1_ch3n_sleep_pins_a>;
+		pinctrl-names = "default", "sleep";
+		status = "okay";
+	};
+};
+
 &timers3 {
 	/delete-property/dmas;
 	/delete-property/dma-names;