Only one PWM Channel supported in STM32L4 ?

[alfonsotames]

Describe the bug

I don't know if this is a bug or an incomplete implementation. The stm32l432k(b-c)ux-pinctrl.dtsi file located in the stm32 HAL module lists these pin configurations for the timers:

			tim1_ch1n_pa7: tim1_ch1n_pa7 {
				pinmux = <STM32_PINMUX('A', 7, AF1)>;
			};

			tim1_ch1_pa8: tim1_ch1_pa8 {
				pinmux = <STM32_PINMUX('A', 8, AF1)>;
			};

			tim1_ch2_pa9: tim1_ch2_pa9 {
				pinmux = <STM32_PINMUX('A', 9, AF1)>;
			};

			tim1_ch3_pa10: tim1_ch3_pa10 {
				pinmux = <STM32_PINMUX('A', 10, AF1)>;
			};

			tim1_ch4_pa11: tim1_ch4_pa11 {
				pinmux = <STM32_PINMUX('A', 11, AF1)>;
			};

			tim1_ch2n_pb0: tim1_ch2n_pb0 {
				pinmux = <STM32_PINMUX('B', 0, AF1)>;
			};

			tim1_ch3n_pb1: tim1_ch3n_pb1 {
				pinmux = <STM32_PINMUX('B', 1, AF1)>;
			};

			tim2_ch1_pa0: tim2_ch1_pa0 {
				pinmux = <STM32_PINMUX('A', 0, AF1)>;
			};

			tim2_ch2_pa1: tim2_ch2_pa1 {
				pinmux = <STM32_PINMUX('A', 1, AF1)>;
			};

			tim2_ch3_pa2: tim2_ch3_pa2 {
				pinmux = <STM32_PINMUX('A', 2, AF1)>;
			};

			tim2_ch4_pa3: tim2_ch4_pa3 {
				pinmux = <STM32_PINMUX('A', 3, AF1)>;
			};

			tim2_ch1_pa5: tim2_ch1_pa5 {
				pinmux = <STM32_PINMUX('A', 5, AF1)>;
			};

			tim2_ch1_pa15: tim2_ch1_pa15 {
				pinmux = <STM32_PINMUX('A', 15, AF1)>;
			};

			tim2_ch2_pb3: tim2_ch2_pb3 {
				pinmux = <STM32_PINMUX('B', 3, AF1)>;
			};

			tim15_ch1n_pa1: tim15_ch1n_pa1 {
				pinmux = <STM32_PINMUX('A', 1, AF14)>;
			};

			tim15_ch1_pa2: tim15_ch1_pa2 {
				pinmux = <STM32_PINMUX('A', 2, AF14)>;
			};

			tim15_ch2_pa3: tim15_ch2_pa3 {
				pinmux = <STM32_PINMUX('A', 3, AF14)>;
			};

			tim16_ch1_pa6: tim16_ch1_pa6 {
				pinmux = <STM32_PINMUX('A', 6, AF14)>;
			};

			tim16_ch1n_pb6: tim16_ch1n_pb6 {
				pinmux = <STM32_PINMUX('B', 6, AF14)>;
			};

But trying to use anything outside Channel 1 for PWM output doesn't work. No errors reported.

To Reproduce

1. Configure a devicetree file for an STM32L432KC board (like a Nucleo) with a timer with any channel that's not Channel 1:

/ {
    aliases {
       pwm-led0 = &red_pwm_led;
       red-pwm-led = &red_pwm_led;
    };

    pwmleds {
		compatible = "pwm-leds";
		red_pwm_led: led_pwm_0 {
			pwms = <&pwm0 1 4 PWM_POLARITY_NORMAL>;
		};
    };
}

&timers1 {
	status = "okay";
	pwm0: pwm {
		status = "okay";
		pinctrl-0 = <&tim1_ch3_pa10>;
	};
};

2. Run the fade_led example in zephyr/samples/basic/fade_led

Expected behavior

• Fading led in pin PA10

Impact
Only having Channel 1 for timer (maybe other peripherals) limits severely the functionality in many boards.

Environment (please complete the following information):

• Ubuntu Linux
• Zephyr OS build v2.5.0-rc1-172-gfd382b4c480b
• Zephyr SDK

[alfonsotames]

Oh! My error.

I had an error in my DTS:

This line:

pwms = <&pwm0 1 4 PWM_POLARITY_NORMAL>;

Should be:

pwms = <&pwm0 2 4 PWM_POLARITY_NORMAL>;

Second argument is the channel!