No PWM

[tlamarc]

I am trying to get a pwm signal on gpio 1 1 for an i.MX7s processor.  Here is my device tree configuration but I see nothing on the pin.  Any help would be greatly appreciated.

/ {

   pwm-leds {

   compatible = "pwm-leds";

      pwm_led1 {

         label = "pwm_led1";

         pwms = <&pwm1 0 100000 50000>;

         max-brightness = <255>;

      };

   };

};

&pwm1 {

   pinctrl-names = "default";

   pinctrl-0 = <&pinctrl_pwm_led1>;

   status = "okay";

};

&iomuxc {

   pinctrl_pwm_led1: pwm_led1 {

   fsl,pins = <

      MX7D_PAD_LPSR_GPIO1_IO01__PWM1_OUT 0x14

   >;

   };

};

[JosephAtNXP]

Hi,

Thank you for your interest in NXP Semiconductor products,

Please change the driver according to this document.

Also, this solution provided by a colleague may help debug this issue.

Regards

[tlamarc]

I updated the line from:   compatible = "pwm-leds";

to:   compatible = "fsl,imx7d-pwm";

but I still have no pwm signal on the pin,

[JosephAtNXP]

Hi,

You can base on 7d-sdb device tree,

pwm1: pwm@30660000 {
				compatible = "fsl,imx7d-pwm", "fsl,imx27-pwm";
				reg = <0x30660000 0x10000>;
				interrupts = <GIC_SPI 81 IRQ_TYPE_LEVEL_HIGH>;
				clocks = <&clks IMX7D_PWM1_ROOT_CLK>,
					 <&clks IMX7D_PWM1_ROOT_CLK>;
				clock-names = "ipg", "per";
				#pwm-cells = <3>;
				status = "disabled";
			};

...

&pwm1 {
	pinctrl-names = "default";
	pinctrl-0 = <&pinctrl_pwm1>;
	status = "okay";
};

...

- backlight: backlight {
- 		compatible = "pwm-backlight";
- 		pwms = <&pwm1 0 5000000 0>;
- 		brightness-levels = <0 4 8 16 32 64 128 255>;
- 		default-brightness-level = <6>;
- 		status = "okay";
- 	};

I reproduced in 8mp-evk with the device tree,

pwm1: pwm@30660000 {
				compatible = "fsl,imx8mp-pwm", "fsl,imx27-pwm";
				reg = <0x30660000 0x10000>;
				interrupts = <GIC_SPI 81 IRQ_TYPE_LEVEL_HIGH>;
				clocks = <&clk IMX8MP_CLK_PWM1_ROOT>,
					 <&clk IMX8MP_CLK_PWM1_ROOT>;
				clock-names = "ipg", "per";
				#pwm-cells = <3>;
				status = "disabled";
			};

...

&pwm1 {
	pinctrl-names = "default";
	pinctrl-0 = <&pinctrl_pwm1>;
	status = "okay";
};

And these steps from the post I mentioned,

root@imx8mpevk:~# cat /sys/class/pwm/pwmchip0/npwm
1
root@imx8mpevk:~# echo 0 > /sys/class/pwm/pwmchip0/export
root@imx8mpevk:~# ls /sys/class/pwm/pwmchip0/pwm0/
capture  duty_cycle  enable  period  polarity  power  uevent
root@imx8mpevk:~# echo 10000 > /sys/class/pwm/pwmchip0/pwm0/period
root@imx8mpevk:~# echo 2000 > /sys/class/pwm/pwmchip0/pwm0/duty_cycle
root@imx8mpevk:~# echo 1 > /sys/class/pwm/pwmchip0/pwm0/enable

Regards,