i.MX8MM PWM Issues

[oprata]

Hello Folks,

I trying to setup PWM pin on imx8mm but I doesn't work. At my configuration, I add those lines

&pwm1 {

pinctrl-names = "default";

pinctrl-0 = <&pinctrl_pwm1>;

status = "okay";

};

&pwm2 {

pinctrl-names = "default";

pinctrl-0 = <&pinctrl_pwm2>;

status = "okay";

};

and

pinctrl_pwm1: pwm1grp {

fsl,pins = <

MX8MM_IOMUXC_I2C4_SDA_PWM1_OUT 0x16

>;

};

pinctrl_pwm2: pwm2grp {

fsl,pins = <

MX8MM_IOMUXC_I2C4_SCL_PWM2_OUT 0x16

>;

};

on dts file and I include this line

CONFIG_PWM=y

CONFIG_PWM_IMX_TPM=y 

on my *_deconfig file. After bake my image with Yocto builder and download the image for my Single Board Computer I saw at /sys/class/pwm folder this

lrwxrwxrwx 1 root root 0 Apr 28 2022 pwmchip0 -> ../../devices/platform/soc@0/30400000.bus/30660000.pwm/pwm/pwmchip0
lrwxrwxrwx 1 root root 0 Apr 28 2022 pwmchip1 -> ../../devices/platform/soc@0/30400000.bus/30670000.pwm/pwm/pwmchip1

But on the /dev folder I didn't see the nodes for pwmchip0 and pwmchip1. Does anyone could give me a tips what I missing or what do I mistake?

Thanks in advance.

[Harvey021 · Accepted solution]

Hi @oprata 

There is no missing or mistake in your configuration. As you can see the pwmchipN existing in the /sys/class/pwm folder which is defined by Kernel.

Best regards

Harvey