Hi ,
I am unable to reverse polarity to PWM port P8_19.
My Linux version Linux arm 4.4.6-ti-r15 #1 SMP Tue Apr 5 08:05:26 UTC 2016 armv7l GNU/Linux
I get Invalid argument error.
root@arm:/sys/devices/platform/ocp/48304000.epwmss/48304200.ehrpwm/pwm/pwmchip0/pwm1# echo 1000000 > period
root@arm:/sys/devices/platform/ocp/48304000.epwmss/48304200.ehrpwm/pwm/pwmchip0/pwm1# echo 500000 > duty_cycle
root@arm:/sys/devices/platform/ocp/48304000.epwmss/48304200.ehrpwm/pwm/pwmchip0/pwm1# echo 1 > enable
root@arm:/sys/devices/platform/ocp/48304000.epwmss/48304200.ehrpwm/pwm/pwmchip0/pwm1# echo 0 > enable
root@arm:/sys/devices/platform/ocp/48304000.epwmss/48304200.ehrpwm/pwm/pwmchip0/pwm1# cat polarity
normal
root@arm:/sys/devices/platform/ocp/48304000.epwmss/48304200.ehrpwm/pwm/pwmchip0/pwm1# echo 1 > polarity
bash: echo: write error: Invalid argument
root@arm:/sys/devices/platform/ocp/48304000.epwmss/48304200.ehrpwm/pwm/pwmchip0/pwm1#
I am using the ehrpwm2A PWM on P8_19. The following device tree overlay (BB-PWM2-00A0.dts):
/dts-v1/;
/plugin/;
/{
compatible = “ti,beaglebone”, “ti,beaglebone-black”;
part-number = “BB-PWM2”;
version = “00A0”;
fragment@0 {
target = <&am33xx_pinmux>;
overlay {
pinctrl_spec: Panel_Pins {
pinctrl-single,pins = <
0x020 0x04 /* P8_19 MODE4 ehrpwm2A PWM */
;
};
};
};
fragment@1 {
target = <&ocp>;
overlay {
test_helper: helper {
compatible = “bone-pinmux-helper”;
pinctrl-names = “default”;
pinctrl-0 = <&pinctrl_spec>;
status = “okay”;
};
};
};
fragment@2 {
target = <&epwmss2>;
overlay {
status = “okay”;
};
};
fragment@3 {
target = <&ehrpwm2>;
overlay {
status = “okay”;
};
};
};