Yes. I can control (enable/disable) the POE on port 3.
first find the gpio base
cat /sys/class/gpio/gpiochip*/base | head -n1
that is 412.
in the dts file I found this:
+&tlmm {
+ /*
+ * In addition to the Pins listed below,
+ * the following GPIOs have "features":
+ * 39 - out - active low to force HW reset
+ * 32 - out - active low to reset TPM
+ * 43 - out - active low to reset BLE radio
+ * 41 - out - pulse to set warm reset status
+ * 34 - out - active low to enable PSE port
+ * 22 - in - active low when 802.3at powered
+ * 29 - in - active high when DC powered
+ * 40 - in - active low when reset due to cold HW reset
+ * 30 - in - active low when USB overcurrent detected
+ * 35 - in - interrupt line for power monitor chip
+ * 31 - in - active low when PSE port active
so 34 is the value. You must create and gpio 412+34=446
echo "446" > /sys/class/gpio/export
echo "out" > /sys/class/gpio/gpio446/direction
echo "0" > /sys/class/gpio/gpio446/value Turns it on
echo "1" > /sys/class/gpio/gpio446/value Turns it off