I have an imx7D Sabre board on which I have actived the UART4 ( available on mikro BUS).
The UART4 works perfectly ( I can send/receive data to a PC)
Before sending the board to standby I enable the wakeup from UART4 sending by the console the following comand:
echo enabled > /sys/bus/platform/drivers/imx-uart/30a70000.serial/tty/ttymxc4/power/wakeup
then I put the board in standby with the command:
echo standby > /sys/power/state
Sending then some bytes to the UART4, the Sabre board doesn't wake up.
Instead the wake up works fine from the console.
Console Enable wakeup comand used:
echo enabled > /sys/bus/platform/drivers/imx-uart/30860000.serial/tty/ttymxc0/power/wakeup
Have I forgotten some further setting to enable the Wakeup from standby for the UART4?