Important PM change for omap folks in v5.7-rc1

Important PM change for omap folks in v5.7-rc1

[Tony Lindgren]

Hi all,

FYI, starting with v5.7-rc1, kernel serial console now must be detached
for the UARTs to idle. This has changed starting with commit a3cb39d258ef
("serial: core: Allow detach and attach serial device for console").

So folks may want to run something similar to the following on boot to
detach serial console and idle the UARTs for PM.

Regards,

Tony

8< -------------
#!/bin/sh

# Detach kernel serial console
consoles=$(find /sys/bus/platform/devices/4*.serial/ -name console)
for console in ${consoles}; do
	echo N > ${console}
done

# Configure PM runtime autosuspend
uarts=$(find /sys/bus/platform/devices/4*.serial/power/ -type d)
for uart in ${uarts}; do
	echo 1500 > ${uart}/autosuspend_delay_ms
	echo enabled > ${uart}/wakeup
	echo auto > ${uart}/control
done

# Configure wake-up from suspend
uarts=$(find /sys/class/tty/tty[SO]*/power/ -type d 2>/dev/null)
for uart in ${uarts}; do
	echo enabled > ${uart}/wakeup
done

# Enable off mode during idle if supported
echo 1 > /sys/kernel/debug/pm_debug/enable_off_mode