I've used the latest BSP to generate a bootloader and kernel, then based on the DTS from the evk and the default one from the manufacturer of the carrier board (attached) I made a DTS (attached) to suit my needs which are:
- one ethernet
- as many as possible UART
- two i²c
I think I disabled pretty much everything else. But power consumption is nowhere as low as i hoped...
- idle (eth0 'okay' but no cable attached, usb eth gadget) 953mW
- idle but eth0 and usb0 down 750mW
- standby 580mW (and 'mem' doesn't seem to make a noticable difference)
When using the default dtb from the carrier manufacturer (single uart,no i2c, both eth available)
- idle (both eth okay but no cable attached, usb eth gadget, single uart ok) is 815mW
- idle both eth down, usb0 down 335mW
According to the power consumption app note i should use
echo 1 > /sys/bus/platform/drivers/imx_busfreq/soc\:busfreq/enable
But this doesn't make a difference in the above scenario's.
So before i try to dig even deeper:
- is it normal that UART's make such a big difference to the 'idle' state?
- what would be the reason standby and mem don't make a difference?
- is there a document/table somewhere that shows things like 'if you enable this module, then this will be the result of on the overall current draw?
I've attached imx6ull-das which is the dtb for the uarts etc and imx6ull-seeed with is the default i'm referring to.