We have a custom iMX28 board largely based on the IMX28 EVK. All going well but I've found that when needing to save power and using the "ifconfig eth0 down" command the fec goes down okay but still consumes a lot of power. I've found most of the imx28 fec output interface pins are driven high and the power to the fec is still on. If I remove power from the fec with the imx28 output pins to the fec in the state in which they were after the ifconfig eth0 down command the outputs are loaded and draw half the current as when the fec is running in normal mode. My aim is to get the fec down to a power consumption level before "ifconfig eth0 up" is called.
I see in the mx28evk_pins.c a function called mx28evk_enet_io_lowerpower_enter(), my question is how to call this function from the "ifconfig eth0 down" command or is there another way to expose this function to be called. Also conversely I need to call the mx28evk_enet_io_lowerpower_exit() on the ifconfig eth0 up command also, and with this function I've noticed that it's called on the initialization of the fec.
We have the 2.6.35 kernel patched to the current patches from Freescale.
any advise would be helpful