The original idea was to make an SPI connection between i.MX and LPC, which physically exists (just take look at the schematics!), but it is not used because I couldn’t get it to work before shipping (couldn’t measure any SPI activity on the lines when poking around with userspace SPI on Linux).
There is a backup solution which is the UART connection between i.MX and LPC:
echo "xUAR1" >/dev/hidraw0
This will enable LPC responses to be output to /dev/ttymxc2. So with screen /dev/ttymxc2 57600 you will get regular strings in this format (~ every 30 seconds):
31 31 31 31 31 31 31 31 mA 0277mV25329 12%
The first 8 columns are cell voltages x10. The last column is the battery gauge. mA and mV are total batterry current and voltage.
turn it off with:
echo "xUAR0" >/dev/hidraw0