Add soctemp and pmutemp shell function to A20 based distros

#/bin/sh

# SoCTempAdjustment is needed because the A20 SoC delivers uncalibrated temp values
SoCTempAdjustment=1447

soctemp() {
        # ensure module sunxi-dbgreg.ko is loaded
        grep -q sunxi_dbgreg </proc/modules || ( modprobe sunxi-dbgreg ; sleep 0.1 )

        # prepare registers
        echo 'f1c25000:27003f' > /sys/devices/virtual/misc/sunxi-dbgreg/rw/write;
        echo 'f1c25010:40000' > /sys/devices/virtual/misc/sunxi-dbgreg/rw/write;
        echo 'f1c25018:10fff' > /sys/devices/virtual/misc/sunxi-dbgreg/rw/write;
        echo 'f1c25004:10' > /sys/devices/virtual/misc/sunxi-dbgreg/rw/write;

        # let the value be written to syslog
        echo 'f1c25020' > /sys/devices/virtual/misc/sunxi-dbgreg/rw/read;

        # wait 0.1 seconds
        sleep 0.1

        # read return value from syslog and transform it into degrees Celsius
        HexVal=$(tail /var/log/syslog | awk -F" 0x" '/ 0x/ {print $2}' | tail -n1 )
        echo $(( 0x${HexVal} - ${SoCTempAdjustment} )) | awk '{printf ("%0.1f",$1/10); }'
} # soctemp

pmutemp() {
        awk '{printf ("%0.1f",$1/1000); }' </sys/devices/platform/sunxi-i2c.0/i2c-0/0-0034/temp1_input
} # pmutemp