rc: start drivers for attached BeagleBone Capes

BeagleBone Capes add additional hardware to the BeagleBone to
improve functionality.

This patch probes the third i2c bus for capes and loads the
appropriate drivers for each detected cape. Currently only
the 'BeagleBone Weather' cape is supported.

Change-Id: Id8c133810db6de7c21625c2d5a794b8874673a0f

etc/usr/rc

@@ -112,6 +112,70 @@ get_eth_labels() {
     grep -v '^vlan_'
 }
 
+# Detect expansion boards on the BeagleBone and load the proper drivers.
+capemgr() {
+
+    # Probe each possible cape EEPROM slave address for a BeagleBone cape.
+    for slave_addr in 54 55 56 57
+    do
+
+        # See if there is a readable EEPROM with address ${slave_addr}.
+        eepromread -f /dev/i2c-3 -a 0x${slave_addr} > /dev/null 2>&1
+        RESULT=$?
+	if [ $RESULT -eq 0 ]
+	then
+
+	    # Found an alive EEPROM. Try reading the cape name.
+            CAPE=`eepromread -i -f /dev/i2c-3 -a 0x${slave_addr} | \
+	        sed -n 's/^PART_NUMBER     : \(.*\)$/\1/p'`
+
+            # Load the drivers for the cape and do any other configuration.
+            case "${CAPE}" in
+
+                # Weather Cape
+	        BB-BONE-WTHR-01.)
+
+                    # CAT24C256 EEPROM
+		    test -e /dev/eepromb3s${slave_addr} || \
+		        (cd /dev && MAKEDEV eepromb3s${slave_addr})
+		    up cat24c256 -dev /dev/eepromb3s${slave_addr} \
+		        -label cat24c256.3.${slave_addr} \
+			-args "bus=3 address=0x${slave_addr}"
+
+                    # TSL2550 Ambient Light Sensor
+		    test -e /dev/tsl2550b3s39 || \
+		        (cd /dev && MAKEDEV tsl2550b3s39)
+		    up tsl2550 -dev /dev/tsl2550b3s39 \
+		        -label tsl2550.3.39 \
+			-args 'bus=3 address=0x39'
+
+		    # SHT21 Temperature and Humidity Sensor
+		    test -e /dev/sht21b3s40 || \
+		        (cd /dev && MAKEDEV sht21b3s40)
+		    up sht21 -dev /dev/sht21b3s40 \
+		        -label sht21.3.40 \
+			-args 'bus=3 address=0x40'
+
+		    # BMP085 Temperature and Pressure Sensor
+		    test -e /dev/bmp085b3s77 || \
+		        (cd /dev && MAKEDEV bmp085b3s77)
+		    up bmp085 -dev /dev/bmp085b3s77 \
+		        -label bmp085.3.77 \
+			-args 'bus=3 address=0x77'
+
+		    ;;
+
+                *)
+                    # Do nothing if the cape isn't recognized
+		    echo ""
+                    echo "** UNSUPPORTED CAPE: ${CAPE}"
+		    echo ""
+                    ;;
+	    esac
+	fi
+    done
+}
+
 DAEMONS=/etc/rc.daemons
 
 case $action in
@@ -230,6 +294,9 @@ start)
 				# fb hasn't been ported to AM335X yet.
 			fi
 
+			# Detect expansion boards and start drivers.
+			capemgr
+
 			;;
 
 		A335BNLT)
@@ -255,6 +322,9 @@ start)
 			#up fb -dev /dev/fb0 -args edid.0=tda19988.1.3470
 			# fb hasn't been ported to AM335X yet.
 
+			# Detect expansion boards and start drivers.
+			capemgr
+
 			;;
 
 		UNKNOWN)