wedge400: Add setup-avs.sh to setup TH3 avs voltage on booting (#96)

Summary:
setup-avs.sh to setup TH3 avs voltage on booting
Pull Request resolved: facebookexternal/openbmc.celestica#96

Test Plan: No yet.

Reviewed By: joancaneus

fbshipit-source-id: 65a3ee4e88

meta-facebook/meta-wedge400/recipes-utils/openbmc-utils/files/setup_avs.sh

@@ -0,0 +1,54 @@
+#!/bin/sh
+#
+# Copyright 2019-present Facebook. All Rights Reserved.
+#
+# This program file is free software; you can redistribute it and/or modify it
+# under the terms of the GNU General Public License as published by the
+# Free Software Foundation; version 2 of the License.
+#
+# This program is distributed in the hope that it will be useful, but WITHOUT
+# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+# FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+# for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program in a file named COPYING; if not, write to the
+# Free Software Foundation, Inc.,
+# 51 Franklin Street, Fifth Floor,
+# Boston, MA 02110-1301 USA
+#
+
+PATH=/sbin:/bin:/usr/sbin:/usr/bin:/usr/local/bin
+
+VID_START=1.6 # Unit Voltage
+VID_STEP=0.00625 # Unit Voltage
+ISL_VOUT_PMBUS_COMMAND=0x21
+
+TH3_ROV=$(i2cget -f -y 12 0x3e 0x46) # Get TH3 AVS value from SYSCPLD
+
+if [[ $TH3_ROV -lt 0x72 || $TH3_ROV -gt 0x8A ]]; then 
+    echo "Invalid AVS value (0x72 - 0x8A)."
+    exit -1
+fi
+
+TH3_ROV_DEC=$(printf "%d" $TH3_ROV) 
+
+VRM_VCC_MAX=$(echo $VID_START $TH3_ROV_DEC $VID_STEP|awk '{printf "%.5f", $1-(($2-2)*$3)}')
+
+ISL_VOUT_mV=$(echo $VRM_VCC_MAX|awk '{printf "%d", $1*1000}') # Convert to mV
+
+ISL_VOUT_PMBUS_VALUE=$(printf "0x%04x" $ISL_VOUT_mV) # Convert to HEX
+
+i2cset -f -y 1 0x60 $ISL_VOUT_PMBUS_COMMAND $ISL_VOUT_PMBUS_VALUE w # Set VOUT to ISL68317
+
+if [ $? -ne 0 ]; then 
+    echo "Cannot communicate with ISL68317."
+    exit -1
+fi
+
+ISL_VOUT_READBACK=$(i2cget -f -y 1 0x60 0x21 w | awk '{printf "%d", $1}') # Readback ISL68317 VOUT
+
+if [ $ISL_VOUT_READBACK  -ne $ISL_VOUT_mV  ]; then
+    echo "Failed to write the value to ISL68317."
+    exit -1
+fi