hwstub: implement i2c and i2c eeprom dump

Change-Id: Iff1b4f40affb88c104e7322e25cdbe34f8886476

utils/hwstub/tools/lua/i2c_scan.lua

@@ -8,4 +8,41 @@ function I2CSCAN.scan()
             print(string.format("%#x OK", i))
         end
     end 
-    end
+end
+
+-- if file is nil, return array
+-- if size is nil, dump the whole EEPROM
+function I2CSCAN.dump_rom(file, size)
+    STMP.i2c.init()
+    STMP.i2c.set_speed(true)
+    if not STMP.i2c.transmit(0xa0, {0, 0}, false) then
+        error("Cannot send address")
+    end
+    local res = {}
+    if size == nil then
+        size = 0xffff
+    end
+    for i = 0, size do
+        local l = STMP.i2c.receive(0xa0, 1)
+        if l == nil then
+            error("error during transfer")
+        end
+        for i = 1, #l do
+            table.insert(res, l[i])
+        end
+    end
+    if file == nil then
+        return res
+    end
+    local f = file
+    if type(file) == "string" then
+        f = io.open(file, "w")
+    end
+    if f == nil then error("Cannot open file or write to nil") end
+    for i = 1, #res do
+        f:write(string.char(res[i]))
+    end
+    if type(file) == "string" then
+        io.close(f)
+    end
+end