Add a way to set indiviual sensitivity factor for each TMP006 sensor

Each TMP006 temperature sensor has different sensitivity factor. Let's
add a field to set different sensitivity factor for each sensor. Also
update the factors to get more reasonable temperature readings, but
still need more precise calibration.

BUG=chrome-os-partner:9599
TEST=Build and read tempearture succeeded.

Change-Id: Ib4feea3b78b71f6d37c9a02668ffa7bd9e63d390

board/link/board_temp_sensor.c

@@ -56,8 +56,9 @@ const struct temp_sensor_t temp_sensors[TEMP_SENSOR_COUNT] = {
 };
 
 const struct tmp006_t tmp006_sensors[TMP006_COUNT] = {
-	{"CPU", TEMP_CPU_ADDR},
-	{"PCH", TEMP_PCH_ADDR},
-	{"DDR", TEMP_DDR_ADDR},
-	{"Charger", TEMP_CHARGER_ADDR},
+	/* TODO: Calibrate sensitivity factors. See crosbug.com/p/9599 */
+	{"CPU", TEMP_CPU_ADDR, 2771},
+	{"PCH", TEMP_PCH_ADDR, 4762},
+	{"DDR", TEMP_DDR_ADDR, 6400},
+	{"Charger", TEMP_CHARGER_ADDR, 7154},
 };

common/tmp006.c

@@ -160,7 +160,8 @@ static int tmp006_read_object_temp(int idx)
 		v);
 
 	/* TODO: Calibrate the sensitivity factor. */
-	return tmp006_calculate_object_temp(t, v, 6400) / 100;
+	return tmp006_calculate_object_temp(t, v,
+			tmp006_sensors[idx].sens) / 100;
 }
 
 static int tmp006_poll_sensor(int sensor_id)

include/tmp006.h

@@ -16,6 +16,8 @@ struct tmp006_t {
 	const char* name;
 	/* I2C address formed by TMP006_ADDR macro. */
 	int addr;
+	/* Sensitivity factor, in 10^11. */
+	int sens;
 };
 
 /* Poll all TMP006 sensors. Return 0 on success. */