diff --git a/drivers/hwmon/it87.c b/drivers/hwmon/it87.c
index 6a182e1..ad6c8a3 100644
--- a/drivers/hwmon/it87.c
+++ b/drivers/hwmon/it87.c
@@ -2,6 +2,14 @@
     it87.c - Part of lm_sensors, Linux kernel modules for hardware
              monitoring.
 
+    The IT8705F is an LPC-based Super I/O part that contains UARTs, a
+    parallel port, an IR port, a MIDI port, a floppy controller, etc., in
+    addition to an Environment Controller (Enhanced Hardware Monitor and
+    Fan Controller)
+
+    This driver supports only the Environment Controller in the IT8705F and
+    similar parts.  The other devices are supported by different drivers.
+
     Supports: IT8705F  Super I/O chip w/LPC interface
               IT8712F  Super I/O chip w/LPC interface
               IT8716F  Super I/O chip w/LPC interface
@@ -118,9 +126,15 @@
 /* Length of ISA address segment */
 #define IT87_EXTENT 8
 
-/* Where are the ISA address/data registers relative to the base address */
-#define IT87_ADDR_REG_OFFSET 5
-#define IT87_DATA_REG_OFFSET 6
+/* Length of ISA address segment for Environmental Controller */
+#define IT87_EC_EXTENT 2
+
+/* Offset of EC registers from ISA base address */
+#define IT87_EC_OFFSET 5
+
+/* Where are the ISA address/data registers relative to the EC base address */
+#define IT87_ADDR_REG_OFFSET 0
+#define IT87_DATA_REG_OFFSET 1
 
 /*----- The IT87 registers -----*/
 
@@ -968,10 +982,10 @@
 	};
 
 	res = platform_get_resource(pdev, IORESOURCE_IO, 0);
-	if (!request_region(res->start, IT87_EXTENT, DRVNAME)) {
+	if (!request_region(res->start, IT87_EC_EXTENT, DRVNAME)) {
 		dev_err(dev, "Failed to request region 0x%lx-0x%lx\n",
 			(unsigned long)res->start,
-			(unsigned long)(res->start + IT87_EXTENT - 1));
+			(unsigned long)(res->start + IT87_EC_EXTENT - 1));
 		err = -EBUSY;
 		goto ERROR0;
 	}
@@ -1124,7 +1138,7 @@
 	platform_set_drvdata(pdev, NULL);
 	kfree(data);
 ERROR1:
-	release_region(res->start, IT87_EXTENT);
+	release_region(res->start, IT87_EC_EXTENT);
 ERROR0:
 	return err;
 }
@@ -1137,7 +1151,7 @@
 	sysfs_remove_group(&pdev->dev.kobj, &it87_group);
 	sysfs_remove_group(&pdev->dev.kobj, &it87_group_opt);
 
-	release_region(data->addr, IT87_EXTENT);
+	release_region(data->addr, IT87_EC_EXTENT);
 	platform_set_drvdata(pdev, NULL);
 	kfree(data);
 
@@ -1402,8 +1416,8 @@
 				  const struct it87_sio_data *sio_data)
 {
 	struct resource res = {
-		.start	= address ,
-		.end	= address + IT87_EXTENT - 1,
+		.start	= address + IT87_EC_OFFSET,
+		.end	= address + IT87_EC_OFFSET + IT87_EC_EXTENT - 1,
 		.name	= DRVNAME,
 		.flags	= IORESOURCE_IO,
 	};