hwmon: (lm90) Add support for the W83L771W/G

I was wondering if that chip ever existed publicly... Apparently yes,
so add support for it.
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Tested-by: Alexander Stein <alexander.stein@informatik.tu-chemnitz.de>
Acked-by: Guenter Roeck <guenter.roeck@ericsson.com>

Documentation/hwmon/lm90

@@ -95,6 +95,10 @@ Supported chips:
                            0x4c, 0x4d and 0x4e
     Datasheet: Publicly available at the Maxim website
                http://www.maxim-ic.com/datasheet/index.mvp/id/4199
+  * Winbond/Nuvoton W83L771W/G
+    Prefix: 'w83l771'
+    Addresses scanned: I2C 0x4c
+    Datasheet: No longer available
   * Winbond/Nuvoton W83L771AWG/ASG
     Prefix: 'w83l771'
     Addresses scanned: I2C 0x4c
@@ -169,11 +173,15 @@ MAX6695 and MAX6696:
   * Second critical temperature limit
   * Two remote sensors
 
+W83L771W/G
+  * The G variant is lead-free, otherwise similar to the W.
+  * Filter and alert configuration register at 0xBF
+  * Moving average (depending on conversion rate)
+
 W83L771AWG/ASG
+  * Successor of the W83L771W/G, same features.
   * The AWG and ASG variants only differ in package format.
-  * Filter and alert configuration register at 0xBF
   * Diode ideality factor configuration (remote sensor) at 0xE3
-  * Moving average (depending on conversion rate)
 
 All temperature values are given in degrees Celsius. Resolution
 is 1.0 degree for the local temperature, 0.125 degree for the remote

drivers/hwmon/Kconfig

@@ -615,7 +615,7 @@ config SENSORS_LM90
 	  LM86, LM89 and LM99, Analog Devices ADM1032 and ADT7461, Maxim
 	  MAX6646, MAX6647, MAX6648, MAX6649, MAX6657, MAX6658, MAX6659,
 	  MAX6680, MAX6681, MAX6692, MAX6695, MAX6696, and Winbond/Nuvoton
-	  W83L771AWG/ASG sensor chips.
+	  W83L771W/G/AWG/ASG sensor chips.
 
 	  This driver can also be built as a module.  If so, the module
 	  will be called lm90.

drivers/hwmon/lm90.c

@@ -88,8 +88,8 @@
  * Addresses to scan
  * Address is fully defined internally and cannot be changed except for
  * MAX6659, MAX6680 and MAX6681.
- * LM86, LM89, LM90, LM99, ADM1032, ADM1032-1, ADT7461, MAX6649, MAX6657
- * and MAX6658 have address 0x4c.
+ * LM86, LM89, LM90, LM99, ADM1032, ADM1032-1, ADT7461, MAX6649, MAX6657,
+ * MAX6658 and W83L771 have address 0x4c.
  * ADM1032-2, ADT7461-2, LM89-1, LM99-1 and MAX6646 have address 0x4d.
  * MAX6647 has address 0x4e.
  * MAX6659 can have address 0x4c, 0x4d or 0x4e.
@@ -1237,10 +1237,23 @@ static int lm90_detect(struct i2c_client *new_client,
 	} else
 	if (address == 0x4C
 	 && man_id == 0x5C) { /* Winbond/Nuvoton */
-		if ((chip_id & 0xFE) == 0x10 /* W83L771AWG/ASG */
-		 && (reg_config1 & 0x2A) == 0x00
-		 && reg_convrate <= 0x08) {
-			name = "w83l771";
+		int reg_config2;
+
+		reg_config2 = i2c_smbus_read_byte_data(new_client,
+						LM90_REG_R_CONFIG2);
+		if (reg_config2 < 0)
+			return -ENODEV;
+
+		if ((reg_config1 & 0x2A) == 0x00
+		 && (reg_config2 & 0xF8) == 0x00) {
+			if (chip_id == 0x01 /* W83L771W/G */
+			 && reg_convrate <= 0x09) {
+				name = "w83l771";
+			} else
+			if ((chip_id & 0xFE) == 0x10 /* W83L771AWG/ASG */
+			 && reg_convrate <= 0x08) {
+				name = "w83l771";
+			}
 		}
 	}