hwmon: (k8temp) Fix temperature reporting for (most) K8 RevG CPUs

Current Temperature for K8 RevG desktop CPUs is a "normalized value"
which can be below ambient temperature.

As a consequence lots of RevG systems report temperatures like:

$ sensors
k8temp-pci-00c3
Adapter: PCI adapter
Core0 Temp:    +17 C
Core0 Temp:     +3 C
Core1 Temp:    +21 C
Core1 Temp:     +5 C

being quite below ambient temperature.
There are even reports of negative temperature values.

This patch corrects the temperature reporting of k8temp for
RevG desktop CPUs.

Cc: Rudolf Marek <r.marek@assembler.cz>
Signed-off-by: Andreas Herrmann <andreas.herrmann3@amd.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>

drivers/hwmon/k8temp.c

@@ -49,6 +49,7 @@ struct k8temp_data {
 	u8 sensorsp;		/* sensor presence bits - SEL_CORE & SEL_PLACE */
 	u32 temp[2][2];		/* core, place */
 	u8 swap_core_select;    /* meaning of SEL_CORE is inverted */
+	u32 temp_offset;
 };
 
 static struct k8temp_data *k8temp_update_device(struct device *dev)
@@ -116,13 +117,15 @@ static ssize_t show_temp(struct device *dev,
 	    to_sensor_dev_attr_2(devattr);
 	int core = attr->nr;
 	int place = attr->index;
+	int temp;
 	struct k8temp_data *data = k8temp_update_device(dev);
 
 	if (data->swap_core_select)
 		core = core ? 0 : 1;
 
-	return sprintf(buf, "%d\n",
-		       TEMP_FROM_REG(data->temp[core][place]));
+	temp = TEMP_FROM_REG(data->temp[core][place]) + data->temp_offset;
+
+	return sprintf(buf, "%d\n", temp);
 }
 
 /* core, place */
@@ -176,6 +179,16 @@ static int __devinit k8temp_probe(struct pci_dev *pdev,
 				 "wrong - check erratum #141\n");
 		}
 
+		if ((model >= 0x69) &&
+		    !(model == 0xc1 || model == 0x6c || model == 0x7c)) {
+			/*
+			 * RevG desktop CPUs (i.e. no socket S1G1 parts)
+			 * need additional offset, otherwise reported
+			 * temperature is below ambient temperature
+			 */
+			data->temp_offset = 21000;
+		}
+
 		break;
 	}