platform/x86: dell-ddv: Fix temperature calculation

On the Dell Inspiron 3505 the battery temperature is always
0.1 degrees larger than the temperature show inside the OEM
application.

Emulate this behaviour to avoid showing strange looking values
like 29.1 degrees.

Fixes: 0331b1b ("platform/x86: dell-ddv: Fix temperature scaling")
Signed-off-by: Armin Wolf <[email protected]>
Reviewed-by: Sebastian Reichel <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Reviewed-by: Ilpo Järvinen <[email protected]>
Signed-off-by: Ilpo Järvinen <[email protected]>

Author: Wer-Wolf

drivers/platform/x86/dell/dell-wmi-ddv.c

@@ -665,8 +665,10 @@ static ssize_t temp_show(struct device *dev, struct device_attribute *attr, char
 	if (ret < 0)
 		return ret;
 
-	/* Use 2731 instead of 2731.5 to avoid unnecessary rounding */
-	return sysfs_emit(buf, "%d\n", value - 2731);
+	/* Use 2732 instead of 2731.5 to avoid unnecessary rounding and to emulate
+	 * the behaviour of the OEM application which seems to round down the result.
+	 */
+	return sysfs_emit(buf, "%d\n", value - 2732);
 }
 
 static ssize_t eppid_show(struct device *dev, struct device_attribute *attr, char *buf)