hwmon: (sht15) add support for CRC validation

The sht15 sensor allows validating exchanges to and from the device
using a crc8 function. An utility function to reverse a byte has also
been added.

Signed-off-by: Jerome Oufella <jerome.oufella@savoirfairelinux.com>
Acked-by: Jonathan Cameron <jic23@cam.ac.uk>
Signed-off-by: Guenter Roeck <guenter.roeck@ericsson.com>
diff --git a/include/linux/sht15.h b/include/linux/sht15.h
index d836ca6..f85c7c5 100644
--- a/include/linux/sht15.h
+++ b/include/linux/sht15.h
@@ -19,6 +19,7 @@
  * @gpio_sck:		no. of gpio to which the data clock is connected.
  * @supply_mv:		supply voltage in mv. Overridden by regulator if
  *			available.
+ * @checksum:		flag to indicate the checksum should be validated.
  * @no_otp_reload:	flag to indicate no reload from OTP.
  * @low_resolution:	flag to indicate the temp/humidity resolution to use.
  */
@@ -26,6 +27,7 @@
 	int gpio_data;
 	int gpio_sck;
 	int supply_mv;
+	bool checksum;
 	bool no_otp_reload;
 	bool low_resolution;
 };