hwmon: (ina238) Correctly clamp shunt voltage limit

[ Upstream commit bd7e7bc ]

When clamping a register value, the result needs to be masked against the
register size. This was missing, resulting in errors when trying to write
negative limits. Fix by masking the clamping result against the register
size.

Fixes: eacb52f ("hwmon: Driver for Texas Instruments INA238")
Cc: Nathan Rossi <nathan.rossi@digi.com>
Cc: Chris Packham <chris.packham@alliedtelesis.co.nz>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>

Author: groeck

drivers/hwmon/ina238.c

@@ -300,7 +300,7 @@ static int ina238_write_in(struct device *dev, u32 attr, int channel,
 		regval = clamp_val(val, -163, 163);
 		regval = (regval * 1000 * 4) /
 			 (INA238_SHUNT_VOLTAGE_LSB * data->gain);
-		regval = clamp_val(regval, S16_MIN, S16_MAX);
+		regval = clamp_val(regval, S16_MIN, S16_MAX) & 0xffff;
 
 		switch (attr) {
 		case hwmon_in_max: