hwmon: (ina2xx) Fix current value calculation

[ Upstream commit 38cd989ee38c16388cde89db5b734f9d55b905f9 ]

The current register (04h) has a sign bit at MSB. The comments
for this calculation also mention that it's a signed register.

However, the regval is unsigned type so result of calculation
turns out to be an incorrect value when current is negative.

This patch simply fixes this by adding a casting to s16.

Fixes: 5d389b125186c ("hwmon: (ina2xx) Make calibration register value fixed")
Signed-off-by: Nicolin Chen <nicoleotsuka@gmail.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/hwmon/ina2xx.c b/drivers/hwmon/ina2xx.c
index c2252cf..07ee195 100644 (file)
--- a/drivers/hwmon/ina2xx.c
+++ b/drivers/hwmon/ina2xx.c
@@ -274,7 +274,7 @@ static int ina2xx_get_value(struct ina2xx_data *data, u8 reg,
                break;
        case INA2XX_CURRENT:
                /* signed register, result in mA */
-               val = regval * data->current_lsb_uA;
+               val = (s16)regval * data->current_lsb_uA;
                val = DIV_ROUND_CLOSEST(val, 1000);
                break;
        case INA2XX_CALIBRATION: