[PATCH] hwmon: (ina2xx) Fix current value calculation

From: Nicolin Chen
Date: Tue Nov 13 2018 - 22:49:04 EST


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.

Signed-off-by: Nicolin Chen <nicoleotsuka@xxxxxxxxx>
---
drivers/hwmon/ina2xx.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/hwmon/ina2xx.c b/drivers/hwmon/ina2xx.c
index c2252cf452f5..07ee19573b3f 100644
--- 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:
--
2.17.1