Commit b2446a16 authored by Yikai Tsai's avatar Yikai Tsai Committed by Guenter Roeck
Browse files

hwmon: (isl28022) Fix current reading calculation 



According to the ISL28022 datasheet, bit15 of the current register is
representing -32768. Fix the calculation to properly handle this bit,
ensuring correct measurements for negative values.

Signed-off-by: default avatarYikai Tsai <yikai.tsai.wiwynn@gmail.com>
Link: https://lore.kernel.org/r/20250519084055.3787-2-yikai.tsai.wiwynn@gmail.com


Signed-off-by: default avatarGuenter Roeck <linux@roeck-us.net>
parent 0ddce554

drivers/hwmon/isl28022.c

+4 −2
Original line number Diff line number Diff line
@@ -154,6 +154,7 @@ static int isl28022_read_current(struct device *dev, u32 attr, long *val) 
	struct isl28022_data *data = dev_get_drvdata(dev);

	unsigned int regval;

	int err;

	u16 sign_bit;



	switch (attr) {

	case hwmon_curr_input:
@@ -161,8 +162,9 @@ static int isl28022_read_current(struct device *dev, u32 attr, long *val) 
				  ISL28022_REG_CURRENT, &regval);

		if (err < 0)

			return err;

		*val = ((long)regval * 1250L * (long)data->gain) /

			(long)data->shunt;

		sign_bit = (regval >> 15) & 0x01;

		*val = (((long)(((u16)regval) & 0x7FFF) - (sign_bit * 32768)) *

			1250L * (long)data->gain) / (long)data->shunt;

		break;

	default:

		return -EOPNOTSUPP;