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Commit 9ad0df1a authored by Guenter Roeck's avatar Guenter Roeck
Browse files

hwmon: (ina3221) Fix negative limits 



The result of an integer divide by an unsigned is undefined.
This causes unexpected results when writing negative values
into the limit registers.

Maintain the shunt_resistors variables as signed integer to avoid
the problem. Also, for simplicity and ease of use, clamp shunt
resistor value on writes instead of rejecting bad values.

Cc: Andrew F. Davis <afd@ti.com>
Acked-by: default avatarAndrew F. Davis <afd@ti.com>
Signed-off-by: default avatarGuenter Roeck <linux@roeck-us.net>
parent 51b8c2cd

drivers/hwmon/ina3221.c

+6 −7
Original line number Diff line number Diff line
@@ -95,7 +95,7 @@ static const unsigned int register_channel[] = { 
struct ina3221_data {

	struct regmap *regmap;

	struct regmap_field *fields[F_MAX_FIELDS];

	unsigned int shunt_resistors[INA3221_NUM_CHANNELS];

	int shunt_resistors[INA3221_NUM_CHANNELS];

};



static int ina3221_read_value(struct ina3221_data *ina, unsigned int reg,
@@ -155,7 +155,7 @@ static ssize_t ina3221_show_current(struct device *dev, 
	struct ina3221_data *ina = dev_get_drvdata(dev);

	unsigned int reg = sd_attr->index;

	unsigned int channel = register_channel[reg];

	unsigned int resistance_uo = ina->shunt_resistors[channel];

	int resistance_uo = ina->shunt_resistors[channel];

	int val, current_ma, voltage_nv, ret;



	ret = ina3221_read_value(ina, reg, &val);
@@ -176,7 +176,7 @@ static ssize_t ina3221_set_current(struct device *dev, 
	struct ina3221_data *ina = dev_get_drvdata(dev);

	unsigned int reg = sd_attr->index;

	unsigned int channel = register_channel[reg];

	unsigned int resistance_uo = ina->shunt_resistors[channel];

	int resistance_uo = ina->shunt_resistors[channel];

	int val, current_ma, voltage_uv, ret;



	ret = kstrtoint(buf, 0, &current_ma);
@@ -223,15 +223,14 @@ static ssize_t ina3221_set_shunt(struct device *dev, 
	struct sensor_device_attribute *sd_attr = to_sensor_dev_attr(attr);

	struct ina3221_data *ina = dev_get_drvdata(dev);

	unsigned int channel = sd_attr->index;

	unsigned int val;

	int val;

	int ret;



	ret = kstrtouint(buf, 0, &val);

	ret = kstrtoint(buf, 0, &val);

	if (ret)

		return ret;



	if (val == 0)

		return -EINVAL;

	val = clamp_val(val, 1, INT_MAX);



	ina->shunt_resistors[channel] = val;