From 9ad0df1adac20d694fbb8e7cb7bac04e0645a927 Mon Sep 17 00:00:00 2001 From: Guenter Roeck Date: Fri, 24 Jun 2016 19:41:57 -0700 Subject: [PATCH] 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 Acked-by: Andrew F. Davis Signed-off-by: Guenter Roeck --- drivers/hwmon/ina3221.c | 13 ++++++------- 1 file changed, 6 insertions(+), 7 deletions(-) diff --git a/drivers/hwmon/ina3221.c b/drivers/hwmon/ina3221.c index d055b6a2266b..e6b49500c52a 100644 --- a/drivers/hwmon/ina3221.c +++ b/drivers/hwmon/ina3221.c @@ -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, ¤t_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;