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hwmon: (it87) Properly handle wrong sensor type requests

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Currently, if someone tries to set the thermal sensor type to an
unsupported value, subsequent accesses to the chip may temporarily
show the sensor in question as disabled. Use a temporary variable
and only update the cached value on success, to prevent such
confusion.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
This commit is contained in:
Jean Delvare 2010-04-14 16:14:09 +02:00
parent a00afb97e2
commit 8acf07c5a7
1 changed files with 10 additions and 10 deletions
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20
drivers/hwmon/it87.c
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@ -539,15 +539,14 @@ static ssize_t set_sensor(struct device *dev, struct device_attribute *attr,
struct it87_data *data = dev_get_drvdata(dev); struct it87_data *data = dev_get_drvdata(dev);
long val; long val;
u8 reg;
if (strict_strtol(buf, 10, &val) < 0) if (strict_strtol(buf, 10, &val) < 0)
return -EINVAL; return -EINVAL;
mutex_lock(&data->update_lock); reg = it87_read_value(data, IT87_REG_TEMP_ENABLE);
reg &= ~(1 << nr);
data->sensor = it87_read_value(data, IT87_REG_TEMP_ENABLE); reg &= ~(8 << nr);
data->sensor &= ~(1 << nr);
data->sensor &= ~(8 << nr);
if (val == 2) { /* backwards compatibility */ if (val == 2) { /* backwards compatibility */
dev_warn(dev, "Sensor type 2 is deprecated, please use 4 " dev_warn(dev, "Sensor type 2 is deprecated, please use 4 "
"instead\n"); "instead\n");
@ -555,13 +554,14 @@ static ssize_t set_sensor(struct device *dev, struct device_attribute *attr,
} }
/* 3 = thermal diode; 4 = thermistor; 0 = disabled */ /* 3 = thermal diode; 4 = thermistor; 0 = disabled */
if (val == 3) if (val == 3)
data->sensor |= 1 << nr; reg |= 1 << nr;
else if (val == 4) else if (val == 4)
data->sensor |= 8 << nr; reg |= 8 << nr;
else if (val != 0) { else if (val != 0)
mutex_unlock(&data->update_lock);
return -EINVAL; return -EINVAL;
}
mutex_lock(&data->update_lock);
data->sensor = reg;
it87_write_value(data, IT87_REG_TEMP_ENABLE, data->sensor); it87_write_value(data, IT87_REG_TEMP_ENABLE, data->sensor);
mutex_unlock(&data->update_lock); mutex_unlock(&data->update_lock);
return count; return count;