diff options
| author | Chris Packham <chris.packham@alliedtelesis.co.nz> | 2016-10-05 10:40:54 +1300 |
|---|---|---|
| committer | Guenter Roeck <linux@roeck-us.net> | 2016-10-17 10:16:20 -0700 |
| commit | 667f4bab81ea8357d260aa14bb6fb1a4834248d5 (patch) | |
| tree | a0cadcf223dbfcfe8a7b708d88cb957bbca7b3c7 /drivers/hwmon/adm9240.c | |
| parent | 1001354ca34179f3db924eb66672442a173147dc (diff) | |
hwmon: (adm9240) handle temperature readings below 0
Unlike the temperature thresholds the temperature data is a 9-bit signed
value. This allows and additional 0.5 degrees of precision on the
reading but makes handling negative values slightly harder. In order to
have sign-extension applied correctly the 9-bit value is stored in the
upper bits of a signed 16-bit value. When presenting this in sysfs the
value is shifted and scaled appropriately.
Signed-off-by: Chris Packham <chris.packham@alliedtelesis.co.nz>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Diffstat (limited to 'drivers/hwmon/adm9240.c')
| -rw-r--r-- | drivers/hwmon/adm9240.c | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/drivers/hwmon/adm9240.c b/drivers/hwmon/adm9240.c index 98114cef1e43..2fe1828bd10b 100644 --- a/drivers/hwmon/adm9240.c +++ b/drivers/hwmon/adm9240.c @@ -194,10 +194,10 @@ static struct adm9240_data *adm9240_update_device(struct device *dev) * 0.5'C per two measurement cycles thus ignore possible * but unlikely aliasing error on lsb reading. --Grant */ - data->temp = ((i2c_smbus_read_byte_data(client, + data->temp = (i2c_smbus_read_byte_data(client, ADM9240_REG_TEMP) << 8) | i2c_smbus_read_byte_data(client, - ADM9240_REG_TEMP_CONF)) / 128; + ADM9240_REG_TEMP_CONF); for (i = 0; i < 2; i++) { /* read fans */ data->fan[i] = i2c_smbus_read_byte_data(client, @@ -263,7 +263,7 @@ static ssize_t show_temp(struct device *dev, struct device_attribute *dummy, char *buf) { struct adm9240_data *data = adm9240_update_device(dev); - return sprintf(buf, "%d\n", data->temp * 500); /* 9-bit value */ + return sprintf(buf, "%d\n", data->temp / 128 * 500); /* 9-bit value */ } static ssize_t show_max(struct device *dev, struct device_attribute *devattr, |