On 08/09/2018 09:15 PM, Guenter Roeck wrote:
On 08/09/2018 03:24 PM, Linus Walleij wrote:
S.M.A.R.T. temperature sensors have been supported for
years by userspace tools such as smarttools.
The temperature readout is however also a good fit for
Linux' hwmon subsystem. By adding a hwmon interface to dig
out SMART parameter 194, we can expose the drive temperature
as a standard hwmon sensor.
[ ... ]
+
+static int ata_hwmon_read_temp(struct ata_hwmon *ata, int *temp,
+ int *min, int *max)
+{
[ ... ]
+ if (id == SMART_TEMP_PROP_194)
+ break;
231 also seems to report the temperature if available, as does 190.
Not sure if 190 is worth it, though - Samsung SSD 840 PRO Series supports
it but reports a static value of 28. And it seems to be either as
degrees C or as 100 - degrees C, depending on the drive manufacturer,
which makes it quite unreliable.
[ ... ]
+
+static int ata_hwmon_read(struct device *dev, enum hwmon_sensor_types type,
+ u32 attr, int channel, long *val)
+{
+ struct ata_hwmon *ata = dev_get_drvdata(dev);
+ int temp, min, max;
+ int ret;
+
+ if (type != hwmon_temp)
+ return -EINVAL;
+
+ ret = ata_hwmon_read_temp(ata, &temp, &min, &max);
+ if (ret)
+ return ret;
+
+ switch (attr) {
+ case hwmon_temp_input:
+ *val = temp;
+ break;
+ case hwmon_temp_min:
+ *val = min;
+ break;
+ case hwmon_temp_max:
+ *val = max;
+ break;
Those numbers need to be multiplied by 1,000 (hwmon ABI expects milli-degrees C).
Guenter
