2021-06-04 03:12:41

by Riwen Lu

Subject: [PATCH v3] hwmon: (scpi-hwmon) shows the negative temperature properly

The scpi hwmon shows the sub-zero temperature in an unsigned integer,
which would confuse the users when the machine works in low temperature
environment. This shows the sub-zero temperature in an signed value and
users can get it properly from sensors.

Signed-off-by: Riwen Lu <[email protected]>
Tested-by: Xin Chen <[email protected]>

---
Changes since v1:
- Add judgment for sensor->info.class. If it is TEMPERATURE situation,
return the sensor value as a signed value, otherwise return it as a
unsigned value.

Changes since v2:
- Add a typecast u64 to s64 when it is a temperature value.
- Add a comment ahead of the if statement.
- Remove the unnecessary 'else' statement.
---
drivers/hwmon/scpi-hwmon.c | 9 +++++++++
1 file changed, 9 insertions(+)

diff --git a/drivers/hwmon/scpi-hwmon.c b/drivers/hwmon/scpi-hwmon.c
index 25aac40f2764..919877970ae3 100644
--- a/drivers/hwmon/scpi-hwmon.c
+++ b/drivers/hwmon/scpi-hwmon.c
@@ -99,6 +99,15 @@ scpi_show_sensor(struct device *dev, struct device_attribute *attr, char *buf)

scpi_scale_reading(&value, sensor);

+ /*
+ * Temperature sensor values are treated as signed values based on
+ * observation even though that is not explicitly specified, and
+ * because an unsigned u64 temperature does not really make practical
+ * sense especially when the temperature is below zero degrees Celsius.
+ */
+ if (sensor->info.class == TEMPERATURE)
+ return sprintf(buf, "%lld\n", (s64)value);
+
return sprintf(buf, "%llu\n", value);
}

--
2.25.1


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2021-06-04 11:11:09

by Guenter Roeck

Subject: Re: [PATCH v3] hwmon: (scpi-hwmon) shows the negative temperature properly

On Fri, Jun 04, 2021 at 11:09:59AM +0800, Riwen Lu wrote:
> The scpi hwmon shows the sub-zero temperature in an unsigned integer,
> which would confuse the users when the machine works in low temperature
> environment. This shows the sub-zero temperature in an signed value and
> users can get it properly from sensors.
>
> Signed-off-by: Riwen Lu <[email protected]>
> Tested-by: Xin Chen <[email protected]>

Applied.

Thanks,
Guenter

> ---
> Changes since v1:
> - Add judgment for sensor->info.class. If it is TEMPERATURE situation,
> return the sensor value as a signed value, otherwise return it as a
> unsigned value.
>
> Changes since v2:
> - Add a typecast u64 to s64 when it is a temperature value.
> - Add a comment ahead of the if statement.
> - Remove the unnecessary 'else' statement.
> ---
> drivers/hwmon/scpi-hwmon.c | 9 +++++++++
> 1 file changed, 9 insertions(+)
>
> diff --git a/drivers/hwmon/scpi-hwmon.c b/drivers/hwmon/scpi-hwmon.c
> index 25aac40f2764..919877970ae3 100644
> --- a/drivers/hwmon/scpi-hwmon.c
> +++ b/drivers/hwmon/scpi-hwmon.c
> @@ -99,6 +99,15 @@ scpi_show_sensor(struct device *dev, struct device_attribute *attr, char *buf)
>
> scpi_scale_reading(&value, sensor);
>
> + /*
> + * Temperature sensor values are treated as signed values based on
> + * observation even though that is not explicitly specified, and
> + * because an unsigned u64 temperature does not really make practical
> + * sense especially when the temperature is below zero degrees Celsius.
> + */
> + if (sensor->info.class == TEMPERATURE)
> + return sprintf(buf, "%lld\n", (s64)value);
> +
> return sprintf(buf, "%llu\n", value);
> }
>