lkml.org 
[lkml]   [2021]   [Jun]   [3]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH v3] hwmon: (scpi-hwmon) shows the negative temperature properly
Date
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 <luriwen@kylinos.cn>
Tested-by: Xin Chen <chenxin@kylinos.cn>

---
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

No virus found
Checked by Hillstone Network AntiVirus

\
 
 \ /
  Last update: 2021-06-04 05:10    [W:0.063 / U:0.176 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site