lkml.org 
[lkml]   [2022]   [May]   [16]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH 4.9 09/19] hwmon: (f71882fg) Fix negative temperature
Date
From: Ji-Ze Hong (Peter Hong) <hpeter@gmail.com>

[ Upstream commit 4aaaaf0f279836f06d3b9d0ffeec7a1e1a04ceef ]

All temperature of Fintek superio hwmonitor that using 1-byte reg will use
2's complement.

In show_temp()
temp = data->temp[nr] * 1000;

When data->temp[nr] read as 255, it indicate -1C, but this code will report
255C to userspace. It'll be ok when change to:
temp = ((s8)data->temp[nr]) * 1000;

Signed-off-by: Ji-Ze Hong (Peter Hong) <hpeter+linux_kernel@gmail.com>
Link: https://lore.kernel.org/r/20220418090706.6339-1-hpeter+linux_kernel@gmail.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/hwmon/f71882fg.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/hwmon/f71882fg.c b/drivers/hwmon/f71882fg.c
index cb28e4b4fb10..b87ca56fb774 100644
--- a/drivers/hwmon/f71882fg.c
+++ b/drivers/hwmon/f71882fg.c
@@ -1590,8 +1590,9 @@ static ssize_t show_temp(struct device *dev, struct device_attribute *devattr,
temp *= 125;
if (sign)
temp -= 128000;
- } else
- temp = data->temp[nr] * 1000;
+ } else {
+ temp = ((s8)data->temp[nr]) * 1000;
+ }

return sprintf(buf, "%d\n", temp);
}
--
2.35.1


\
 
 \ /
  Last update: 2022-05-16 21:41    [W:0.862 / U:2.108 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site