[PATCH 5.15 021/120] hwmon: (ltc2947) fix temperature scaling

Greg Kroah-Hartman
2022-12-05T19:38:21Z

From: Derek Nguyen <derek.nguyen@collins.com>

[ Upstream commit 07e06193ead86d4812f431b4d87bbd4161222e3f ]

The LTC2947 datasheet (Rev. B) calls out in the section "Register
Description: Non-Accumulated Result Registers" (pg. 30) that "To
calculate temperature, multiply the TEMP register value by 0.204°C
and add 5.5°C". Fix to add 5.5C and not 0.55C.

Fixes: 9f90fd652bed ("hwmon: Add support for ltc2947")
Signed-off-by: Derek Nguyen <derek.nguyen@collins.com>
Signed-off-by: Brandon Maier <brandon.maier@collins.com>
Link: https://lore.kernel.org/r/20221110192108.20624-1-brandon.maier@collins.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/hwmon/ltc2947-core.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/hwmon/ltc2947-core.c b/drivers/hwmon/ltc2947-core.c
index 5423466de697..e918490f3ff7 100644
--- a/drivers/hwmon/ltc2947-core.c
+++ b/drivers/hwmon/ltc2947-core.c
@@ -396,7 +396,7 @@ static int ltc2947_read_temp(struct device *dev, const u32 attr, long *val,
return ret;

/* in milidegrees celcius, temp is given by: */
- *val = (__val * 204) + 550;
+ *val = (__val * 204) + 5500;

return 0;
}
--
2.35.1