This is a note to let you know that I've just added the patch titled
hwmon: (tmp421) fix rounding for negative values
to the 4.19-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
hwmon-tmp421-fix-rounding-for-negative-values.patch
and it can be found in the queue-4.19 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 6528dad97e34ce59df080c9115a2470af259868f
Author: Paul Fertser <fercerpav@xxxxxxxxx>
Date: Fri Sep 24 12:30:11 2021 +0300
hwmon: (tmp421) fix rounding for negative values
[ Upstream commit 724e8af85854c4d3401313b6dd7d79cf792d8990 ]
Old code produces -24999 for 0b1110011100000000 input in standard format due to
always rounding up rather than "away from zero".
Use the common macro for division, unify and simplify the conversion code along
the way.
Fixes: 9410700b881f ("hwmon: Add driver for Texas Instruments TMP421/422/423 sensor chips")
Signed-off-by: Paul Fertser <fercerpav@xxxxxxxxx>
Link: https://lore.kernel.org/r/20210924093011.26083-3-fercerpav@xxxxxxxxx
Signed-off-by: Guenter Roeck <linux@xxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/hwmon/tmp421.c b/drivers/hwmon/tmp421.c
index c2113c00b635..cdd01a848301 100644
--- a/drivers/hwmon/tmp421.c
+++ b/drivers/hwmon/tmp421.c
@@ -109,23 +109,17 @@ struct tmp421_data {
s16 temp[4];
};
-static int temp_from_s16(s16 reg)
+static int temp_from_raw(u16 reg, bool extended)
{
/* Mask out status bits */
int temp = reg & ~0xf;
- return (temp * 1000 + 128) / 256;
-}
-
-static int temp_from_u16(u16 reg)
-{
- /* Mask out status bits */
- int temp = reg & ~0xf;
-
- /* Add offset for extended temperature range. */
- temp -= 64 * 256;
+ if (extended)
+ temp = temp - 64 * 256;
+ else
+ temp = (s16)temp;
- return (temp * 1000 + 128) / 256;
+ return DIV_ROUND_CLOSEST(temp * 1000, 256);
}
static struct tmp421_data *tmp421_update_device(struct device *dev)
@@ -162,10 +156,8 @@ static int tmp421_read(struct device *dev, enum hwmon_sensor_types type,
switch (attr) {
case hwmon_temp_input:
- if (tmp421->config & TMP421_CONFIG_RANGE)
- *val = temp_from_u16(tmp421->temp[channel]);
- else
- *val = temp_from_s16(tmp421->temp[channel]);
+ *val = temp_from_raw(tmp421->temp[channel],
+ tmp421->config & TMP421_CONFIG_RANGE);
return 0;
case hwmon_temp_fault:
/*
