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Commit c37d3287 authored by Paul Fertser's avatar Paul Fertser Committed by Greg Kroah-Hartman
Browse files

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: 9410700b ("hwmon: Add driver for Texas Instruments TMP421/422/423 sensor chips")
Signed-off-by: default avatarPaul Fertser <fercerpav@gmail.com>
Link: https://lore.kernel.org/r/20210924093011.26083-3-fercerpav@gmail.com


Signed-off-by: default avatarGuenter Roeck <linux@roeck-us.net>
Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
parent 8a07d5ab

drivers/hwmon/tmp421.c

+8 −16
Original line number Diff line number Diff line
@@ -100,23 +100,17 @@ 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)
@@ -153,10 +147,8 @@ 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:

		/*