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| author | Tom Levens <tom.levens@cern.ch> | 2017-07-03 06:28:58 +0200 |
|---|---|---|
| committer | Guenter Roeck <linux@roeck-us.net> | 2018-05-21 07:52:00 -0700 |
| commit | a6282d170339f86e05fd24bdf3104ca644a4b3a4 (patch) | |
| tree | 2540ca650a1368e51f40914d3df8f0d156453224 | |
| parent | 59df4f4e8e0b9a0abb14ad5128d36d844c3e2689 (diff) | |
| download | lwn-a6282d170339f86e05fd24bdf3104ca644a4b3a4.tar.gz lwn-a6282d170339f86e05fd24bdf3104ca644a4b3a4.zip | |
hwmon: (ltc2990) Fix incorrect conversion of negative temperatures
Fix incorrect conversion of negative temperatures by using
sign_extend32() instead of a home-grown conversion function.
Fixes: df922703574e ("hwmon: Add LTC2990 sensor driver")
Signed-off-by: Tom Levens <tom.levens@cern.ch>
[groeck: Updated subject and description]
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
| -rw-r--r-- | drivers/hwmon/ltc2990.c | 18 |
1 files changed, 4 insertions, 14 deletions
diff --git a/drivers/hwmon/ltc2990.c b/drivers/hwmon/ltc2990.c index 8f8fe059ab48..e320d212ac27 100644 --- a/drivers/hwmon/ltc2990.c +++ b/drivers/hwmon/ltc2990.c @@ -11,6 +11,7 @@ * the chip's internal temperature and Vcc power supply voltage. */ +#include <linux/bitops.h> #include <linux/err.h> #include <linux/hwmon.h> #include <linux/hwmon-sysfs.h> @@ -34,15 +35,6 @@ #define LTC2990_CONTROL_MODE_CURRENT 0x06 #define LTC2990_CONTROL_MODE_VOLTAGE 0x07 -/* convert raw register value to sign-extended integer in 16-bit range */ -static int ltc2990_voltage_to_int(int raw) -{ - if (raw & BIT(14)) - return -(0x4000 - (raw & 0x3FFF)) << 2; - else - return (raw & 0x3FFF) << 2; -} - /* Return the converted value from the given register in uV or mC */ static int ltc2990_get_value(struct i2c_client *i2c, u8 reg, int *result) { @@ -55,18 +47,16 @@ static int ltc2990_get_value(struct i2c_client *i2c, u8 reg, int *result) switch (reg) { case LTC2990_TINT_MSB: /* internal temp, 0.0625 degrees/LSB, 13-bit */ - val = (val & 0x1FFF) << 3; - *result = (val * 1000) >> 7; + *result = sign_extend32(val, 12) * 1000 / 16; break; case LTC2990_V1_MSB: case LTC2990_V3_MSB: /* Vx-Vy, 19.42uV/LSB. Depends on mode. */ - *result = ltc2990_voltage_to_int(val) * 1942 / (4 * 100); + *result = sign_extend32(val, 14) * 1942 / 100; break; case LTC2990_VCC_MSB: /* Vcc, 305.18μV/LSB, 2.5V offset */ - *result = (ltc2990_voltage_to_int(val) * 30518 / - (4 * 100 * 1000)) + 2500; + *result = sign_extend32(val, 14) * 30518 / (100 * 1000) + 2500; break; default: return -EINVAL; /* won't happen, keep compiler happy */ |