hwmon: (lm75) Strengthen detect function

A chip returning 0x00 in all registers is erroneously detected
as LM75. Check hysteresis and temperature limit registers and
abort if both are 0 to reduce the likelyhood for this to happen.

Reviewed-by: Rob Coulson <[email protected]>
Reviewed-by: Jean Delvare <[email protected]>
Signed-off-by: Guenter Roeck <[email protected]>
This commit is contained in:
Guenter Roeck 2014-12-04 09:58:15 -08:00
commit 4ad40cc568

View file

@ -415,6 +415,12 @@ static int lm75_detect(struct i2c_client *new_client,
|| i2c_smbus_read_byte_data(new_client, 7) != os)
return -ENODEV;
}
/*
* It is very unlikely that this is a LM75 if both
* hysteresis and temperature limit registers are 0.
*/
if (hyst == 0 && os == 0)
return -ENODEV;
/* Addresses cycling */
for (i = 8; i <= 248; i += 40) {