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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 <rob.coulson@gmail.com>
Reviewed-by: Jean Delvare <jdelvare@suse.de>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
This commit is contained in:
Guenter Roeck 2014-12-04 09:58:15 -08:00
parent b95579cd87
commit 4ad40cc568
1 changed files with 6 additions and 0 deletions
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6
drivers/hwmon/lm75.c
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@ -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) {