diff options
| author |   Guenter Roeck <linux@roeck-us.net> | 2014-12-04 09:58:15 -0800 |
|---|---|---|
| committer | Guenter Roeck <linux@roeck-us.net> | 2014-12-05 10:18:02 -0800 |
| commit | 4ad40cc568c5537de11092d3362f9cb287f915d9 (patch) | |
| tree | d645f9b83c36b6aa231740ab1f8926f2158f7c99 /drivers/hwmon/lm75.c | |
| parent | hwmon: (gpio-fan) Add a shutdown handler to poweroff the fans (diff) | |
| download | linux-dev-4ad40cc568c5537de11092d3362f9cb287f915d9.tar.xz linux-dev-4ad40cc568c5537de11092d3362f9cb287f915d9.zip | |
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>
Diffstat (limited to 'drivers/hwmon/lm75.c')
| -rw-r--r-- | drivers/hwmon/lm75.c | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/drivers/hwmon/lm75.c b/drivers/hwmon/lm75.c index f58439b817b5..6753fd940c76 100644 --- a/drivers/hwmon/lm75.c +++ b/drivers/hwmon/lm75.c @@ -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) { |