From 4ad40cc568c5537de11092d3362f9cb287f915d9 Mon Sep 17 00:00:00 2001 From: Guenter Roeck Date: Thu, 4 Dec 2014 09:58:15 -0800 Subject: 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 Reviewed-by: Jean Delvare Signed-off-by: Guenter Roeck --- drivers/hwmon/lm75.c | 6 ++++++ 1 file changed, 6 insertions(+) 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) { -- cgit v1.2.3-59-g8ed1b