Commit 4ad40cc5 authored Dec 04, 2014 by Guenter Roeck

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>

parent b95579cd

drivers/hwmon/lm75.c

+6 −0

Original line number	Diff line number	Diff line
		@@ -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) {

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