1 files changed, 24 insertions, 13 deletions

diff --git a/drivers/hwmon/lm75.c b/drivers/hwmon/lm75.c
index 669481baac00..90126a2a1e44 100644
--- a/drivers/hwmon/lm75.c
+++ b/drivers/hwmon/lm75.c
@@ -249,19 +249,30 @@ static int lm75_detect(struct i2c_client *new_client,
 				     I2C_FUNC_SMBUS_WORD_DATA))
 		return -ENODEV;
 
-	/* Now, we do the remaining detection. There is no identification-
-	   dedicated register so we have to rely on several tricks:
-	   unused bits, registers cycling over 8-address boundaries,
-	   addresses 0x04-0x07 returning the last read value.
-	   The cycling+unused addresses combination is not tested,
-	   since it would significantly slow the detection down and would
-	   hardly add any value.
-
-	   The National Semiconductor LM75A is different than earlier
-	   LM75s.  It has an ID byte of 0xaX (where X is the chip
-	   revision, with 1 being the only revision in existence) in
-	   register 7, and unused registers return 0xff rather than the
-	   last read value. */
+	/*
+	 * Now, we do the remaining detection. There is no identification-
+	 * dedicated register so we have to rely on several tricks:
+	 * unused bits, registers cycling over 8-address boundaries,
+	 * addresses 0x04-0x07 returning the last read value.
+	 * The cycling+unused addresses combination is not tested,
+	 * since it would significantly slow the detection down and would
+	 * hardly add any value.
+	 *
+	 * The National Semiconductor LM75A is different than earlier
+	 * LM75s.  It has an ID byte of 0xaX (where X is the chip
+	 * revision, with 1 being the only revision in existence) in
+	 * register 7, and unused registers return 0xff rather than the
+	 * last read value.
+	 *
+	 * Note that this function only detects the original National
+	 * Semiconductor LM75 and the LM75A. Clones from other vendors
+	 * aren't detected, on purpose, because they are typically never
+	 * found on PC hardware. They are found on embedded designs where
+	 * they can be instantiated explicitly so detection is not needed.
+	 * The absence of identification registers on all these clones
+	 * would make their exhaustive detection very difficult and weak,
+	 * and odds are that the driver would bind to unsupported devices.
+	 */
 
 	/* Unused bits */
 	conf = i2c_smbus_read_byte_data(new_client, 1);