hwmon: (lm83) Explain why LM82 may be misdetected as LM83

According to the March 2013 revision of the LM82 datasheet, the latest
LM82 die revision is 0x03. This was confirmed and observed with a real
chip. Further details in this revision of the LM82 datasheet suggest that
LM82 is now just a repackaged LM83. Such versions of LM82 will be detected
as LM83. Add comment to the code explaining why this may happen.

Signed-off-by: Guenter Roeck <linux@roeck-us.net>

diff --git a/drivers/hwmon/lm83.c b/drivers/hwmon/lm83.c
index 82d7ef2..d9ee01c 100644 (file)
--- a/drivers/hwmon/lm83.c
+++ b/drivers/hwmon/lm83.c
@@ -334,6 +334,14 @@ static int lm83_detect(struct i2c_client *client,
        chip_id = i2c_smbus_read_byte_data(client, LM83_REG_R_CHIP_ID);
        switch (chip_id) {
        case 0x03:
+               /*
+                * According to the LM82 datasheet dated March 2013, recent
+                * revisions of LM82 have a die revision of 0x03. This was
+                * confirmed with a real chip. Further details in this revision
+                * of the LM82 datasheet strongly suggest that LM82 is just a
+                * repackaged LM83. It is therefore impossible to distinguish
+                * those chips from LM83, and they will be misdetected as LM83.
+                */
                name = "lm83";
                break;
        case 0x01: