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[7/8] hwmon: (lm83) Explain why LM82 may be misdetected as LM83

Message ID 20220114163512.1094472-8-linux@roeck-us.net (mailing list archive)
State Accepted
Headers show
Series [1/8] hwmon: (lm83) Reorder include files to be in alphabetic order | expand

Commit Message

Guenter Roeck Jan. 14, 2022, 4:35 p.m. UTC
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>
---
 drivers/hwmon/lm83.c | 8 ++++++++
 1 file changed, 8 insertions(+)
diff mbox series

Patch

diff --git a/drivers/hwmon/lm83.c b/drivers/hwmon/lm83.c
index 82d7ef264f6f..d9ee01ca8aed 100644
--- 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: