hwmon: (lm90) Add basic support for TI TMP461

[ Upstream commit f8344f7693a25d9025a59d164450b50c6f5aa3c0 ]

TMP461 is almost identical to TMP451 and was actually detected as TMP451
with the existing lm90 driver if its I2C address is 0x4c. Add support
for it to the lm90 driver. At the same time, improve the chip detection
function to at least try to distinguish between TMP451 and TMP461.

As a side effect, this fixes commit 24333ac26d ("hwmon: (tmp401) use
smb word operations instead of 2 smb byte operations"). TMP461 does not
support word operations on temperature registers, which causes bad
temperature readings with the tmp401 driver. The lm90 driver does not
perform word operations on temperature registers and thus does not have
this problem.

Support is listed as basic because TMP461 supports a sensor resolution
of 0.0625 degrees C, while the lm90 driver assumes a resolution of 0.125
degrees C. Also, the TMP461 supports negative temperatures with its
default temperature range, which is not the case for similar chips
supported by the lm90 and the tmp401 drivers. Those limitations will be
addressed with follow-up patches.

Fixes: 24333ac26d ("hwmon: (tmp401) use smb word operations instead of 2 smb byte operations")
Reported-by: David T. Wilson <[email protected]>
Cc: David T. Wilson <[email protected]>
Signed-off-by: Guenter Roeck <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>

Documentation/hwmon/lm90.rst

@@ -265,6 +265,16 @@ Supported chips:
 
 	       http://www.ti.com/litv/pdf/sbos686
 
+  * Texas Instruments TMP461
+
+    Prefix: 'tmp461'
+
+    Addresses scanned: I2C 0x48 through 0x4F
+
+    Datasheet: Publicly available at TI website
+
+	       https://www.ti.com/lit/gpn/tmp461
+
 Author: Jean Delvare <[email protected]>