Re: [PATCH 2/3] hwmon: (tmp513) Fix Current Register value interpretation

[Guenter Roeck <linux@roeck-us.net>]

On Mon, Dec 16, 2024 at 08:36:47PM +0300, Murad Masimov wrote:
> The value returned by the driver after processing the contents of the Current
> Register does not correspond to the TMP512/TMP513 specifications. A raw
> register value is converted to a signed integer value by a sign extension in
> accordance with the algorithm provided in the specification, but due to the
> off-by-one error in the sign bit index, the result is incorrect. Moreover,
> negative values will be reported as large positive due to missing sign
> extension from u32 to long.
> 
> According to the TMP512 and TMP513 datasheets, the Current Register (07h) is a
> 16-bit two's complement integer value. E.g., if regval = 1000 0011 0000 0000,
> then the value must be (-32000 * lsb), but the driver will return (33536 * lsb).
> 
> Fix off-by-one bug, and also cast data->curr_lsb_ua (which is of type u32) to
> long to prevent incorrect cast for negative values.
> 
> Found by Linux Verification Center (linuxtesting.org) with SVACE.
> 
> Fixes: 59dfa75e5d82 ("hwmon: Add driver for Texas Instruments TMP512/513 sensor chips.")
> Signed-off-by: Murad Masimov <m.masimov@maxima.ru>

Applied, after fixing checkpatch complaints.

Guenter