Re: [PATCH] hwmon: (lm70) Fix rounding of negative temperatures

[Guenter Roeck]

On Thu, Sep 24, 2026 at 08:53:23PM +0000, Ridham Khurana wrote:
> temp1_input_show() drops the low bits of the temperature register by
> dividing the raw value (raw / 32 on the LM70). These bits are not part
> of the temperature: the LM70, LM71, LM74 and TMP122/TMP124 always
> return some of them as 1, and the TMP125 fills them with copies of the
> temperature LSB. Division rounds toward zero, so a negative temperature
> with any of these bits set is reported one LSB too high.
> 
> For example, the TMP122 returns 0xffff for -0.0625 degrees C, which the
> driver reports as 0. The LM70 returns 0xf39f for -25 degrees C, which
> the driver reports as -24750.
> 
> Use an arithmetic right shift instead, which drops the low bits and
> rounds down. tmp421 had a similar problem with negative values, fixed
> by commit 724e8af85854 ("hwmon: (tmp421) fix rounding for negative
> values").

Please stop providing those "had a similar problem" messages (or tell your
AI to do it). This is irrelevant for this fix.

> 
> Fixes: e1a8e913f97e ("[PATCH] lm70: New hardware monitoring driver")
> Fixes: a86e94dc946d ("hwmon: (lm70) Add support for LM71 and LM74")
> Fixes: cd929672a9ef ("hwmon: (lm70) Add ti,tmp125 support")
> Signed-off-by: Ridham Khurana <khurana.ridham222@xxxxxxxxx>

Applied.

Thanks,
Guenter