diff mbox series

[v2,5/5] hw/sensor/tmp105: Lower 4 bit of limit registers are always 0

Message ID 20240906154911.86803-6-philmd@linaro.org
State Superseded
Headers show
Series tmp105: Improvements and fixes | expand

Commit Message

Philippe Mathieu-Daudé Sept. 6, 2024, 3:49 p.m. UTC 
From: Guenter Roeck <linux@roeck-us.net>

Per datasheet, "HIGH AND LOW LIMIT REGISTERS", the lower 4 bit
of the limit registers are unused and always report 0.
The lower 4 bit should not be used for temperature comparisons,
so mask the unused bits before storing the limits.

Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
---
 hw/sensor/tmp105.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Comments

Philippe Mathieu-Daudé Sept. 7, 2024, 4:12 a.m. UTC | #1 
On 6/9/24 17:49, Philippe Mathieu-Daudé wrote:
> From: Guenter Roeck <linux@roeck-us.net>
> 
> Per datasheet, "HIGH AND LOW LIMIT REGISTERS", the lower 4 bit
> of the limit registers are unused and always report 0.
> The lower 4 bit should not be used for temperature comparisons,
> so mask the unused bits before storing the limits.
> 
> Signed-off-by: Guenter Roeck <linux@roeck-us.net>

Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Cédric Le Goater <clg@kaod.org>

> Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
> ---
>   hw/sensor/tmp105.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/hw/sensor/tmp105.c b/hw/sensor/tmp105.c
> index f5101af919..9d7b911f59 100644
> --- a/hw/sensor/tmp105.c
> +++ b/hw/sensor/tmp105.c
> @@ -171,7 +171,7 @@ static void tmp105_write(TMP105State *s)
>       case TMP105_REG_T_HIGH:
>           if (s->len >= 3) {
>               s->limit[s->pointer & 1] = (int16_t)
> -                    ((((uint16_t) s->buf[0]) << 8) | s->buf[1]);
> +                    ((((uint16_t) s->buf[0]) << 8) | (s->buf[1] & 0xf0));
>           }
>           tmp105_alarm_update(s, false);
>           break;
diff mbox series

Patch

diff --git a/hw/sensor/tmp105.c b/hw/sensor/tmp105.c
index f5101af919..9d7b911f59 100644
--- a/hw/sensor/tmp105.c
+++ b/hw/sensor/tmp105.c
@@ -171,7 +171,7 @@  static void tmp105_write(TMP105State *s)
     case TMP105_REG_T_HIGH:
         if (s->len >= 3) {
             s->limit[s->pointer & 1] = (int16_t)
-                    ((((uint16_t) s->buf[0]) << 8) | s->buf[1]);
+                    ((((uint16_t) s->buf[0]) << 8) | (s->buf[1] & 0xf0));
         }
         tmp105_alarm_update(s, false);
         break;