Re: [PATCH] iio: accel: adxl380: fix FIFO watermark bit 8 always written as 0

[David Lechner <dlechner@baylibre.com>]

On 2/27/26 6:43 AM, Antoniu Miclaus wrote:
> FIELD_PREP(BIT(0), fifo_samples & BIT(8)) produces either 0 or 256,
> and since FIELD_PREP masks to bit 0, 256 & 1 evaluates to 0. Use !!
> to convert the result to a proper 0-or-1 value.
> 
> Fixes: df36de13677a ("iio: accel: add ADXL380 driver")
> Signed-off-by: Antoniu Miclaus <antoniu.miclaus@analog.com>
> ---
>  drivers/iio/accel/adxl380.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/iio/accel/adxl380.c b/drivers/iio/accel/adxl380.c
> index 8fab2fdbe147..a51d1d61c412 100644
> --- a/drivers/iio/accel/adxl380.c
> +++ b/drivers/iio/accel/adxl380.c
> @@ -877,7 +877,7 @@ static int adxl380_set_fifo_samples(struct adxl380_state *st)

Some relevant context...

	u16 fifo_samples = st->watermark * st->fifo_set_size;

>  	ret = regmap_update_bits(st->regmap, ADXL380_FIFO_CONFIG_0_REG,
>  				 ADXL380_FIFO_SAMPLES_8_MSK,
>  				 FIELD_PREP(ADXL380_FIFO_SAMPLES_8_MSK,
> -					    (fifo_samples & BIT(8))));
> +					    !!(fifo_samples & BIT(8))));

Technically, this works, but in terms of understanding the code I think
fifo_samples >= BIT(8) would make more sense.

fifo_samples is a count, not bit flags.


>  	if (ret)
>  		return ret;
>