Re: [PATCH v5 6/6] iio: adc: ad4851: add ad485x driver

[Jonathan Cameron <jic23@kernel.org>]

On Fri, 1 Nov 2024 13:23:58 +0200
Antoniu Miclaus <antoniu.miclaus@analog.com> wrote:

> Add support for the AD485X a fully buffered, 8-channel simultaneous
> sampling, 16/20-bit, 1 MSPS data acquisition system (DAS) with
> differential, wide common-mode range inputs.
> 
> Signed-off-by: Antoniu Miclaus <antoniu.miclaus@analog.com>
Hi Antoniu.

I only took a very quick look and one thing jumped out at me.

Jonathan

> diff --git a/drivers/iio/adc/ad4851.c b/drivers/iio/adc/ad4851.c
> new file mode 100644
> index 000000000000..0ef8ea0d2fc2
> --- /dev/null
> +++ b/drivers/iio/adc/ad4851.c

> +
> +static int ad4851_set_calibscale(struct ad4851_state *st, int ch, int val,
> +				 int val2)
> +{
> +	u64 gain;
> +	u8 buf[0];

A zero size array?

> +	int ret;
> +
> +	if (val < 0 || val2 < 0)
> +		return -EINVAL;
> +
> +	gain = val * MICRO + val2;
> +	gain = DIV_U64_ROUND_CLOSEST(gain * 32768, MICRO);
> +
> +	put_unaligned_be16(gain, buf);
> +
> +	guard(mutex)(&st->lock);
> +
> +	ret = regmap_write(st->regmap, AD4851_REG_CHX_GAIN_MSB(ch),
> +			   buf[0]);
> +	if (ret)
> +		return ret;
> +
> +	return regmap_write(st->regmap, AD4851_REG_CHX_GAIN_LSB(ch),
> +			    buf[1]);
> +}