Re: [PATCH v8 5/6] iio: core: Add support for writing 64 bit attrs

[Jonathan Cameron <jic23@kernel.org>]

On Fri, 28 Mar 2025 13:48:30 -0400
Sam Winchenbach <sam.winchenbach@framepointer.org> wrote:

> From: Sam Winchenbach <swinchenbach@arka.org>
> 
> Prior to this patch it was only possible to read 64 bit integers.
> 
> Signed-off-by: Sam Winchenbach <swinchenbach@arka.org>
> ---
>  drivers/iio/industrialio-core.c | 12 ++++++++++++
>  1 file changed, 12 insertions(+)
> 
> diff --git a/drivers/iio/industrialio-core.c b/drivers/iio/industrialio-core.c
> index a2117ad1337d5..b2436b8f3eeae 100644
> --- a/drivers/iio/industrialio-core.c
> +++ b/drivers/iio/industrialio-core.c
> @@ -965,8 +965,10 @@ static ssize_t iio_write_channel_info(struct device *dev,
>  	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
>  	int ret, fract_mult = 100000;
>  	int integer, fract = 0;
> +	long long integer64;
>  	bool is_char = false;
>  	bool scale_db = false;
> +	bool is_64bit = false;
>  
>  	/* Assumes decimal - precision based on number of digits */
>  	if (!indio_dev->info->write_raw)
> @@ -990,6 +992,9 @@ static ssize_t iio_write_channel_info(struct device *dev,
>  		case IIO_VAL_CHAR:
>  			is_char = true;
>  			break;
> +		case IIO_VAL_INT_64:
> +			is_64bit = true;
> +			break;
>  		default:
>  			return -EINVAL;
>  		}
> @@ -1000,6 +1005,13 @@ static ssize_t iio_write_channel_info(struct device *dev,
>  		if (sscanf(buf, "%c", &ch) != 1)
>  			return -EINVAL;
>  		integer = ch;
> +	} else if (is_64bit) {
> +		ret = kstrtoll(buf, 0, &integer64);
> +		if (ret)
> +			return ret;
> +
> +		fract = (int)(integer64 >> 32);
> +		integer = (int)(integer64 & 0xFFFFFFFF);
I forgot on previous reviews but for this case we have wordpart.h

		fract = lower_32_bits(integer64);
		integer = upper_32_bits(integer64);

I'll tweak that whilst applying.

>  	} else {
>  		ret = __iio_str_to_fixpoint(buf, fract_mult, &integer, &fract,
>  					    scale_db);