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

Jonathan Cameron
2025-03-30T15:20:58Z

On Sun, 30 Mar 2025 16:17:21 +0100
Jonathan Cameron <jic23@kernel.org> wrote:

> 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);
oops. Other way around obviously!

>
> I'll tweak that whilst applying.
>
> > } else {
> > ret = __iio_str_to_fixpoint(buf, fract_mult, &integer, &fract,
> > scale_db);
>
>