Rework ti_adc_trigger_handler() to properly handle data on big-endian
architectures. The scan data format is 16-bit CPU-endian, so we can't
cast it to a int * on big-endian and expect it to work. Instead, we
introduce a local int variable to read the data into, and then copy it
to the buffer.

Since the buffer isn't passed to any SPI functions, we don't need it to
be DMA-safe. So we can drop it from the driver data struct and just
use stack memory for the scan data.

Since there is only one data value (plus timestamp), we don't need an
array and can just declare a struct with the correct data type instead.

Also fix alignment of iio_get_time_ns() to ( while we are touching this.

Fixes: 4d671b71beef ("iio: adc: ti-adc161s626: add support for TI 1-channel differential ADCs")
Signed-off-by: David Lechner <dlechner@baylibre.com>
---
 drivers/iio/adc/ti-adc161s626.c | 22 ++++++++++++----------
 1 file changed, 12 insertions(+), 10 deletions(-)

diff --git a/drivers/iio/adc/ti-adc161s626.c b/drivers/iio/adc/ti-adc161s626.c
index 28aa6b80160c..1d427548e0b3 100644
--- a/drivers/iio/adc/ti-adc161s626.c
+++ b/drivers/iio/adc/ti-adc161s626.c
@@ -70,8 +70,6 @@ struct ti_adc_data {
 
 	u8 read_size;
 	u8 shift;
-
-	u8 buffer[16] __aligned(IIO_DMA_MINALIGN);
 };
 
 static int ti_adc_read_measurement(struct ti_adc_data *data,
@@ -114,14 +112,18 @@ static irqreturn_t ti_adc_trigger_handler(int irq, void *private)
 	struct iio_poll_func *pf = private;
 	struct iio_dev *indio_dev = pf->indio_dev;
 	struct ti_adc_data *data = iio_priv(indio_dev);
-	int ret;
-
-	ret = ti_adc_read_measurement(data, &indio_dev->channels[0],
-				     (int *) &data->buffer);
-	if (!ret)
-		iio_push_to_buffers_with_timestamp(indio_dev,
-					data->buffer,
-					iio_get_time_ns(indio_dev));
+	int ret, val;
+	struct {
+		s16 data;
+		aligned_s64 timestamp;
+	} scan = { };
+
+	ret = ti_adc_read_measurement(data, &indio_dev->channels[0], &val);
+	if (!ret) {
+		scan.data = val;
+		iio_push_to_buffers_with_timestamp(indio_dev, &scan,
+						   iio_get_time_ns(indio_dev));
+	}
 
 	iio_trigger_notify_done(indio_dev->trig);
 

-- 
2.43.0

On Sat, Mar 14, 2026 at 06:13:31PM -0500, David Lechner wrote:
> Rework ti_adc_trigger_handler() to properly handle data on big-endian
> architectures. The scan data format is 16-bit CPU-endian, so we can't
> cast it to a int * on big-endian and expect it to work. Instead, we
> introduce a local int variable to read the data into, and then copy it
> to the buffer.
> 
> Since the buffer isn't passed to any SPI functions, we don't need it to
> be DMA-safe. So we can drop it from the driver data struct and just
> use stack memory for the scan data.
> 
> Since there is only one data value (plus timestamp), we don't need an
> array and can just declare a struct with the correct data type instead.
> 
> Also fix alignment of iio_get_time_ns() to ( while we are touching this.

...

>  	struct iio_poll_func *pf = private;
>  	struct iio_dev *indio_dev = pf->indio_dev;
>  	struct ti_adc_data *data = iio_priv(indio_dev);

> +	int ret, val;

Can this be put after the 'scan'?

> +	struct {
> +		s16 data;
> +		aligned_s64 timestamp;
> +	} scan = { };
> +
> +	ret = ti_adc_read_measurement(data, &indio_dev->channels[0], &val);

> +	if (!ret) {

Personally I prefer goto approach over unusual pattern and TAB indentation.

> +		scan.data = val;
> +		iio_push_to_buffers_with_timestamp(indio_dev, &scan,
> +						   iio_get_time_ns(indio_dev));
> +	}
>  
> +	ret = ti_adc_read_measurement(data, &indio_dev->channels[0], &val);

	if (ret)
		goto exit_notify_done;

	scan.data = val;
	// Also can we consider moving towards new API?
	iio_push_to_buffers_with_timestamp(indio_dev, &scan, iio_get_time_ns(indio_dev));

exit_notify_done:

>  	iio_trigger_notify_done(indio_dev->trig);

-- 
With Best Regards,
Andy Shevchenko

On Mon, 16 Mar 2026 15:56:26 +0200
Andy Shevchenko <andriy.shevchenko@intel.com> wrote:

> On Sat, Mar 14, 2026 at 06:13:31PM -0500, David Lechner wrote:
> > Rework ti_adc_trigger_handler() to properly handle data on big-endian
> > architectures. The scan data format is 16-bit CPU-endian, so we can't
> > cast it to a int * on big-endian and expect it to work. Instead, we
> > introduce a local int variable to read the data into, and then copy it
> > to the buffer.
> > 
> > Since the buffer isn't passed to any SPI functions, we don't need it to
> > be DMA-safe. So we can drop it from the driver data struct and just
> > use stack memory for the scan data.
> > 
> > Since there is only one data value (plus timestamp), we don't need an
> > array and can just declare a struct with the correct data type instead.
> > 
> > Also fix alignment of iio_get_time_ns() to ( while we are touching this.  
> 
> ...

I agree with Andy's comments, so applied with diff below.
Please sanity check this. Applied to the fixes-togreg branch of iio.git and marked
for stable.

Thanks,

J

diff --git a/drivers/iio/adc/ti-adc161s626.c b/drivers/iio/adc/ti-adc161s626.c
index 1d427548e0b3..42968d96572b 100644
--- a/drivers/iio/adc/ti-adc161s626.c
+++ b/drivers/iio/adc/ti-adc161s626.c
@@ -112,19 +112,20 @@ static irqreturn_t ti_adc_trigger_handler(int irq, void *private)
        struct iio_poll_func *pf = private;
        struct iio_dev *indio_dev = pf->indio_dev;
        struct ti_adc_data *data = iio_priv(indio_dev);
-       int ret, val;
        struct {
                s16 data;
                aligned_s64 timestamp;
        } scan = { };
+       int ret, val;
 
        ret = ti_adc_read_measurement(data, &indio_dev->channels[0], &val);
-       if (!ret) {
-               scan.data = val;
-               iio_push_to_buffers_with_timestamp(indio_dev, &scan,
-                                                  iio_get_time_ns(indio_dev));
-       }
+       if (ret)
+               goto exit_notify_done;
+
+       scan.data = val;
+       iio_push_to_buffers_with_timestamp(indio_dev, &scan, iio_get_time_ns(indio_dev));
 
+ exit_notify_done:
        iio_trigger_notify_done(indio_dev->trig);
 
        return IRQ_HANDLED;

> 
> >  	struct iio_poll_func *pf = private;
> >  	struct iio_dev *indio_dev = pf->indio_dev;
> >  	struct ti_adc_data *data = iio_priv(indio_dev);  
> 
> > +	int ret, val;  
> 
> Can this be put after the 'scan'?
> 
> > +	struct {
> > +		s16 data;
> > +		aligned_s64 timestamp;
> > +	} scan = { };
> > +
> > +	ret = ti_adc_read_measurement(data, &indio_dev->channels[0], &val);  
> 
> > +	if (!ret) {  
> 
> Personally I prefer goto approach over unusual pattern and TAB indentation.
> 
> > +		scan.data = val;
> > +		iio_push_to_buffers_with_timestamp(indio_dev, &scan,
> > +						   iio_get_time_ns(indio_dev));
> > +	}
> >  
> > +	ret = ti_adc_read_measurement(data, &indio_dev->channels[0], &val);  
> 
> 	if (ret)
> 		goto exit_notify_done;
> 
> 	scan.data = val;
> 	// Also can we consider moving towards new API?
> 	iio_push_to_buffers_with_timestamp(indio_dev, &scan, iio_get_time_ns(indio_dev));
> 
> exit_notify_done:
> 
> >  	iio_trigger_notify_done(indio_dev->trig);  
>