Re: [PATCH v2 1/2] iio: accel: kionix-kx022a: use scan struct for one-shot and trigger reads

[Jonathan Cameron]

On Wed, 19 Aug 2026 10:17:33 +0300
Andy Shevchenko <andriy.shevchenko@xxxxxxxxx> wrote:

> On Tue, Aug 18, 2026 at 10:51:21PM +0100, Gabriel Rondon wrote:
> > The driver kept two separate staging areas that hold the same thing:
> > buffer[8], a DMA-aligned area used by the one-shot read in
> > kx022a_get_axis() and by the triggered handler, and the scan struct,
> > used by the FIFO flush path. Both are three __le16 channels plus room
> > for the timestamp.
> > 
> > Drop buffer and route the one-shot read and the triggered handler
> > through scan.channels, so the driver has a single staging area. Move the
> > IIO_DMA_MINALIGN alignment onto scan, since it now backs the regmap bulk
> > reads that buffer used to.
> > 
> > No functional change. get_axis() only runs via read_raw() under
> > iio_device_claim_direct(), so it cannot run while the triggered buffer is
> > active, and the triggered handler only runs while it is; the two never
> > touch scan concurrently, exactly as they previously shared buffer.  
> 
> ...
> 
> > static int kx022a_get_axis(struct kx022a_data *data,  
> 
> >  {  
> 
> I would rather do this
> 
> 	__le16 *buf = &data->scan.channels[0];
> 
> >  	int ret;
> >  
> > -	ret = regmap_bulk_read(data->regmap, chan->address, &data->buffer[0],
> > -			       sizeof(__le16));
> > +	ret = regmap_bulk_read(data->regmap, chan->address,
> > +			       &data->scan.channels[0], sizeof(__le16));  
> 
> 	ret = regmap_bulk_read(data->regmap, chan->address, buf, sizeof(*buf));
> 
> >  	if (ret)
> >  		return ret;
> >  
> > -	*val = (s16)le16_to_cpu(data->buffer[0]);
> > +	*val = (s16)le16_to_cpu(data->scan.channels[0]);  
> 
> 	*val = (s16)le16_to_cpup(buf);
True - that is nicer. Tweaked.  Diff just to check I didn't get it wrong:

diff --git a/drivers/iio/accel/kionix-kx022a.c b/drivers/iio/accel/kionix-kx022a.c
index 86f17431aa23..8f2810c8ffeb 100644
--- a/drivers/iio/accel/kionix-kx022a.c
+++ b/drivers/iio/accel/kionix-kx022a.c
@@ -610,14 +610,15 @@ static int kx022a_get_axis(struct kx022a_data *data,
                           struct iio_chan_spec const *chan,
                           int *val)
 {
+       __le16 *buf = &data->scan.channels[0];
        int ret;
 
        ret = regmap_bulk_read(data->regmap, chan->address,
-                              &data->scan.channels[0], sizeof(__le16));
+                              buf, sizeof(*buf));
        if (ret)
                return ret;
 
-       *val = (s16)le16_to_cpu(data->scan.channels[0]);
+       *val = (s16)le16_to_cpup(buf);
 
        return IIO_VAL_INT;
 }



>