staging:iio:adc:ad7606 remove buffer access to data from sysfs read.

No known use case and complicates in kernel interface work.
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
Acked-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/staging/iio/adc/ad7606.h

@@ -99,7 +99,6 @@ enum ad7606_supported_device_ids {
 	ID_AD7606_4
 };
 
-int ad7606_scan_from_ring(struct iio_dev *indio_dev, unsigned ch);
 int ad7606_register_ring_funcs_and_init(struct iio_dev *indio_dev);
 void ad7606_ring_cleanup(struct iio_dev *indio_dev);
 #endif /* IIO_ADC_AD7606_H_ */

drivers/staging/iio/adc/ad7606_core.c

@@ -91,7 +91,7 @@ static int ad7606_read_raw(struct iio_dev *indio_dev,
 	case 0:
 		mutex_lock(&indio_dev->mlock);
 		if (iio_buffer_enabled(indio_dev))
-			ret = ad7606_scan_from_ring(indio_dev, chan->address);
+			ret = -EBUSY;
 		else
 			ret = ad7606_scan_direct(indio_dev, chan->address);
 		mutex_unlock(&indio_dev->mlock);

drivers/staging/iio/adc/ad7606_ring.c

@@ -18,30 +18,6 @@
 
 #include "ad7606.h"
 
-int ad7606_scan_from_ring(struct iio_dev *indio_dev, unsigned ch)
-{
-	struct iio_buffer *ring = indio_dev->buffer;
-	int ret;
-	u16 *ring_data;
-
-	ring_data = kmalloc(ring->access->get_bytes_per_datum(ring),
-			    GFP_KERNEL);
-	if (ring_data == NULL) {
-		ret = -ENOMEM;
-		goto error_ret;
-	}
-	ret = ring->access->read_last(ring, (u8 *) ring_data);
-	if (ret)
-		goto error_free_ring_data;
-
-	ret = ring_data[ch];
-
-error_free_ring_data:
-	kfree(ring_data);
-error_ret:
-	return ret;
-}
-
 /**
  * ad7606_trigger_handler_th() th/bh of trigger launched polling to ring buffer
  *