diff options
| -rw-r--r-- | Documentation/ABI/testing/sysfs-bus-iio-dma-buffer | 19 | ||||
| -rw-r--r-- | drivers/iio/buffer/industrialio-buffer-dmaengine.c | 21 |
2 files changed, 40 insertions, 0 deletions
diff --git a/Documentation/ABI/testing/sysfs-bus-iio-dma-buffer b/Documentation/ABI/testing/sysfs-bus-iio-dma-buffer new file mode 100644 index 000000000000..d526e6571001 --- /dev/null +++ b/Documentation/ABI/testing/sysfs-bus-iio-dma-buffer @@ -0,0 +1,19 @@ +What: /sys/bus/iio/devices/iio:deviceX/buffer/length_align_bytes +KernelVersion: 5.4 +Contact: linux-iio@vger.kernel.org +Description: + DMA buffers tend to have a alignment requirement for the + buffers. If this alignment requirement is not met samples might + be dropped from the buffer. + + This property reports the alignment requirements in bytes. + This means that the buffer size in bytes needs to be a integer + multiple of the number reported by this file. + + The alignment requirements in number of sample sets will depend + on the enabled channels and the bytes per channel. This means + that the alignment requirement in samples sets might change + depending on which and how many channels are enabled. Whereas + the alignment requirement reported in bytes by this property + will remain static and does not depend on which channels are + enabled. diff --git a/drivers/iio/buffer/industrialio-buffer-dmaengine.c b/drivers/iio/buffer/industrialio-buffer-dmaengine.c index e0b92f3dec0e..744abd7e1269 100644 --- a/drivers/iio/buffer/industrialio-buffer-dmaengine.c +++ b/drivers/iio/buffer/industrialio-buffer-dmaengine.c @@ -13,6 +13,7 @@ #include <linux/module.h> #include <linux/iio/iio.h> +#include <linux/iio/sysfs.h> #include <linux/iio/buffer.h> #include <linux/iio/buffer_impl.h> #include <linux/iio/buffer-dma.h> @@ -126,6 +127,24 @@ static const struct iio_dma_buffer_ops iio_dmaengine_default_ops = { .abort = iio_dmaengine_buffer_abort, }; +static ssize_t iio_dmaengine_buffer_get_length_align(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct iio_dev *indio_dev = dev_to_iio_dev(dev); + struct dmaengine_buffer *dmaengine_buffer = + iio_buffer_to_dmaengine_buffer(indio_dev->buffer); + + return sprintf(buf, "%u\n", dmaengine_buffer->align); +} + +static IIO_DEVICE_ATTR(length_align_bytes, 0444, + iio_dmaengine_buffer_get_length_align, NULL, 0); + +static const struct attribute *iio_dmaengine_buffer_attrs[] = { + &iio_dev_attr_length_align_bytes.dev_attr.attr, + NULL, +}; + /** * iio_dmaengine_buffer_alloc() - Allocate new buffer which uses DMAengine * @dev: Parent device for the buffer @@ -179,6 +198,8 @@ struct iio_buffer *iio_dmaengine_buffer_alloc(struct device *dev, iio_dma_buffer_init(&dmaengine_buffer->queue, chan->device->dev, &iio_dmaengine_default_ops); + iio_buffer_set_attrs(&dmaengine_buffer->queue.buffer, + iio_dmaengine_buffer_attrs); dmaengine_buffer->queue.buffer.access = &iio_dmaengine_buffer_ops; |