On Fri, 1 Dec 2017 15:46:20 -0500
mfornero@xxxxxxxxx wrote:
> From: Matt Fornero <matt.fornero@xxxxxxxxxxxxx>
>
> Add a sysfs attribute that exposes the buffer data available to
> userspace. This attribute can be checked at runtime to determine the
> overall buffer fill level (across all allocated DMA buffers).
>
> Signed-off-by: Matt Fornero <matt.fornero@xxxxxxxxxxxxx>
Seems sensible to me.
Lars?
Thanks,
Jonathan
> ---
> drivers/iio/buffer/industrialio-buffer-dma.c | 24 ++++++++++++++++++++++++
> 1 file changed, 24 insertions(+)
>
> diff --git a/drivers/iio/buffer/industrialio-buffer-dma.c b/drivers/iio/buffer/industrialio-buffer-dma.c
> index ff03324..8739a41 100644
> --- a/drivers/iio/buffer/industrialio-buffer-dma.c
> +++ b/drivers/iio/buffer/industrialio-buffer-dma.c
> @@ -16,6 +16,7 @@
> #include <linux/iio/buffer.h>
> #include <linux/iio/buffer_impl.h>
> #include <linux/iio/buffer-dma.h>
> +#include <linux/iio/sysfs.h>
> #include <linux/dma-mapping.h>
> #include <linux/sizes.h>
>
> @@ -599,6 +600,28 @@ int iio_dma_buffer_set_length(struct iio_buffer *buffer, int length)
> }
> EXPORT_SYMBOL_GPL(iio_dma_buffer_set_length);
>
> +
> +static ssize_t iio_dma_get_data_available(struct device *dev,
> + struct device_attribute *attr,
> + char *buf)
> +{
> + struct iio_dev *indio_dev = dev_to_iio_dev(dev);
> + size_t bytes;
> +
> + bytes = iio_dma_buffer_data_available(indio_dev->buffer);
> +
> + return sprintf(buf, "%llu\n", (unsigned long long)bytes);
> +}
> +
> +static IIO_DEVICE_ATTR(data_available, S_IRUGO,
> + iio_dma_get_data_available, NULL, 0);
> +
> +static const struct attribute *iio_dma_buffer_attributes[] = {
> + &iio_dev_attr_data_available.dev_attr.attr,
> + NULL,
> +};
> +
> +
> /**
> * iio_dma_buffer_init() - Initialize DMA buffer queue
> * @queue: Buffer to initialize
> @@ -615,6 +638,7 @@ int iio_dma_buffer_init(struct iio_dma_buffer_queue *queue,
> iio_buffer_init(&queue->buffer);
> queue->buffer.length = PAGE_SIZE;
> queue->buffer.watermark = queue->buffer.length / 2;
> + queue->buffer.attrs = iio_dma_buffer_attributes;
> queue->dev = dev;
> queue->ops = ops;
>
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