Commit 350f6c75 authored by Matt Fornero's avatar Matt Fornero Committed by Greg Kroah-Hartman
Browse files

iio: buffer: Expose data available 



Add a sysfs attribute that exposes buffer data available to userspace.
This attribute can be checked at runtime to determine the overall buffer
fill level (across all allocated buffers).

Signed-off-by: default avatarMatt Fornero <matt.fornero@mathworks.com>
Signed-off-by: default avatarJonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 80e3f010

Documentation/ABI/testing/sysfs-bus-iio

+10 −0
Original line number Diff line number Diff line
@@ -1413,6 +1413,16 @@ Description: 
		the available samples after the timeout expires and thus have a

		maximum delay guarantee.



What:		/sys/bus/iio/devices/iio:deviceX/buffer/data_available

KernelVersion: 4.16

Contact:	linux-iio@vger.kernel.org

Description:

		A read-only value indicating the bytes of data available in the

		buffer. In the case of an output buffer, this indicates the

		amount of empty space available to write data to. In the case of

		an input buffer, this indicates the amount of data available for

		reading.



What:		/sys/bus/iio/devices/iio:deviceX/buffer/hwfifo_enabled

KernelVersion: 4.2

Contact:	linux-iio@vger.kernel.org

drivers/iio/industrialio-buffer.c

+15 −0
Original line number Diff line number Diff line
@@ -1198,6 +1198,18 @@ static ssize_t iio_buffer_store_watermark(struct device *dev, 
	return ret ? ret : len;

}



static ssize_t iio_dma_show_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_buffer_data_available(indio_dev->buffer);



	return sprintf(buf, "%zu\n", bytes);

}



static DEVICE_ATTR(length, S_IRUGO | S_IWUSR, iio_buffer_read_length,

		   iio_buffer_write_length);

static struct device_attribute dev_attr_length_ro = __ATTR(length,
@@ -1208,11 +1220,14 @@ static DEVICE_ATTR(watermark, S_IRUGO | S_IWUSR, 
		   iio_buffer_show_watermark, iio_buffer_store_watermark);

static struct device_attribute dev_attr_watermark_ro = __ATTR(watermark,

	S_IRUGO, iio_buffer_show_watermark, NULL);

static DEVICE_ATTR(data_available, S_IRUGO,

		iio_dma_show_data_available, NULL);



static struct attribute *iio_buffer_attrs[] = {

	&dev_attr_length.attr,

	&dev_attr_enable.attr,

	&dev_attr_watermark.attr,

	&dev_attr_data_available.attr,

};



int iio_buffer_alloc_sysfs_and_mask(struct iio_dev *indio_dev)