From: Matt Fornero <matt.fornero@xxxxxxxxxxxxx>
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: Matt Fornero <matt.fornero@xxxxxxxxxxxxx>
---
v2 -> v3:
- Use %zu for sprintf instead of %llu
- Add documentation
Documentation/ABI/testing/sysfs-bus-iio | 10 ++++++++++
drivers/iio/industrialio-buffer.c | 15 +++++++++++++++
2 files changed, 25 insertions(+)
diff --git a/Documentation/ABI/testing/sysfs-bus-iio b/Documentation/ABI/testing/sysfs-bus-iio
index a478740..9cc0ea1 100644
--- a/Documentation/ABI/testing/sysfs-bus-iio
+++ b/Documentation/ABI/testing/sysfs-bus-iio
@@ -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@xxxxxxxxxxxxxxx
+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@xxxxxxxxxxxxxxx
diff --git a/drivers/iio/industrialio-buffer.c b/drivers/iio/industrialio-buffer.c
index d2b4651..eda2a0f 100644
--- a/drivers/iio/industrialio-buffer.c
+++ b/drivers/iio/industrialio-buffer.c
@@ -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)
--
1.8.3.1
--
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