From 350f6c75f6933d5d58548d68f9336543c56b4a02 Mon Sep 17 00:00:00 2001 From: Matt Fornero Date: Wed, 6 Dec 2017 14:43:30 -0500 Subject: [PATCH] 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: Matt Fornero Signed-off-by: Jonathan Cameron Signed-off-by: Greg Kroah-Hartman --- 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 a478740e2783..9cc0ea1c0273 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@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 diff --git a/drivers/iio/industrialio-buffer.c b/drivers/iio/industrialio-buffer.c index d2b465140a6b..eda2a0f1658f 100644 --- a/drivers/iio/industrialio-buffer.c +++ b/drivers/iio/industrialio-buffer.c @@ -1198,6 +1198,18 @@ out: 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)