iio: Add support for indicating fixed watermarks

For buffers which have a fixed wake-up watermark the watermark attribute
should be read-only. Add a new FIXED_WATERMARK flag to the
struct iio_buffer_access_funcs, which can be set by a buffer
implementation.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
This commit is contained in:
Lars-Peter Clausen 2015-10-13 18:10:26 +02:00 committed by Jonathan Cameron
parent 4a60535726
commit b440655b89
2 changed files with 13 additions and 0 deletions

View file

@ -998,6 +998,8 @@ static DEVICE_ATTR(enable, S_IRUGO | S_IWUSR,
iio_buffer_show_enable, iio_buffer_store_enable);
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 struct attribute *iio_buffer_attrs[] = {
&dev_attr_length.attr,
@ -1040,6 +1042,9 @@ int iio_buffer_alloc_sysfs_and_mask(struct iio_dev *indio_dev)
if (!buffer->access->set_length)
attr[0] = &dev_attr_length_ro.attr;
if (buffer->access->flags & INDIO_BUFFER_FLAG_FIXED_WATERMARK)
attr[2] = &dev_attr_watermark_ro.attr;
if (buffer->attrs)
memcpy(&attr[ARRAY_SIZE(iio_buffer_attrs)], buffer->attrs,
sizeof(struct attribute *) * attrcount);

View file

@ -17,6 +17,12 @@
struct iio_buffer;
/**
* INDIO_BUFFER_FLAG_FIXED_WATERMARK - Watermark level of the buffer can not be
* configured. It has a fixed value which will be buffer specific.
*/
#define INDIO_BUFFER_FLAG_FIXED_WATERMARK BIT(0)
/**
* struct iio_buffer_access_funcs - access functions for buffers.
* @store_to: actually store stuff to the buffer
@ -30,6 +36,7 @@ struct iio_buffer;
* @release: called when the last reference to the buffer is dropped,
* should free all resources allocated by the buffer.
* @modes: Supported operating modes by this buffer type
* @flags: A bitmask combination of INDIO_BUFFER_FLAG_*
*
* The purpose of this structure is to make the buffer element
* modular as event for a given driver, different usecases may require
@ -54,6 +61,7 @@ struct iio_buffer_access_funcs {
void (*release)(struct iio_buffer *buffer);
unsigned int modes;
unsigned int flags;
};
/**