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@xxxxxxxxxx>
---
drivers/iio/industrialio-buffer.c | 5 +++++
include/linux/iio/buffer.h | 8 ++++++++
2 files changed, 13 insertions(+)
diff --git a/drivers/iio/industrialio-buffer.c b/drivers/iio/industrialio-buffer.c
index 5f2c8c8..98a6447 100644
--- a/drivers/iio/industrialio-buffer.c
+++ b/drivers/iio/industrialio-buffer.c
@@ -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);
diff --git a/include/linux/iio/buffer.h b/include/linux/iio/buffer.h
index 1600c55..4d99a53 100644
--- a/include/linux/iio/buffer.h
+++ b/include/linux/iio/buffer.h
@@ -18,6 +18,12 @@
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
* @read_first_n: try to get a specified number of bytes (must exist)
@@ -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;
};
/**
--
2.1.4
--
To unsubscribe from this list: send the line "unsubscribe linux-iio" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
