iio: kfifo: add devm_iio_triggered_buffer_setup_ext variant

This is similar to the {devm_}iio_triggered_buffer_setup_ext variants added
via commit 5164c788 ("iio: triggered-buffer: add
{devm_}iio_triggered_buffer_setup_ext variants").

These can be used to pass extra buffer attributes to the buffer object.
This is a bit of temporary mechanism (hopefully) so that drivers that want
to allocate a kfifo buffer with extra buffer attributes, don't need to
include 'buffer_impl.h' directly. This can also become an API function (in
it's own right, unfortunately), but it may be a little less bad vs drivers
having to include 'buffer_impl.h'.

So, far the drivers that want to pass buffer attributes, all have to do
with some HW FIFO attributes, so there may be a chance of unifying them
into IIO core somehow (as some standard API). But, until that happens, we
just need to let them register their HW FIFO attributes directly (without
having to let them include 'buffer_impl.h' directly).
Signed-off-by: Alexandru Ardelean <aardelean@deviqon.com>
Link: https://lore.kernel.org/r/20210311091042.22417-1-aardelean@deviqon.comSigned-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/iio/buffer/kfifo_buf.c

@@ -206,22 +206,24 @@ static struct iio_buffer *devm_iio_kfifo_allocate(struct device *dev)
 }
 
 /**
- * devm_iio_kfifo_buffer_setup - Allocate a kfifo buffer & attach it to an IIO device
+ * devm_iio_kfifo_buffer_setup_ext - Allocate a kfifo buffer & attach it to an IIO device
  * @dev: Device object to which to attach the life-time of this kfifo buffer
  * @indio_dev: The device the buffer should be attached to
  * @mode_flags: The mode flags for this buffer (INDIO_BUFFER_SOFTWARE and/or
  *		INDIO_BUFFER_TRIGGERED).
  * @setup_ops: The setup_ops required to configure the HW part of the buffer (optional)
+ * @buffer_attrs: Extra sysfs buffer attributes for this IIO buffer
  *
  * This function allocates a kfifo buffer via devm_iio_kfifo_allocate() and
  * attaches it to the IIO device via iio_device_attach_buffer().
  * This is meant to be a bit of a short-hand/helper function as there are a few
  * drivers that seem to do this.
  */
-int devm_iio_kfifo_buffer_setup(struct device *dev,
+int devm_iio_kfifo_buffer_setup_ext(struct device *dev,
 				    struct iio_dev *indio_dev,
 				    int mode_flags,
-				const struct iio_buffer_setup_ops *setup_ops)
+				    const struct iio_buffer_setup_ops *setup_ops,
+				    const struct attribute **buffer_attrs)
 {
 	struct iio_buffer *buffer;
 
@@ -237,8 +239,10 @@ int devm_iio_kfifo_buffer_setup(struct device *dev,
 	indio_dev->modes |= mode_flags;
 	indio_dev->setup_ops = setup_ops;
 
+	buffer->attrs = buffer_attrs;
+
 	return iio_device_attach_buffer(indio_dev, buffer);
 }
-EXPORT_SYMBOL_GPL(devm_iio_kfifo_buffer_setup);
+EXPORT_SYMBOL_GPL(devm_iio_kfifo_buffer_setup_ext);
 
 MODULE_LICENSE("GPL");

include/linux/iio/kfifo_buf.h

@@ -10,9 +10,13 @@ struct device;
 struct iio_buffer *iio_kfifo_allocate(void);
 void iio_kfifo_free(struct iio_buffer *r);
 
-int devm_iio_kfifo_buffer_setup(struct device *dev,
+int devm_iio_kfifo_buffer_setup_ext(struct device *dev,
 				    struct iio_dev *indio_dev,
 				    int mode_flags,
-				const struct iio_buffer_setup_ops *setup_ops);
+				    const struct iio_buffer_setup_ops *setup_ops,
+				    const struct attribute **buffer_attrs);
+
+#define devm_iio_kfifo_buffer_setup(dev, indio_dev, mode_flags, setup_ops)	\
+	devm_iio_kfifo_buffer_setup_ext((dev), (indio_dev), (mode_flags), (setup_ops), NULL)
 
 #endif