Merge tag 'iio-for-4.1b' of git://git.kernel.org/pub/scm/linux/kernel/git/jic23/iio into staging-next

Jonathan writes:

Second set of new devices, functionality and cleanup for IIO in the 4.1 cycle.

New Functionality
* Watermark logic for buffers.  Allows for blocking reads to block until
  their requested amount is available - previously they only blocked until
  a single scan of data was available.  Also allows for polling for a
  watermark amount of data to be available.  This feature was first proposed
  some time ago to good responses, but not taken further by the original author
  Octavian has picked up the gauntlet and taken it through
  to merging (along with the hardware fifo support that follows).
* New approach to hardware fifo handling - in particular handling the
  interaction of a hardware fifo feeding into a software fifo and their
  watershed events.  We don't have every possible case well covered yet,
  but this is certainly a good, flexible starting point.  This will replace
  the previous approach used in ancient drivers (sca3000) where we just
  exposed the hardware buffer directly to userspace.  Very few pieces of
  hardware have sufficiently long buffers for that to be an adequate solution.
* bmc150_accel - hardware fifo support.
* mlx90614 - support dual IR sensor devices + some refactoring to clean up the
  code and allow some other functionality currently under review.
* L3GD20H gyroscope support added to the st_gyro driver.
* lis3lv02d accelerometer added to the st_gyro driver. Note this part is
  also supported by the older lis3 driver under misc.  A lengthy discussion
  took place and concluded that holding parts out on the basis that whole
  driver would be subsumed into this one was counter productive.  Better
  to add part support and add additional features as people need them.
  Basically there was not advantage in not merging the support.
* max517 driver gains support for MAX520 and MAX521 DACs.

Documentation
* 3.20 -> 4.0 renaming for recent docs. Whilst technically a fix, I think
  people will cope until the next merge merge window.
* An ABI typo hat -> What:  More ABIs should have hats.
* Document in_rot_offset, illuminance_raw and illuminance_scale.

Cleanups
* Fix a scale extraction bug in generic_buffer.c example.
* Constify a load of device tree related structures.

3 files changed, 19 insertions, 4 deletions

diff --git a/include/linux/iio/buffer.h b/include/linux/iio/buffer.h
index b65850a41127..eb8622b78ec9 100644
--- a/include/linux/iio/buffer.h
+++ b/include/linux/iio/buffer.h
@@ -21,8 +21,8 @@ struct iio_buffer;
  * 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)
- * @data_available:	indicates whether data for reading from the buffer is
- *			available.
+ * @data_available:	indicates how much data is available for reading from
+ *			the buffer.
  * @request_update:	if a parameter change has been marked, update underlying
  *			storage.
  * @set_bytes_per_datum:set number of bytes per datum
@@ -43,7 +43,7 @@ struct iio_buffer_access_funcs {
 	int (*read_first_n)(struct iio_buffer *buffer,
 			    size_t n,
 			    char __user *buf);
-	bool (*data_available)(struct iio_buffer *buffer);
+	size_t (*data_available)(struct iio_buffer *buffer);
 
 	int (*request_update)(struct iio_buffer *buffer);
 
@@ -72,6 +72,7 @@ struct iio_buffer_access_funcs {
  * @demux_bounce:	[INTERN] buffer for doing gather from incoming scan.
  * @buffer_list:	[INTERN] entry in the devices list of current buffers.
  * @ref:		[INTERN] reference count of the buffer.
+ * @watermark:		[INTERN] number of datums to wait for poll/read.
  */
 struct iio_buffer {
 	int					length;
@@ -90,6 +91,7 @@ struct iio_buffer {
 	void					*demux_bounce;
 	struct list_head			buffer_list;
 	struct kref				ref;
+	unsigned int				watermark;
 };
 
 /**
diff --git a/include/linux/iio/dac/max517.h b/include/linux/iio/dac/max517.h
index f6d1d252f08d..7668716cd73c 100644
--- a/include/linux/iio/dac/max517.h
+++ b/include/linux/iio/dac/max517.h
@@ -9,7 +9,7 @@
 #define IIO_DAC_MAX517_H_
 
 struct max517_platform_data {
-	u16				vref_mv[2];
+	u16				vref_mv[8];
 };
 
 #endif /* IIO_DAC_MAX517_H_ */
diff --git a/include/linux/iio/iio.h b/include/linux/iio/iio.h
index 80d855061064..d86b753e9b30 100644
--- a/include/linux/iio/iio.h
+++ b/include/linux/iio/iio.h
@@ -338,6 +338,16 @@ struct iio_dev;
  *			provide a custom of_xlate function that reads the
  *			*args* and returns the appropriate index in registered
  *			IIO channels array.
+ * @hwfifo_set_watermark: function pointer to set the current hardware
+ *			fifo watermark level; see hwfifo_* entries in
+ *			Documentation/ABI/testing/sysfs-bus-iio for details on
+ *			how the hardware fifo operates
+ * @hwfifo_flush_to_buffer: function pointer to flush the samples stored
+ *			in the hardware fifo to the device buffer. The driver
+ *			should not flush more than count samples. The function
+ *			must return the number of samples flushed, 0 if no
+ *			samples were flushed or a negative integer if no samples
+ *			were flushed and there was an error.
  **/
 struct iio_info {
 	struct module			*driver_module;
@@ -399,6 +409,9 @@ struct iio_info {
 				  unsigned *readval);
 	int (*of_xlate)(struct iio_dev *indio_dev,
 			const struct of_phandle_args *iiospec);
+	int (*hwfifo_set_watermark)(struct iio_dev *indio_dev, unsigned val);
+	int (*hwfifo_flush_to_buffer)(struct iio_dev *indio_dev,
+				      unsigned count);
 };
 
 /**