Merge tag 'iio-for-4.4a' of git://git.kernel.org/pub/scm/linux/kernel/git/jic23/iio into staging-next

Jonathan writes:

First round of new driver, new functionality and cleanups for IIO in the 4.4 cycle

New device support
* APDS9960 ALS + proximity driver
* bmg160 SPI devices.
* HDC100x humidity sensors
* Holt HI-8435 threshold detector
* mma8453Q accelerometer added to the mma8452 driver
* mma86452FC and mma8653FC accelerometers added to the mma8452 driver
* mxc4005 accelerometer
* PulsedLight LIDAR
* SensorTech VZ89x volatile organic compound sensor
* UPISEMI uS5182d ALS and proximity sensors

New core functionality
* triggered events - use triggers to check for changes in threshold type
  detectors on devices with out interrupt support.  First user is the holt
  comparator.
* chemical concentration and resistance channel types.

New driver functionality
* vf610
  - buffer support.
  - followup coccinelle warning fix.

Core rework
* buffers
  - break out callback buffer to own module.
  - move buffer implementations to a new subdirectory
* percolate the error code form iio_event_getfd out to userspace
  rather than giving a missleading error later on.

Cleanups
* adddac drivers
  - use BIT macro where appropriate.
* meter drivers
  - use BIT macro where appropriate.

* ad7303
 - add an OF match table to line up with the binding docs.
* adc128s052
  - add an OF match table to line up with the binding docs.
* adf4350
  - add an OF match table to line up with the binding docs
* as3935
  - add an OF match table to line up with the binding docs.
* berlin2-adc
  - use GENMASK and BIT for masks
  - prevent attempting to sample multiple channels at once by moving a
    mutex scop
  - coding style cleanups
* bmg150_magn
  - kconfig sort order was wrong - fix it.
* bmg160
  - use i2c regmap and drop all uses of i2c_client
  - separate i2c and core driver
* cc10001_adc
  - kconfig sort order was wrong - fix it.
* evgen (dummy driver helper module)
  - move interrupt generation to irq_work to reduce differences between
    the dummy driver and real hardware drivers.
* hmc5843
  - set the name dynamically rather than to a fixed value for one of the
    suported parts.
  - export module alias information to allow autoprobing of module.
* lpc32xx
  - on failure to get resource or irq return -ENXIO as uppose to -EBUSY
* max1027
  - set .of_match_table to actually allow OF style matching.
* max5821
  - add MODULE_DEVICE_TABLE for OF table.
* mma8452
  - refactor to separate out chip specific data.
  - add freefall / motion interrupt source for devices that do their
    interrupts slightly differently.
  - update copywrite notice.
  - leave naming of events directory in sysfs to the core
* mcp320x
  - set .of_match_table so that it can be use for OF style matching.
* mlx90614
  - Implement filter configuration (note the datasheet changed as a result
    of the driver reviews to include the values we needed ;)
* opt3001
  - drop .owner field as assigned by platform driver core.
* si7020
  - replace a bitmask on the humidity values with a more correct range
    check.
* stk310
  - improved error handling.
  - use BIT macro where appropriate and use the resulting defines
    instead of magic numbers in the code.
  - fix indentation
* st-sensors
  - add debugfs register read hook
* tsl4531
  - fix error handling in check_id
* twl6030
  - fix module autoload for OF
* iio-trig-sysfs
  - document add and remove attribute
* trigger in staging
  - code alignment fixes.
  - braces on both branches of if statement if needed for one.
* xilinx-xadc
  - push interrupts into hardirq context as there isn't much in them
    any more and it avoids breaking PREEMPT_RT builds due to the use
    of a spinlock between the hardirq and the thread.

Tools
* event-monitor
  - report unsupported events.  We keep expanding what can come from drivers
    so give a helpful error if one turns up in an out of date userspace
    program.
* generic-buffer
  - helpful message about needing to enable a channel to start the buffer.

2 files changed, 14 insertions, 1 deletions

diff --git a/tools/iio/generic_buffer.c b/tools/iio/generic_buffer.c
index 9f7b85b..01c4f67 100644
--- a/tools/iio/generic_buffer.c
+++ b/tools/iio/generic_buffer.c
@@ -328,6 +328,15 @@ int main(int argc, char **argv)
 			"diag %s\n", dev_dir_name);
 		goto error_free_triggername;
 	}
+	if (!num_channels) {
+		fprintf(stderr,
+			"No channels are enabled, we have nothing to scan.\n");
+		fprintf(stderr, "Enable channels manually in "
+			FORMAT_SCAN_ELEMENTS_DIR
+			"/*_en and try again.\n", dev_dir_name);
+		ret = -ENOENT;
+		goto error_free_triggername;
+	}
 
 	/*
 	 * Construct the directory name for the associated buffer.
diff --git a/tools/iio/iio_event_monitor.c b/tools/iio/iio_event_monitor.c
index cd3fd41..d51eb04 100644
--- a/tools/iio/iio_event_monitor.c
+++ b/tools/iio/iio_event_monitor.c
@@ -284,7 +284,11 @@ int main(int argc, char **argv)
 	ret = ioctl(fd, IIO_GET_EVENT_FD_IOCTL, &event_fd);
 	if (ret == -1 || event_fd == -1) {
 		ret = -errno;
-		fprintf(stderr, "Failed to retrieve event fd\n");
+		if (ret == -ENODEV)
+			fprintf(stderr,
+				"This device does not support events\n");
+		else
+			fprintf(stderr, "Failed to retrieve event fd\n");
 		if (close(fd) == -1)
 			perror("Failed to close character device file");