iio: Extend the event config interface

The event configuration interface of the IIO framework has not been getting the
same attention as other parts. As a result it has not seen the same improvements
as e.g. the channel interface has seen with the introduction of the channel spec
struct. Currently all the event config callbacks take a u64 (the so called event
code) to pass all the different information about for which event the callback
is invoked. The callback function then has to extract the information it is
interested in using some macros with rather long names. Most information encoded
in the event code comes straight from the iio_chan_spec struct the event was
registered for. Since we always have a handle to the channel spec when we call
the event callbacks the first step is to add the channel spec as a parameter to
the event callbacks. The two remaining things encoded in the event code are the
type and direction of the event. Instead of passing them in one parameter, add
one parameter for each of them and remove the eventcode from the event
callbacks. The patch also adds a new iio_event_info parameter to the
{read,write}_event_value callbacks. This makes it possible, similar to the
iio_chan_info_enum for channels, to specify additional properties other than
just the value for an event. Furthermore the new interface will allow to
register shared events. This is e.g. useful if a device allows configuring a
threshold event, but the threshold setting is the same for all channels.

To implement this the patch adds a new iio_event_spec struct which is similar to
the iio_chan_spec struct. It as two field to specify the type and the direction
of the event. Furthermore it has a mask field for each one of the different
iio_shared_by types. These mask fields holds which kind of attributes should be
registered for the event. Creation of the attributes follows the same rules as
the for the channel attributes. E.g. for the separate_mask there will be a
attribute for each channel with this event, for the shared_by_type there will
only be one attribute per channel type. The iio_chan_spec struct gets two new
fields, 'event_spec' and 'num_event_specs', which is used to specify which the
events for this channel. These two fields are going to replace the channel's
event_mask field.

For now both the old and the new event config interface coexist, but over the
few patches all drivers will be converted from the old to the new interface.
Once that is done all code for supporting the old interface will be removed.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

3 files changed, 77 insertions, 14 deletions

diff --git a/include/linux/iio/events.h b/include/linux/iio/events.h
index 13ce220c7003..5dab2c41031f 100644
--- a/include/linux/iio/events.h
+++ b/include/linux/iio/events.h
@@ -26,20 +26,6 @@ struct iio_event_data {
 
 #define IIO_GET_EVENT_FD_IOCTL _IOR('i', 0x90, int)
 
-enum iio_event_type {
-	IIO_EV_TYPE_THRESH,
-	IIO_EV_TYPE_MAG,
-	IIO_EV_TYPE_ROC,
-	IIO_EV_TYPE_THRESH_ADAPTIVE,
-	IIO_EV_TYPE_MAG_ADAPTIVE,
-};
-
-enum iio_event_direction {
-	IIO_EV_DIR_EITHER,
-	IIO_EV_DIR_RISING,
-	IIO_EV_DIR_FALLING,
-};
-
 /**
  * IIO_EVENT_CODE() - create event identifier
  * @chan_type:	Type of the channel. Should be one of enum iio_chan_type.
diff --git a/include/linux/iio/iio.h b/include/linux/iio/iio.h
index ac1cb8f1858c..256a90a1bea6 100644
--- a/include/linux/iio/iio.h
+++ b/include/linux/iio/iio.h
@@ -139,6 +139,29 @@ ssize_t iio_enum_write(struct iio_dev *indio_dev,
 }
 
 /**
+ * struct iio_event_spec - specification for a channel event
+ * @type:		    Type of the event
+ * @dir:		    Direction of the event
+ * @mask_separate:	    Bit mask of enum iio_event_info values. Attributes
+ *			    set in this mask will be registered per channel.
+ * @mask_shared_by_type:    Bit mask of enum iio_event_info values. Attributes
+ *			    set in this mask will be shared by channel type.
+ * @mask_shared_by_dir:	    Bit mask of enum iio_event_info values. Attributes
+ *			    set in this mask will be shared by channel type and
+ *			    direction.
+ * @mask_shared_by_all:	    Bit mask of enum iio_event_info values. Attributes
+ *			    set in this mask will be shared by all channels.
+ */
+struct iio_event_spec {
+	enum iio_event_type type;
+	enum iio_event_direction dir;
+	unsigned long mask_separate;
+	unsigned long mask_shared_by_type;
+	unsigned long mask_shared_by_dir;
+	unsigned long mask_shared_by_all;
+};
+
+/**
  * struct iio_chan_spec - specification of a single channel
  * @type:		What type of measurement is the channel making.
  * @channel:		What number do we wish to assign the channel.
@@ -163,6 +186,9 @@ ssize_t iio_enum_write(struct iio_dev *indio_dev,
  * @info_mask_shared_by_all: What information is to be exported that is shared
  *			by all channels.
  * @event_mask:		What events can this channel produce.
+ * @event_spec:		Array of events which should be registered for this
+ *			channel.
+ * @num_event_specs:	Size of the event_spec array.
  * @ext_info:		Array of extended info attributes for this channel.
  *			The array is NULL terminated, the last element should
  *			have its name field set to NULL.
@@ -201,6 +227,8 @@ struct iio_chan_spec {
 	long			info_mask_shared_by_dir;
 	long			info_mask_shared_by_all;
 	long			event_mask;
+	const struct iio_event_spec *event_spec;
+	unsigned int		num_event_specs;
 	const struct iio_chan_spec_ext_info *ext_info;
 	const char		*extend_name;
 	const char		*datasheet_name;
@@ -283,6 +311,12 @@ struct iio_dev;
  *			is event dependant. event_code specifies which event.
  * @write_event_value:	write the value associated with the event.
  *			Meaning is event dependent.
+ * @read_event_config_new: find out if the event is enabled. New style interface.
+ * @write_event_config_new: set if the event is enabled. New style interface.
+ * @read_event_value_new: read a configuration value associated with the event.
+ *                         New style interface.
+ * @write_event_value_new: write a configuration value for the event. New style
+ *			   interface.
  * @validate_trigger:	function to validate the trigger when the
  *			current trigger gets changed.
  * @update_scan_mode:	function to configure device and scan buffer when
@@ -323,6 +357,30 @@ struct iio_info {
 	int (*write_event_value)(struct iio_dev *indio_dev,
 				 u64 event_code,
 				 int val);
+
+	int (*read_event_config_new)(struct iio_dev *indio_dev,
+				 const struct iio_chan_spec *chan,
+				 enum iio_event_type type,
+				 enum iio_event_direction dir);
+
+	int (*write_event_config_new)(struct iio_dev *indio_dev,
+				  const struct iio_chan_spec *chan,
+				  enum iio_event_type type,
+				  enum iio_event_direction dir,
+				  int state);
+
+	int (*read_event_value_new)(struct iio_dev *indio_dev,
+				const struct iio_chan_spec *chan,
+				enum iio_event_type type,
+				enum iio_event_direction dir,
+				enum iio_event_info info, int *val, int *val2);
+
+	int (*write_event_value_new)(struct iio_dev *indio_dev,
+				 const struct iio_chan_spec *chan,
+				 enum iio_event_type type,
+				 enum iio_event_direction dir,
+				 enum iio_event_info info, int val, int val2);
+
 	int (*validate_trigger)(struct iio_dev *indio_dev,
 				struct iio_trigger *trig);
 	int (*update_scan_mode)(struct iio_dev *indio_dev,
diff --git a/include/linux/iio/types.h b/include/linux/iio/types.h
index 88bf0f0d27b4..18339ef4ff5d 100644
--- a/include/linux/iio/types.h
+++ b/include/linux/iio/types.h
@@ -54,6 +54,25 @@ enum iio_modifier {
 	IIO_MOD_LIGHT_BLUE,
 };
 
+enum iio_event_type {
+	IIO_EV_TYPE_THRESH,
+	IIO_EV_TYPE_MAG,
+	IIO_EV_TYPE_ROC,
+	IIO_EV_TYPE_THRESH_ADAPTIVE,
+	IIO_EV_TYPE_MAG_ADAPTIVE,
+};
+
+enum iio_event_info {
+	IIO_EV_INFO_ENABLE,
+	IIO_EV_INFO_VALUE,
+};
+
+enum iio_event_direction {
+	IIO_EV_DIR_EITHER,
+	IIO_EV_DIR_RISING,
+	IIO_EV_DIR_FALLING,
+};
+
 #define IIO_VAL_INT 1
 #define IIO_VAL_INT_PLUS_MICRO 2
 #define IIO_VAL_INT_PLUS_NANO 3