In HID sensor hub, HID physical ids are used to represent different sensors.
For example physical id of 0x73 in usage page = 0x20, represents an
accelerometer. The HID sensor hub driver uses this physical ids to create
platform devices using MFD. There is 1:1 correspondence between an phy id and a
client driver.

But in some cases these physical ids are reused. There is a phy id 0xe1, which
specifies a custom sensor, which can exist multiple times to represent various
custom sensors. In this case there can be multiple instances of client MFD
drivers, processing specific custom sensor. In this case when client driver
looks for report id or a field index, it should still get the report id
specific to its own type. This is also true for reports, they should be
directed towards correct instance.  This change introduce a way to parse and
tie physical devices to their correct instance.

Summary of changes:
- To get physical ids, use collections. If a collection of type=physical
  exist then use usage id as in the name of platform device name
- As part of the platform data, we assign a hdsev instance, which has
  start and end of collection indexes. Using these indexes attributes
  can be tied to correct MFD client instances
- When a report is received, call callback with correct hsdev instance.
  In this way using its private data stored as part of its registry, it
  can distinguish different sensors even when they have same physical and
  logical ids.

  This patch is co-authored with Archana Patni <archna.patni@intel.com>.
Reported-by: NArchana Patni <archana.patni@intel.com>
Signed-off-by: NSrinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: NArchana Patni <archana.patni@intel.com>
Signed-off-by: NJiri Kosina <jkosina@suse.cz>

In some report descriptors, they leave holes in the selectors. In
this case if we use hardcoded selector values, this will result
in invalid values. For example, if there is selectors defined for
Power State from OFF to D0 to D3. We can't use indexes of these states
if some states are not implemented or not present in the report decriptors.
In this case, we need to get the indexes from report descriptors.

One API is added to get the index of a selector. This API will
search for usage id in the field usage list and return the index.
Signed-off-by: NSrinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: NJiri Kosina <jkosina@suse.cz>

Exporting logical minimum and maximum of HID fields as part of the
hid sensor attribute info. This can be used for range checking and
to calculate enumeration base for NAry fields of HID sensor hub.
Signed-off-by: NSrinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>

We can't store the trigger instance created by iio_trigger_alloc, in
trig field of iio_device structure. This needs to be stored in the
driver private data. Othewise it can result in crash during module
unload. Hence created a trig_ptr in the common data structure
for each HID sensor IIO driver and storing here.
Signed-off-by: NSrinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>

Don't call hid_open_device till there is actually an user. This saves
power by not opening underlying transport for HID. Also close device
if there are no active mfd client using HID sensor hub.
Signed-off-by: NSrinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: NJiri Kosina <jkosina@suse.cz>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>

This patch fixes the style of the comments to be like following
	/* The commentary */

There is no functional change.
Signed-off-by: NAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: NJiri Kosina <jkosina@suse.cz>

The structure with common attributes for hid-sensors isn't specific
to the iio-subsystem, so rename it to hid_sensor_common.
Signed-off-by: NAlexander Holler <holler@ahsoftware.de>
Acked-by: NJiri Kosina <jkosina@suse.cz>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>

The stuff in hid-sensor-attributes.h is needed by every piece which
uses hid-sensor-hub and merging it into hid-sensor-hub.h makes it accessible
from outside the iio subdirectory.
Signed-off-by: NAlexander Holler <holler@ahsoftware.de>
Acked-by: NJiri Kosina <jkosina@suse.cz>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>

Adding processing for HID Sensor usage table as defined by
HID 1.12, Request #: HUTRR39, dated 05 May, 2011.
This driver uses HID driver framework to register, send and
receive events.
This uses MFD framework, so that actual processing for a
specific usage id can be done in a different driver. For
example an accelerometer driver can be a separate driver and
use the interface provided by this driver to register for
events.
Signed-off-by: Nsrinivas pandruvada <srinivas.pandruvada@intel.com>
Signed-off-by: NJiri Kosina <jkosina@suse.cz>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>