[PATCH v9 00/11] iio: accel: adxl345: add interrupt based sensor events

[Lothar Rubusch <l.rubusch@gmail.com>]

Add several interrupt based sensor detection events:
- refactoring and fixes
- activity
- inactivity
- documentation

In brief, this implementation uses the inactivity registers for inactivity
events with a period >1s. For a configured period <1s the free-fall
registers will be used. The related features, such as setting the link-bit,
auto-sleep, the AC-coupling events, etc. are turned on/off accordingly. For
instance, activity and inactivity enabled imply a link-bit set. Disabling
one, removes the link-bit. Setting e.g. activity AC with inactivity DC, sets
the link bit and so on.

Due to several items found for the ADXL313, I tried to apply those refacs
here as well. I'm still unsure, if I should rathe wrap them up in one big
refac patch or keep them separated by the items as I tried here.

By the number of possible combinations of configurations and their
verification, as additionally the refactorings - I implemented an automated
verification by a labgrid/pytest setup with over 300 test steps and hardware
in the loop. Hopefully the setup is mostly correct. Further I extended the
codespell githook by an ispell check (which gave better results).

Let's see how good that works out. Somehow I'm sure you guys will (still)
find something...

Signed-off-by: Lothar Rubusch <l.rubusch@gmail.com>
---
v8 -> v9:
- githook: apply codespell checks, extend by spellcheck using ispell
- refac: apply `regmap_assing_bits()` in several places
- refac: remove ADXL345_POWER_CTL_STANDBY in adxl345.h not needed anymore
- refac: rename `ADXL345_ACT_INACT_DC/AC` to `ADXL345_COUPLING_DC/AC`
- refac: remove variable irq from `struct adxl345_state`
- refac: apply expressions, such as MILLI or MICRO from linux/units.h
- refac: apply (missing) scaling factor 62.5mg/LSB to tap detection
- change `IIO_EV_TYPE_MAG_REFERENCED` to `IIO_EV_TYPE_MAG_ADAPTIVE`
- `adxl345_fifo_transfer()`: eliminate variable for expression count / 2
- `adxl345_is_act_inact_ac()`: make return boolean, or negative error
- make activity enable cover x, y and z axis together, while signals come
  on particular axis
- `adxl345_read_mag_value()`: separate `MAG` and `MAG_ADAPTIVE` event
  value read and write function to reduce redundant code
- `adxl345_read_mag_config()`: separate `MAG` and `MAG_ADAPTIVE` event
  config read and write functions to reduce redundant code
- `adxl345_set_act_inact_en()`: move linkbit detection out to
  `adxl345_set_act_inact_linkbit()`
- `adxl345_set_act_inact_en()`: fix unsetting register INT ENABLE at
  disabling feature(s)
- apply scaling factor 62.5mg/LSB to activity/inactivity
- apply scaling factor 62.5mg/LSB to activity AC/inactivity AC
- drop dedicated freefall patch
- add patch: fix missing scale factor for tap detection
- add patch: make irq a function local variable
- add patch: simplify measure enable
- add patch: simplify interrupt mapping
- add patch: simplify FIFO reading
- add patch: replace magic numbers by unit expressions
- rename `adxl345_set_inact_time_s()` to `adxl345_set_inact_time()`
- `adxl345_set_inact_time()`: implement inactivity using inactivity
  register (period 1s or higher), freefall register (below 1s) or let it
  setup a period based on given ODR (0s provided)
- doc: update documentation

v7 -> v8:
- activity/inactivity are MAG events
- separate AC coupled activity/inactivity events as MAG_REFERENCED events,
  since AC coupling introduces a (some kind of) reference relation
- since freefall and inactivity (DC coupled) are then actually identical,
  this results in a challenging situation for the freefall patch. Thus,
  the freefall patch is moved to end of this series (before documentation)
- freefall: provide separate sysfs handles to configure and enable freefall
- documentation: update sections on activity/inactivity, freefall, event
  names and examples

v6 -> v7:
- freefall: add a virtual channel, replace OR'ing the axis by AND'ing them
- inactivity: add a virtual channel, replace OR'ing the axis by AND'ing them

v5 -> v6:
- replace bool axis_en for tap and activity/inactivity
- apply freefall bit mask
- change `measure_en` to use `regmap_update_bits()` for POWER_CTL register
- fix comments and update documentation, particularly on inactivity time

v4 -> v5:
- read_config_value() and write_config_value() now use direct returns,
  in case of a failure, measurement stays turned off
- fifo evaluation returns 0 in case of success
- axis enum turned into three different set of defines for tap, act and inact
- turn the suppress bit into a separate define macro
- variable naming, generally use axis_ctrl for similar variables

v3 -> v4:
- rename patch "add double tap suppress bit" to
  "set the tap suppress bit permanently" to make it more comprehensive
- added patch "cleanup regmap return values"
- added patch "introduce adxl345_push_event function", as a solution
  to the return value problem, group all int_stat evaluating pieces
  in the same function
- tap, act and inact axis enabling are using now regmap cache
- activity enable depending on individual axis now, as the sensor offers
  such feature
- inactivity enable depending on individual axis now, as the sensor offers
  such feature
- fix bug in previous patch: separate axis direction in interrupt handler
  sharing the same variable for tap and activity, if tap and activity
  enabled together
- refac of the direction identification of previous patch: only read
  act/tap axis once now in interrupt handler if both is enabled
- fix bug in previous patch: return value of pushed event in interrupt
  handler
- several cleanups

v2 -> v3:
- generally introduction of regmap cache for all directly stored 8-bit
  values, specification of volatile regs and cleanup
- moving thresholds, unchanged values and flags to regmap cache, in
  consequence removal of corresponding member values of the state
  instance
- removal of intio and int_map member fields due to regmap cache, thus
  split of set_interrupts() patches in two parts
- rework documentation
- rework of ac-bit comment

v1 -> v2:
- implementation of all events (but tap2 suppress bit) by means IIO ABI
- add sample frequency / ODR configuration
- add g ranges configuration
- add activity/inactivity using auto-sleep and powersave
- add dynamic adjustment of default values for
  activity/inactivity thresholds and time for inactivity based on ODR
  and g range (can be overwritten)
- add sensor documentation
---
Lothar Rubusch (11):
  iio: accel: adxl345: apply scale factor to tap threshold
  iio: accel: adxl345: make data struct variable irq function local
  iio: accel: adxl345: simplify measure enable
  iio: accel: adxl345: simplify interrupt mapping
  iio: accel: adxl345: simplify reading the FIFO
  iio: accel: adxl345: replace magic numbers by unit expressions
  iio: accel: adxl345: add activity event feature
  iio: accel: adxl345: add inactivity feature
  iio: accel: adxl345: add coupling detection for activity/inactivity
  iio: accel: adxl345: extend inactivity time for less than 1s
  docs: iio: add documentation for adxl345 driver

 Documentation/iio/adxl345.rst    | 429 +++++++++++++++++
 Documentation/iio/index.rst      |   1 +
 drivers/iio/accel/adxl345.h      |   1 -
 drivers/iio/accel/adxl345_core.c | 793 +++++++++++++++++++++++++++++--
 4 files changed, 1195 insertions(+), 29 deletions(-)
 create mode 100644 Documentation/iio/adxl345.rst

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2.39.5