[PATCH v4 00/11] iio: accel: adxl313: add power-save on activity/inactivity

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

The patch set covers the following topics:
- add debug register and regmap cache
- prepare iio channel scan_type and scan_index
- prepare interrupt handling
- implement fifo with watermark
- add activity/inactivity together with auto-sleep with link bit
- add ac coupled activity/inactivity, integrate with auto-sleep and link bit
- documentation

Since activity and inactivity here are implemented covering all axis, I
assumed x&y&z and x|y|z, respectively. Thus the driver uses a fake
channel for activity/inactiviy. AC-coupling is similar to other Analog Device
accelerometers, so MAG_ADAPTIVE events are chosen. Combinations are
documented and functionality tested and verified working.

Signed-off-by: Lothar Rubusch <l.rubusch@gmail.com>
---
v3 -> v4:
- squash patches [v3 02/12 + 03/12]: buffer usage into the patch that adds buffered support
- squash patches [v3 07/12 + 08/12]: interrupt handler with watermark implementation
- add patch: (in)activity / AC coupled as `MAG_ADAPTIVE` event
- `ADXL313_MEASUREMENT_MODE`: adjust commit message on removal of define and adding measurement enable function
- remove irq variable from driver data struct, make it a local variable
- `adxl313_core_probe()`: flip logic to condition `int_line != ADXL313_INT_NONE`
- `adxl313_core_probe()`: change mapping interrupts from 0xff to an explicit local mask
- `adxl313_core_probe()`: add comment on FIFO bypass mode
- reduce odd selection of headers to add [`adxl313_core.c`]
- `adxl313_set_fifo()`: this function was turning measurement off/on before changing `fifo_mode`,
   called in postenable and predisable this firstly excluded setting of interrupts, and secondly
   still configured watermark where unnecessary, this function was thus removed (covers unhandled
   return value, and refactoring of function parameters)
- `adxl313_fifo_transfer()`: simplify computation of `sizeof(i*count/2)`
- `adxl313_irq_handler()`: make call of `adxl313_reset_fifo()` conditional to OVERRUN one patch earlier
- includes: rework adding included headers
- activity: change to work with or'd axis and related changes to the fake channel and arrays
- `adxl313_set_act_inact_en()`: generally turn off measurement when adjusting config
  activity/inactivity related config registers, turn measurement on after
- doc: adjust code block highlighting and remove links

v2 -> v3:
- verify keeping trailing comma when it's multi-line assignment [v1 02/12]
- `adxl313_set_fifo()`: verify have two on one line to make it easier to read [v1 07/12]
- `adxl313_fifo_transfer()`: verify removal of useless initialization of ret [v1 07/12]
- `adxl313_fifo_transfer()`: verify usage of array_size() from overflow.h [v1 07/12]
- `adxl313_fifo_transfer()`: verify return 0 here [v1 07/12]
- `adxl313_irq_handler()`: verify "Why do we need the label?" / moving the call under the conditional [v1 07/12]
- verify reorganization of half condition for Activity [v1 09/12] and Inactivity [v1 10/12]
- verify usage of MICRO instead of 1000000
- `adxl313_is_act_inact_en()`: restructure according to return logic value, or negative error
- `adxl313_set_act_inact_en()`: restructure function, use regmap_assign_bits()
- `adxl313_set_act_inact_en()`: verify makeing it a logical split [v1 11/12]
- `adxl313_fifo_transfer()`: change iterator variable type from int to unsigned int [v2 07/12]
- `adxl313_fifo_reset()`: add comment on why reset status registers does not do error check ("At least comment...") [v2 07/12]
- `adxl313_fifo_push()`: change iterator variable from int to unsigned int [v2 08/12]
- `adxl313_fifo_push()`: remove duplicate check for samples being <0 [v2 08/12]
- apply `regmap_assign_bits()` in several places to replace regmap_update_bits() depending on bools
- `adxl313_set_watermark()`: rename mask variable to make it more comprehensive
- removal of duplicate blanks in various places (sry, my keyboard died) [v1 07/12]

v1 -> v2:
- usage of units.h
- simplify approach for return values
---
Lothar Rubusch (11):
  iio: accel: adxl313: add debug register
  iio: accel: adxl313: introduce channel buffer
  iio: accel: adxl313: make use of regmap cache
  iio: accel: adxl313: add function to enable measurement
  iio: accel: adxl313: prepare interrupt handling
  iio: accel: adxl313: add basic interrupt handling for FIFO watermark
  iio: accel: adxl313: add activity sensing
  iio: accel: adxl313: add inactivity sensing
  iio: accel: adxl313: implement power-save on inactivity
  iio: accel: adxl313: add AC coupled activity/inactivity events
  docs: iio: add ADXL313 accelerometer

 Documentation/iio/adxl313.rst    | 289 ++++++++++
 Documentation/iio/index.rst      |   1 +
 drivers/iio/accel/adxl313.h      |  33 +-
 drivers/iio/accel/adxl313_core.c | 905 ++++++++++++++++++++++++++++++-
 drivers/iio/accel/adxl313_i2c.c  |   6 +
 drivers/iio/accel/adxl313_spi.c  |   6 +
 6 files changed, 1229 insertions(+), 11 deletions(-)
 create mode 100644 Documentation/iio/adxl313.rst

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2.39.5