[PATCH v3 0/2] add support for MCP998X

[<victor.duicu@microchip.com>]

From: Victor Duicu <victor.duicu@microchip.com>

Add support for Microchip MCP998X/33 and MCP998XD/33D
Multichannel Automotive Temperature Monitor Family.

The chips in the family have different numbers of external
channels, ranging from 1 (MCP9982) to 4 channels (MCP9985).
Reading diodes in anti-parallel connection is supported
by MCP9984/85/33 and MCP9984D/85D/33D.
Dedicated hardware shutdown circuitry is present only
in MCP998XD and MCP9933D.

Current version of driver does not support interrupts, events and data
buffering.

Differences related to previous patch:
v3:
- move beta parameters to devicetree.
- change the name of the interrupts and add
  check to match them to the device in yaml.
- remove label for device and remove "0x" from
  channel registers in example in yaml.
- edit comments in yaml and driver.
- add minItems to interrupts in yaml.
- rename microchip,recd12 and microchip,recd34 to
  microchip,resistance-comp-ch1-2-enable
  and microchip,resistance-comp-ch3-4-enable.
- rename microchip,apdd-state to microchip,enable-anti-parallel.
- add static to mcp9982_3db_values_map_tbl to fix
  kernel test robot warning.
- in mcp9982_init() add check to ensure that hardware
  shutdown feature can't be overridden.
- replace div_u64_rem with do_div and add
  asm/div64.h to includes.
- remove unused includes.
- add iio_chan_spec in the macro definition of MCP9982_CHAN.
- remove MCP9982_EXT_BETA_ENBL.
- in mcp9982_init() replace regmap_assign_bits
  with regmap_write when setting beta compensation.
- remove custom attribute enable_extended_temp_range and
  map it to IIO_CHAN_INFO_OFFSET.
- add unsigned to int variables that allow it.
- reorder parameters in mcp9982_priv, change some
  from int to bool, add const to labels and add dev_name.
- add check for chips with "D" in the name to not
  allow sampling frequencies lower than 1 to
  prevent overriding of hardware shutdown.
- remove mcp9982_attributes.
- move mcp9982_calc_all_3db_values() to before
  mcp9982_init().
- use MICRO instead of number constant.
- in mcp9982_write_raw replace ">=" with "==".
- rename index2 to idx in mcp9982_read_raw().
- remove i2c_set_clientdata() in mcp9982_probe().
- since there are no more custom ABI attributes
  the testing file was removed.

v2:
- move hysteresis, extended temperature range and beta parameters
  from devicetree into user space.
- edit comments in yaml and driver.
- remove "|" in descpriptions, remove "+" from PatternProperties in yaml.
- add default to microchip,ideality-factor, delete blank lines and wrap to
  80 chars in yaml.
- remove variables with upper case.
- add check for microchip,apdd-state and microchip,recd34 in yaml.
- improve coding style in driver code.
- add includes for all functions used.
- rename MCP9982_INT_HIGH_BYTE_ADDR to MCP9982_INT_VALUE_ADDR and
  MCP9982_INT_LOW_BYTE_ADDR to MCP9982_FRAC_VALUE_ADDR.
- remove custom attribute running_average_window and
  running_average_window_available and map them to a low pass filter.
- update sysfs-bus-iio-temperature-mcp9982 to reflect current
  driver attributes and point to next kernel version (6.17).
- use compound literal to define driver channels.
- replace device_property_read_string() with i2c_get_match_data() to read
  chip name from devicetree.
- remove MCP9982_DEV_ATTR and mcp9982_prep_custom_attributes().
- remove client, chip_name, iio_info from mcp9982_priv.
- replace sprintf() with sysfs_emit().
- remove error messages which are triggered by keyboard input.
- replace devm_kzalloc() with devm_kcalloc(), array mcp9982_chip_config[] with
  individual structures, device_property_present() with device_property_read_bool().
- reordered parameters in mcp9982_features and mcp9982_priv to optimize memory
  allocation.
- remove .endianness from channel properties.
- change name of some parameters in mcp9982_priv.
- add check for reg value 0 from devicetree (channel 0 is for internal temperature
  and can't be disabled).

v1:
- inital version.

Victor Duicu (2):
  dt-bindings: iio: temperature: add support for MCP998X
  iio: temperature: add support for MCP998X

 .../iio/temperature/microchip,mcp9982.yaml    | 211 +++++
 MAINTAINERS                                   |   7 +
 drivers/iio/temperature/Kconfig               |  10 +
 drivers/iio/temperature/Makefile              |   1 +
 drivers/iio/temperature/mcp9982.c             | 778 ++++++++++++++++++
 5 files changed, 1007 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/iio/temperature/microchip,mcp9982.yaml
 create mode 100644 drivers/iio/temperature/mcp9982.c


base-commit: 0c86e33819785fe50616b6ee3fb35c1e4be406d5
-- 
2.48.1