AD7768 upstream

[jansunil]

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PR Type

• Bug fix (a change that fixes an issue)
• New feature (a change that adds new functionality)
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PR Checklist

• I have conducted a self-review of my own code changes
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• I have tested the changes on the relevant hardware
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[ahmetalincak]

Hey @jansunil. Is it possible to add a custom property to the channels for enabling/disabling it over dt overlay? For example, 'adi,enable' or 'adi,status'. It would be great to be able to manage channels without removing the whole node from dt. @nunojsa any thoughts?

[jansunil]

Changlog v1:
1) Update maintainers file to include an entry for the DT binding header
2) Move required section in the adi,ad7768.yaml after pattern properties
3) Drop '-v' in the adi,common-mode-output-v property
4) Add a better doxygen description for the CRC enable/disable function
5) Update commit message for the adi-axi-adc.c file changes
6) Update kconfig entries to use one liners wherever necessary, remove wrong addition of REGMAP_SPI in config AXI ADC
7) Use pm_ptr for pm ops
8) Modify incorrect indentation in the ad7768_driver definition
9) Remove trailing comma in the last entry in ad7768_of_match[] and ad7768_spi_id[] declaration, add spaces between {}
10) Use scoped guards from cleanup.h in relevant instances in the driver
11) Add regmap_config member in the chip_info
12) Use devm_mutex_init and devm_err_probe wherever applicable
13) Remove initialization fro prebuf1_mask_val and prebuf2_mask_val
14) Use static_assert in place of BUILD_BUG_ON()
15) Add helper functions for IIO_CHAN_INFO_CALIBBIAS and IIO_CHAN_INFO_CALIBSCALE cases
16) Add reset framework with GPIO based fallback
Wrap lines to 80 column width wherever applicable