Add support for LT8491

[jemfgeronimo]

Pull Request Description

The LT8491 is a buck-boost switching regulator battery charger that implements a constant-current constant-voltage (CCCV) charging profile used for most battery types, including sealed lead-acid (SLA), flooded, gel and lithium-ion.

The device operates from input voltages above, below or equal to the output voltage and can be powered by a solar panel or a DC power supply. On-chip logic provides automatic maximum power point tracking (MPPT) for solar powered applications. The LT8491 can perform automatic temperature compensation by sensing an external thermistor thermally coupled to the battery. The STATUS pin can be used to drive an LED indicator lamp. The device is available in a low profile (0.75mm) 7mm x 11mm 64-lead QFN package.

PR Type

• [ ] Bug fix (change that fixes an issue)
• [x] New feature (change that adds new functionality)
• [ ] Breaking change (has dependencies in other repos or will cause CI to fail)

PR Checklist

• [x] I have followed the Coding style guidelines
• [x] I have performed a self-review of the changes
• [x] I have commented my code, at least hard-to-understand parts
• [ ] I have build all projects affected by the changes in this PR
• [x] I have tested in hardware affected projects, at the relevant boards
• [x] I have signed off all commits from this PR
• [ ] I have updated the documentation (wiki pages, ReadMe etc), if applies

[jemfgeronimo]

V2

• moved global attributes to debug attributes
• some global attributes are now iio channel attributes
• renamed lt8491_device to lt8491_desc
• removed big comments, e.g., /*Macros and Constants Definitions*/
• modified lt8491_read_charging_stage to get int rather than char
• used uint16_t temp in lt8491_iio_reg_read()

[jemfgeronimo]

V3

• improved Overview in projects/dc2703a/README.rst
• fixed typo in projects/dc2703a/src/platform/maxim/main.c
• updated license headers to BSD 3 clause license (from ADI BSD)