drivers/imu/bmi270: Improved and extended BMI270 drivers.

[easytarget]

Summary

Two drivers for the popular BMI270 IMU

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The first replaces the existing bmi270 driver with a updated version using a much smaller device configuration and timings. This results in a 'drop in' replacement driver that is 25x faster to load and 5x smaller in size.

• The existing driver loads a 8Kb 'full configuration' during init via I2C with extremely conservative timings, taking over 2 seconds to load.
• This new version now uses a minimal (340b) configuration with an improved uploader which respects the Bosch specified timings, and can upload partial config fragments.
• These 'device configurations' are actually the ASIC firmware for the sensor unit; Bosch provide several different public configurations with feature sets for specific scenarios.

In addition this version of the driver has been extended to allow sensor scaling and data rates to be adjusted after init.

• The device powersave modes can also now be set.
• It also and exposes the internal temperature sensor.

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The second is a a greatly extended bmi270_legacy driver; this uses the 'legacy' device config from Bosch.

• This has all the features of the basic driver
• Adds many Tablet and Phone related features:
  • Orientation, Motion, Drop detection, Step counting, Tap detection and more.
  • Allows setting and detecting interrupts based on the above features
• It is larger than the original driver but due to improved upload timings still has a fast init() time.

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Both drivers have extensive in-line documentation; dedicated examples and extended README files

This is based on the work I did earlier this year here: https://codeberg.org/easytarget/bmi270-micropython

Testing

Both of these drivers have been extensively tested during development on a M5Stack Tab5 (ESP32P4 based) which has a BMI270 device on board.

Generative AI

I did not use generative AI tools when creating this PR.