drivers: dac: Add drivers for TI DAC family X311 on SPI bus

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Summary

This PR submits the device driver code for the Texas Instrument chip family DAC N311, with N indicating the resolution (see below).
These chips provide a single output channel and support "power mode" selection by reserving the two MSB values for this.
There is a single "register" that is updated with each 16-bit write to the chip via SPI.

Code Changes

The driver was code was modeled after DAC drivers for other chip families, where different resolutions are supported.

• The new Kconfig.tx311 enables the driver when a matching entry is added to the device tree;
• The new driver (dac_tx311.c) processes the device tree to set the correct resolution value;

  Chip	Resolution
  5311	8 bits
  6311	10 bits
  7311	12 bits
  8311	14 bits

• The related YAML files use a "base" file to share the configuration "schema".
• The configuration adds the property power-down-mode to set the power mode bits.

Tests

Normal Mode

This driver was developed to control the TI 6311 DAC chip that is part of an external PCB. The SPI bus was connected to a Raspberry Pico W and a sample program was created to generate a "saw tooth" signal with a period of a few seconds and the power mode set to "normal".

A oscilloscope was connected to the Vout pin of the chip to confirm the full voltage range, 0 to 3.3 V, is produced.

Resistor to GND Mode

The power mode was set to "power-down-100k" and the test program was recompiled. The DAC output shows no saw-tooth signal.

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud