Changes from v1 -> v2:

 - Rebase from 6.0 to 6.1-rc2 to get access to devm_regulator_get_enable.
 - Use regmap instead of raw SPI commands. This fixes multiple issues:
   - Remove need to assemble register address using bit shifts.
   - Remove non DMA-safe stack-allocated buffers.
   - Regmap has internal lock handling, removing the need for locking in the
     driver read code using mlock.
 - Use be16_to_cpu() instead of manually assembling values using bit shifts.
 - Use generic device_property_read_u32() instead of devicetree specific
   of_property_read_u32().
 - Rename the "shunt-resistor" devicetree property to
   "shunt-resistor-micro-ohms".
 - Add supply regulator support for the two voltage domains of the chip
   (vdd and vdig).
 - Only perform soft reset if no GPIO line for hard resets is available.
 - Change the error returned if the device does not respond after a reset
   from "EBUSY" to "ENXIO" to indicate that this is likely a persistent
   error (like a broken connection).
 - Don't set the SPI mode manually.
 - Provide a spi_device_id table.
 - Declare local variables in reverse christmas tree order.
 - Fix formatting of multi-line comments and some whitespace issues.
 - Fix typos and missing "allOf:$ref to spi-peripheral-props.yaml"
   in devicetree bindings.

See https://lore.kernel.org/lkml/20221004134238.3144326-1-l.goehrs@pengutronix.de/
for the v1.
 
Thanks to Marcus, Jonathan and Krzysztof for the reviews.