[PATCH v3 0/2] iio: dac: mcp47a1: add support for new device

This patch series adds support for the MCP47A1 DAC.

The Microchip MCP47A1 is a volatile 6-bit Digital-to-Analog converter
which communicates via I2C. It is a low-power, low-cost DAC commonly
used in embedded systems.

Reasons for adding a new driver:
- Existing Microchip DACs use a more complicated set of commands
  whereas the MCP47A1 communicates via SMBus using only one command.
- The closest Microchip DAC already in the tree - the MCP4725 - uses
  an EEPROM while the MCP47A1 is volatile, meaning that altering
  the driver of the former would worsen the code flow.
- The MCP47A1 maps cleanly to a standard regmap.

The driver was tested on a Raspberry Pi 4 using a breakout board with
the MCP47A1.

The datasheet can be viewed here:
https://ww1.microchip.com/downloads/aemDocuments/documents/OTH/ProductDocuments/DataSheets/25154A.pdf

Signed-off-by: Joshua Crofts <[email protected]>
---
Changes in v3:
- remove iio_chan_spec array and define a separate single channel as
  only one is used
- change scale denominator from 63 to 64 as former would produce scaling
  errors
- Link to v2: https://lore.kernel.org/r/20260727-mcp47a1-add-support-v2-0-d4591a2ce69e-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org

Changes in v2:
- dt-bindings: add slave address enum to dt-binding
- dt-bindings: remove unnecessary example
- move driver from regmap to i2c_smbus_* functions to reduce overhead
- remove read test on probe as it's too unstable
- add 20us delay on startup
- style changes
- remove excess mailing list entry from MAINTAINERS
- Link to v1: https://lore.kernel.org/r/20260721-mcp47a1-add-support-v1-0-da045a2567e3-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org

---
Joshua Crofts (2):
      dt-bindings: iio: dac: add support for mcp47a1
      iio: dac: mcp47a1: add support for new device

 .../bindings/iio/dac/microchip,mcp47a1.yaml        |  50 +++++++
 MAINTAINERS                                        |   6 +
 drivers/iio/dac/Kconfig                            |  10 ++
 drivers/iio/dac/Makefile                           |   1 +
 drivers/iio/dac/mcp47a1.c                          | 166 +++++++++++++++++++++
 5 files changed, 233 insertions(+)
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base-commit: e0484d62e8e1cff75b210938be835ea6221bda59
change-id: 20260711-mcp47a1-add-support-3af1248f13a5

Best regards,
-- 
Kind regards,
Joshua Crofts