[PATCH v3 0/2] Add STM32H7 DAC driver

[Fabrice Gasnier]

This patchset adds support for the STM32H7 DAC controller

It's a 12-bit, voltage output digital-to-analog converter. It has two
output channels, each with its own converter, trigger sources and
waveform generator.

Each channel can be used independently, so common resources are managed
in stm32-dac-core driver (e.g. clock, reset, regulator, registers).
One IIO device is instantiated per DAC output channel, in stm32-dac
driver, so each channel can have its own trigger.

Examples, using this driver to generate DC voltage output on channel1:
# set max DC voltage / enable / min DC voltage / disable on out1
cd /sys/bus/iio/devices/iio\:device0
echo 4095 > out_voltage1_raw
echo 0 > out_voltage1_powerdown
echo 0 > out_voltage1_raw
echo 1 > out_voltage1_powerdown
cat out_voltage_powerdown_mode_available
three_state

---
Changes in v3:
- Fix powerdown mode, use 'three_state' as documented in sysfs-bus-iio
- For now, drop support for triggers & waveform generator that requires more work.
  This needs to be discussed more deeply.

Changes in v2:
- Update dt binding, use 'reg' property to select channel
- Use 'powerdown' attribute instead of 'enable'
- Added set_trigger callback
- Use 'offset' attribute in waveform generation mode to add DC offset
- rework ABI for waveform generation mode
- Various typos, comments

Fabrice Gasnier (2):
  dt-bindings: iio: stm32-dac: Add support for STM32 DAC
  iio: dac: add support for stm32 DAC

 .../devicetree/bindings/iio/dac/st,stm32-dac.txt   |  61 ++++
 drivers/iio/dac/Kconfig                            |  15 +
 drivers/iio/dac/Makefile                           |   2 +
 drivers/iio/dac/stm32-dac-core.c                   | 180 +++++++++++
 drivers/iio/dac/stm32-dac-core.h                   |  51 ++++
 drivers/iio/dac/stm32-dac.c                        | 334 +++++++++++++++++++++
 6 files changed, 643 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/iio/dac/st,stm32-dac.txt
 create mode 100644 drivers/iio/dac/stm32-dac-core.c
 create mode 100644 drivers/iio/dac/stm32-dac-core.h
 create mode 100644 drivers/iio/dac/stm32-dac.c

-- 
1.9.1