This series adds support for the MAX40080, a bidirectional current-sense
amplifier with an integrated 12-bit ADC.
The driver is placed in IIO rather than hwmon because:
- IIO's scale/raw model naturally exposes the selectable gain ranges and
lets userspace apply the correct scale per range.
- Buffered capture support is planned for a follow-up series -- each
conversion returns a matched current+voltage pair, which maps cleanly
to IIO's buffered/triggered model.
Changes since v4:
- Initialize tmp = 0 in max40080_read_iv() before read_poll_timeout to
avoid using potentially uninitialized value in the condition check
(Sashiko, Jonathan).
- Simplify max40080_get_oversampling_ratio() to use cached value instead
of reading from the device (Jonathan).
- Remove DMA-safe buffer from struct -- I2C layer already bounces data
internally for i2c_smbus_* calls (Jonathan).
- Make shunt-resistor-micro-ohms required in DT binding. The default
1 Ohm was arbitrary and rarely correct for real hardware (Jonathan).
- Remove PM ops entirely. Having only resume without suspend was flagged
as "papering over" possible power loss issues (Jonathan).
- Remove the {} scope around propname, declare it at function top (Andy).
- Remove mod_devicetable.h include -- i2c.h provides necessary types
(Jonathan).
Changes since v3:
- Removed all regmap usage -- regmap doesn't support SMBus PEC or Quick
Command, both required by this device (Nuno).
- Fixed locking: max40080_update_bits() now takes the lock internally,
and callers update cached state after the call returns (Nuno).
- Consistent comment style: capital first letter + period (Andy).
- Use propname variable to deduplicate "shunt-resistor-micro-ohms" (Andy).
- Return IIO_VAL_* inline instead of break + return pattern (Nuno).
Changes since v2:
- Added shunt-resistor-micro-ohms DT property with default value.
- Use single-shot mode with SMBus Quick Command trigger for correlated
current/voltage reads.
- Precompute current scale per range at probe time.
Link: https://lore.kernel.org/linux-iio/20260717123852.1140893-1-stefan.popa@analog.com/ [v4]
Link: https://lore.kernel.org/linux-iio/20260715063652.368501-1-stefan.popa@analog.com/ [v3]
Link: https://lore.kernel.org/linux-iio/20260713120226.90303-1-stefan.popa@analog.com/ [v2]
Link: https://lore.kernel.org/linux-iio/20260703102941.1141341-1-stefan.popa@analog.com/ [v1]
Stefan Popa (2):
dt-bindings: iio: adc: add maxim,max40080
iio: adc: add MAX40080 current-sense amplifier driver
.../bindings/iio/adc/maxim,max40080.yaml | 56 ++
MAINTAINERS | 9 +
drivers/iio/adc/Kconfig | 11 +
drivers/iio/adc/Makefile | 1 +
drivers/iio/adc/max40080.c | 586 ++++++++++++++++++
5 files changed, 663 insertions(+)
create mode 100644 Documentation/devicetree/bindings/iio/adc/maxim,max40080.yaml
create mode 100644 drivers/iio/adc/max40080.c
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2.53.0