lwn.git/drivers/iio/dac, branch master

iio: dac: ad5686: fix powerdown control on dual-channel devices

2026-05-15T11:05:35+00:00

Fix powerdown control by using a proper bit shift for the powerdown mask values. During initialization, powerdown bits are initialized so that unused bits are set to 1 and the correct bit shift is used. Dual-channel devices use one-hot encoding in the address and that reflects on the position of the powerdown bits, which are not channel-index based for that case. Quad-channel devices also use one-hot encoding for the channel address but the result of log2(address) coincides with the channel index value. Mask as 0x3U is used rather than 0x3, because shift can reach value of 30 (last channel of a 16-channel device), which would mess with the sign bit. The issue was introduced when first adding support for dual-channel devices, which overlooked powerdown control differences. Fixes: 7dc8faeab3e3 ("iio: dac: ad5686: add support for AD5338R") Signed-off-by: Rodrigo Alencar Cc: Signed-off-by: Jonathan Cameron

iio: dac: ad5686: acquire lock when doing powerdown control

2026-05-15T11:05:35+00:00

Protect access of pwr_down_mode and pwr_down_mask fields with existing mutex lock. Each channel exposes their own attributes for controlling powerdown modes and powerdown state. This fixes potential race conditions as those the write functions perform non-atomic read-modify-write operations to those pwr_down_* fields. This issue exists since the ad5686 driver was first introduced. Fixes: c2f37c8dcadc ("iio: dac: New driver for AD5686R, AD5685R, AD5684R Digital to analog converters") Signed-off-by: Rodrigo Alencar Cc: Signed-off-by: Jonathan Cameron

iio: dac: ad3530r: Fix AD3531/AD3531R powerdown mode strings

2026-05-15T11:05:35+00:00

The AD3531/AD3531R has different output operating modes from the AD3530/AD3530R. According to the AD3531/AD3531R datasheet, the powerdown modes are: 01: 500 Ohm output impedance 10: 3.85 kOhm output impedance 11: 16 kOhm output impedance The driver currently uses the AD3530R modes (1k, 7.7k, 32k) for all variants, which is incorrect for AD3531/AD3531R. Add AD3531R-specific powerdown mode strings and assign them to the AD3531/AD3531R chip variants. Fixes: 93583174a3df ("iio: dac: ad3530r: Add driver for AD3530R and AD3531R") Signed-off-by: Kim Seer Paller Cc: Signed-off-by: Jonathan Cameron

iio: dac: ad5686: fix input raw value check

2026-05-15T11:05:34+00:00

Fix range check for input raw value, which is off by one, i.e., for a 10-bit DAC the max valid value is 1023, but 1 << 10 equals 1024, which passes the previous check, allowing an out-of-range write. The issue exists since the ad5686 driver was first introduced. Fixes: c2f37c8dcadc ("iio: dac: New driver for AD5686R, AD5685R, AD5684R Digital to analog converters") Reviewed-by: Andy Shevchenko Signed-off-by: Rodrigo Alencar Cc: Signed-off-by: Jonathan Cameron

iio: dac: ad5686: fix ref bit initialization for single-channel parts

2026-05-15T11:05:34+00:00

The reference bit position was ignored when writing the register at the probe() function (!!val was used). When such bit is 1, internal voltage reference is disabled so that an external one can be used. For multi-channel devices, bit 0 of the Internal Reference Setup command behaves the same way, so AD5686_REF_BIT_MSK is created. The issue exists since support for single-channel devices were first introduced. Fixes: be1b24d24541 ("iio:dac:ad5686: Add AD5691R/AD5692R/AD5693/AD5693R support") Reviewed-by: Andy Shevchenko Signed-off-by: Rodrigo Alencar Cc: Signed-off-by: Jonathan Cameron

iio: dac: max5821: fix return value check in powerdown sync

2026-05-15T11:05:34+00:00

The function max5821_sync_powerdown_mode() returned the result of i2c_master_send() directly. If a partial transfer occurred, it would be incorrectly treated as a success by the caller. While the caller currently handles the positive return value of 2 as success, this patch refactors the function to return 0 on full success and -EIO on short writes. This ensures robust error handling for incomplete transfers and improves code maintainability by using sizeof(outbuf). Fixes: 472988972737 ("iio: add support of the max5821") Signed-off-by: Salah Triki Reviewed-by: Andy Shevchenko Cc: Signed-off-by: Jonathan Cameron

Merge tag 'v7.0-rc7' into char-misc-next

2026-04-06T07:04:53+00:00

We need the char/misc/iio/comedi fixes in here as well for testing Signed-off-by: Greg Kroah-Hartman

iio: dac: ds4424: add Rfs-based scale and per-variant limits

2026-03-22T12:44:23+00:00

Parse optional maxim,rfs-ohms values to derive the per-channel output current scale (mA per step) for the IIO current ABI. Behavior changes: - If maxim,rfs-ohms is present, IIO_CHAN_INFO_SCALE becomes available and reports mA/step derived from Rfs. - If maxim,rfs-ohms is missing, SCALE is not exposed to keep older DTs working without requiring updates. Signed-off-by: Oleksij Rempel Reviewed-by: Andy Shevchenko Signed-off-by: Jonathan Cameron

iio: dac: ds4424: convert to regmap

2026-03-22T12:44:23+00:00

Refactor the driver to use the regmap API. Replace the driver-specific mutex and manual shadow buffers with the standard regmap infrastructure for locking and caching. This ensures the cache is populated from hardware at probe, preventing state desynchronization (e.g. across suspend/resume). Define access tables to validate the different register maps of DS44x2 and DS44x4. Signed-off-by: Oleksij Rempel Reviewed-by: Sander Vanheule Reviewed-by: Andy Shevchenko Signed-off-by: Jonathan Cameron

iio: dac: ds4424: support per-variant output range limits

2026-03-22T12:43:48+00:00

The DS4402/DS4404 variants operate with a 5-bit resolution (31 steps), whereas the DS4422/DS4424 support 7-bit (127 steps). Previously, the driver enforced a hardcoded 7-bit mask (DS4424_DAC_MASK) for all variants. This allowed users to write values exceeding the 5-bit range to DS4402/DS4404 devices, resulting in silent truncation or undefined behavior. Add a `result_mask` field to the chip_info structure to define the valid data range for each variant. Use this mask to: 1. Correctly mask register values in read_raw(). 2. Return -EINVAL in write_raw() if the input value exceeds the variant's capabilities. Signed-off-by: Oleksij Rempel Reviewed-by: Andy Shevchenko Signed-off-by: Jonathan Cameron