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path: root/drivers/iio/adc/ad7944.c
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2025-06-27iio: adc: ad7944: mask high bits on direct readDavid Lechner
commit 7cdfbc0113d087348b8e65dd79276d0f57b89a10 upstream. Apply a mask to the raw value received over the SPI bus for unsigned direct reads. As we found recently, SPI controllers may not set unused bits to 0 when reading with bits_per_word != {8,16,32}. The ad7944 uses bits_per_word of 14 and 18, so we need to mask the value to be sure we returning the correct value to userspace during a direct read. Fixes: d1efcf8871db ("iio: adc: ad7944: add driver for AD7944/AD7985/AD7986") Signed-off-by: David Lechner <dlechner@baylibre.com> Reviewed-by: Nuno Sá <nuno.sa@analog.com> Link: https://patch.msgid.link/20250505-iio-adc-ad7944-max-high-bits-on-direct-read-v1-1-b173facceefe@baylibre.com Cc: <Stable@vger.kernel.org> Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-05-29iio: adc: ad7944: don't use storagebits for sizingDavid Lechner
[ Upstream commit 503d20ed8cf7c7b40ec0bd94f53c490c1d91c31b ] Replace use of storagebits with realbits for determining the number of bytes needed for SPI transfers. When adding SPI offload support, storagebits will always be 32 rather than 16 for 16-bit 16-bit chips so we can no longer rely on storagebits being the correct size expected by the SPI framework (it always uses 4 bytes for > 16-bit xfers and 2 bytes for > 8-bit xfers). Instead, derive the correct size from realbits since it will always be correct even when SPI offloading is used. Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Reviewed-vy: Nuno Sa <nuno.sa@analog.com> Signed-off-by: David Lechner <dlechner@baylibre.com> Link: https://patch.msgid.link/20250207-dlech-mainline-spi-engine-offload-2-v8-10-e48a489be48c@baylibre.com Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-06-30iio: adc: ad7944: use devm_spi_optimize_message()David Lechner
Use new devm_spi_optimize_message() helper to simplify repeated code in the ad7944 driver. Signed-off-by: David Lechner <dlechner@baylibre.com> Link: https://patch.msgid.link/20240624-devm_spi_optimize_message-v3-2-912138c27b66@baylibre.com Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
2024-06-22iio: adc: ad7944: use devm_regulator_get_enable_read_voltageDavid Lechner
This makes use of the new devm_regulator_get_enable_read_voltage() function to reduce boilerplate code. Signed-off-by: David Lechner <dlechner@baylibre.com> Reviewed-by: Nuno Sa <nuno.sa@analog.com> Link: https://patch.msgid.link/20240612-iio-adc-ref-supply-refactor-v2-5-fa622e7354e9@baylibre.com Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
2024-06-04iio: adc: ad7944: remove unused parameterDavid Lechner
In the ad7944 driver, the ad7944_convert_and_acquire() had an unused `chan` parameter. This patch removes the parameter. Signed-off-by: David Lechner <dlechner@baylibre.com> Link: https://lore.kernel.org/r/20240524-iio-ad7944-remove-unused-parameter-v1-1-fd824d7122a0@baylibre.com Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
2024-04-29iio: adc: ad7944: add support for chain modeDavid Lechner
This adds support for the chain mode of the AD7944 ADC. This mode allows multiple ADCs to be daisy-chained together. Data from all of the ADCs in is read by reading multiple words from the first ADC in the chain. Each chip in the chain adds an extra IIO input voltage channel to the IIO device. Only the wiring configuration where the SPI controller CS line is connected to the CNV pin of all of the ADCs in the chain is supported in this patch. Signed-off-by: David Lechner <dlechner@baylibre.com> Link: https://lore.kernel.org/r/20240425-iio-ad7944-chain-mode-v1-1-9d9220ff21e1@baylibre.com Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
2024-04-13iio: adc: ad7944: Consolidate spi_sync() wrapperDavid Lechner
Since commit 6020ca4de8e5 ("iio: adc: ad7944: use spi_optimize_message()"), The helper functions wrapping spi_sync() for 3-wire and 4-wire modes are virtually identical. Since gpiod_set_value_cansleep() does a NULL check internally, we can consolidate the two functions into one and avoid switch statements at the call sites. The default cases of the removed switch statement were just to make the compiler happy and are not reachable since the mode is validated in the probe function. So removing those should be safe. Signed-off-by: David Lechner <dlechner@baylibre.com> Link: https://lore.kernel.org/r/20240412-ad7944-consolidate-msg-v1-1-7fdeff89172f@baylibre.com Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
2024-03-30iio: adc: ad7944: use spi_optimize_message()David Lechner
This modifies the ad7944 driver to use spi_optimize_message() to reduce CPU usage and increase the max sample rate by avoiding repeating validation of the spi message on each transfer. Signed-off-by: David Lechner <dlechner@baylibre.com> Link: https://lore.kernel.org/r/20240328-ad7944-spi-optimize-message-v2-1-a142b2576379@baylibre.com Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
2024-03-28iio: adc: ad7944: simplify adi,spi-mode property parsingDavid Lechner
This simplifies the adi,spi-mode property parsing by using device_property_match_property_string() instead of two separate functions. Also, the error return value is now more informative in cases where there was a problem parsing the property. Suggested-by: Andy Shevchenko <andy.shevchenko@gmail.com> Signed-off-by: David Lechner <dlechner@baylibre.com> Link: https://lore.kernel.org/r/20240325-ad7944-cleanups-v3-1-3a19120cdd06@baylibre.com Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
2024-03-25iio: adc: ad7944: Add support for "3-wire mode"David Lechner
This adds support for AD7944 ADCs wired in "3-wire mode". (NOTE: 3-wire is the datasheet name for this wiring configuration and has nothing to do with SPI_3WIRE.) In the 3-wire mode, the SPI controller CS line can be wired to the CNV line on the ADC and used to trigger conversions rather that using a separate GPIO line. The turbo/chain mode compatibility check at the end of the probe function is technically can't be triggered right now but adding it now anyway so that we don't forget to add it later when support for daisy-chaining is added. Reviewed-by: Nuno Sa <nuno.sa@analog.com> Signed-off-by: David Lechner <dlechner@baylibre.com> Link: https://lore.kernel.org/r/20240314-mainline-ad7944-3-wire-mode-v2-1-d469da0705d2@baylibre.com Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
2024-03-25iio: adc: ad7944: add driver for AD7944/AD7985/AD7986David Lechner
This adds a driver for the Analog Devices Inc. AD7944, AD7985, and AD7986 ADCs. These are a family of pin-compatible ADCs that can sample at rates up to 2.5 MSPS. The initial driver adds support for sampling at lower rates using the usual IIO triggered buffer and can handle all 3 possible reference voltage configurations. Signed-off-by: David Lechner <dlechner@baylibre.com> Reviewed-by: Nuno Sa <nuno.sa@analog.com> Link: https://lore.kernel.org/r/20240304-ad7944-mainline-v5-2-f0a38cea8901@baylibre.com Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>