Rename AD4695_MAX_CHANNELS to AD4695_MAX_VIN_CHANNELS. It has been a
point of confusion that this macro is only the voltage input channels
and not all channels.
Reviewed-by: Trevor Gamblin <tgamblin@baylibre.com>
Reviewed-by: Nuno Sá <nuno.sa@analog.com>
Signed-off-by: David Lechner <dlechner@baylibre.com>
Link: https://patch.msgid.link/20250507-iio-introduce-iio_declare_buffer_with_ts-v6-4-4aee1b9f1b89@baylibre.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Use IIO_DECLARE_DMA_BUFFER_WITH_TS() to declare the buffer that gets
used with iio_push_to_buffers_with_ts(). This makes the code a bit
easier to read and understand.
Reviewed-by: Trevor Gamblin <tgamblin@baylibre.com>
Reviewed-by: Nuno Sá <nuno.sa@analog.com>
Signed-off-by: David Lechner <dlechner@baylibre.com>
Link: https://patch.msgid.link/20250507-iio-introduce-iio_declare_buffer_with_ts-v6-3-4aee1b9f1b89@baylibre.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Change the type of the buffer elements to u16 since we currently only
support 16-bit word size. The code was originally written to also allow
for 32-bit word size when oversampling is enabled, but so far,
oversampling is only implemented when using SPI offload and therefore
doesn't use this buffer.
AD4695_MAX_CHANNEL_SIZE macro is dropped since it no longer adds any
value.
AD4695_MAX_CHANNELS + 2 is changed to AD4695_MAX_CHANNELS + 1 because
previously we were overallocating. AD4695_MAX_CHANNELS is the number of
of voltage channels and + 1 is for the temperature channel.
Signed-off-by: David Lechner <dlechner@baylibre.com>
Reviewed-by: Trevor Gamblin <tgamblin@baylibre.com>
Link: https://patch.msgid.link/20250428-iio-introduce-iio_declare_buffer_with_ts-v4-2-6f7f6126f1cb@baylibre.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
This new function allows us to perform debug checks in the helper to ensure
that the overrun does not occur. Use it in all the simple cases where
either a static buffer or a structure is used in the drivers.
Reviewed-by: David Lechner <dlechner@baylibre.com>
Link: https://patch.msgid.link/20250413103443.2420727-10-jic23@kernel.org
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
We already have a local variable that holds a pointer to
st->channels_cfg[chan->scan_index]. Use that to simplify the code.
Signed-off-by: David Lechner <dlechner@baylibre.com>
Reviewed-by: Trevor Gamblin <tgamblin@baylibre.com>
Reviewed-by: Nuno Sá <nuno.sa@analog.com>
Link: https://patch.msgid.link/20250218-iio-adc-ad4695-fix-out-of-bounds-array-access-v1-2-57fef8c7a3fd@baylibre.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Fix some out of bounds array access of st->channels_cfg in the ad4695
driver. This array only has elements for voltage channels, but it was
also being accessed for the temperature channel in a few cases causing
reading past the end of the array.
In some cases, this was harmless because the value was read but not
used. However, the in_temp_sampling_frequency attribute shares code
with the in_voltageY_sampling_frequency attributes and was trying to
read the oversampling ratio from the st->channels_cfg array. This
resulted in a garbage value being used in the calculation and the
resulting in_temp_sampling_frequency value was incorrect.
To fix, make sure we always check that we are dealing with a voltage
channel before accessing the st->channels_cfg array and use an
oversampling ratio of 1 for the temperature channel (multiplicative
identity value) since that channel doesn't support oversampling.
Fixes: 67d63185db ("iio: adc: ad4695: add offload-based oversampling support")
Signed-off-by: David Lechner <dlechner@baylibre.com>
Reviewed-by: Trevor Gamblin <tgamblin@baylibre.com>
Reviewed-by: Nuno Sá <nuno.sa@analog.com>
Link: https://patch.msgid.link/20250218-iio-adc-ad4695-fix-out-of-bounds-array-access-v1-1-57fef8c7a3fd@baylibre.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
This complex cleanup.h use case of conditional guards has proved
to be more trouble that it is worth in terms of false positive compiler
warnings and hard to read code.
Move directly to the new claim/release_direct() that allow sparse
to check for unbalanced context. In some cases code is factored
out to utility functions that can do a direct return with the
claim and release around the call.
Reviewed-by: David Lechner <dlechner@baylibre.com>
Reviewed-by: Nuno Sa <nuno.sa@analog.com>
Link: https://patch.msgid.link/20250209180624.701140-12-jic23@kernel.org
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Add support for the ad4695's oversampling feature when SPI offload is
available. This allows the ad4695 to set oversampling ratios on a
per-channel basis, raising the effective-number-of-bits from 16
(OSR == 1) to 17 (4), 18 (16), or 19 (64) for a given sample (i.e. one
full cycle through the auto-sequencer). The logic for reading and
writing sampling frequency for a given channel is also adjusted based on
the current oversampling ratio.
The non-offload case isn't supported as there isn't a good way to
trigger the CNV pin in this mode. Support could be added in the future
if a use-case arises.
Signed-off-by: Trevor Gamblin <tgamblin@baylibre.com>
Reviewed-by: Nuno Sa <nuno.sa@analog.com>
Tested-by: David Lechner <dlechner@baylibre.com>
Link: https://patch.msgid.link/20250109-ad4695-oversampling-v2-1-a46ac487082c@baylibre.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Add a custom implementation of regmap read/write callbacks using the SPI
bus. This allows them to be performed at a lower SCLK rate than data
reads. Previously, all SPI transfers were being performed at a lower
speed, but with this change sample data is read at the max bus speed
while the register reads/writes remain at the lower rate.
Also remove .can_multi_write from the AD4695 driver's regmap_configs, as
this isn't implemented or needed.
For some background context, see:
https://lore.kernel.org/linux-iio/20241028163907.00007e12@Huawei.com/
Suggested-by: David Lechner <dlechner@baylibre.com>
Signed-off-by: Trevor Gamblin <tgamblin@baylibre.com>
Reviewed-by: David Lechner <dlechner@baylibre.com>
Tested-by: David Lechner <dlechner@baylibre.com>
Link: https://patch.msgid.link/20241113-tgamblin-ad4695_improvements-v2-3-b6bb7c758fc4@baylibre.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Ensure that conversion mode is successfully exited when the command is
issued by adding an extra transfer beforehand, matching the minimum CNV
high and low times from the AD4695 datasheet. The AD4695 has a quirk
where the exit command only works during a conversion, so guarantee this
happens by triggering a conversion in ad4695_exit_conversion_mode().
Then make this even more robust by ensuring that the exit command is run
at AD4695_REG_ACCESS_SCLK_HZ rather than the bus maximum.
Signed-off-by: Trevor Gamblin <tgamblin@baylibre.com>
Reviewed-by: David Lechner <dlechner@baylibre.com>
Tested-by: David Lechner <dlechner@baylibre.com>
Link: https://patch.msgid.link/20241113-tgamblin-ad4695_improvements-v2-2-b6bb7c758fc4@baylibre.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
We need the IIO fixes in here as well, and it resolves a merge conflict
in:
drivers/iio/adc/ti-ads1119.c
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Move the dt-bindings header file to the include/dt-bindings/iio/adc/
directory. ad4695 is an ADC driver, so it should be in the adc/
subdirectory for better organization. Previously, it was in the iio/
subdirectory.
Signed-off-by: David Lechner <dlechner@baylibre.com>
Link: https://patch.msgid.link/20241113-iio-adc-ad4695-move-dt-bindings-header-v1-1-aba1f0f9b628@baylibre.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Modify ad4695_buffer_preenable() by adding an extra SPI transfer after
each data read to help ensure that the timing requirement between the
last SCLK rising edge and the next CNV rising edge is met. This requires
a restructure of the buf_read_xfer array in ad4695_state. Also define
AD4695_T_SCK_CNV_DELAY_NS to use for each added transfer. Without this
change it is possible for the data to become corrupted on sequential
buffered reads due to the device not properly exiting conversion mode.
Similarly, make adjustments to ad4695_read_one_sample() so that timings
are respected, and clean up the function slightly in the process.
Fixes: 6cc7e4bf2e ("iio: adc: ad4695: implement triggered buffer")
Co-developed-by: David Lechner <dlechner@baylibre.com>
Signed-off-by: David Lechner <dlechner@baylibre.com>
Signed-off-by: Trevor Gamblin <tgamblin@baylibre.com>
Reviewed-by: David Lechner <dlechner@baylibre.com>
Tested-by: David Lechner <dlechner@baylibre.com>
Link: https://patch.msgid.link/20241113-tgamblin-ad4695_improvements-v2-1-b6bb7c758fc4@baylibre.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
The AD4695 has a calibration feature that allows the user to compensate
for variations in the analog front end. This implements this feature in
the driver using the standard `calibgain` and `calibbias` attributes.
Signed-off-by: David Lechner <dlechner@baylibre.com>
Link: https://patch.msgid.link/20240820-ad4695-gain-offset-v1-2-c8f6e3b47551@baylibre.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
The AD4695 and similar chips have some multibyte registers that have
to be read/written in a single operation. So we need to add a 2nd regmap
for these registers.
These registers are removed from the 8-bit regmap allowable ranges and
AD4695_MAX_REG is dropped since it would be ambiguous now.
debugfs register access is also updated to automatically use the correct
regmap depending on the register address.
Signed-off-by: David Lechner <dlechner@baylibre.com>
Link: https://patch.msgid.link/20240820-ad4695-gain-offset-v1-1-c8f6e3b47551@baylibre.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
This implements buffered reads for the ad4695 driver using the typical
triggered buffer implementation, including adding a soft timestamp
channel.
The chip has 4 different modes for doing conversions. The driver is
using the advanced sequencer mode since that is the only mode that
allows individual configuration of all aspects each channel (e.g.
bipolar config currently and oversampling to be added in the future).
Signed-off-by: David Lechner <dlechner@baylibre.com>
Link: https://patch.msgid.link/20240813-iio-adc-ad4695-buffered-read-v2-1-9bb19fc1924b@baylibre.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
This is a new driver for Analog Devices Inc. AD4695 and similar ADCs.
The initial driver supports initializing the chip including configuring
all possible LDO and reference voltage sources as well as any possible
voltage input channel wiring configuration.
Only the 4-wire SPI wiring mode where the CNV pin is tied to the CS pin
is supported at this time. And reading sample data from the ADC can only
be done in direct mode for now.
Co-developed-by: Ramona Gradinariu <ramona.gradinariu@analog.com>
Signed-off-by: Ramona Gradinariu <ramona.gradinariu@analog.com>
Signed-off-by: David Lechner <dlechner@baylibre.com>
Reviewed-by: Nuno Sa <nuno.sa@analog.com>
Link: https://patch.msgid.link/20240711-iio-adc-ad4695-v4-2-c31621113b57@baylibre.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
