Move the call to fwnode_irq_get_byname() from the driver-specific
ad7173_fw_parse_device_config() to the shared ad_sd_init() function.

The main reason for this is that we want struct ad_sigma_delta_info to
be static const data that describes the actual ADC chip, not the
application-specific configuration or any runtime state.

Previously, this struct was being used to pass the IRQ number to the
shared ad_sd_init() function. Now, this is replaced by a boolean flag
that is set at compile time and the ad_sd_init() function handles
looking up the IRQ number instead. This also has the added benefit that
if any other drivers need to make use of this in the future, they just
have to set the flag and the shared code will take care of the rest
rather than duplicating the code in each driver.

Signed-off-by: David Lechner <dlechner@baylibre.com>
Link: https://patch.msgid.link/20250113-iio-adc-ad7313-fix-non-const-info-struct-v4-1-b63be3ecac4a@baylibre.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

The various chips can be reset using a sequence of SPI transfers with
MOSI = 1. The length of such a sequence varies from chip to chip. Store
that length in struct ad_sigma_delta_info and replace the respective
parameter to ad_sd_reset() with it.

Note the ad7192 used to pass 48 as length but the documentation
specifies 40 as the required length. Assuming the latter is right.
(Using a too long sequence doesn't hurt apart from using a longer spi
transfer than necessary, so this is no relevant fix.)

The motivation for storing this information is that this is useful to
clear a pending R̅D̅Y̅ signal in the next change.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@baylibre.com>
Link: https://patch.msgid.link/9750db62fce638bf140ff48172c23bff7f785e5b.1733504533.git.u.kleine-koenig@baylibre.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

The ad_sigma_delta driver helper uses irq_disable_nosync(). With that
one it is possible that the irq handler still runs after the
irq_disable_nosync() function call returns. Also to properly synchronize
irq disabling in the different threads proper locking is needed and
because it's unclear if the irq handler's irq_disable_nosync() call
comes first or the one in the enabler's error path, all code locations
that disable the irq must check for .irq_dis first to ensure there is
exactly one disable call per enable call.

So add a spinlock to the struct ad_sigma_delta and use it to synchronize
irq enabling and disabling. Also only act in the irq handler if the irq
is still enabled.

Fixes: af3008485ea0 ("iio:adc: Add common code for ADI Sigma Delta devices")
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@baylibre.com>
Link: https://patch.msgid.link/9e6def47e2e773e0e15b7a2c29d22629b53d91b1.1733504533.git.u.kleine-koenig@baylibre.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

Some of the ADCs by Analog signal their irq condition on the MISO line.
So typically that line is connected to an SPI controller and a GPIO. The
GPIO is used as input and the respective interrupt is enabled when the
last SPI transfer is completed.

Depending on the GPIO controller the toggling MISO line might make the
interrupt pending even while it's masked. In that case the irq handler
is called immediately after irq_enable() and so before the device
actually pulls that line low which results in non-sense values being
reported to the upper layers.

The only way to find out if the line was actually pulled low is to read
the GPIO. (There is a flag in AD7124's status register that also signals
if an interrupt was asserted, but reading that register toggles the MISO
line and so might trigger another spurious interrupt.)

Add the possibility to specify an interrupt GPIO in the machine
description in addition to the plain interrupt. This GPIO is used then
to check if the irq line is actually active in the irq handler.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@baylibre.com>
Link: https://patch.msgid.link/5be9a4cc4dc600ec384c88db01dd661a21506b9c.1733504533.git.u.kleine-koenig@baylibre.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

Align the irq_line field in struct ad_sigma_delta with the other fields.

Signed-off-by: David Lechner <dlechner@baylibre.com>
Link: https://patch.msgid.link/20241122-iio-adc-ad_signal_delta-fix-align-v1-1-d0a071d2dc83@baylibre.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

Sigma delta ADCs with a sequencer need to disable the previously enabled
channel when reading using ad_sigma_delta_single_conversion(). This was
done manually in drivers for devices with sequencers.

This patch implements handling of single channel disabling after a
single conversion.

Reviewed-by: Nuno Sa <nuno.sa@analog.com>
Signed-off-by: Dumitru Ceclan <dumitru.ceclan@analog.com>
Reviewed-by: David Lechner <dlechner@baylibre.com>
Link: https://patch.msgid.link/20240607-ad4111-v7-3-97e3855900a0@analog.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

Add optional irq_num attribute to ad_sigma_delta_info structure for
selecting the used interrupt line for ADC's conversion completion.

Signed-off-by: Dumitru Ceclan <mitrutzceclan@gmail.com>
Reviewed-by: Nuno Sa <nuno.sa@analog.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Link: https://lore.kernel.org/r/20240228110622.25114-2-mitrutzceclan@gmail.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

Jonathan writes:

IIO: 1st set of new device support, features and cleanup for 6.9

IIO Backend support
===================

New approach from Nuno Sa to the problem of reuse of drivers with
IIO devices that are actually the combination of a highspeed chip
and an FPGA core handling the data capture and flows. It will hopefully
also apply to some other split designs. The ad9467 and axi-adi drivers
are converted over to this framework.

New device support
==================

adi,admfm2000
- New driver for this dual microwave down converter.
ams,as73211
- Add support for as7331 UV sensor.
richtek,rtq6056
- Add support for related parts RTQ6053 and RTQ6059
st,lsm6dsx
- Add ASM330LHHXG1 accelerometer and gyro support (mainly IDs)
ti,ads1298
- New driver for this medical ADC.

Features
========

tests
- Unit tests for the gain-time-scale helper library.
bosch,bmi088
- I2C support.
bosh,bmi160
- Add 10EC5280 ACPI ID. Used in a number of devices that won't get fixed.
  The ID is actually a PCI ID belonging to realtech. No response was received
  to earlier attempts to notify them of this.
  The manufacturers of some devices have replied to say they will not fix
  this incorrect ID. Add the ID and hope it isn't a problem.
bosch,bmi323
- Add BOSC0200 ACPI ID. Note this is a duplicate of one in the bmc150
  driver (it appears these parts share a windows driver).
  Both drivers perform an ID check that is safe on the other part before
  successfully probing.
hid-sensors-als
- Add color temperature and chromaticity support. Note this is a replacement
  for the series reverted in 6.8 that correctly handles all the potential
  channel combinations.
honeywell,hsc030pa
- Triggered buffer support (after driver cleanup).
honeywell,mprls00025pa
- Improved error handling.
- New DT binding to allow use of part number triplet as provided in data sheet
  to specify equivalent of most of the binding more efficiently.
- SPI support.
memsic,mxc4005
- ACPI ID MDA6655 as seen in the Chuwi Minibook X 2023
ti,hdc3020
- Add threshold event support (after some driver cleanup)
veml,vcnl4000
- Switch to high resolution proximity measurement.

Cleanup
=======
Various minor typo fixes and better use of defines etc.

Treewide
- Stop using ACPI_PTR(). The savings in space are small and not worth
  the complexity of __maybe_unused of ifdef guards.  To avoid use in
  new IIO drivers based on copy and paste, clean it out.
- cleanup.h based handling of iio_device_claim_direct_mode()/
  iio_device_release_direct_mode() using scope_cond_guard().
  In many drivers this is combined with other automated cleanup
  to give maximum simplifications.
  An initial set of drivers are converted over to this infrastructure.

Tools
- Use rewinddir() instead of seekdir() to return to start of file.

core
- Make iio_bus_type constant.

adi,ad16475
- Use irq_get_trigger_type() instead of opencoding.
adi,ad16480
- Use irq_get_trigger_type() instead of opencoding.
adi,ad-sigma-delta
- Avoid overwriting IRQ flags if provided by firmware.
ams,as73211
- Use IIO_VAL_FRACTIONAL for scales to simplify the code and potentially
  improve accuracy.
gts-library
- Use a div64_u64() instead of a loop to do a division.
honeywell,mprls00025pa
- Clean up dt-binding doc.
- Drop defaults when DT binding not providing values. Very unlikely
  these were useful given they were wrong for vast majority of supported
  devices.
- Whitespace cleanup
miramems,da280
- Use i2c_get_match_data() to replace hand rolled ACPI matching code.
semtech,sx9324
- Avoid unnecessary copying of property strings.
st,lsm6dsx
- Improve docs, particularly wrt to making addition of new device
  support less noisy.
st,lsm9ds0
- Use dev_err_probe() in all probe() error handling.
- Improved header includes.
- Tidy up termination of ID tables.
ti,ads1014
- Correct upper bound on PGA (wrong value had no actual impact)
ti,afe4403/4404
- devm_ useage to simplify error handling in probe() and allow() remove to
  be dropped.
voltage-divider
- Add dt-binding for io-channel-cells to allow such a device to be both
  an IIO consumer and IIO producer at the same time.

* tag 'iio-for-6.9a' of http://git.kernel.org/pub/scm/linux/kernel/git/jic23/iio: (106 commits)
  iio: imu: bmi323: Add ACPI Match Table
  iio: accel: bmc150: Document duplicate ACPI entries with bmi323 driver
  iio: adc: ti-ads1298: Add driver
  dt-bindings: iio: adc: ti-ads1298: Add bindings
  iio: pressure: hsc030pa add triggered buffer
  iio: pressure: hsc030pa add mandatory delay
  iio: pressure: hsc030pa: update datasheet URLs
  iio: pressure: hsc030pa: include cleanup
  iio: pressure: hsc030pa: use signed type to hold div_64() result
  dt-bindings: iio: pressure: honeywell,hsc030pa.yaml add spi props
  iio: st_sensors: lsm9ds0: Use common style for terminator in ID tables
  iio: st_sensors: lsm9ds0: Don't use "proxy" headers
  iio: st_sensors: lsm9ds0: Use dev_err_probe() everywhere
  iio: adc: adi-axi-adc: move to backend framework
  iio: adc: ad9467: convert to backend framework
  iio: add the IIO backend framework
  iio: buffer-dmaengine: export buffer alloc and free functions
  of: property: add device link support for io-backends
  dt-bindings: adc: axi-adc: update bindings for backend framework
  dt-bindings: adc: ad9467: add new io-backend property
  ...

Move to the IIO backend framework. Devices supported by adi-axi-adc now
register themselves as backend devices.

Signed-off-by: Nuno Sa <nuno.sa@analog.com>
Link: https://lore.kernel.org/r/20240210-iio-backend-v11-7-f5242a5fb42a@analog.com
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

Aligning the buffer to the L1 cache is not sufficient in some platforms
as they might have larger cacheline sizes for caches after L1 and thus,
we can't guarantee DMA safety.

That was the whole reason to introduce IIO_DMA_MINALIGN in [1]. Do the same
for the sigma_delta ADCs.

[1]: https://lore.kernel.org/linux-iio/20220508175712.647246-2-jic23@kernel.org/

Fixes: 0fb6ee8d0b5e ("iio: ad_sigma_delta: Don't put SPI transfer buffer on the stack")
Signed-off-by: Nuno Sa <nuno.sa@analog.com>
Link: https://lore.kernel.org/r/20240117-dev_sigma_delta_no_irq_flags-v1-1-db39261592cf@analog.com
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>