iio: adc: stm32-dfsdm-adc: Convert to platform remove callback returning void

The .remove() callback for a platform driver returns an int which makes
many driver authors wrongly assume it's possible to do error handling by
returning an error code. However the value returned is ignored (apart
from emitting a warning) and this typically results in resource leaks.
To improve here there is a quest to make the remove callback return
void. In the first step of this quest all drivers are converted to
.remove_new() which already returns void. Eventually after all drivers
are converted, .remove_new() will be renamed to .remove().

Trivially convert this driver from always returning zero in the remove
callback to the void returning variant.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Link: https://lore.kernel.org/r/20230919174931.1417681-23-u.kleine-koenig@pengutronix.de
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: adc: Explicitly include correct DT includes

The DT of_device.h and of_platform.h date back to the separate
of_platform_bus_type before it as merged into the regular platform bus.
As part of that merge prepping Arm DT support 13 years ago, they
"temporarily" include each other. They also include platform_device.h
and of.h. As a result, there's a pretty much random mix of those include
files used throughout the tree. In order to detangle these headers and
replace the implicit includes with struct declarations, users need to
explicitly include the correct includes.

Signed-off-by: Rob Herring <robh@kernel.org>
Acked-by: Heiko Stuebner <heiko@sntech.de>
Link: https://lore.kernel.org/r/20230714174628.4057920-1-robh@kernel.org
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: adc: stm32-dfsdm: fill module aliases

When STM32 DFSDM driver is built as module, no modalias information
is available. This prevents module to be loaded by udev.
Add MODULE_DEVICE_TABLE() to fill module aliases.

Fixes: e2e6771c6462 ("IIO: ADC: add STM32 DFSDM sigma delta ADC support")
Signed-off-by: Olivier Moysan <olivier.moysan@foss.st.com>
Link: https://lore.kernel.org/r/20221202152848.45585-1-olivier.moysan@foss.st.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: adc: stm32-dfsdm: Avoid dereferencing ->currentmode

This is an internal variable of the core, let's use the
iio_buffer_enabled() helper which is exported for the following purpose:
telling if the current mode is a buffered mode, which is precisely what
this driver looks for.

Cc: Olivier Moysan <olivier.moysan@foss.st.com>
Cc: Fabrice Gasnier <fabrice.gasnier@foss.st.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Reviewed-by: Fabrice Gasnier <fabrice.gasnier@foss.st.com>
Link: https://lore.kernel.org/r/20220207143840.707510-4-miquel.raynal@bootlin.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio:adc:stm32*: Use pm[_sleep]_ptr() etc to avoid need to make pm __maybe_unused

The combinations of either
* pm_sleep_ptr() and DEFINE_SIMPLE_DEV_PM_OPS()
* pm_ptr() and RUNTIME_PM_OPS()/SYSTEM_SLEEP_PM_OPS
Make sure the functions are always visible to the compiler and removed by
it rather than requring #ifdef magic.

This removes the need to mark the functions as __maybe_unused and saves
additional space with some build options as the dev_pm_ops structure
itself can be dropped automatically if CONFIG_PM is not enabled.

Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Olivier Moysan <olivier.moysan@st.com>
Cc: Fabrice Gasnier <fabrice.gasnier@foss.st.com>
Reviewed-by: Fabrice Gasnier <fabrice.gasnier@foss.st.com>
Reviewed-by: Paul Cercueil <paul@crapouillou.net>
Link: https://lore.kernel.org/r/20220130193147.279148-51-jic23@kernel.org

iio: adc: stm32-dfsdm: drop __func__ while using Dynamic debug

Dropped __func__ while using dev_dbg() and pr_debug()
If the function name is desired, it can be configured using
dynamic debug.

Signed-off-by: Mugilraj Dhavachelvan <dmugil2000@gmail.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Link: https://lore.kernel.org/r/20210401154343.41527-1-dmugil2000@gmail.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

ASoC: stm32: dfsdm: add actual resolution trace

Add a trace to report actual resolution of audio samples.

Signed-off-by: Olivier Moysan <olivier.moysan@st.com>
Link: https://lore.kernel.org/r/20201007153459.22155-3-olivier.moysan@st.com
Signed-off-by: Mark Brown <broonie@kernel.org>

iio: adc: stm32: Simplify with dev_err_probe()

Common pattern of handling deferred probe can be simplified with
dev_err_probe(). Less code and also it prints the error value.

Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Link: https://lore.kernel.org/r/20200829064726.26268-8-krzk@kernel.org
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: Move attach/detach of the poll func to the core

All devices using a triggered buffer need to attach and detach the trigger
to the device in order to properly work. Instead of doing this in each and
every driver by hand move this into the core.

At this point in time, all drivers should have been resolved to
attach/detach the poll-function in the same order.

This patch removes all explicit calls of iio_triggered_buffer_postenable()
& iio_triggered_buffer_predisable() in all drivers, since the core handles
now the pollfunc attach/detach.

The more peculiar change is for the 'at91-sama5d2_adc' driver, since it's
not immediately obvious that removing the hooks doesn't break anything.
Eugen was able to test on at91-sama5d2-adc driver, sama5d2-xplained board.
All seems to be fine.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
Tested-by: Eugen Hristev <eugen.hristev@microchip.com> #for at91-sama5d2-adc
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: stm32-dfsdm-adc: remove usage of iio_priv_to_dev() helper

We may want to get rid of the iio_priv_to_dev() helper. The reason is that
we will hide some of the members of the iio_dev structure (to prevent
drivers from accessing them directly), and that will also mean hiding the
implementation of the iio_priv_to_dev() helper inside the IIO core.

Hiding the implementation of iio_priv_to_dev() implies that some fast-paths
may not be fast anymore, so a general idea is to try to get rid of the
iio_priv_to_dev() altogether.
The iio_priv() helper won't be affected by the rework, as the iio_dev
struct will keep a reference to the private information.

For this driver, not using iio_priv_to_dev(), means reworking some paths to
pass the iio device and using iio_priv() to access the private information.

Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: remove explicit IIO device parent assignment

This patch applies the semantic patch:
@@
expression I, P, SP;
@@
I = devm_iio_device_alloc(P, SP);
...
- I->dev.parent = P;

It updates 302 files and does 307 deletions.
This semantic patch also removes some comments like
'/* Establish that the iio_dev is a child of the i2c device */'

But this is is only done in case where the block is left empty.

The patch does not seem to cover all cases. It looks like in some cases a
different variable is used in some cases to assign the parent, but it
points to the same reference.
In other cases, the block covered by ... may be just too big to be covered
by the semantic patch.

However, this looks pretty good as well, as it does cover a big bulk of the
drivers that should remove the parent assignment.

Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: adc: stm32-dfsdm: fix device used to request dma

DMA channel request should use device struct from platform device struct.
Currently it's using iio device struct. But at this stage when probing,
device struct isn't yet registered (e.g. device_register is done in
iio_device_register). Since commit 71723a96b8b1 ("dmaengine: Create
symlinks between DMA channels and slaves"), a warning message is printed
as the links in sysfs can't be created, due to device isn't yet registered:
- Cannot create DMA slave symlink
- Cannot create DMA dma:rx symlink

Fix this by using device struct from platform device to request dma chan.

Fixes: eca949800d2d ("IIO: ADC: add stm32 DFSDM support for PDM microphone")

Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com>
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: adc: stm32-dfsdm: fix sleep in atomic context

This commit fixes the error message:
"BUG: sleeping function called from invalid context at kernel/irq/chip.c"
Suppress the trigger irq handler. Make the buffer transfers directly
in DMA callback, instead.
Push buffers without timestamps, as timestamps are not supported
in DFSDM driver.

Fixes: 11646e81d775 ("iio: adc: stm32-dfsdm: add support for buffer modes")

Signed-off-by: Olivier Moysan <olivier.moysan@st.com>
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: adc: stm32-dfsdm: adapt sampling rate to oversampling ratio

Update sampling rate when oversampling ratio is changed
through the IIO ABI.

Signed-off-by: Olivier Moysan <olivier.moysan@st.com>
Acked-by: Fabrice Gasnier <fabrice.gasnier@st.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: adc: stm32-dfsdm: fix single conversion

Apply data formatting to single conversion,
as this is already done in continuous and trigger modes.

Fixes: 102afde62937 ("iio: adc: stm32-dfsdm: manage data resolution in trigger mode")

Signed-off-by: Olivier Moysan <olivier.moysan@st.com>
Cc: <Stable@vger.kernel.org>
Acked-by: Fabrice Gasnier <fabrice.gasnier@st.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: adc: stm32-dfsdm: Use dma_request_chan() instead dma_request_slave_channel()

dma_request_slave_channel() is a wrapper on top of dma_request_chan()
eating up the error code.

By using dma_request_chan() directly the driver can support deferred
probing against DMA.

Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Acked-by: Olivier Moysan <olivier.moysan@st.com>
Acked-by: Fabrice Gasnier <fabrice.gasnier@st.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: Remove dev_err() usage after platform_get_irq()

We don't need dev_err() messages when platform_get_irq() fails now that
platform_get_irq() prints an error message itself when something goes
wrong. Let's remove these prints with a simple semantic patch.

// <smpl>
@@
expression ret;
struct platform_device *E;
@@

ret =
(
platform_get_irq(E, ...)
|
platform_get_irq_byname(E, ...)
);

if ( \( ret < 0 \| ret <= 0 \) )
{
(
-if (ret != -EPROBE_DEFER)
-{ ...
-dev_err(...);
-... }
|
...
-dev_err(...);
)
...
}
// </smpl>

While we're here, remove braces on if statements that only have one
statement (manually).

Cc: Jonathan Cameron <jic23@kernel.org>
Cc: Hartmut Knaack <knaack.h@gmx.de>
Cc: Lars-Peter Clausen <lars@metafoo.de>
Cc: Peter Meerwald-Stadler <pmeerw@pmeerw.net>
Cc: linux-iio@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Stephen Boyd <swboyd@chromium.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: adc: stm32-dfsdm: add comment for 16 bits record

Add a comment on DMA configuration for 16 bits record.

Signed-off-by: Olivier Moysan <olivier.moysan@st.com>
Acked-by: Fabrice Gasnier <fabrice.gasnier@st.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: adc: stm32-dfsdm: add fast mode support

The use of fast mode allows to get a larger set of solution
for filter parameters. This can be useful to reach a better
output sample resolution, when fast mode can be used.

Fast mode is selected at startup if it is relevant.
The startup is performed in postenable callback context,
where there are too tight time constraints for filter parameters
computation. For this reason both fast and non fast filter parameters
are pre-computed previously.

Signed-off-by: Olivier Moysan <olivier.moysan@st.com>
Acked-by: Fabrice Gasnier <fabrice.gasnier@st.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: adc: stm32-dfsdm: manage data resolution in trigger mode

Add output sample resolution management in scan mode.
Add stm32_dfsdm_process_data() function to share sample
processing between continuous and trigger modes.

Signed-off-by: Olivier Moysan <olivier.moysan@st.com>
Acked-by: Fabrice Gasnier <fabrice.gasnier@st.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: adc: stm32-dfsdm: fix data type

Fix the data type as DFSDM raw output is complements 2,
24bits left aligned in a 32-bit register.
This change does not affect AUDIO path
- Set data as signed for IIO (as for AUDIO)
- Set 8 bit right shift for IIO.
The 8 LSBs bits of data contains channel info and are masked.

Signed-off-by: Olivier Moysan <olivier.moysan@st.com>
Fixes: e2e6771c6462 ("IIO: ADC: add STM32 DFSDM sigma delta ADC support")
Acked-by: Fabrice Gasnier <fabrice.gasnier@st.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: adc: stm32-dfsdm: fix output resolution

In buffered mode, output samples are shifted left
unconditionally. This works for filter order 3,
but this shift is not adapted for other filter orders.
Compute required shift, left or right, and shift
output data accordingly.
Add also saturation management to avoid wrap-around
when maximum positive sample is reached.

Signed-off-by: Olivier Moysan <olivier.moysan@st.com>
Fixes: eca949800d2d ("IIO: ADC: add stm32 DFSDM support for PDM microphone")
Acked-by: Fabrice Gasnier <fabrice.gasnier@st.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: adc: stm32-dfsdm: manage the get_irq error case

During probe, check the "get_irq" error value.

Signed-off-by: Fabien Dessenne <fabien.dessenne@st.com>
Acked-by: Fabrice Gasnier <fabrice.gasnier@st.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: adc: stm32-dfsdm: add PM support

Add PM and runtime PM support to STM32 DFSDM drivers:
- stm32-dfsdm-core: manage clocks.
- stm32-dfsdm-adc: restore channels configuration upon resume. Also stop
restart everything in case of buffer mode.

Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: adc: stm32-dfsdm: improve sampling frequency accuracy

The sample frequency is driven using the oversampling ratio depending
on the SPI bus frequency.
Currently, oversampling ratio is computed by an entire division:
- spi_freq / sample_freq. This may result in inaccurate value.
Using DIV_ROUND_CLOSEST improves resulting sample frequency, which is
useful for audio that requests fixed rates (such as: 8, 16 or 32 kHz).
BTW, introduce new routine to re-factor sample frequency setting, and
move frequency accuracy message from warning to debug level.

Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: adc: stm32-dfsdm: claim direct mode for raw read and settings

Claim direct mode to ensure no buffer mode is in use for:
- single conversion
- sample rate setting (must be set when filter isn't enabled).
- oversampling ratio (must be set when filter isn't enabled).

Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: adc: stm32-dfsdm: add support for buffer modes

DFSDM conversions can be launched continuously, or using various
triggers:
- by software
- hardware triggers (e.g. like in stm32-adc: TIM, LPTIM, EXTI)
- synchronously with DFSDM filter 0. e.g. for filters 1, 2

Launching conversions can be done using two methods:
a - injected:
- scan mode can be used to convert several channels each time a
trigger occurs.
- When not is scan mode, channels are converted in sequence, one upon
each trigger.
b - regular:
- supports software triggers or synchronous with filter 0
- single or continuous conversions

This patch finalizes DFSDM operating modes using IIO buffer modes:
- INDIO_BUFFER_SOFTWARE: regular continuous conversions (no trigger)
but limited to 1 channel. Users must set sampling frequency in this case.
For filters > 1, conversions can be started synchronously with filter 0.
- INDIO_BUFFER_TRIGGERED: triggered conversions uses injected mode for
launching conversions. DFSDM can use hardware triggers (e.g. STM32 timer
or lptimer), so add INDIO_HARDWARE_TRIGGERED to supported modes.
- INDIO_DIRECT_MODE: Only support DMA-based buffer modes. In case no DMA is
available, only support single conversions.

From userland perspective, to summarize various use cases:
1 - single conversion on any filter:
$ cd iio:deviceX
$ cat in_voltageY_raw
This uses regular a conversion (not continuous)

2 - Using sampling frequency without trigger (single channel, buffer)
$ cd iio:deviceX
$ echo 100 > sampling_frequency
$ echo "" > trigger/current_trigger
$ echo 1 > scan_elements/in_voltageY_en
$ echo 1 > buffer/enable
This uses regular conversion in continuous mode (Frequency is achieved
by tuning filter parameters)

3 - sync mode with filter 0: other filters can be converted when using
"st,filter0-sync" dt property. The conversions will get started at the
same time as filter 0. So for any filters > 1:
$ cd iio:deviceX
$ echo 100 > sampling_frequency
$ echo "" > trigger/current_trigger
$ echo 1 > scan_elements/in_voltageY_en
$ echo 1 > buffer/enable
Then start filter 0 as in 2 above.

4 - Using a hardware trigger (with one channel):
- check trigger, configure it:
$ cat /sys/bus/iio/devices/trigger1/name
tim6_trgo
$ echo 100 > /sys/bus/iio/devices/trigger1/sampling_frequency
- go to any filter:
$ echo 1 > scan_elements/in_voltageY_en
$ echo tim6_trgo > trigger/current_trigger
$ echo 1 > buffer/enable
This uses injected conversion as it uses a hardware trigger (without scan)

5 - Using a hardware trigger (with 2+ channel):
Same as in 4/ above, but enable two or more channels in scan_elements.
This uses injected conversion as it uses a hardware trigger (with scan mode)

Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: adc: stm32-dfsdm: add support for scan mode

In order to support multiple channels in buffer mode, add support for scan
mode. This is precursor patch to ease support of triggered buffer mode.
Currently, only audio uses buffer mode: Regular continuous conversions
with a single channel (per filter).
DFSDM hardware supports scan mode (only) with injected conversions.
Conversions can be launched by software (JSWSTART), trigger or
synchronously with filter 0 (e.g. JSYNC). Continuous conversion mode isn't
available for injected.

Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: adc: stm32-dfsdm: enable hw consumer

Optionally enable IIO hw consumer, when provided (e.g. for DFSDM_IIO type).
This is precursor patch to introduce buffer modes.

Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: adc: stm32-dfsdm: move dma slave config to start routine

Move DMA slave configuration to start routine: depending on regular or
injected mode is in use, DMA needs to read resp. RDATAR or JDATAR.
This is precursor patch to introduce injected mode (used for scan).

Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: adc: stm32-dfsdm: move dma enable from start_conv() to start_dma()

Move DMA enable (e.g. set RDMAEN bit) away from start_conv() that is used
for both buffer and single conversions. Thus, single conv rely on
interrupt, not dma.
Note: take care to prepare all DMA stuff and set RDMAEN before starting
filter (can be set only when DFEN=0).

This is precursor patch to ease support of triggered buffer mode.

Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: adc: stm32-dfsdm: continuous mode depends on current mode

DFSDM regular continuous mode usage depends on current mode (not DMA):
- for single conversion, RCONT doesn't need to be set.
- for buffer mode, RCONT has to be set (e.g. INDIO_BUFFER_SOFTWARE
used by audio currently).
This is related to filter configuration, move it to relevant routine.

This is precursor patch to ease support of triggered buffer mode.

Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: adc: stm32-dfsdm: include stm32-dfsdm-adc.h

Fix the following sparse warnings:
CHECK drivers/iio/adc/stm32-dfsdm-adc.c
symbol 'stm32_dfsdm_get_buff_cb' was not declared. Should it be static?
symbol 'stm32_dfsdm_release_buff_cb' was not declared. Should it be static?

BTW, move interrupt.h to sort headers alphabetically.

Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: adc: stm32-dfsdm: add check on max filter id

reg property should be checked against number of available filters.
BTW, dfsdm->num_fls wasn't used. But it can be used for this purpose.
This prevents using data out of allocated dfsdm->fl_list array.

Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: adc: stm32-dfsdm: misc style improvements and fixes

Misc fixes & style improvements:
- checkpatch warns about line over 80 characters.
- remove extra spaces and a blank line (e.g. checkpatch --strict)
- remove bad error message always printed in probe routine.

Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: adc: stm32-dfsdm: fix sample rate for div2 spi clock

When channel clk source is set to "CLKOUT_F" or "CLKOUT_R" (e.g. div2),
sample rate is currently set to half the requested value.

Fixes: eca949800d2d ("IIO: ADC: add stm32 DFSDM support for PDM
microphone")

Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com>
Acked-by: Arnaud Pouliquen <arnaud.pouliquen@st.com>
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: adc: stm32-dfsdm: fix successive oversampling settings

When doing successive oversampling settings, it may fail to update filter
parameters silently:
- First time oversampling is being set, it will be successful, as fl->res
is 0 initially.
- Next attempts with various oversamp value may return 0 (success), but
keep previous filter parameters, due to 'res' never reaches above or
equal current 'fl->res'.

This is particularly true when setting sampling frequency (that relies on
oversamp). Typical failure without error:
- run 1st test @16kHz samp freq will succeed
- run new test @8kHz will succeed as well
- run new test @16kHz (again): sample rate will remain 8kHz without error

Fixes: e2e6771c6462 ("IIO: ADC: add STM32 DFSDM sigma delta ADC support")

Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com>
Acked-by: Arnaud Pouliquen <arnaud.pouliquen@st.com>
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: adc: stm32-dfsdm: fix multiple channel initialization

When several channels are registered (e.g. via st,adc-channels property):
- channels array is wrongly filled in. Only 1st element in array is being
initialized with last registered channel.
Fix it by passing reference to relevant channel (e.g. array[index]).
- only last initialized channel can work properly (e.g. unique 'ch_id'
is used). Converting any other channel result in conversion timeout.
Fix it by getting rid of 'ch_id', use chan->channel instead.

Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com>
Acked-by: Arnaud Pouliquen <arnaud.pouliquen@st.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: adc: stm32-dfsdm: fix call to stop channel

stm32_dfsdm_stop_channel must be called with channel id, not filter id.

Fixes: e2e6771c6462 ("IIO: ADC: add STM32 DFSDM sigma delta ADC support")

Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com>
Acked-by: Arnaud Pouliquen <arnaud.pouliquen@st.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

IIO: ADC: stm32-dfsdm: fix static check warning

iio_priv does not return an error pointer, so check is not valid.
Patch suppresses it.

Signed-off-by: Arnaud Pouliquen <arnaud.pouliquen@st.com>
Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

IIO: ADC: stm32-dfsdm: code optimization

Use of_device_get_match_data to optimize the source code.
No check is needed on dev_data as match table is defined in driver.

Signed-off-by: Arnaud Pouliquen <arnaud.pouliquen@st.com>
Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

IIO: ADC: fix return value check in stm32_dfsdm_adc_probe()

In case of error, the function devm_iio_device_alloc() returns NULL
pointer not ERR_PTR(). The IS_ERR() test in the return value check
should be replaced with NULL test.

Fixes: e2e6771c6462 ("IIO: ADC: add STM32 DFSDM sigma delta ADC support")
Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

IIO: ADC: stm32_dfsdm_stop_filter() can be static

Fixes: e2e6771c6462 ("IIO: ADC: add STM32 DFSDM sigma delta ADC support")
Signed-off-by: Fengguang Wu <fengguang.wu@intel.com>
Acked-by: Arnaud Pouliquen <arnaud.pouliquen@st.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

IIO: ADC: add stm32 DFSDM support for PDM microphone

This code offers a way to handle PDM audio microphones in
ASOC framework. Audio driver should use consumer API.
A specific management is implemented for DMA, with a
callback, to allows to handle audio buffers efficiently.

Signed-off-by: Arnaud Pouliquen <arnaud.pouliquen@st.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

IIO: ADC: add STM32 DFSDM sigma delta ADC support

Add DFSDM driver to handle sigma delta ADC.

Signed-off-by: Arnaud Pouliquen <arnaud.pouliquen@st.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Mark Brown <broonie@kernel.org>