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: ad7124: Silence no spi_device_id warnings

SPI devices use the spi_device_id for module autoloading even on
systems using device tree, after commit 5fa6863ba692 ("spi: Check
we have a spi_device_id for each DT compatible"), kernel warns as
follows since the spi_device_id is missing:

SPI driver ad7124 has no spi_device_id for adi,ad7124-4
SPI driver ad7124 has no spi_device_id for adi,ad7124-8

Add spi_device_id entries to silence the warnings, and ensure driver
module autoloading works.

Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
Link: https://lore.kernel.org/r/20220921163620.805879-6-weiyongjun@huaweicloud.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: adc: ad7124: Benefit from devm_clk_get_enabled() to simplify

Make use of devm_clk_get_enabled() to replace some code that effectively
open codes this new function.

Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Link: https://lore.kernel.org/r/20220808204740.307667-1-u.kleine-koenig@pengutronix.de
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: adc: ad7124: add sequencer support

Add sequencer support for AD7124.

Signed-off-by: Alexandru Tachici <alexandru.tachici@analog.com>
Link: https://lore.kernel.org/r/20220322105029.86389-6-alexandru.tachici@analog.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: adc: ad7124: Add update_scan_mode

The callback .set_channel cannot be used to enable and
disable multiple channels at once as they are presented
in the active_scan_mask.

By adding an update_scan_mode callback, every time the
continuous mode is activated, channels will be
enabled/disabled accordingly.

Signed-off-by: Alexandru Tachici <alexandru.tachici@analog.com>
Link: https://lore.kernel.org/r/20220322105029.86389-3-alexandru.tachici@analog.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: adc: ad7124: Remove shift from scan_type

The 24 bits data is stored in 32 bits in BE. There
is no need to shift it. This confuses user-space apps.

Fixes: b3af341bbd966 ("iio: adc: Add ad7124 support")
Signed-off-by: Alexandru Tachici <alexandru.tachici@analog.com>
Link: https://lore.kernel.org/r/20220322105029.86389-2-alexandru.tachici@analog.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio:adc:ad_sigma_delta: Move exports into IIO_AD_SIGMA_DELTA namespace

In order to avoid unnecessary pollution of the global symbol namespace
move the core/library functions into a specific namespace and import
that into the various specific device drivers that use them.

For more information see https://lwn.net/Articles/760045/

Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Renato Lui Geh <renatogeh@gmail.com>
Cc: Michael Hennerich <Michael.Hennerich@analog.com>
Cc: Lars-Peter Clausen <lars@metafoo.de>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Link: https://lore.kernel.org/r/20220130205701.334592-2-jic23@kernel.org

iio: adc: ad7124: fix mask used for setting AIN_BUFP & AIN_BUFM bits

According to page 90 of the datasheet [1], AIN_BUFP is bit 6 and
AIN_BUFM is bit 5 of the CONFIG_0 -> CONFIG_7 registers.

Fix the mask used for setting these bits.

[1]: https://www.analog.com/media/en/technical-documentation/data-sheets/ad7124-8.pdf

Fixes: 0eaecea6e487 ("iio: adc: ad7124: Add buffered input support")
Signed-off-by: Cosmin Tanislav <cosmin.tanislav@analog.com>
Link: https://lore.kernel.org/r/20220112200036.694490-1-cosmin.tanislav@analog.com
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

all: replace find_next{,_zero}_bit with find_first{,_zero}_bit where appropriate

find_first{,_zero}_bit is a more effective analogue of 'next' version if
start == 0. This patch replaces 'next' with 'first' where things look
trivial.

Signed-off-by: Yury Norov <yury.norov@gmail.com>
Tested-by: Wolfram Sang <wsa+renesas@sang-engineering.com>

iio: adc: ad7124: Use devm_ managed calls for all of probe() + drop remove()

As not many steps were not already devm_ managed, use
devm_add_action_or_reset() to handle the rest.

This also uses the new devm_ad_sd_setup_buffer_and_trigger() function.

Reviewed-by: Alexandru Ardelean <ardeleanalex@gmail.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Alexandru Ardelean <aardelean@deviqon.com>
Link: https://lore.kernel.org/r/20210513120752.90074-12-aardelean@deviqon.com

iio: adc: ad7124: Fix potential overflow due to non sequential channel numbers

Channel numbering must start at 0 and then not have any holes, or
it is possible to overflow the available storage. Note this bug was
introduced as part of a fix to ensure we didn't rely on the ordering
of child nodes. So we need to support arbitrary ordering but they all
need to be there somewhere.

Note I hit this when using qemu to test the rest of this series.
Arguably this isn't the best fix, but it is probably the most minimal
option for backporting etc.

Alexandru's sign-off is here because he carried this patch in a larger
set that Jonathan then applied.

Fixes: d7857e4ee1ba6 ("iio: adc: ad7124: Fix DT channel configuration")
Reviewed-by: Alexandru Ardelean <ardeleanalex@gmail.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Alexandru Ardelean <aardelean@deviqon.com>
Cc: <Stable@vger.kernel.org>

iio: adc: ad7124: Fix missbalanced regulator enable / disable on error.

If the devm_regulator_get() call succeeded but not the regulator_enable()
then regulator_disable() would be called on a regulator that was not
enabled.

Fix this by moving regulator enabling / disabling over to
devm_ management via devm_add_action_or_reset.

Alexandru's sign-off here because he pulled Jonathan's patch into
a larger set which Jonathan then applied.

Fixes: b3af341bbd96 ("iio: adc: Add ad7124 support")
Reviewed-by: Alexandru Ardelean <ardeleanalex@gmail.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Alexandru Ardelean <aardelean@deviqon.com>
Cc: <Stable@vger.kernel.org>

iio: adc: ad7124: allow more than 8 channels

Currently AD7124-8 driver cannot use more than 8 IIO channels
because it was assigning the channel configurations bijectively
to channels specified in the device-tree. This is not possible
to do when using more than 8 channels as AD7124-8 has only 8
configuration registers.

To allow the user to use all channels at once the driver
will keep in memory configurations for all channels but
will program only 8 of them at a time on the device.
If multiple channels have the same configuration, only
one configuration register will be used. If there
are more configurations than available registers only
the last 8 used configurations will be allowed to exist
on the device in a LRU fashion.

Signed-off-by: Alexandru Tachici <alexandru.tachici@analog.com>
Reported-by: kernel test robot <lkp@intel.com>
Link: https://lore.kernel.org/r/20210311091154.47785-2-alexandru.tachici@analog.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: adc: ad7124: Fix typo in device name

This patch fixes the device name typo.

Fixes: 951ad4700313 ("iio: adc: ad7124: move chip ID & name on the chip_info table")
Signed-off-by: Mircea Caprioru <mircea.caprioru@analog.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Link: https://lore.kernel.org/r/20200902134222.28357-1-mircea.caprioru@analog.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: adc: ad7124: move chip ID & name on the chip_info table

This change does the following:
* removes the SPI device table in favor of the OF device table
* adds 'name' && 'chip_id' fields to chip_info
* implements chip ID & silicon revision checking; the device ID for
AD7124-4 is 0x0, so just checking that value can be useless;
but at least the silicon revision isn't 0, so a non-zero value can be
used to check that "a" device is on the SPI bus; it's probably the best
way to narrow it down to one of the 2 AD7124 chip IDs

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: ad7124: Add direct reg access

This patch adds the posibility do read and write registers from userspace
using the kernel debug direct register access option.

Signed-off-by: Mircea Caprioru <mircea.caprioru@analog.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: adc: ad7124: add 3db filter

This patch adds the LOW_PASS_FILTER_3DB_FREQUENCY attribute
in iio_chan_spec for each channel. The used filters are sinc3
or sinc4. The filter type with the highest output data rate
is used when setting a low pass frequency in the channel's sysfs.

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

iio: adc: ad7124: Set IRQ type to falling

Ad7124 data-sheet specifies that the falling edge
of the DOUT line should be used for an interrupt.
The current irq flag (IRQF_TRIGGER_LOW) used will
cause unwanted behaviour. When enabling the interrupt
it will fire once because the DOUT line is already low.
This will make the driver to read an unfinished conversion
from the chip.

This patch sets the irq type to the one specified in
the data-sheet.

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

iio: adc: ad-sigma-delta: Allow custom IRQ flags

Before this patch the ad_sigma_delta implementation hardcoded
the irq trigger type to low, assuming that all Sigma-Delta ADCs
have the same interrupt-type.

This patch allows all drivers using the ad_sigma_delta layer to set the
irq trigger type to the one specified in the datasheet.

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

iio: adc: ad7124: Fix DT channel configuration

This patch fixes device tree channel configuration.

ad7124 driver reads channels configuration from the device tree.
It expects to find channel specifications as child nodes.
Before this patch ad7124 driver assumed that the child nodes are parsed
by for_each_available_child_of_node in the order 0,1,2,3...

This is wrong and the real order of the children can be seen by running:
dtc -I fs /sys/firmware/devicetree/base on the machine.

For example, running this on an rpi 3B+ yields the real
children order: 4,2,0,7,5,3,1,6

Before this patch the driver assigned the channel configuration
like this:
- 0 <- 4
- 1 <- 2
- 2 <- 0
........
For example, the symptoms can be observed by connecting the 4th channel
to a 1V tension and then reading the in_voltage0-voltage19_raw sysfs
(multiplied of course by the scale) one would see that channel 0
measures 1V and channel 4 measures only noise.

Now the driver uses the reg property of each child in order to
correctly identify to which channel the parsed configuration
belongs to.

Fixes b3af341bbd966: ("iio: adc: Add ad7124 support")
Signed-off-by: Alexandru Tachici <alexandru.tachici@analog.com>
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

iio: adc: ad7124: Enable internal reference

When the internal reference was selected by a channel it was not enabled.
This patch fixes that and enables it.

Fixes: b3af341bbd96 ("iio: adc: Add ad7124 support")
Signed-off-by: Mircea Caprioru <mircea.caprioru@analog.com>
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: adc: ad7124: Shift to dynamic allocation for channel configuration

This patch changes the channel configuration member of the device
structure from a fixed size array to a dynamic allocated one with a size
equal to the number of channels specified in the device tree. This will
ensure a more flexibility for compatible devices.

Ex. ad7124-4 - can have 4 differential or 8 pseudo-differential channels
ad7124-8 - can have 8 differential or 16 pseudo-differential channels

Also the device can suspport any other combination of differential and
pseudo-differential channels base on the physical number of inputs
available.

Signed-off-by: Mircea Caprioru <mircea.caprioru@analog.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: adc: ad7124: Add buffered input support

This patch adds the option to enable the buffered mode for positive and
negative inputs. Each option can be enabled independently.

In buffered mode, the input channel feeds into a high impedance input stage
of the buffer amplifier. Therefore, the input can tolerate significant
source impedances and is tailored for direct connection to external
resistive type sensors such as strain gages or RTDs.

Signed-off-by: Mircea Caprioru <mircea.caprioru@analog.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: adc: ad7124: Remove input number limitation

The driver limits the user to use only 4/8 differential inputs, but this
device has the option to use pseudo-differential channels. This will
increase the number of channels to be equal with the number of inputs so 8
channels for ad7124-4 and 16 for ad7124-8.

This patch removes the check between channel nodes and num_inputs value.

Signed-off-by: Mircea Caprioru <mircea.caprioru@analog.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: adc: ad7124 fix indentation issue, remove extra tab

A return statement is indented one level too deeply; clean this
up by removing a tab.

Signed-off-by: Colin Ian King <colin.king@canonical.com>
Acked-by: Stefan Popa <stefan.popa@analog.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: adc: Add ad7124 support

The ad7124-4 and ad7124-8 are a family of 4 and 8 channel sigma-delta ADCs
with 24-bit precision and reference.

Three power modes are available which in turn affect the output data rate:
* Full power: 9.38 SPS to 19,200 SPS
* Mid power: 2.34 SPS to 4800 SPS
* Low power: 1.17 SPS to 2400 SPS

The ad7124-4 can be configured to have four differential inputs, while
ad7124-8 can have 8. Moreover, ad7124 also supports per channel
configuration. Each configuration consists of gain, reference source,
output data rate and bipolar/unipolar configuration.

Datasheets:
Link: http://www.analog.com/media/en/technical-documentation/data-sheets/AD7124-4.pdf
Link: http://www.analog.com/media/en/technical-documentation/data-sheets/ad7124-8.pdf

Signed-off-by: Stefan Popa <stefan.popa@analog.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>