iio: adc: max1118: Fix alignment for DMA safety

____cacheline_aligned is an insufficient guarantee for non-coherent DMA
on platforms with 128 byte cachelines above L1. Switch to the updated
IIO_DMA_MINALIGN definition.

Fixes: a9e9c7153e96 ("iio: adc: add max1117/max1118/max1119 ADC driver")
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Akinobu Mita <akinobu.mita@gmail.com>
Acked-by: Nuno Sá <nuno.sa@analog.com>
Link: https://lore.kernel.org/r/20220508175712.647246-26-jic23@kernel.org

iio: adc: max1118: Make use of the helper function dev_err_probe()

When possible use dev_err_probe help to properly deal with the
PROBE_DEFER error, the benefit is that DEFER issue will be logged
in the devices_deferred debugfs file.
Using dev_err_probe() can reduce code size, and the error value
gets printed.

Signed-off-by: Cai Huoqing <caihuoqing@baidu.com>
Link: https://lore.kernel.org/r/20211008092858.495-4-caihuoqing@baidu.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: adc: max1118: Avoid jumping back and forth between spi and iio structures

Changing from passing the spi structure into various functions to
passing struct iio_dev avoids use of spi_get_drvdata and lets us
stop setting that at all. Previous code was unnecessarily complex.

Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Alexandru Ardelean <aardelean@deviqon.com>
Link: https://lore.kernel.org/r/20210516172520.1398835-5-jic23@kernel.org

iio: adc: max1118: Use devm_ managed functions for all of probe

This simplifies error handling and allows us to drop the remove
function entirely.

Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Akinobu Mita <akinobu.mita@gmail.com>
Reviewed-by: Alexandru Ardelean <aardelean@deviqon.com>
Link: https://lore.kernel.org/r/20210516172520.1398835-4-jic23@kernel.org

iio:adc:max1118 Fix alignment of timestamp and data leak issues

One of a class of bugs pointed out by Lars in a recent review.
iio_push_to_buffers_with_timestamp assumes the buffer used is aligned
to the size of the timestamp (8 bytes). This is not guaranteed in
this driver which uses an array of smaller elements on the stack.
As Lars also noted this anti pattern can involve a leak of data to
userspace and that indeed can happen here. We close both issues by
moving to a suitable structure in the iio_priv() data.

This data is allocated with kzalloc so no data can leak apart
from previous readings.

The explicit alignment of ts is necessary to ensure correct padding
on architectures where s64 is only 4 bytes aligned such as x86_32.

Fixes: a9e9c7153e96 ("iio: adc: add max1117/max1118/max1119 ADC driver")
Reported-by: Lars-Peter Clausen <lars@metafoo.de>
Cc: Akinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Cc: <Stable@vger.kernel.org>

iio:adc:max1118: Drop CONFIG_OF / of_match_ptr protections

These just stop the driver being used with ACPI PRP0001 and
we are trying to clear them out of IIO to avoid them getting copied
into new drivers.
Also add the mod_devicetable.h include as we are using
struct of_device_id which is defined in there.

Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Akinobu Mita <akinobu.mita@gmail.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.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: max1118: Use new structure for SPI transfer delays

In a recent change to the SPI subsystem [1], a new `delay` struct was added
to replace the `delay_usecs`. This change replaces the current
`delay_usecs` with `delay` for this driver.

The `spi_transfer_delay_exec()` function [in the SPI framework] makes sure
that both `delay_usecs` & `delay` are used (in this order to preserve
backwards compatibility).

[1] commit bebcfd272df6 ("spi: introduce `delay` field for
`spi_transfer` + spi_transfer_delay_exec()")

Signed-off-by: Sergiu Cuciurean <sergiu.cuciurean@analog.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 330

Based on 1 normalized pattern(s):

this file is subject to the terms and conditions of version 2 of the
gnu general public license see the file copying in the main
directory of this archive for more details

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-only

has been chosen to replace the boilerplate/reference in 55 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Alexios Zavras <alexios.zavras@intel.com>
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190530000436.108941081@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

iio:adc: drop assign iio_info.driver_module and iio_trigger_ops.owner

The equivalent of both of these are now done via macro magic when
the relevant register calls are made. The actual structure
elements will shortly go away.

Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Lars-Peter Clausen <lars@metafoo.de>

iio: adc: add max1117/max1118/max1119 ADC driver

This adds max1117/max1118/max1119 8-bit, dual-channel ADC driver.

This new driver uses the zero length spi_transfers with the cs_change
flag set and/or the non-zero delay_usecs.

1. The zero length transfer with the spi_transfer.cs_change set is
required in order to select CH1. The chip select line must be brought
high and low again without transfer.

2. The zero length transfer with the spi_transfer.delay_usecs > 0 is
required for waiting the conversion to be complete. The conversion
begins with the falling edge of the chip select. During the conversion
process, SCLK is ignored.

These two usages are unusual. But the spi controller drivers that use
a default implementation of transfer_one_message() are likely to work.
(I've tested this adc driver with spi-omap2-mcspi and spi-xilinx)

On the other hand, some spi controller drivers that have their own
transfer_one_message() may not work. But at least for the zero length
transfer with delay_usecs > 0, I'm proposing a new testcase for the
spi-loopback-test that can test whether the delay_usecs setting has
taken effect.

Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
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: Rob Herring <robh+dt@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mark Brown <broonie@kernel.org>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>