iio: adc: max1241: simplify using devm_regulator_get_enable()

Drop open-coded pattern: 'devm_regulator_get(), regulator_enable(),
add_action_or_reset(regulator_disable)' and use the
devm_regulator_get_enable() and drop the pointer to the regulator.
This simplifies code and makes it less tempting to add manual control
for the regulator which is also controlled by devm.

Signed-off-by: Matti Vaittinen <mazziesaccount@gmail.com>
Acked-by: Alexandru Lazar <alazar@startmail.com>
Link: https://lore.kernel.org/r/7c759bf6c06e72ae70bffeebc1939d9903427278.1660934107.git.mazziesaccount@gmail.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: adc: max1241: 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: 8a80a71d9020 ("iio: adc: Add MAX1241 driver")
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Acked-by: Alexandru Lazar <alazar@startmail.com>
Acked-by: Nuno Sá <nuno.sa@analog.com>
Link: https://lore.kernel.org/r/20220508175712.647246-27-jic23@kernel.org

iio: adc: max1241: 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/20211008092858.495-5-caihuoqing@baidu.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: adc: remove unused private data assigned with spi_set_drvdata()

These were usually used before the conversion to devm_ functions, so that
the remove hook would be able to retrieve the pointer and do cleanups on
remove.
When the conversion happened, they should have been removed, but were
omitted.

Some drivers were copied from drivers that fit the criteria described
above. In any case, in order to prevent more drivers from being used as
example (and have spi_set_drvdata() needlessly set), this change removes it
from the IIO ADC group.

Signed-off-by: Alexandru Ardelean <aardelean@deviqon.com>
Link: https://lore.kernel.org/r/20210513111035.77950-1-aardelean@deviqon.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: Add MAX1241 driver

Add driver for the Maxim MAX1241 12-bit, single-channel ADC.

Datasheet: https://datasheets.maximintegrated.com/en/ds/MAX1240-MAX1241.pdf
Reviewed-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
Signed-off-by: Alexandru Lazar <alazar@startmail.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>