iio: adc: ad7606: 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.

Whilst here also switch to dev_err_probe() to provide more information
if a deferred probe occurs.

Signed-off-by: Matti Vaittinen <mazziesaccount@gmail.com>
Acked-by: Nuno Sá <nuno.sa@analog.com>
Link: https://lore.kernel.org/r/521c52f5a9bdc2db04d5775b36df4b233ae338da.1660934107.git.mazziesaccount@gmail.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: adc: ad7606: 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_ALIGN definition.

Update the comment to reflect the fact DMA safety 'may' require
separate cachelines.

Fixes: 7989b4bb23fe ("iio: adc: ad7616: Add support for AD7616 ADC")
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Acked-by: Nuno Sá <nuno.sa@analog.com>
Link: https://lore.kernel.org/r/20220508175712.647246-15-jic23@kernel.org

iio: adc: ad7606: Fix syntax errors in comments

Delete the redundant word 'the'.

Signed-off-by: Xiang wangx <wangxiang@cdjrlc.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: adc: ad7606: Add support for AD7606B ADC

The AD7606B is a 16-bit ADC that supports simultaneous sampling of 8
channels. It is pin compatible to AD7606, but adds extra modes by
writing to the register map.

The AD7606B can be configured to work in software mode by setting all
oversampling pins to high. This mode is selected by default.
The oversampling ratio is configured from the OS_MODE register (address
0x08) with the addition of OS=128 and OS=256 that were not available in
hardware mode.

The device is configured to output data on a single spi channel, but this
configuration must be done right after restart. That is why the delay was
removed for devices which doesn't require it.

Moreover, in software mode, the range gpio has no longer its function.
Instead, the scale can be configured individually for each channel from
the RANGE_CH registers (address 0x03 to 0x06). Besides the already
supported ±10 V and ±5 V ranges, software mode can also accommodate the
±2.5 V range.

Signed-off-by: Stefan Popa <stefan.popa@analog.com>
Co-developed-by: Beniamin Bia <beniamin.bia@analog.com>
Signed-off-by: Beniamin Bia <beniamin.bia@analog.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: adc: ad7606: Add support for software mode for ad7616

Support for ad7616 running in software was added. In order
to activate the software mode, HW_RNGSEL pins must be pulled low.
Oversampling and input ranges are now configured in corresponding
registers. Ad7616 has multiple scale options when it is configured
in software mode.
Also, in order to support multiple devices in software mode, the spi
calculation of registers address must be generic. Because
the length of address and bit which specifies the read/write operation is
different for every device, calculation of address was made generic.

Signed-off-by: Beniamin Bia <beniamin.bia@analog.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: adc: ad7606: Move spi dependent features to spi file

Because software mode and register access are only available in spi, they
were moved in spi file and are accessbile via bops structure.
The write_os/scale will be overwritten by sw_mode_config function.
This patch was made in order to support devices in software mode without
making the driver dependent to spi and increase the abstraction of the
core.

Signed-off-by: Beniamin Bia <beniamin.bia@analog.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: adc: ad7606: Move common channel definition to header

The common channel definition which are going to be used by both core
file but also spi file, were moved in header file. Some devices have
different channel definitions when are used in software mode, feature
available only with spi, and those definitions will be added in spi file.

Signed-off-by: Beniamin Bia <beniamin.bia@analog.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: adc: ad7606: Add software configuration

Because this driver will support multiple configurations for software,
the software configuration was made generic.

Signed-off-by: Beniamin Bia <beniamin.bia@analog.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: adc: ad7606: Move oversampling and scale options to chip info

The device dependent options which are going to be different for devices
which will be supported in the future by this driver,
were moved in chip info for a more generic driver. This patch allows
supporting more devices by the driver. Also, it is an intermediate
step of adding support for ad7616 in software mode.

Signed-off-by: Beniamin Bia <beniamin.bia@analog.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: adc: ad7616: Add support for AD7616 ADC

The AD7616 is a 12-bit ADC with 16 channels.

The AD7616 can be configured to work in hardware mode by controlling it via
gpio pins and read data via spi. No support for software mode yet, but it
is a work in progress.

This device requires a reset in order to update oversampling, so chip info
has got a new attribute to mark this.

The current assumption that this driver makes for AD7616, is that it's
working in Hardware Mode with Serial, Burst and Sequencer modes activated.
To activate them, following pins must be pulled high:
-SER/PAR
-SEQEN
And following must be pulled low:
-WR/BURST
-DB4/SEQEN

Datasheets:
Link: https://www.analog.com/media/en/technical-documentation/data-sheets/ad7616.pdf

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

iio: adc: ad7606: Move oversampling options in chip info and rework *_avail attributes

Available oversampling ratios and scales can be shown by calling a
common ad7606_show_avail function which takes as parameters the array
which stores the values, together with the size of the array.

Oversampling options are now defined in chip info
structure and they are loaded at probe.

Has_Oversampling attribute was removed because oversampling_num was added
and it is not needed anymore.

The purpose of this patch is to deal with the scale_avail and
oversampling_avail arrays in a generic way. This makes it easier to add
support for new devices which will work with different scales and
oversampling ratios. It is also an intermediate step for adding support
for ad7616 which has different oversampling sampling ratios available.

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

staging: iio: adc: ad7606: Move out of staging

Move ad7606 ADC driver out of staging and into the mainline.

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