This patch solves the register readback issue with the bit shift. When the
dac resolution was lower than the register size (ex. 12 bits out of 16
bits) the readback value was not shifted with the difference in bits and
the value was higher. Also a mask is applied on the read value in order to
get the value relative to the actual bit size.

Fixes: 0357e488b8 ("iio:dac:ad5686: Refactor the driver")
Signed-off-by: Mircea Caprioru <mircea.caprioru@analog.com>
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

The AD5310R is a single channel DAC with 10-bit precision, which is
part of the same family as AD5311R, except that it uses the spi interface
instead of i2c. The device has a built-in 2.5V reference which is enabled
by default.

Another important difference is that the SPI write command operation is
16 bits long. The first four bits represent the command, while the
remaining 12 bits are for data. In the control reg, DB9 and DB10 are used
for power-down modes, while DB8 is the REF bit. In order to accommodate
this change, a new regmap type was defined and checked accordingly.

Because AD5310R does not have a readback register, the read_raw operation
will return "Operation is not supported".

Datasheet:
Link: http://www.analog.com/media/en/technical-documentation/data-sheets/AD5310R_5311R.pdf

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

It is a driver for Texas Instruments 8/10/12-bit 1-channel
compatible with DAC6311 and DAC5311 chips.

Datasheet of this chip:
http://www.ti.com/lit/ds/symlink/dac7311.pdf

Signed-off-by: Charles-Antoine Couret <charles-antoine.couret@essensium.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

In preparation to enabling -Wimplicit-fallthrough, mark switch cases
where we are expecting to fall through.

Notice that in this particular case, I replaced "...and fall through."
with the specific string "fall through", which is what GCC is
expecting to find thus supressing this false positive.

As Peter has observed this breaks the nice English flow, which is
less than ideal, but short of teaching GCC to read English, there
isn't a lot that we can do about it.

Addresses-Coverity-ID: 1462408 ("Missing break in switch")
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

The correct way to handle errors returned by regualtor_get() and friends is
to propagate the error since that means that an regulator was specified,
but something went wrong when requesting it.

For handling optional regulators, e.g. when the device has an internal
vref, regulator_get_optional() should be used to avoid getting the dummy
regulator that the regulator core otherwise provides.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

Jonathan writes:

1st round of IIO new device support, features and cleanups in the 4.20 cycle.

There is a merge commit in here to pull in regmap support for repeatedly
reading the same register (to read out FIFOs).  Used by the adxl372 driver.
This will find uses elsewhere once we tidy up various drivers that are
effectively doing this and relying on not enabling regcache.

New device support
* Analog devices ADXL372 accelerometer
  - new driver for this accelerometer including fifo and and interrupt support.
    Follow up patches enforce trigger validation, add sampling frequency
    control and filter bandwidth control.  A later series added i2c support
    to the existing SPI support.
* ST lsm6dsx
  - rework and add support fo the LSM6DSO 6 axis mems sensor.
* Linear LTC 1660 DAC
  - new driver supporting the LTC 1660 and LTC 1665 SPI DACs.
* Microchip mcp3911 ADC.
  - new driver for this integrated analog front end and ADC.
* Qualcomm SPMI PMIC5 adc driver
  - using the spmi framework, new driver and bindings for this ADC.
    Follow up patch adds some missing channels.

Features
* ad5758
  - support hard reset using a gpio (if provided).
* mpu6050
  - Regulator support
* qcom-spmi-adc5
  - Sanity check the channel numbers provided by DT to make sure the
    driver actually knows about them.
* sc27xx
  - give raw data for channel 20 as it's used on all known boards for
    the headset which needs a custom converstion function.  If it turns
    out someone builds a board where this isn't true we will deal with it
    when it happens.
  - add ADC scale calibration.
* tsl2772
  - support device tree binding to set the proximity led settings.
  - regulator supprot.
  - binding for apds9930 - trivial addition as register compatible with tsl2772.

Cleanups / Minor fixes

* adxl345
  - supress a static checker warning but explicitly checking if the id
    object is null.
* bh1750
  - avoid CONFIG_PM_SLEEP checks.
  - SPDX.
* bme680
  - spelling mistake
  - use clamp rather than open coding.
  - white space and other similar fixes.
  - rename MSK to MASK for clarifty and use GENMASK to specify them.
  - use the FIELD_GET macro rather than a very odd accessor of dividing by
    16 to get the shift.
  - rework to share handing for oversampling of the various channels in a
    unified way.
  - check explicitly for val2 in write_raw function to ensure it is 0.
  - drop some field defines that don't add anything.
* dpot-adc
  - SPDX
* envelope detector
  - SPDX
* isl29501
  - fix an ancient compiler warning mostly because it results in much
    nicer code.
* max30102
  - mark switch fall throughs.
* max44000
  - drop an unused variable.
* max512
  - avoid CONFIG_PM_SLEEP checks.
* max5481
  - use of_device_get_match_data rather than open coding it.
* max5821
  - avoid CONFIG_PM_SLEEP checks.
* max9611
  - explicity cast an enum to an integer to make it totally clear that
    this is intended.
* mcp4018
  - fix an inconsistent MODULE_LICENSE.
  - use of_device_get_match_data rather than open coding it.
* mcp4531
  - use of_device_get_match_data rather than open coding it.
  - SPDX
* mcp4725
  - avoid CONFIG_PM_SLEEP checks.
* mcp4922
  - Fix error handling and prevent writing a negative to when setting the
    output voltage.
* ms5611
  - drop deprecated compatible strings without manufacturer from being
    explicitly listed.  They are handled anyway.
  - SPDX
* multiplexer
  - SPDX
* qcom-vadc
  - fix inconsistent documentation for reg.
* ti-dac5571
  - provide and of_match_table.

* treewide
  - update Michael Hennerich's email address.
  - Use %pOFn rather than device_node.name.
* documentation.
  - tidy up a wrong kernel version for the introduction of the
    position_relative ABI.

The ad5758 has a hardware reset active low input pin. This patch adds a
devicetree entry for a reset GPIO and a new ad5758_reset() function.
During
initialization, it is checked if the reset property is specified and the
the GPIO is being asserted, therefore the device will become active.

When the reset function is called, if the gpio_reset var is set, then
the
GPIO will be toggled, otherwise a software reset is performed.

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

Use the created list of of_device_id's as a match table.

Signed-off-by: Marcus Folkesson <marcus.folkesson@gmail.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

Do not try to write negative values and make sure that the write goes well.

Signed-off-by: Marcus Folkesson <marcus.folkesson@gmail.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

LTC1665/LTC1660 is a 8/10-bit Digital-to-Analog Converter
(DAC) with eight individual channels.

Signed-off-by: Marcus Folkesson <marcus.folkesson@gmail.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>