iio: adc: vf610_adc: Convert to platform remove callback returning void

The .remove() callback for a platform driver returns an int which makes
many driver authors wrongly assume it's possible to do error handling by
returning an error code. However the value returned is ignored (apart
from emitting a warning) and this typically results in resource leaks.
To improve here there is a quest to make the remove callback return
void. In the first step of this quest all drivers are converted to
.remove_new() which already returns void. Eventually after all drivers
are converted, .remove_new() will be renamed to .remove().

Trivially convert this driver from always returning zero in the remove
callback to the void returning variant.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Link: https://lore.kernel.org/r/20230919174931.1417681-29-u.kleine-koenig@pengutronix.de
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: adc: vf610_adc: vf610_adc: do not use internal iio_dev lock

In order to drop the internal lock usage we needed two different things:

1) The first place where 'mlock' was being used was a typical case where
iio_device_claim_direct_mode() fits perfectly.
2) In the second case, it was being used to prevent concurrent accesses
to the device and shared data but nothing was being enforced with
regards to buffering (i.e, there was nothing preventing from changing
the conversion mode while buffering). Hence, in this case, a new lock
was introduced in the state structure.

Note that the goal is not to introduce any functional change and that is
the reason why a new lock was introduced to guarantee 2).

While at it, properly include "mutex.h" for mutex related APIs.

Signed-off-by: Nuno Sá <nuno.sa@analog.com>
Reviewed-by: Haibo Chen <haibo.chen@nxp.com>
Link: https://lore.kernel.org/r/20221004134909.1692021-11-nuno.sa@analog.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: adc: vf610_adc: add helper function to read samples

This is a precursor change to make it simpler to remove the 'mlock'
usage. Having the code in it's own helper function, also makes it easier
to read the error paths.

Signed-off-by: Nuno Sá <nuno.sa@analog.com>
Reviewed-by: Haibo Chen <haibo.chen@nxp.com>
Link: https://lore.kernel.org/r/20221004134909.1692021-10-nuno.sa@analog.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: adc: vf610_adc: Make use of device properties

Convert the module to be property provider agnostic and allow
it to be used on non-OF platforms.

Add mod_devicetable.h include.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20220531142353.64925-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio:adc:vf610: Switch from CONFIG_PM_SLEEP guards to pm_sleep_ptr() etc

Letting the compiler remove these functions when the kernel is built
without CONFIG_PM_SLEEP support is simpler and less error prone than the
use of ifdef based config guards.

Removing instances of this approach from IIO also stops them being
copied into new drivers.

Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Stefan-Gabriel Mirea <stefan-gabriel.mirea@nxp.com>
Reviewed-by: Paul Cercueil <paul@crapouillou.net>
Link: https://lore.kernel.org/r/20220130193147.279148-16-jic23@kernel.org

iio: adc: vf610: Fix buffer alignment in iio_push_to_buffers_with_timestamp()

To make code more readable, use a structure to express the channel
layout and ensure the timestamp is 8 byte aligned.

Found during an audit of all calls of uses of
iio_push_to_buffers_with_timestamp()

Fixes: 0010d6b44406 ("iio: adc: vf610: Add IIO buffer support for Vybrid ADC")
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Stefan-Gabriel Mirea <stefan-gabriel.mirea@nxp.com>
Cc: Sanchayan Maity <maitysanchayan@gmail.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Link: https://lore.kernel.org/r/20210501170121.512209-10-jic23@kernel.org

iio: Move attach/detach of the poll func to the core

All devices using a triggered buffer need to attach and detach the trigger
to the device in order to properly work. Instead of doing this in each and
every driver by hand move this into the core.

At this point in time, all drivers should have been resolved to
attach/detach the poll-function in the same order.

This patch removes all explicit calls of iio_triggered_buffer_postenable()
& iio_triggered_buffer_predisable() in all drivers, since the core handles
now the pollfunc attach/detach.

The more peculiar change is for the 'at91-sama5d2_adc' driver, since it's
not immediately obvious that removing the hooks doesn't break anything.
Eugen was able to test on at91-sama5d2-adc driver, sama5d2-xplained board.
All seems to be fine.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
Tested-by: Eugen Hristev <eugen.hristev@microchip.com> #for at91-sama5d2-adc
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: Remove superfluous of_node assignments

If a driver does not assign an of_node to a IIO device to IIO core will
automatically assign the of_node of the parent device. This automatic
assignment is done in the iio_device_register() function.

There is a fair amount of drivers that currently manually assign the
of_node of the IIO device. All but 4 of them can make use of the automatic
assignment though.

The exceptions are:
* mxs-lradc-adc: Which uses the of_node of the parent of the parent.
* stm32-dfsdm-adc, stm32-adc and stm32-dac: Which reference the of_node
assigned to the IIO device before iio_device_register() is called.

All other drivers are updated to use automatic assignment. This reduces
the amount of boilerplate code involved in setting up the IIO device.

The patch has mostly been auto-generated with the following semantic patch

// <smpl>
@exists@
expression indio_dev;
expression parent;
@@
indio_dev = \(devm_iio_device_alloc\|iio_device_alloc\)(&parent, ...)
...
-indio_dev->dev.of_node = parent.of_node;

@exists@
expression indio_dev;
expression parent;
@@
indio_dev = \(devm_iio_device_alloc\|iio_device_alloc\)(parent, ...)
...
-indio_dev->dev.of_node = parent->of_node;
// </smpl>

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.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: vf610: use devm_platform_ioremap_resource

Reduces boilerplate.

Suggested by coccinelle
CHECK drivers/iio/adc/vf610_adc.c
drivers/iio/adc/vf610_adc.c:819:1-11: WARNING: Use devm_platform_ioremap_resource for info -> regs

Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
Cc: Fugang Duan <b38611@freescale.com>

iio: Remove dev_err() usage after platform_get_irq()

We don't need dev_err() messages when platform_get_irq() fails now that
platform_get_irq() prints an error message itself when something goes
wrong. Let's remove these prints with a simple semantic patch.

// <smpl>
@@
expression ret;
struct platform_device *E;
@@

ret =
(
platform_get_irq(E, ...)
|
platform_get_irq_byname(E, ...)
);

if ( \( ret < 0 \| ret <= 0 \) )
{
(
-if (ret != -EPROBE_DEFER)
-{ ...
-dev_err(...);
-... }
|
...
-dev_err(...);
)
...
}
// </smpl>

While we're here, remove braces on if statements that only have one
statement (manually).

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: linux-iio@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Stephen Boyd <swboyd@chromium.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 61

Based on 1 normalized pattern(s):

this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license as published by
the free software foundation either version 2 of the license or at
your option any later version this program is distributed in the
hope that it will be useful but without any warranty without even
the implied warranty of merchantability or fitness for a particular
purpose see the gnu general public license for more details you
should have received a copy of the gnu general public license along
with this program if not write to the free software foundation inc
675 mass ave cambridge ma 02139 usa

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 441 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc)
Reviewed-by: Richard Fontana <rfontana@redhat.com>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190520071858.739733335@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: vf610_adc: Fix VALT selection value for REFSEL bits

In order to select the alternate voltage reference pair (VALTH/VALTL), the
right value for the REFSEL field in the ADCx_CFG register is "01", leading
to 0x800 as register mask. See section 8.2.6.4 in the reference manual[1].

[1] http://www.nxp.com/docs/en/reference-manual/VFXXXRM.pdf

Fixes: a775427632fd ("iio:adc:imx: add Freescale Vybrid vf610 adc driver")
Signed-off-by: Stefan-Gabriel Mirea <stefan-gabriel.mirea@nxp.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: adc: Remove unnecessary cast on void pointer

The following Coccinelle script was used to detect this:
@r@
expression x;
void* e;
type T;
identifier f;
@@
(
*((T *)e)
|
((T *)x)[...]
|
((T*)x)->f
|
- (T*)
e
)

Signed-off-by: simran singhal <singhalsimran0@gmail.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio:core: timestamping clock selection support

Adds a new per-device sysfs attribute "current_timestamp_clock" to allow
userspace to select a particular POSIX clock for buffered samples and
events timestamping.

Following clocks, as listed in clock_gettime(2), are supported:
CLOCK_REALTIME, CLOCK_MONOTONIC, CLOCK_MONOTONIC_RAW,
CLOCK_REALTIME_COARSE, CLOCK_MONOTONIC_COARSE, CLOCK_BOOTTIME and
CLOCK_TAI.

Signed-off-by: Gregor Boirie <gregor.boirie@parrot.com>
Acked-by: Sanchayan Maity <maitysanchayan@gmail.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio: adc: vf610_adc: fix case label indent

This fixes the error reported by checkpatch.pl:

ERROR: switch and case should be at the same indent

Signed-off-by: Slawomir Stepien <sst@poczta.fm>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio: adc: vf610_adc: Fix division by zero error

In case the fsl,adck-max-frequency property is not present in
the device tree, a division by zero error results during the
probe call on kernel boot (see below). This patch fixes it and
also restores device tree compatibility in case kernels are
booting with old device trees without this property specified.

[ 1.063229] Division by zero in kernel.
[ 1.067152] CPU: 0 PID: 1 Comm: swapper Not tainted
4.3.0-rc5-00212-gcc88cef #37
[ 1.074650] Hardware name: Freescale Vybrid VF5xx/VF6xx (Device Tree)
[ 1.081135] Backtrace:
[ 1.083694] [<800134a4>] (dump_backtrace) from [<8001369c>]
(show_stack+0x18/0x1c)
[ 1.091340] r7:00000008 r6:8e0ae210 r5:00000000 r4:8e299800
[ 1.097146] [<80013684>] (show_stack) from [<80297b1c>]
(dump_stack+0x24/0x28)
[ 1.104483] [<80297af8>] (dump_stack) from [<80013608>]
(__div0+0x1c/0x20)
[ 1.111421] [<800135ec>] (__div0) from [<802968b4>] (Ldiv0+0x8/0x10)
[ 1.117865] [<80424350>] (vf610_adc_probe) from [<803153b4>]
(platform_drv_probe+0x4c/0xac)
[ 1.126311] r10:00000000 r9:8076a5ec r8:00000000 r7:fffffdfb
r6:807cc67c r5:8e0ae210
[ 1.134319] r4:807f6c54
[ 1.136915] [<80315368>] (platform_drv_probe) from [<803138bc>]
(driver_probe_device+0x20c/0x2f8)
[ 1.145882] r7:807cc67c r6:00000000 r5:8e0ae210 r4:807f6c54
[ 1.151657] [<803136b0>] (driver_probe_device) from [<80313a3c>]
(__driver_attach+0x94/0x98)
[ 1.160190] r9:8076a5ec r8:00000098 r7:00000000 r6:8e0ae244
r5:807cc67c r4:8e0ae210
[ 1.168112] [<803139a8>] (__driver_attach) from [<80311cb8>]
(bus_for_each_dev+0x70/0xa4)
[ 1.176383] r7:00000000 r6:803139a8 r5:807cc67c r4:00000000
[ 1.182159] [<80311c48>] (bus_for_each_dev) from [<80313318>]
(driver_attach+0x24/0x28)
[ 1.190260] r6:807bb568 r5:8e2a5b00 r4:807cc67c
[ 1.194996] [<803132f4>] (driver_attach) from [<80312f50>]
(bus_add_driver+0x1a4/0x21c)
[ 1.203113] [<80312dac>] (bus_add_driver) from [<803142a8>]
(driver_register+0x80/0x100)
[ 1.211275] r7:8e2a7dc0 r6:807a8160 r5:80789e14 r4:807cc67c
[ 1.217075] [<80314228>] (driver_register) from [<803152f8>]
(__platform_driver_register+0x5c/0x64)
[ 1.226216] r5:80789e14 r4:807a8160
[ 1.229877] [<8031529c>] (__platform_driver_register) from
[<80789e30>] (vf610_adc_driver_init+0x1c/0x20)
[ 1.239556] [<80789e14>] (vf610_adc_driver_init) from [<800095f8>]
(do_one_initcall+0x94/0x1dc)
[ 1.248365] [<80009564>] (do_one_initcall) from [<8076ae34>]
(kernel_init_freeable+0x13c/0x1e0)
[ 1.257155] r10:80794830 r9:8076a5ec r8:00000098 r7:807d5780
r6:807d5780 r5:00000006
[ 1.265153] r4:807a0ee8
[ 1.267753] [<8076acf8>] (kernel_init_freeable) from [<80590ef0>]
(kernel_init+0x18/0xf0)
[ 1.276021] r10:00000000 r9:00000000 r8:00000000 r7:00000000
r6:00000000 r5:80590ed8
[ 1.284015] r4:807d5780
[ 1.286615] [<80590ed8>] (kernel_init) from [<8000f878>]
(ret_from_fork+0x14/0x3c)
[ 1.294278] r5:80590ed8 r4:00000000

Signed-off-by: Sanchayan Maity <maitysanchayan@gmail.com>
Acked-by: Fugang Duan <B38611@freescale.com>
Acked-by: Stefan Agner <stefan@agner.ch>
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

vf610_adc: Fix internal temperature calculation

Calculate ADCR_VTEMP25 using VTEMP25 at VREFH_ADC 3V3. Existing
calculations consider the typical values provided in datasheet.
Those typical values are valid for VREFH_ADC at 3.0V. VTEMP25
is different for different VREFH_ADC voltages. With VREFH_ADC
at 3.3V, voltage at 25°C is 0.699V. Hence update the VTEMP25
to 0.699V which gives ADCR@Temp25 as 867.

Formula for finding ADCR@Temp25:
ADCR@Temp25 = (ADCR@Vdd * V@TEMP25 * 10) / VDDconv

ADCR@Vdd for 12-Bit ADC = 4095
VDDconv = VREFH_ADC * 10

VREFH_ADC@3.3V
ADCR@Temp25 = (4095 * .699 * 10) / 33
ADCR@Temp25 ~= 867

| VREFH_ADC | V@TEMP25 | VDDconv | ADCR@Temp25 |
| 3.0V | 0.696mV | 30 | 950 |
| 3.3V | 0.699mV | 33 | 867 |

Signed-off-by: Bhuvanchandra DV <bhuvanchandra.dv@toradex.com>
Acked-by: Fugang Duan <B38611@freescale.com>
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio: adc: vf610: fix simple_return.cocci warnings

drivers/iio/adc/vf610_adc.c:766:1-4: WARNING: end returns can be simpified and declaration on line 755 can be dropped

Simplify a trivial if-return sequence. Possibly combine with a
preceding function call.

Generated by: scripts/coccinelle/misc/simple_return.cocci

CC: Sanchayan Maity <maitysanchayan@gmail.com>
Signed-off-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio: adc: vf610: Add IIO buffer support for Vybrid ADC

This patch adds support for IIO buffer to the Vybrid ADC driver.
IIO triggered buffer infrastructure along with iio sysfs trigger
is used to leverage continuous sampling support provided by the
ADC block.

Signed-off-by: Sanchayan Maity <maitysanchayan@gmail.com>
Acked-by: Fugang Duan <B38611@freescale.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio: adc: vf610: Determine sampling frequencies by using minimum sample time

The driver currently does not take into account the minimum sample time
as per the Figure 6-8 Chapter 9.1.1 12-bit ADC electrical characteristics.
We set a static amount of cycles instead of considering the sample time
as a given value, which depends on hardware characteristics.

Determine sampling frequencies by first reading the device tree property
node and then calculating the required Long Sample Time Adder (LSTAdder)
value, based on the ADC clock frequency and sample time value obtained
from the device tree. This LSTAdder value is then used for calculating
the sampling frequencies possible.

In case the sample time property is not specified through the device
tree, a safe default value of 1000ns is assumed.

Signed-off-by: Sanchayan Maity <maitysanchayan@gmail.com>
Acked-by: Stefan Agner <stefan@agner.ch>
Acked-by: Fugang Duan <B38611@freescale.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio: adc: vf610: fix the adc register read fail issue

Read the register only when the adc register address is 4 byte aligned.
(rather than the other way around).

Signed-off-by: Haibo Chen <haibo.chen@freescale.com>
Signed-off-by: Fugang Duan <B38611@freescale.com>
Cc: <Stable.vger.kernel.org>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio: adc: vf610: implement configurable conversion modes

Support configurable conversion mode through sysfs. So far, the
mode used was low-power, which is enabled by default now. Beside
that, the modes normal and high-speed are selectable as well.

Use the new device tree property which specifies the maximum ADC
conversion clock frequencies. Depending on the mode used, the
available resulting conversion frequency are calculated
dynamically.

Acked-by: Fugang Duan <B38611@freescale.com>
Signed-off-by: Stefan Agner <stefan@agner.ch>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio: adc: vf610: use ADC clock within specification

Depending on conversion mode used, the ADC clock (ADCK) needs
to be below a maximum frequency. According to Vybrid's data
sheet this is 20MHz for the low power conversion mode.

The ADC clock is depending on input clock, which is the bus
clock by default. Vybrid SoC are typically clocked at at 400MHz
or 500MHz, which leads to 66MHz or 83MHz bus clock respectively.
Hence, a divider of 8 is required to stay below the specified
maximum clock of 20MHz.

Due to the different bus clock speeds, the resulting sampling
frequency is not static. Hence use the ADC clock and calculate
the actual available sampling frequency dynamically.

This fixes bogous values observed on some 500MHz clocked Vybrid
SoC. The resulting value usually showed Bit 9 being stuck at 1,
or 0, which lead to a value of +/-512.

Signed-off-by: Stefan Agner <stefan@agner.ch>
Acked-by: Fugang Duan <B38611@freescale.com>
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio: vf610_adc: cleanup wait_for_completion return handling

return type of wait_for_completion_timeout is unsigned long not int, this
patch only fixes up the return handling.

Signed-off-by: Nicholas Mc Guire <hofrat@osadl.org>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio: adc: vf610: Propagate the real error when platform_get_irq() fails

There is no need to pass a 'fake' return value when platform_get_irq() fails.

Propagate the real error instead.

While at it, only consider negative numbers returned by platform_get_irq()
as error.

Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio: adc: vf610: SIMPLE_DEV_PM_OPS can fit on a single line

No need to call the SIMPLE_DEV_PM_OPS() macro in several lines.

It can fit into the 80-column range.

Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio: adc: vf610: Disable the regulator on error

If clk_prepare_enable() fails we should disable the regulator that was
previously enabled.

Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio: adc: vf610: Return the error code directly

There is no need to pass the error clock code to the variable 'ret'.

Just return the error directly.

Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio:adc:vf610-adc: Add temperature sensor support

Vybrid ADC peripheral includes a temperature sensor
which is connected to channel number 26. This patch
adds support for the sensor. The raw value is read
and the temperature calculated in milli degree Celsius,
which is returned using IIO_CHAN_INFO_PROCESSED option.

Signed-off-by: Sanchayan Maity <maitysanchayan@gmail.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio: remove .owner field for driver using module_platform_driver

This patch removes the .owner field for drivers which use the
platform_driver_register api because this is overriden in
_platform_driver_register.

Signed-off-by: Sanjeev Sharma <Sanjeev_Sharma@mentor.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio:adc:vf610 ensure correct handing of interruption of wait for completion

Issue highlighted by smatch warning:

CHECK drivers/iio/adc/vf610_adc.c
drivers/iio/adc/vf610_adc.c:466 vf610_read_raw() warn: unsigned 'ret' is never less than zero.

As wait_for_completion_interruptible_timeout can return -ERESTARTSTSYS, if
interrupted, ret must be signed.

Signed-off-by: Jonathan Cameron <jic23@kernel.org>
Acked-by: Fugang Duan <B38611@freescale.com>

iio:adc:imx: add Freescale Vybrid vf610 adc driver

Add Freescale Vybrid vf610 adc driver. The driver only support
ADC software trigger.

VF610 ADC device documentation is available at below reference manual
(chapter 37):
http://cache.freescale.com/files/32bit/doc/ref_manual/VYBRIDRM.pdf?
fpsp=1&WT_TYPE=Reference%20Manuals&WT_VENDOR=FREESCALE&WT_FILE_FORMAT
=pdf&WT_ASSET=Documentation

CC: Shawn Guo <shawn.guo@linaro.org>
CC: Jonathan Cameron <jic23@kernel.org>
CC: Mark Rutland <mark.rutland@arm.com>
CC: Otavio Salvador <otavio@ossystems.com.br>
CC: Peter Meerwald <pmeerw@pmeerw.net>
CC: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Fugang Duan <B38611@freescale.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>