iio: adc: xilinx-xadc: Correct temperature offset/scale for UltraScale

The driver was previously using offset and scale values for the
temperature sensor readings which were only valid for 7-series devices.
Add per-device-type values for offset and scale and set them appropriately
for each device type.

Note that the values used for the UltraScale family are for UltraScale+
(i.e. the SYSMONE4 primitive) using the internal reference, as that seems
to be the most common configuration and the device tree values Xilinx's
device tree generator produces don't seem to give us anything to tell us
which configuration is used. However, the differences within the UltraScale
family seem fairly minor and it's closer than using the 7-series values
instead in any case.

Fixes: c2b7720a7905 ("iio: xilinx-xadc: Add basic support for Ultrascale System Monitor")
Signed-off-by: Robert Hancock <robert.hancock@calian.com>
Acked-by: O'Griofa, Conall <conall.ogriofa@amd.com>
Tested-by: O'Griofa, Conall <conall.ogriofa@amd.com>
Link: https://lore.kernel.org/r/20230915001019.2862964-3-robert.hancock@calian.com
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: adc: xilinx-xadc: Don't clobber preset voltage/temperature thresholds

In the probe function, the driver was reading out the thresholds already
set in the core, which can be configured by the user in the Vivado tools
when the FPGA image is built. However, it later clobbered those values
with zero or maximum values. In particular, the overtemperature shutdown
threshold register was overwritten with the max value, which effectively
prevents the FPGA from shutting down when the desired threshold was
eached, potentially risking hardware damage in that case.

Remove this code to leave the preconfigured default threshold values
intact.

The code was also disabling all alarms regardless of what enable state
they were left in by the FPGA image, including the overtemperature
shutdown feature. Leave these bits in their original state so they are
not unconditionally disabled.

Fixes: bdc8cda1d010 ("iio:adc: Add Xilinx XADC driver")
Signed-off-by: Robert Hancock <robert.hancock@calian.com>
Acked-by: O'Griofa, Conall <conall.ogriofa@amd.com>
Tested-by: O'Griofa, Conall <conall.ogriofa@amd.com>
Link: https://lore.kernel.org/r/20230915001019.2862964-2-robert.hancock@calian.com
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: adc: Use devm_krealloc_array

Now that it exists, use it instead of doing the multiplication and
checking for overflow manually.

Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: James Clark <james.clark@arm.com>
Link: https://lore.kernel.org/r/20230509094942.396150-4-james.clark@arm.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

iio: adc: xilinx-xadc: Benefit from devm_clk_get_enabled() to simplify

Make use of devm_clk_get_enabled() to replace some code that effectively
open codes this new function.

Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Link: https://lore.kernel.org/r/20220808204740.307667-9-u.kleine-koenig@pengutronix.de
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: adc: xilinx-xadc: Drop duplicate NULL check in xadc_parse_dt()

The fwnode_for_each_child_node() is NULL-aware, no need to check
its parameters outside. Drop duplicate NULL check in xadc_parse_dt().

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20220531141118.64540-2-andriy.shevchenko@linux.intel.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: adc: xilinx-xadc: 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>
Acked-by: Michal Simek <michal.simek@amd.com>
Link: https://lore.kernel.org/r/20220531141118.64540-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: xilinx-xadc-core: Use local variable in xadc_read_raw

Minor cleanup: bit is already defined as chan->scan_type.realbits,
use bit when needed.

Signed-off-by: Gwendal Grignou <gwendal@chromium.org>
Link: https://lore.kernel.org/r/20211104082413.3681212-13-gwendal@chromium.org
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: xilinx-xadc: Make IRQ optional

In some setups the IRQ signal of the XADC might not be wired to the host
system. The driver currently requires that an interrupt is specified. Make
the interrupt optional so the driver can be used in such setups where the
interrupt is not connected.

Since both the internal triggers as well as events depend on the interrupt
being connected both are not available when the interrupt is not connected.

Buffered access is still supported even without an interrupt since an
external trigger can be used.

The IRQ is only optional when using the AXI interface, since the PCAP
interface needs the IRQ for reading and writing registers.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Link: https://lore.kernel.org/r/20211021125950.28707-1-lars@metafoo.de
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: xilinx-xadc: Remove `irq` field from state struct

Since commit 2a9685d1a3b7 ("iio: adc: xilinx: use more devres helpers and
remove remove()") the `irq` field from XADC driver state struct is only
used in the `probe()` function.

Use the local `irq` variable throughout the `probe()` function and remove
the now unused field from the state struct.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Link: https://lore.kernel.org/r/20211017121551.24063-1-lars@metafoo.de
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: core: move @id from struct iio_dev to struct iio_dev_opaque

Continuing from Alexandru Ardelean's introduction of the split between
driver modifiable fields and those that should only be set by the core.

This could have been done in two steps to make the actual move after
introducing iio_device_id() but there seemed limited point to that
given how mechanical the majority of the patch is.

Includes fixup from Alex for missing mxs-lradc-adc conversion.

Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Alexandru Ardelean <ardeleanalex@gmail.com>
Link: https://lore.kernel.org/r/20210426174911.397061-2-jic23@kernel.org

iio: xilinx-xadc: Remove code to set trigger parent

iio_trigger_set_drvdata() sets the trigger device parent to first
argument of viio_trigger_alloc(), no need to do it again in the driver
code.

In xadc_alloc_trigger, given dev is indio_dev->dev.parent, and we call
devm_iio_trigger_alloc wit dev as argument, we do not have to set
data->trig->dev.parent to indio_dev->dev.parent anymore.

Signed-off-by: Gwendal Grignou <gwendal@chromium.org>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Link: https://lore.kernel.org/r/20210309193620.2176163-9-gwendal@chromium.org
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: adc: xilinx: use more devres helpers and remove remove()

In order to simplify resource management and error paths in probe() and
entirely drop the remove() callback - use devres helpers wherever
possible. Define devm actions for cancelling the delayed work and
disabling the clock.

Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Tested-by: Anand Ashok Dumbre <anandash@xilinx.com>
Reviewed-by: Anand Ashok Dumbre <anandash@xilinx.com>
Link: https://lore.kernel.org/r/20201130142759.28216-4-brgl@bgdev.pl
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: adc: xilinx: use devm_krealloc() instead of kfree() + kcalloc()

We now have devm_krealloc() in the kernel Use it indstead of calling
kfree() and kcalloc() separately.

Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Tested-by: Anand Ashok Dumbre <anandash@xilinx.com>
Reviewed-by: Anand Ashok Dumbre <anandash@xilinx.com>
Link: https://lore.kernel.org/r/20201130142759.28216-3-brgl@bgdev.pl
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: adc: xilinx: use helper variable for &pdev->dev

It's more elegant to use a helper local variable to store the address
of the underlying struct device than to dereference pdev everywhere.

Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Tested-by: Anand Ashok Dumbre <anandash@xilinx.com>
Reviewed-by: Anand Ashok Dumbre <anandash@xilinx.com>
Link: https://lore.kernel.org/r/20201130142759.28216-2-brgl@bgdev.pl
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: xilinx-xadc: Add basic support for Ultrascale System Monitor

The xilinx-xadc IIO driver currently has support for the XADC in the Xilinx
7 series FPGAs. The system-monitor is the equivalent to the XADC in the
Xilinx UltraScale and UltraScale+ FPGAs.

The IP designers did a good job at maintaining backwards compatibility and
only minor changes are required to add basic support for the system-monitor
core.

The non backwards compatible changes are:
* Register map offset was moved from 0x200 to 0x400
* Only one ADC compared to two in the XADC
* 10 bit ADC instead of 12 bit ADC
* Two of the channels monitor different supplies

Add the necessary logic to accommodate these changes to support the
system-monitor in the XADC driver.

Note that this patch does not include support for some new features found
in the system-monitor like additional alarms, user supply monitoring and
secondary system-monitor access. This might be added at a later time.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Tested-by: Anand Ashok Dumbre <anandash@xilinx.com>
Reviewed-by: Anand Ashok Dumbre <anandash@xilinx.com>
Link: https://lore.kernel.org/r/20200922134624.13191-2-lars@metafoo.de
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: adc: xilinx-xadc: use devm_krealloc()

Use the managed variant of krealloc() and shrink the code a bit.

Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Link: https://lore.kernel.org/r/20200824173859.4910-4-brgl@bgdev.pl
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.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: xilinx-xadc: Make sure not exceed maximum samplerate

The XADC supports a samplerate of up to 1MSPS. Unfortunately the hardware
does not have a FIFO, which means it generates an interrupt for each
conversion sequence. At one 1MSPS this creates an interrupt storm that
causes the system to soft-lock.

For this reason the driver limits the maximum samplerate to 150kSPS.
Currently this check is only done when setting a new samplerate. But it is
also possible that the initial samplerate configured in the FPGA bitstream
exceeds the limit.

In this case when starting to capture data without first changing the
samplerate the system can overload.

To prevent this check the currently configured samplerate in the probe
function and reduce it to the maximum if necessary.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Fixes: bdc8cda1d010 ("iio:adc: Add Xilinx XADC driver")
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: xilinx-xadc: Fix sequencer configuration for aux channels in simultaneous mode

The XADC has two internal ADCs. Depending on the mode it is operating in
either one or both of them are used. The device manual calls this
continuous (one ADC) and simultaneous (both ADCs) mode.

The meaning of the sequencing register for the aux channels changes
depending on the mode.

In continuous mode each bit corresponds to one of the 16 aux channels. And
the single ADC will convert them one by one in order.

In simultaneous mode the aux channels are split into two groups the first 8
channels are assigned to the first ADC and the other 8 channels to the
second ADC. The upper 8 bits of the sequencing register are unused and the
lower 8 bits control both ADCs. This means a bit needs to be set if either
the corresponding channel from the first group or the second group (or
both) are set.

Currently the driver does not have the special handling required for
simultaneous mode. Add it.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Fixes: bdc8cda1d010 ("iio:adc: Add Xilinx XADC driver")
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: xilinx-xadc: Fix clearing interrupt when enabling trigger

When enabling the trigger and unmasking the end-of-sequence (EOS) interrupt
the EOS interrupt should be cleared from the status register. Otherwise it
is possible that it was still set from a previous capture. If that is the
case the interrupt would fire immediately even though no conversion has
been done yet and stale data is being read from the device.

The old code only clears the interrupt if the interrupt was previously
unmasked. Which does not make much sense since the interrupt is always
masked at this point and in addition masking the interrupt does not clear
the interrupt from the status register. So the clearing needs to be done
unconditionally.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Fixes: bdc8cda1d010 ("iio:adc: Add Xilinx XADC driver")
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: xilinx-xadc: Fix ADC-B powerdown

The check for shutting down the second ADC is inverted. This causes it to
be powered down when it should be enabled. As a result channels that are
supposed to be handled by the second ADC return invalid conversion results.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Fixes: bdc8cda1d010 ("iio:adc: Add Xilinx XADC driver")
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: xilinx-xadc: Fix typo

Fix a typo. 'at the a time' -> 'at a time'.

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

iio: xilinx-xadc: Fix typo in author's name

It appears the author of the xilinx-xadc driver can't even spell his own
name correctly. Fix that.

Reported-by: Lars Möllendorf <lars.moellendorf@plating.de>
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: adc: xilinx-xadc: use devm_platform_ioremap_resource

Reduces local boilerplate.
Suggested by coccinelle.
CHECK drivers/iio/adc/xilinx-xadc-core.c
drivers/iio/adc/xilinx-xadc-core.c:1184:1-11: WARNING: Use devm_platform_ioremap_resource for xadc -> base

Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Manish Narani <manish.narani@xilinx.com>
Reviewed-by: Sven Van Asbroeck <TheSven73@gmail.com>

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 177

Based on 1 normalized pattern(s):

licensed under the gpl 2

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-only

has been chosen to replace the boilerplate/reference in 135 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Richard Fontana <rfontana@redhat.com>
Reviewed-by: Alexios Zavras <alexios.zavras@intel.com>
Reviewed-by: Steve Winslow <swinslow@gmail.com>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190528170026.071193225@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

iio: adc: xilinx: prevent touching unclocked h/w on remove

In remove, the clock is disabled before canceling the
delayed work. This means that the delayed work may be
touching unclocked hardware.

Fix by disabling the clock after the delayed work is
fully canceled. This is consistent with the probe error
path order.

Signed-off-by: Sven Van Asbroeck <TheSven73@gmail.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: adc: xilinx: fix potential use-after-free on probe

If probe errors out after request_irq(), its error path
does not explicitly cancel the delayed work, which may
have been scheduled by the interrupt handler.

This means the delayed work may still be running when
the core frees the private structure (struct xadc).
This is a potential use-after-free.

Fix by inserting cancel_delayed_work_sync() in the probe
error path.

Signed-off-by: Sven Van Asbroeck <TheSven73@gmail.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: adc: xilinx: fix potential use-after-free on remove

When cancel_delayed_work() returns, the delayed work may still
be running. This means that the core could potentially free
the private structure (struct xadc) while the delayed work
is still using it. This is a potential use-after-free.

Fix by calling cancel_delayed_work_sync(), which waits for
any residual work to finish before returning.

Signed-off-by: Sven Van Asbroeck <TheSven73@gmail.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: adc: xilinx: check return value of xadc_write_adc_reg

In function xadc_probe, xadc_write_adc_reg can return an error value
when write fails. The fix checks for the return value consistent with
other invocations of the latter function.

Signed-off-by: Aditya Pakki <pakki001@umn.edu>
Reviewed-by: Michal Simek <michal.simek@xilinx.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: adc: xilinx: Move request_irq before enabling interrupts

Enabling the Interrupts before registering the irq handler is a bad
idea. This patch corrects the same for XADC driver.

Signed-off-by: Manish Narani <manish.narani@xilinx.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: adc: xilinx: Remove platform_get_irq from xadc_remove function

This patch avoids getting irq number in xadc_remove function. Instead
store 'irq' in xadc struct and use xadc->irq wherever needed.
This patch also resolves a warning reported by coverity where it asks to
check return value of platform_get_irq() for any errors in xadc_remove.

Signed-off-by: Manish Narani <manish.narani@xilinx.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: adc: xilinx: limit pcap clock frequency value

This patch limits the xadc pcap clock frequency value to be less than
200MHz. This fixes the issue when zynq is booted at higher frequency
values, pcap crosses the maximum limit of 200MHz(Fmax) as it is derived
from IOPLL.
If this limit is crossed it is required to alter the WEDGE and REDGE
bits of XADC_CFG register to make timings better in the interface. So to
avoid alteration of these bits every time, the pcap value should not
cross the Fmax limit.

Signed-off-by: Manish Narani <manish.narani@xilinx.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: adc: xilinx: Check for return values in clk related functions

This patch adds check for return values from clock related functions.
This was reported by static code analysis tool.

Signed-off-by: Manish Narani <manish.narani@xilinx.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

iio: adc: xilinx: Remove dead code from xadc_zynq_setup

This patch removes dead code from xadc_zynq_setup. The condition
"if (tck_rate > XADC_ZYNQ_TCK_RATE_MAX)" cannot be true at any point of
time. There is also an incompatible parameter used in the code.
This patch fixes the same reported by coverity.

Signed-off-by: Manish Narani <manish.narani@xilinx.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

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: xilinx: Handle return value of clk_prepare_enable

clk_prepare_enable() can fail here and we must check its return value.

Signed-off-by: Arvind Yadav <arvind.yadav.cs@gmail.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio: adc: xilinx: Fix error handling

Reorder error handling labels in order to match the way resources have
been allocated.

Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Acked-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio: adc: xilinx: constify iio_buffer_setup_ops structure

The iio_buffer_setup_ops structures are never modified, so declare this one
as const, like the others.

Done with the help of Coccinelle.

Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
Acked-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio: adc: xilinx: Fix VREFN scale

The scaling factor for VREFN is 3.0/4096 (not 1.0/4096), just as for
VREFP. This is not immediately obvious from the specification (Xilinx
UG480), but has been confirmed by Xilinx support.

Suggested-by: Hartmut Knaack <knaack.h@gmx.de>
Signed-off-by: Thomas Betker <thomas.betker@rohde-schwarz.com>
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio: adc: xilinx-xadc: Push interrupts into hardirq context

The driver currently registers a pair of irq handlers using
request_threaded_irq(), however the synchronization mechanism between the
hardirq and the threadedirq handler is a regular spinlock.

Unfortunately, this breaks PREEMPT_RT builds, where a spinlock can sleep,
and is thus not able to be acquired from a hardirq handler. This patch gets
rid of the threaded handler and pushes all interrupt handling into the
hardirq context, and uses request_irq().

To validate that this change has no impact on RT performance, here are
cyclictest values with no processes running:

$ sudo cyclictest -S -m -p 98
policy: fifo: loadavg: 0.00 0.01 0.05 1/174 2539
T: 0 ( 1405) P:98 I:1000 C:167010520 Min: 9 Act: 12 Avg: 12 Max: 75
T: 1 ( 1862) P:98 I:1500 C:111340339 Min: 9 Act: 12 Avg: 12 Max: 73

Then, all xadc raw handles were accessed in a continuous loop via
/sys/bus/iio/devices/iio:device0:

$ sudo cyclictest -S -m -p 98
policy: fifo: loadavg: 7.84 7.70 7.63 3/182 4260
T: 0 ( 2559) P:98 I:1000 C:241557018 Min: 11 Act: 18 Avg: 21 Max: 74
T: 1 ( 2560) P:98 I:1500 C:161038006 Min: 10 Act: 21 Avg: 20 Max: 73

Signed-off-by: Xander Huff <xander.huff@ni.com>
Acked-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio: adc: xilinx: Fix VREFN sign

The VREFN channel is bipolar, not unipolar. Small negative values do
occur (e.g., -1mV), and unsigned conversion maps them incorrectly to
large positive values (about +1V), so fix this.

Signed-off-by: Thomas Betker <thomas.betker@rohde-schwarz.com>
Cc: <Stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio: adc: xilinx: Fix VREFP scale

The scaling factor for VREFP is 3.0/4096, not 1.0/4096; fix this to get
correct readings.

Signed-off-by: Thomas Betker <thomas.betker@rohde-schwarz.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio: adc: xilinx: Fix "vccaux" channel .address

For the "vccaux" channel, read the VCCAUX register, not VCCINT.

Signed-off-by: Thomas Betker <thomas.betker@rohde-schwarz.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio: adc: xilinx-xadc: assign auxiliary channels address correctly

This patch fixes incorrect logic for assigning address
to auxiliary channels of xilinx xadc.

Signed-off-by: Subbaraya Sundeep Bhatta <sbhatta@xilinx.com>
Acked-by: Lars-Peter Clausen <lars@metafoo.de>
Cc: Stable@vger.kernel.org
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio: adc: xilinx: Remove .owner field for driver

There is no need to init .owner field.

Based on the patch from Peter Griffin <peter.griffin@linaro.org>
"mmc: remove .owner field for drivers using module_platform_driver"

This patch removes the superflous .owner field for drivers which
use the module_platform_driver API, as this is overriden in
platform_driver_register anyway."

Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio: fix error return code

Convert a zero return value on error to a negative one, as returned
elsewhere in the function.

A simplified version of the semantic match that finds this problem is as
follows: (http://coccinelle.lip6.fr/)

// <smpl>
(
if@p1 (\(ret < 0\|ret != 0\))
{ ... return ret; }
|
ret@p1 = 0
)
... when != ret = e1
when != &ret
*if(...)
{
... when != ret = e2
when forall
return ret;
}

// </smpl>

Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio: Remove timestamp argument from iio_trigger_poll() and iio_trigger_poll_chained()

argument has been ignored; adjust drivers accordingly

Signed-off-by: Peter Meerwald <pmeerw@pmeerw.net>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

iio:adc: Add Xilinx XADC driver

The Xilinx XADC is a ADC that can be found in the series 7 FPGAs from Xilinx.
The XADC has a DRP interface for communication. Currently two different
frontends for the DRP interface exist. One that is only available on the ZYNQ
family as a hardmacro in the SoC portion of the ZYNQ. The other one is available
on all series 7 platforms and is a softmacro with a AXI interface. This driver
supports both interfaces and internally has a small abstraction layer that hides
the specifics of these interfaces from the main driver logic.

The ADC has a couple of internal channels which are used for voltage and
temperature monitoring of the FPGA as well as one primary and up to 16 channels
auxiliary channels for measuring external voltages. The external auxiliary
channels can either be directly connected each to one physical pin on the FPGA
or they can make use of an external multiplexer which is responsible for
multiplexing the external signals onto one pair of physical pins.

The voltage and temperature monitoring channels also have an event capability
which allows to generate a interrupt when their value falls below or raises
above a set threshold.

Buffered sampling mode is supported by the driver, but only for AXI-XADC since
the ZYNQ XADC interface does not have capabilities for supporting buffer mode
(no end-of-conversion interrupt). If buffered mode is supported the driver will
register two triggers. One "xadc-samplerate" trigger which will generate samples
with the configured samplerate. And one "xadc-convst" trigger which will
generate one sample each time the CONVST (conversion start) signal is asserted.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>