It is possible for userspace to concurrently access the buffer from multiple
threads or processes. To avoid corruption of the internal state of the buffer we
need to add proper locking. It is possible for multiple processes to try to read
from the buffer concurrently and it is also possible that one process causes a
buffer re-allocation while a different process still access the buffer. Both can
be fixed by protecting the calls to kfifo_to_user() and kfifo_alloc() by the
same mutex. In iio_read_first_n_kfifo() we also use kfifo_recsize() instead of
the buffers bytes_per_datum to avoid a race that can happen if bytes_per_datum
has been changed, but the buffer has not been reallocated yet.

Note that all access to the buffer from within the kernel is already properly
synchronized, so there is no need for extra locking in iio_store_to_kfifo().
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

We need to free the kfifo when we release the buffer, otherwise the fifos memory
will be leaked.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

None of the SPEAr, LPC32XX or MXS ADC drivers have a compile time dependency on
their respective platform. So make it possible to build the drivers when
CONFIG_COMPILE_TEST is set. This makes it easier to compile test changes.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Reviewed-by: Marek Vasut <marex@denx.de>
Cc: Stefan Roese <sr@denx.de>
Cc: Roland Stigge <stigge@antcom.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

The MXS ADC driver uses the stmp_reset_block() which is only provided when the
STMP_DEVICE Kconfig symbol is selected. Hence the driver should select this
symbol. So far this has not been a problem since the driver depends on ARCH_MXS,
which already selects STMP_DEVICE, but will become necessary once we allow the
driver to be built when COMPILE_TEST is selected.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Cc: Marek Vasut <marex@denx.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

The driver is casting from one __iomem pointer to another. Make sure to include
__iomem in the cast, otherwise sparse will complain with the following warning:

	drivers/staging/iio/adc/spear_adc.c:321:18: warning: cast removes address space of expression
	drivers/staging/iio/adc/spear_adc.c:320:33: warning: incorrect type in assignment (different address spaces)
	drivers/staging/iio/adc/spear_adc.c:320:33:    expected struct adc_regs_spear3xx [noderef] <asn:2>*adc_base_spear3xx
	drivers/staging/iio/adc/spear_adc.c:320:33:    got struct adc_regs_spear3xx *<noident>
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Cc: Stefan Roese <sr@denx.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

Remove the scale_mv variable from the read_raw() callback. Fixes the following
warning:
	drivers/staging/iio/adc/spear_adc.c: In function 'spear_read_raw':
	drivers/staging/iio/adc/spear_adc.c:149:6: warning: unused variable 'scale_mv'
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Cc: Stefan Roese <sr@denx.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

Since the kernel now disables all buffers when a device is unregistered it might
happen that a in-kernel consumer tries to disable that buffer again. So ignore
requests where the buffer already is in the desired state.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

Register the event threshold hysteresis attributes by using the new
IIO_EV_INFO_HYSTERESIS event spec type. This allows us to throw away a good
portion of boiler-plate code.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

Register the event threshold hysteresis attributes by using the new
IIO_EV_INFO_HYSTERESIS event spec type. This allows us to throw away a good
portion of boiler-plate code.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

Given a channel number the corresponding threshold and hysteresis registers can
easily be calculated. No need to use a look-up table.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

For some devices it is possible to configure a hysteresis for threshold (or
similar) events. This patch adds a new hysteresis event info type which allows
for easy creation and read/write handling of the sysfs attribute.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

Switch the tsl2x7x driver to the new IIO event config interface as the old one
is going to be removed.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Cc: Jon Brenner <jbrenner@taosinc.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

Switch the simple_dummy driver to the new IIO event config interface as the old
one is going to be removed.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

Switch the ad7150 driver to the new IIO event config interface as the old one
is going to be removed.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

Switch the ad799x driver to the new IIO event config interface as the old one
is going to be removed.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

Switch the ad7291 driver to the new IIO event config interface as the old one
is going to be removed.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

Switch the sca3000 driver to the new IIO event config interface as the old one
is going to be removed.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

The threshold event can be enabled/disabled separately, but the threshold value
is shared between all three axis.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

Switch the lis3l02dq driver to the new IIO event config interface as the old one
is going to be removed.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

Switch the apds9300 driver to the new IIO event config interface as the old one
is going to be removed.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Cc: Oleksandr Kravchenko <o.v.kravchenko@globallogic.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

Switch the tsl2563 driver to the new IIO event config interface as the old one
is going to be removed.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

Switch the gp2ap020a00f driver to the new IIO event config interface as the old
one is going to be removed.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Cc: Jacek Anaszewski <j.anaszewski@samsung.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

Switch the ad5421 driver to the new IIO event config interface as the old one
is going to be removed.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

Switch the max1363 driver to the new IIO event config interface as the old one
is going to be removed.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

The event configuration interface of the IIO framework has not been getting the
same attention as other parts. As a result it has not seen the same improvements
as e.g. the channel interface has seen with the introduction of the channel spec
struct. Currently all the event config callbacks take a u64 (the so called event
code) to pass all the different information about for which event the callback
is invoked. The callback function then has to extract the information it is
interested in using some macros with rather long names. Most information encoded
in the event code comes straight from the iio_chan_spec struct the event was
registered for. Since we always have a handle to the channel spec when we call
the event callbacks the first step is to add the channel spec as a parameter to
the event callbacks. The two remaining things encoded in the event code are the
type and direction of the event. Instead of passing them in one parameter, add
one parameter for each of them and remove the eventcode from the event
callbacks. The patch also adds a new iio_event_info parameter to the
{read,write}_event_value callbacks. This makes it possible, similar to the
iio_chan_info_enum for channels, to specify additional properties other than
just the value for an event. Furthermore the new interface will allow to
register shared events. This is e.g. useful if a device allows configuring a
threshold event, but the threshold setting is the same for all channels.

To implement this the patch adds a new iio_event_spec struct which is similar to
the iio_chan_spec struct. It as two field to specify the type and the direction
of the event. Furthermore it has a mask field for each one of the different
iio_shared_by types. These mask fields holds which kind of attributes should be
registered for the event. Creation of the attributes follows the same rules as
the for the channel attributes. E.g. for the separate_mask there will be a
attribute for each channel with this event, for the shared_by_type there will
only be one attribute per channel type. The iio_chan_spec struct gets two new
fields, 'event_spec' and 'num_event_specs', which is used to specify which the
events for this channel. These two fields are going to replace the channel's
event_mask field.

For now both the old and the new event config interface coexist, but over the
few patches all drivers will be converted from the old to the new interface.
Once that is done all code for supporting the old interface will be removed.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

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

The `ret´ variable is only initialized in the error case. For some reason
it was always != 0 while I played with generic_buffer so here is a patch.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

We have the same code to free a IIO device attribute list in multiple place.
This patch adds a new helper function to take care of this and replaces the
custom instances with a call to the helper function. Note that we do not need to
call list_del() for each of the list items since we will never look at any of
the list items nor the list itself again.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

We need to make sure that in-kernel users of iio_update_buffers() do not race
against each other or against unregistration of the device. So we need to take
both the mlock and the info_exist_lock when calling iio_update_buffers() from a
in-kernel consumer.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

Once the device has been unregistered there won't be any new data no matter how
long a userspace application waits, so we might as well wake them up and let
them know.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

If the IIO device has been unregistered return -ENODEV for any further file
operations like read() and ioctl(). This avoids userspace being able to grab new
references to the device.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

Since the buffer is accessed by userspace we can not just free the buffers
memory once we are done with it in kernel space. There might still be open file
descriptors and userspace still might be accessing the buffer. This patch adds
support for reference counting to the IIO buffers. When a buffer is created and
initialized its initial reference count is set to 1. Instead of freeing the
memory of the buffer the buffer's _free() function will drop that reference
again. But only after the last reference to the buffer has been dropped the
buffer the buffer's memory will be freed. The IIO device will take a reference
to its primary buffer. The patch adds a small helper function for this called
iio_device_attach_buffer() which will get a reference to the buffer and assign
the buffer to the IIO device. This function must be used instead of assigning
the buffer to the device by hand. The reference is only dropped once the IIO
device is freed and we can be sure that there are no more open file handles. A
reference to a buffer will also be taken whenever the buffer is active to avoid
the buffer being freed while data is still being send to it.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

CC: devicetree@vger.kernel.org
Signed-off-by: Josh Wu <josh.wu@atmel.com>
Acked-by: Ludovic Desroches <ludovic.desroches@atmel.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

Since in at91sam9x5, sama5d3x chip. the start up time calucation is changed.
This patch can choose different start up time calculation formula for different
chips.
Signed-off-by: Josh Wu <josh.wu@atmel.com>
Acked-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

Fix checkpatch.pl issues with quoted string split across lines in adt7316-i2c.c
Signed-off-by: Ebru Akagunduz <ebru.akagunduz@gmail.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Fix checkpatch.pl issues with quoted string split across lines in adt7316-spi.c
Signed-off-by: Ebru Akagunduz <ebru.akagunduz@gmail.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Fix checkpatch.pl issues with prefer netdev_info(netdev, .. then dev_info(dev, ..
then pr_info(...  to printk(KERN_INFO .. in lis3l02dq_ring.c
Signed-off-by: Ebru Akagunduz <ebru.akagunduz@gmail.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Fix checkpatch.pl issues with space prohibited before semicolon in
lis3l02dq_ring.c
Signed-off-by: Ebru Akagunduz <ebru.akagunduz@gmail.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Fix checkpatch.pl issues with line over 80 characters in
iio_simple_dummy.c
Signed-off-by: Ebru Akagunduz <ebru.akagunduz@gmail.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Fix checkpatch.pl issues with quoted strings split across lines in xillybus_core.c
Signed-off-by: Ebru Akagunduz <ebru.akagunduz@gmail.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>