name_format already contains the final name and no format characters. So the
code basically reads:

	dev_attr->attr.name = kstrdup(GFP_KERNEL, name_format);
	if (dev_attr->attr.name == NULL)
		...
	kfree(name_format);

Which means we can save one alloc and free pair per attribute name if we
directly assign name_format to dev_attr->attr.name.

The patch also renames name_format to name to denote that this is indeed the
final name and has no format characters in it.
Signed-off-by: NLars-Peter Clausen <lars@metafoo.de>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>

The extended name is channel specific and should not be included in shared
attributes.
Signed-off-by: NLars-Peter Clausen <lars@metafoo.de>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>

Get rid of obsolete uses of goto error_ret and some empty lines.
Signed-off-by: NHartmut Knaack <knaack.h@gmx.de>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>

There are already humidity sensors in the hwmon subsystem,
so we use their unit (milli percent) here as well.
Signed-off-by: NHarald Geyer <harald@ccbib.org>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>

Documentation related to function should be placed above
its implementation. Move it accordingly.
Signed-off-by: NSachin Kamat <sachin.kamat@linaro.org>
Cc: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>

Add device managed devm_iio_device_{register,unregister}()
to automatically unregister IIO drivers thus leading to
simplified IIO driver code.
Signed-off-by: NSachin Kamat <sachin.kamat@linaro.org>
Cc: Lars-Peter Clausen <lars@metafoo.de>
Tested-by: NLars-Peter Clausen <lars@metafoo.de>
Reviewed-by: NLars-Peter Clausen <lars@metafoo.de>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>

Silences the following checkpatch warning:
WARNING: sizeof *iio_attr should be sizeof(*iio_attr)
Signed-off-by: NSachin Kamat <sachin.kamat@linaro.org>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>

Use of pr_err is preferred to printk.
Signed-off-by: NSachin Kamat <sachin.kamat@linaro.org>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>

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

Remove the the debugfs entries in iio_device_unregister(). Otherwise the debugfs
entries might still be accessible even though the device used in the debugfs
callback has already been freed.
Signed-off-by: NLars-Peter Clausen <lars@metafoo.de>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>

Set the IIO device as the parent for the character device

We need to make sure that the IIO device is not freed while the character device
exists, otherwise the freeing of the IIO device might race against the file open
callback. Do this by setting the character device's parent to the IIO device,
this will cause the character device to grab a reference to the IIO device and
only release it once the character device itself has been removed.

Also move the registration of the character device before the registration of
the IIO device to avoid the (rather theoretical case) that the IIO device is
already freed again before we can add the character device and grab a reference
to the IIO device.

We also need to move the call to cdev_del() from iio_dev_release() to
iio_device_unregister() (where it should have been in the first place anyway) to
avoid a reference cycle. As iio_dev_release() is only called once all reference
are dropped, but the character device holds a reference to the IIO device.
Signed-off-by: NLars-Peter Clausen <lars@metafoo.de>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>

Make sure that the IIO device is not freed while we still have file descriptors
for it.
Signed-off-by: NLars-Peter Clausen <lars@metafoo.de>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>

Make sure to stop sampling when the device is removed, otherwise it will
continue to sample forever.
Signed-off-by: NLars-Peter Clausen <lars@metafoo.de>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>

These two additional info_mask bitmaps should allow all 'standard'
numeric attributes to be handled using the read_raw and write_raw
callbacks.  Whilst this should reduce code, the more important element
is that this makes these values easily accessible to in kernel users
of IIO devices.
Signed-off-by: NJonathan Cameron <jic23@kernel.org>
Reviewed-by: NLars-Peter Clausen <lars@metafoo.de>

Introduce an enum to specify whether the attribute is separate or
shared.

Factor out the bitmap handling for loop into a separate function.

Tidy up error handling and add a NULL assignment to squish a false
positive warning from GCC.

Change ext_info shared type from boolean to enum and update in all
drivers.
Signed-off-by: NJonathan Cameron <jic23@kernel.org>
Reviewed-by: NLars-Peter Clausen <lars@metafoo.de>

Integration time is in seconds; it controls the measurement
time and influences the gain of a sensor.

There are two typical ways that scaling is implemented in a device:
1) input amplifier,
2) reference to the ADC is changed.
These both result in the accuracy of the ADC varying (by applying its
sampling over a more relevant range).

Integration time is a way of dealing with noise inherent in the analog
sensor itself.  In the case of a light sensor, a mixture of photon noise
and device specific noise.  Photon noise is dealt with by either improving
the efficiency of the sensor, (more photons actually captured) which is not
easily varied dynamically, or by integrating the measurement over a longer
time period.  Note that this can also be thought of as an averaging of a
number of individual samples and is infact sometimes implemented this way.
Altering integration time implies that the duration of a measurement changes,
a fact the device's user may be interested in.

Hence it makes sense to distinguish between integration time and simple
scale. In some devices both types of control are present and whilst they
will have similar effects on the amplitude of the reading, their effect
on the noise of the measurements will differ considerably.

Used by adjd_s311, tsl4531, tcs3472
The following drivers have similar controls (and could be adapted):
* tsl2563 (integration time is controlled via CALIBSCALE among other things)
* tsl2583 (has integration_time device_attr, but driver doesn't use channels yet)
* tsl2x7x (has integration_time attr)
Signed-off-by: NPeter Meerwald <pmeerw@pmeerw.net>
Cc: Jon Brenner <jon.brenner@ams.com>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>

This patch fixes the issue with double minus in output when
reading channels from sysfs for IIO_VAL_INT_PLUS_MICRO and
IIO_VAL_INT_PLUS_NANO cases. Until this patch if val and val2
both are negatives output string contains "--" before
digits. It is result of "-%d..." in sprintf() format.
Signed-off-by: NOleksandr Kravchenko <o.v.kravchenko@globallogic.com>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>

Add a resource managed devm_iio_device_alloc()/devm_iio_device_free()
to automatically clean up any allocations made by IIO drivers,
thus leading to simplified IIO drivers code.

In addition, this will allow IIO drivers to use other devm_*() API
(like devm_request_irq) and don't care about the race between
iio_device_free() and the release of resources by Device core
during driver removing.
Signed-off-by: NGrygorii Strashko <grygorii.strashko@ti.com>
Signed-off-by: NOleksandr Kravchenko <o.v.kravchenko@globallogic.com>
Tested-by: NOleksandr Kravchenko <o.v.kravchenko@globallogic.com>
Reviewed-by: NLars-Peter Clausen <lars@metafoo.de>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>

This has been replaced by the pair of masks info_mask_separate
and info_mask_shared_by_type.  Other variants may follow.
Signed-off-by: NJonathan Cameron <jic23@kernel.org>
Acked-by: NLars-Peter Clausen <lars@metafoo.de>

This simplifies the code, removes an extensive layer of 'helper' macros
and gives us twice as much room to play with in these masks before we
have any need to be clever.
Signed-off-by: NJonathan Cameron <jic23@kernel.org>
Acked-by: NLars-Peter Clausen <lars@metafoo.de>

Provide bindings and parse OF data during initialization.
Signed-off-by: NGuenter Roeck <linux@roeck-us.net>
Reviewed-by: NLars-Peter Clausen <lars@metafoo.de>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>

Factor out the code for parsing fixed point numbers into its own function and
make this function globally available. This allows us to reuse the code to parse
fixed point numbers in individual IIO drivers.
Signed-off-by: NLars-Peter Clausen <lars@metafoo.de>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>

This patch adds support for a new IIO channel type for pressure measurements.
This can for example be used for barometric pressure sensors.
Signed-off-by: NLars-Peter Clausen <lars@metafoo.de>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>

Route all buffer writes through the demux.
Addition or removal of a buffer results in tear down and
setup of all the buffers for a given device.
Signed-off-by: NJonathan Cameron <jic23@kernel.org>
Tested-by: Nsrinivas pandruvada <srinivas.pandruvada@intel.com>

If we encounter a leading '+' sign just skip over it.
Signed-off-by: NLars-Peter Clausen <lars@metafoo.de>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>

When parsing a fixed point number IIO stops parsing the string once it has
reached the last requested decimal place. This means that the remainder of the
string is silently accepted regardless, of whether it is part of a valid number
or not. This patch modifies the code to scan the whole string and only accept
valid numbers. Since fract_mult is 0 after the last decimal place any digit that
may follows won't affect the result.
Signed-off-by: NLars-Peter Clausen <lars@metafoo.de>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>

Currently when parsing a fix-point number we silently skip any additional '.'
found in the string.  E.g. '1.2.3.4' gets parsed as '1.234'. This patch
disallows this and returns an error if more than one '.' is encountered.
Signed-off-by: NLars-Peter Clausen <lars@metafoo.de>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>

For ADCs or DACs the denominator for fractional types often is a power of two.
In this case we can use a shift operation instead of the rather expensive 64 bit
division. This patch adds a new fractional type which expects the denominator to
be specified as the log2 of the actual denominator. E.g. for ADCs and DACs this
will usually be the number of significant bits.
Signed-off-by: NLars-Peter Clausen <lars@metafoo.de>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>

Currently IIO uses a decimal fixed point representations for real type numbers.
This patch introduces a new representation for rational type numbers. The number
will be expressed by specifying a numerator and denominator. For converting a
raw value to a processed value multiply it by the numerator and divide it by the
denominator.

The reasoning for introducing this new type is that for a lot of devices the
scale can be represented easily by a fractional number, but it is not possible
to represent it as fixed point number without rounding.  E.g. for a simple DAC
the scale is often the reference voltage divided by the number of possible
values (Usually 2**n_bits - 1). Each driver currently implements the conversion
of this fraction to a fixed point number on its own.

Also when it comes to the in-kernel interface this allows to directly use the
fractional factors to convert a raw value to a processed value. This should on
one hand require less instructions and on the other hand increase the
precision.
Signed-off-by: NLars-Peter Clausen <lars@metafoo.de>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>

Added hysteresis to the list of channel info enumeration, shared
/separate bit defines and to postfix channel info strings.
Signed-off-by: Nsrinivas pandruvada <srinivas.pandruvada@intel.com>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>

Signed-off-by: NJonathan Cameron <jic23@kernel.org>

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

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

Add iio channel type and modifiers for Correlated Color Temperature (CCT)
and RGBC (red/green/blue/clear) data.
Add CCT and RGBC descriptions to documentation.

Changes:
Revised/condensed RGBC descriptions.

Merge and trivial fix done by Jonathan Cameron.
Signed-off-by: NJon Brenner <jbrenner@taosinc.com>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>

There will probably be a number of such modifiers eventually but
this one is used in the adis16240 accelerometer driver.
Signed-off-by: NJonathan Cameron <jic23@kernel.org>

There will probably be a number of such modifiers eventually but
this one is used in the adis16204 accelerometer driver.
Signed-off-by: NJonathan Cameron <jic23@kernel.org>