Commit Graph

64 Commits

Author SHA1 Message Date
Irina Tirdea
bcdf28fb1b iio: core: Introduce IIO_CHAN_INFO_CALIBHEIGHT
Some devices need the height of the user to compute various
parameters. One of this devices is Freescale's MMA9553L
(http://www.freescale.com/files/sensors/doc/ref_manual/MMA9553LSWRM.pdf)
that needs the height of the user to compute the stride length which
is used further to determine distance, speed and activity type.

Signed-off-by: Irina Tirdea <irina.tirdea@intel.com>
Signed-off-by: Daniel Baluta <daniel.baluta@intel.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
2014-11-22 11:05:56 +00:00
Irina Tirdea
a88bfe7858 iio: core: Introduce STEPS channel, ENABLE mask and INSTANCE event
These changes are needed to support the functionality of a pedometer.
A pedometer has two basic functionalities: step counter and step detector.

The step counter needs to be enabled and then it will count the steps
in its hardware register. Whenever the application needs to check
the step count, it will read the step counter register. To support the
step counter a new channel type STEPS is added. Since the pedometer needs
to be enabled first so that the hardware can count and store the steps,
we need a specific ENABLE channel info mask.

The step detector will generate an interrupt each time a step is detected.
To support this functionality we add a new event type INSTANCE.

For more information on the Android requirements for step counter and step
detector see:
http://source.android.com/devices/sensors/composite_sensors.html#counter
and http://source.android.com/devices/sensors/composite_sensors.html#detector.

A device that has the pedometer functionality this interface needs to
support is Freescale's MMA9553L:
http://www.freescale.com/files/sensors/doc/ref_manual/MMA9553LSWRM.pdf

Signed-off-by: Irina Tirdea <irina.tirdea@intel.com>
Signed-off-by: Daniel Baluta <daniel.baluta@intel.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
2014-11-22 11:05:51 +00:00
Daniel Baluta
55aebeb926 iio: core: Introduce IIO_ACTIVITY channel
This channel will be used for exposing information about
activity composite sensors. Activities supported so far:
	* running
	* jogging
	* walking
	* still

THRESHOLD event is used to signal a change in the activity
state.

We associate a confidence interval for each activity expressed
as a percentage from 0 to 100.
  * 0, means the sensor IS NOT reporting that activity.
  * 100, means the sensor IS reporting that activity.

Users of this interface have two possible means to gather
information about the ongoing activities.

1. Event based, via event file descriptor
  * sensor may report an event when ENTERING an activity or LEAVING
    an activity based on a threshold value.
  * drivers will wake up applications waiting data on the event fd

2. Polling, by reading the sysfs associated attribute files:
  * /sys/bus/iio/devices/iio:device0/in_activity_running_input
expressed as percentage confidence value from 0 to 100.

This will offer an interface for Android significant motion
composite sensor defined here:
http://source.android.com/devices/sensors/composite_sensors.html

Activities listed above are supported by Freescale's MMA9553 sensor:
http://freescale.com/files/sensors/doc/ref_manual/MMA9553LSWRM.pdf

Signed-off-by: Irina Tirdea <irina.tirdea@intel.com>
Signed-off-by: Daniel Baluta <daniel.baluta@intel.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
2014-11-22 11:05:47 +00:00
Reyad Attiyat
11b8ddab81 iio: types: Added support for rotation from north usage attributes
Added the rotation from north usage attributes to the iio modifier enum and to the iio modifier names array.

Signed-off-by: Reyad Attiyat <reyad.attiyat@gmail.com>
Acked-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
2014-07-20 13:34:45 +01:00
Peter Meerwald
638b43b347 iio: Add TEMP_AMBIENT and TEMP_OBJECT channel modifiers
useful for contactless temperature sensors to distinguish
between the ambient temperature and the temperature of the object

Signed-off-by: Peter Meerwald <pmeerw@pmeerw.net>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
2014-05-03 11:35:23 +01:00
Srinivas Pandruvada
5082f405b7 IIO: core: Add quaternion modifier
Added quaternion in the list of supported modifiers.

Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
2014-04-29 22:09:14 +01:00
Srinivas Pandruvada
9fbfb4b37e IIO: core: Introduce read_raw_multi
This callback is introduced to overcome some limitations of existing
read_raw callback. The functionality of both existing read_raw and
read_raw_multi is similar, both are used to request values from the
device. The current read_raw callback allows only two return values.
The new read_raw_multi allows returning multiple values. Instead of
passing just address of val and val2, it passes length and pointer
to values. Depending on the type and length of passed buffer, iio
client drivers can return multiple values.

Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
2014-04-29 22:05:32 +01:00
Jonathan Cameron
ef4b485659 iio:core: Fix bug in length of event info_mask and catch unhandled bits set in masks.
The unhandled bits case was highlighted by smatch:
  CHECK   drivers/iio/industrialio-core.c
drivers/iio/industrialio-core.c:719 iio_device_add_info_mask_type() error: buffer overflow 'iio_chan_info_postfix' 17 <= 31
  CC [M]  drivers/iio/industrialio-core.o
  CHECK   drivers/iio/industrialio-event.c
drivers/iio/industrialio-event.c:327 iio_device_add_event() error: buffer overflow 'iio_ev_info_text' 3 <= 3

The incorrect limit for the for_each_set_bit loop was noticed whilst fixing
this other case.  Note that as we only have 3 possible entries a the moment
and the value was set to 4, the bug would not have any effect currently.
It will bite fairly soon though, so best fix it now.

Signed-off-by: Jonathan Cameron <jic23@kernel.org>
Cc: Lars-Peter Clausen <lars@metafoo.de>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
2014-03-16 18:00:35 +00:00
Kees Cook
598db58166 iio: force snprintf for PAGE_SIZE bufs
This is a tiny preventative measure to make sure we can't write beyond
PAGE_SIZE on the buffers being used in sysfs for iio. There is currently
no way for this to happen, but the change makes this code more robust
for the future.

Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
2014-03-15 14:45:14 +00:00
Lars-Peter Clausen
7bbcf7e136 iio: Avoid unnecessary kasprintf
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: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
2014-02-18 10:31:11 +00:00
Lars-Peter Clausen
77bfa8baa0 iio: Don't include extended name in shared attributes
The extended name is channel specific and should not be included in shared
attributes.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
2014-02-18 10:26:55 +00:00
Hartmut Knaack
92825ff974 iio get rid of unneccessary error_ret
Get rid of obsolete uses of goto error_ret and some empty lines.

Signed-off-by: Hartmut Knaack <knaack.h@gmx.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
2014-02-18 08:46:36 +00:00
Harald Geyer
ac216aa290 iio: Add support for humidity sensors
There are already humidity sensors in the hwmon subsystem,
so we use their unit (milli percent) here as well.

Signed-off-by: Harald Geyer <harald@ccbib.org>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
2013-12-03 20:22:29 +00:00
Sachin Kamat
a7e57dce02 iio: core: Move kernel doc to the right location
Documentation related to function should be placed above
its implementation. Move it accordingly.

Signed-off-by: Sachin Kamat <sachin.kamat@linaro.org>
Cc: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
2013-11-24 21:07:11 +00:00
Sachin Kamat
8caa07c0e5 iio: core: Implement devm_iio_device_{register,unregister}
Add device managed devm_iio_device_{register,unregister}()
to automatically unregister IIO drivers thus leading to
simplified IIO driver code.

Signed-off-by: Sachin Kamat <sachin.kamat@linaro.org>
Cc: Lars-Peter Clausen <lars@metafoo.de>
Tested-by: Lars-Peter Clausen <lars@metafoo.de>
Reviewed-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
2013-11-24 21:07:09 +00:00
Sachin Kamat
670c11033d iio: core: Add misssing braces
Silences the following checkpatch warning:
WARNING: sizeof *iio_attr should be sizeof(*iio_attr)

Signed-off-by: Sachin Kamat <sachin.kamat@linaro.org>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
2013-10-24 14:42:44 +01:00
Sachin Kamat
3176dd5d3b iio: core: Use pr_err instead of printk
Use of pr_err is preferred to printk.

Signed-off-by: Sachin Kamat <sachin.kamat@linaro.org>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
2013-10-24 14:39:48 +01:00
Lars-Peter Clausen
3661f3f5e9 iio: Factor IIO value formating into its own function
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
2013-10-12 12:23:33 +01:00
Lars-Peter Clausen
84088ebd14 iio: Add a helper to free a list of IIO device attributes
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>
2013-10-12 12:17:34 +01:00
Lars-Peter Clausen
d2f0a48f36 iio: Wakeup poll and blocking reads when the device is unregistered
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>
2013-10-12 12:05:36 +01:00
Lars-Peter Clausen
f18e7a068a iio: Return -ENODEV for file operations if the device has been unregistered
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>
2013-10-12 12:04:17 +01:00
Lars-Peter Clausen
9e69c935fa iio: Add reference counting for buffers
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>
2013-10-12 12:04:01 +01:00
Greg Kroah-Hartman
02ab343f3b Merge 3.12-rc4 into staging-next
We want the staging fixes in this branch as well.

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-10-06 17:22:43 -07:00
Lars-Peter Clausen
bc4c961292 iio: Remove debugfs entries in iio_device_unregister()
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: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
2013-09-30 21:46:10 +01:00
Greg Kroah-Hartman
e2aad1d571 Merge 3.12-rc2 into staging-next.
This resolves the merge problem with two iio drivers that Stephen
Rothwell pointed out.

Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-09-25 08:59:04 -07:00
Lars-Peter Clausen
0d5b7dae89 iio: Prevent race between IIO chardev opening and IIO device free
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: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
2013-09-21 12:50:23 +01:00
Lars-Peter Clausen
cadc2125e1 iio: fix: Keep a reference to the IIO device for open file descriptors
Make sure that the IIO device is not freed while we still have file descriptors
for it.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
2013-09-21 12:45:07 +01:00
Lars-Peter Clausen
a87c82e454 iio: Stop sampling when the device is removed
Make sure to stop sampling when the device is removed, otherwise it will
continue to sample forever.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
2013-09-21 12:36:30 +01:00
Jonathan Cameron
c006ec8384 iio: add info_mask_[shared_by_dir/shared_by_all]
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: Jonathan Cameron <jic23@kernel.org>
Reviewed-by: Lars-Peter Clausen <lars@metafoo.de>
2013-09-15 17:45:49 +01:00
Jonathan Cameron
3704432fb1 iio: refactor info mask and ext_info attribute creation.
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: Jonathan Cameron <jic23@kernel.org>
Reviewed-by: Lars-Peter Clausen <lars@metafoo.de>
2013-09-15 17:43:20 +01:00
Peter Meerwald
899d90bdf4 iio: Add INT_TIME (integration time) channel info attribute
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: Peter Meerwald <pmeerw@pmeerw.net>
Cc: Jon Brenner <jon.brenner@ams.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
2013-09-14 21:16:44 +01:00
Oleksandr Kravchenko
d9a0134e7a iio: core: Avoid double minus in sysfs output
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: Oleksandr Kravchenko <o.v.kravchenko@globallogic.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
2013-08-03 18:41:19 +01:00
Grygorii Strashko
9dabaf5edd iio: core: implement devm_iio_device_alloc/devm_iio_device_free
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: Grygorii Strashko <grygorii.strashko@ti.com>
Signed-off-by: Oleksandr Kravchenko <o.v.kravchenko@globallogic.com>
Tested-by: Oleksandr Kravchenko <o.v.kravchenko@globallogic.com>
Reviewed-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
2013-08-03 18:40:37 +01:00
Jonathan Cameron
b9606e2aa9 iio:core drop info_mask from struct iio_info
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: Jonathan Cameron <jic23@kernel.org>
Acked-by: Lars-Peter Clausen <lars@metafoo.de>
2013-03-17 19:49:44 +00:00
Jonathan Cameron
8655cc490e iio: Add broken out info_mask fields for shared_by_type and separate
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: Jonathan Cameron <jic23@kernel.org>
Acked-by: Lars-Peter Clausen <lars@metafoo.de>
2013-03-17 19:49:09 +00:00
Guenter Roeck
17d82b47a2 iio: Add OF support
Provide bindings and parse OF data during initialization.

Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Reviewed-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
2013-03-16 10:17:59 +00:00
Lars-Peter Clausen
6807d72113 iio: Factor out fixed point number parsing into its own function
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: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
2012-11-20 21:26:39 +00:00
Lars-Peter Clausen
c4f0c69367 iio: Add pressure channel type
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: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
2012-11-20 21:26:38 +00:00
Jonathan Cameron
84b36ce5f7 staging:iio: Add support for multiple buffers
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: Jonathan Cameron <jic23@kernel.org>
Tested-by: srinivas pandruvada <srinivas.pandruvada@intel.com>
2012-11-10 10:17:21 +00:00
Lars-Peter Clausen
ef4f92c064 iio: Accept a leading '+' sign when parsing fixed point numbers
If we encounter a leading '+' sign just skip over it.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
2012-11-02 09:43:48 +00:00
Lars-Peter Clausen
02330acda7 iio: Reject trailing garbage when parsing fixed point numbers
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: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
2012-11-02 09:43:48 +00:00
Lars-Peter Clausen
8f1b7eb114 iio: Do not accept multiple '.' in fixed point numbers
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: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
2012-11-02 09:43:47 +00:00
Lars-Peter Clausen
103d9fb907 iio: Add a logarithmic fractional value type
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: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
2012-10-19 18:46:51 +01:00
Lars-Peter Clausen
7985e7c100 iio: Introduce a new fractional value type
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: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
2012-09-15 10:12:22 +01:00
srinivas pandruvada
7c9ab035ac iio: core: Add hysteresis in channel spec
Added hysteresis to the list of channel info enumeration, shared
/separate bit defines and to postfix channel info strings.

Signed-off-by: srinivas pandruvada <srinivas.pandruvada@intel.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
2012-09-06 19:04:45 +01:00
Jonathan Cameron
c8b95952e7 IIO: Update email address for Jonathan Cameron.
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
2012-09-03 20:26:46 +01:00
Peter Meerwald
99698b4567 iio: whitespace cleanup and removal of semicolon after functions
Signed-off-by: Peter Meerwald <pmeerw@pmeerw.net>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
2012-09-03 20:26:43 +01:00
Peter Meerwald
d25b3808db iio: fix typos
Signed-off-by: Peter Meerwald <pmeerw@pmeerw.net>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
2012-09-03 20:26:43 +01:00
Jon Brenner
21cd1fab05 IIO channel type and modifiers for CCT and RGBC data
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: Jon Brenner <jbrenner@taosinc.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
2012-07-10 18:49:26 +01:00
Jonathan Cameron
cf82cb8128 IIO: Add a modifier for x^2+y^2+z^2
There will probably be a number of such modifiers eventually but
this one is used in the adis16240 accelerometer driver.

Signed-off-by: Jonathan Cameron <jic23@kernel.org>
2012-06-30 10:15:28 +01:00