Used to allow information about a given channel mapping to be passed
through from board files to the consumer drivers.
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>

Fixes the following warnings from coccicheck:
	drivers/iio/inkern.c:81:6-14: WARNING: Comparison to bool
	drivers/iio/dac/ad5686.c:191:5-11: WARNING: Comparison to bool
Signed-off-by: NLars-Peter Clausen <lars@metafoo.de>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>

 When the IIO consumer tries to get specific IIO channel,
 few error cases can be happened.
 (a) Memory allocation failure
 (b) No matched ADC channel error
 (c) Invalid input arguments
 This patch enables cleaning up error handling in case of (a) and (b).

 In error handling code,
 (a): the reference count of the IIO device should be decreased.
 (b): the allocated memory should be freed with restoring the reference count.
 Therefore iio_deivce_put() is called in both cases.
 This can be handled in the last error statement.

 Additionally, integer variable is used for stating each error case explicitly.
 Then, the error returns as ERR_PTR() with this value.
Signed-off-by: NMilo(Woogyom) Kim <milo.kim@ti.com>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>

 The reference count of the IIO device is increased if the IIO map has
 matched consumer name.
 After then, it tries to allocate the iio_channel which is used by the consumer.
 If it fails to allocate memory, the reference count should be decreased.

 This patch enables restoring the reference count of the IIO device.
Signed-off-by: NMilo(Woogyom) Kim <milo.kim@ti.com>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>

Add a function to read a processed value from a channel. The function will first
attempt to read the IIO_CHAN_INFO_PROCESSED attribute. If that fails it will
read the IIO_CHAN_INFO_RAW attribute and convert the result from a raw value to
a processed value.

The patch also introduces a function to convert raw value to a processed value
and exports it, in case a user needs or wants to do the conversion by itself.
Signed-off-by: NLars-Peter Clausen <lars@metafoo.de>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>

 The datasheet name is defined in the IIO driver.
 On the other hand, the adc_channel_label is configured in
 the platform side.
 If the datasheet name is not matched with any adc_channel_label,
 the iio_channel_get() should be returned as error for preventing
 invalid channel data access.

 This can be handled either way.
 (a) checking null data when using it : in the xxx_read_raw()
 or
 (b) error returns when the channel is requested : this patch

 The IIO consumer can't use the channel with invalid channel spec.
 Therefore case (b) is more reasonable.
Signed-off-by: NMilo(Woogyom) Kim <milo.kim@ti.com>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>

 Use kzalloc() rather than kmalloc() for initializing the iio_channel structure.
 This patch enables the iio_dev and iio_chan_spec are set to NULL.
 This may prevent the page fault problem because the pointer of iio_chan_spec
 is initialized as NULL.

 The iio_chan_spec is updated only in case that the IIO map has
 specific channel label.
 When the map has no ADC channel label, then the value of iio_chan_spec
 remains as invalid pointer.
 To prevent this problem, the pointer should be initialized as NULL.
Signed-off-by: NMilo(Woogyom) Kim <milo.kim@ti.com>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>

(a) For better readability, replace 0 with IIO_CHAN_INFO_RAW.
(b) Make same line-format as other apis()
    : iio_read_channel_scale() and iio_read_channel_offset()
Signed-off-by: NMilo(Woogyom) Kim <milo.kim@ti.com>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>

We should be holding the mutex when we goto error_free_chans.
Signed-off-by: NDan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: NJonathan Cameron <jic23@kernel.org>

The device_get is after this point so on error we should not be
removing it.
Signed-off-by: NJonathan Cameron <jic23@kernel.org>

These were originally introduced when the plan was to have parallel
IIO cores in and out of staging with a slow move between them.
Now we have reached the point where the whole core has moved,
they need clearing up!
Signed-off-by: NJonathan Cameron <jic23@kernel.org>

Use iio_device_get and iio_device_put instead of open-coding it.
Signed-off-by: NLars-Peter Clausen <lars@metafoo.de>
Acked-by: NJonathan Cameron <jic23@kernel.org>
Signed-off-by: NLars-Peter Clausen <lars@metafoo.de>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Take the core support + the kfifo buffer implentation out of
staging.  Whilst we are far from done in improving this subsystem
it is now at a stage where the userspae interfaces (provided by
the core) can be considered stable.

Drivers will follow over a longer time scale.
Signed-off-by: NJonathan Cameron <jic23@kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Step 1 in moving the IIO core out of staging.
Signed-off-by: NJonathan Cameron <jic23@kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

staging:iio:core add missing increment of loop index in iio_map_array_unregister()
Signed-off-by: NLothar Waßmann <LW@KARO-electronics.de>
Acked-by: NJonathan Cameron <jic23@kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Lifted from proposal for in kernel interface built on the out of staging
branch.

Two elements here:
* Map as defined in "inkern.h"
* Matching code to actually get the iio_dev and channel
that we want from the global list of IIO devices.
V4: Everything now built if iio is built (rather than being optional)
    Removal race condition prevented by using info pointer as a check
    of removal under a lock.
V3: Drop the option of registering / getting channels using dev pointer.
Stick to name only as suggested by Mark Brown (this has caused user
confusion in the regulator framework.)
V2: As per Greg KH suggestion, move over to registration by passing
the tables into the provider drivers (how regulator does it).
This does not prevent us using the original more flexible approach
if at a later date there is a usecase that demands it.
Signed-off-by: NJonathan Cameron <jic23@kernel.org>
Acked-by: NLinus Walleij <linus.walleij@linaro.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>