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iio: core: Add devm_ APIs for iio_channel_{get,release} 

Some of kernel driver uses the IIO framework to get the sensor
value via ADC or IIO HW driver. The client driver get iio channel
by iio_channel_get() and release it by calling iio_channel_release().

Add resource managed version (devm_*) of these APIs so that if client
calls the devm_iio_channel_get() then it need not to release it explicitly,
it can be done by managed device framework when driver get un-binded.

This reduces the code in error path and also need of .remove callback in
some cases.

Signed-off-by: Laxman Dewangan <ldewangan@nvidia.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
This commit is contained in:
Laxman Dewangan 2016-04-06 16:01:06 +05:30 committed by Jonathan Cameron
parent 5f991a921a
commit 8bf872d8d2
2 changed files with 75 additions and 0 deletions
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48
drivers/iio/inkern.c
View File

@ -356,6 +356,54 @@ void iio_channel_release(struct iio_channel *channel)
}
EXPORT_SYMBOL_GPL(iio_channel_release);
static void devm_iio_channel_free(struct device *dev, void *res)
{
struct iio_channel *channel = *(struct iio_channel **)res;
iio_channel_release(channel);
}
static int devm_iio_channel_match(struct device *dev, void *res, void *data)
{
struct iio_channel **r = res;
if (!r || !*r) {
WARN_ON(!r || !*r);
return 0;
}
return *r == data;
}
struct iio_channel *devm_iio_channel_get(struct device *dev,
const char *channel_name)
{
struct iio_channel **ptr, *channel;
ptr = devres_alloc(devm_iio_channel_free, sizeof(*ptr), GFP_KERNEL);
if (!ptr)
return ERR_PTR(-ENOMEM);
channel = iio_channel_get(dev, channel_name);
if (IS_ERR(channel)) {
devres_free(ptr);
return channel;
}
*ptr = channel;
devres_add(dev, ptr);
return channel;
}
EXPORT_SYMBOL_GPL(devm_iio_channel_get);
void devm_iio_channel_release(struct device *dev, struct iio_channel *channel)
{
WARN_ON(devres_release(dev, devm_iio_channel_free,
devm_iio_channel_match, channel));
}
EXPORT_SYMBOL_GPL(devm_iio_channel_release);
struct iio_channel *iio_channel_get_all(struct device *dev)
{
const char *name;

27
include/linux/iio/consumer.h
View File

@ -48,6 +48,33 @@ struct iio_channel *iio_channel_get(struct device *dev,
*/
void iio_channel_release(struct iio_channel *chan);
/**
* devm_iio_channel_get() - Resource managed version of iio_channel_get().
* @dev: Pointer to consumer device. Device name must match
* the name of the device as provided in the iio_map
* with which the desired provider to consumer mapping
* was registered.
* @consumer_channel: Unique name to identify the channel on the consumer
* side. This typically describes the channels use within
* the consumer. E.g. 'battery_voltage'
*
* Returns a pointer to negative errno if it is not able to get the iio channel
* otherwise returns valid pointer for iio channel.
*
* The allocated iio channel is automatically released when the device is
* unbound.
*/
struct iio_channel *devm_iio_channel_get(struct device *dev,
const char *consumer_channel);
/**
* devm_iio_channel_release() - Resource managed version of
* iio_channel_release().
* @dev: Pointer to consumer device for which resource
* is allocared.
* @chan: The channel to be released.
*/
void devm_iio_channel_release(struct device *dev, struct iio_channel *chan);
/**
* iio_channel_get_all() - get all channels associated with a client
* @dev: Pointer to consumer device.