Commit 7a38b75d authored by Kurt Borja's avatar Kurt Borja Committed by Jonathan Cameron
Browse files

iio: core: Add cleanup.h support for iio_device_claim_*() 



Add guard classes for iio_device_claim_*() conditional locks. This will
aid drivers write safer and cleaner code when dealing with some common
patterns.

These classes are not meant to be used directly by drivers (hence the
__priv__ prefix). Instead, documented wrapper macros are provided to
enforce the use of ACQUIRE() or guard() semantics and avoid the
problematic scoped guard.

Suggested-by: default avatarAndy Shevchenko <andriy.shevchenko@intel.com>
Reviewed-by: default avatarDavid Lechner <dlechner@baylibre.com>
Reviewed-by: default avatarNuno Sá <nuno.sa@analog.com>
Acked-by: default avatarAndy Shevchenko <andriy.shevchenko@intel.com>
Signed-off-by: default avatarKurt Borja <kuurtb@gmail.com>
Signed-off-by: default avatarJonathan Cameron <Jonathan.Cameron@huawei.com>
parent 2daee817

include/linux/iio/iio.h

+65 −0
Original line number Diff line number Diff line
@@ -10,6 +10,7 @@ 
#include <linux/align.h>

#include <linux/device.h>

#include <linux/cdev.h>

#include <linux/cleanup.h>

#include <linux/compiler_types.h>

#include <linux/minmax.h>

#include <linux/slab.h>
@@ -740,6 +741,70 @@ static inline bool iio_device_try_claim_buffer_mode(struct iio_dev *indio_dev) 
 */

#define iio_device_release_buffer_mode(indio_dev) __iio_dev_mode_unlock(indio_dev)



/*

 * These classes are not meant to be used directly by drivers (hence the

 * __priv__ prefix). Instead, documented wrapper macros are provided below to

 * enforce the use of ACQUIRE() or guard() semantics and avoid the problematic

 * scoped guard variants.

 */

DEFINE_GUARD(__priv__iio_dev_mode_lock, struct iio_dev *,

	     __iio_dev_mode_lock(_T), __iio_dev_mode_unlock(_T));

DEFINE_GUARD_COND(__priv__iio_dev_mode_lock, _try_direct,

		  iio_device_claim_direct(_T));



/**

 * IIO_DEV_ACQUIRE_DIRECT_MODE() - Tries to acquire the direct mode lock with

 *				   automatic release

 * @dev: IIO device instance

 * @claim: Variable identifier to store acquire result

 *

 * Tries to acquire the direct mode lock with cleanup ACQUIRE() semantics and

 * automatically releases it at the end of the scope. It most be always paired

 * with IIO_DEV_ACQUIRE_ERR(), for example (notice the scope braces)::

 *

 *	switch() {

 *	case IIO_CHAN_INFO_RAW: {

 *		IIO_DEV_ACQUIRE_DIRECT_MODE(indio_dev, claim);

 *		if (IIO_DEV_ACQUIRE_FAILED(claim))

 *			return -EBUSY;

 *

 *		...

 *	}

 *	case IIO_CHAN_INFO_SCALE:

 *		...

 *	...

 *	}

 *

 * Context: Can sleep

 */

#define IIO_DEV_ACQUIRE_DIRECT_MODE(dev, claim) \

	ACQUIRE(__priv__iio_dev_mode_lock_try_direct, claim)(dev)



/**

 * IIO_DEV_ACQUIRE_FAILED() - ACQUIRE_ERR() wrapper

 * @claim: The claim variable passed to IIO_DEV_ACQUIRE_*_MODE()

 *

 * Return: true if failed to acquire the mode, otherwise false.

 */

#define IIO_DEV_ACQUIRE_FAILED(claim) \

	ACQUIRE_ERR(__priv__iio_dev_mode_lock_try_direct, &(claim))



/**

 * IIO_DEV_GUARD_CURRENT_MODE() - Acquires the mode lock with automatic release

 * @dev: IIO device instance

 *

 * Acquires the mode lock with cleanup guard() semantics. It is usually paired

 * with iio_buffer_enabled().

 *

 * This should *not* be used to protect internal driver state and it's use in

 * general is *strongly* discouraged. Use any of the IIO_DEV_ACQUIRE_*_MODE()

 * variants.

 *

 * Context: Can sleep

 */

#define IIO_DEV_GUARD_CURRENT_MODE(dev) \

	guard(__priv__iio_dev_mode_lock)(dev)



extern const struct bus_type iio_bus_type;



/**