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

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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: Andy Shevchenko <andriy.shevchenko@intel.com>
Reviewed-by: David Lechner <dlechner@baylibre.com>
Reviewed-by: Nuno Sá <nuno.sa@analog.com>
Acked-by: Andy Shevchenko <andriy.shevchenko@intel.com>
Signed-off-by: Kurt Borja <kuurtb@gmail.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
This commit is contained in:
Kurt Borja 2026-01-20 01:20:44 -05:00 committed by Jonathan Cameron
parent 2daee817df
commit 7a38b75da1
1 changed files with 65 additions and 0 deletions
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65
include/linux/iio/iio.h
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@ -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;
/**