iio: core: Refactor iio_device_claim_direct() implementation

In order to eventually unify the locking API, implement
iio_device_claim_direct() fully inline, with the use of
__iio_dev_mode_lock(), which takes care of sparse annotations.

Reviewed-by: David Lechner <dlechner@baylibre.com>
Reviewed-by: Nuno Sá <nuno.sa@analog.com>
Signed-off-by: Kurt Borja <kuurtb@gmail.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

1 files changed, 28 insertions, 12 deletions

diff --git a/include/linux/iio/iio.h b/include/linux/iio/iio.h
index aecda887d833..e263ab5eeccf 100644
--- a/include/linux/iio/iio.h
+++ b/include/linux/iio/iio.h
@@ -664,31 +664,47 @@ int iio_push_event(struct iio_dev *indio_dev, u64 ev_code, s64 timestamp);
 
 void __iio_dev_mode_lock(struct iio_dev *indio_dev) __acquires(indio_dev);
 void __iio_dev_mode_unlock(struct iio_dev *indio_dev) __releases(indio_dev);
-bool __iio_device_claim_direct(struct iio_dev *indio_dev);
-void __iio_device_release_direct(struct iio_dev *indio_dev);
 
 /*
  * Helper functions that allow claim and release of direct mode
  * in a fashion that doesn't generate many false positives from sparse.
  * Note this must remain static inline in the header so that sparse
- * can see the __acquire() marking. Revisit when sparse supports
- * __cond_acquires()
+ * can see the __acquires() and __releases() annotations.
+ */
+
+/**
+ * iio_device_claim_direct() - Keep device in direct mode
+ * @indio_dev:	the iio_dev associated with the device
+ *
+ * If the device is in direct mode it is guaranteed to stay
+ * that way until iio_device_release_direct() is called.
+ *
+ * Use with iio_device_release_direct().
+ *
+ * Returns: true on success, false on failure.
  */
 static inline bool iio_device_claim_direct(struct iio_dev *indio_dev)
 {
-	if (!__iio_device_claim_direct(indio_dev))
-		return false;
+	__iio_dev_mode_lock(indio_dev);
 
-	__acquire(iio_dev);
+	if (iio_buffer_enabled(indio_dev)) {
+		__iio_dev_mode_unlock(indio_dev);
+		return false;
+	}
 
 	return true;
 }
 
-static inline void iio_device_release_direct(struct iio_dev *indio_dev)
-{
-	__iio_device_release_direct(indio_dev);
-	__release(indio_dev);
-}
+/**
+ * iio_device_release_direct() - Releases claim on direct mode
+ * @indio_dev:	the iio_dev associated with the device
+ *
+ * Release the claim. Device is no longer guaranteed to stay
+ * in direct mode.
+ *
+ * Use with iio_device_claim_direct().
+ */
+#define iio_device_release_direct(indio_dev) __iio_dev_mode_unlock(indio_dev)
 
 int iio_device_claim_buffer_mode(struct iio_dev *indio_dev);
 void iio_device_release_buffer_mode(struct iio_dev *indio_dev);