After introduction a few years ago the devm_acpi_dma_controller_free()
was never used. Drop it.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
---
 Documentation/driver-api/driver-model/devres.rst |  1 -
 drivers/dma/acpi-dma.c                           | 15 ---------------
 include/linux/acpi_dma.h                         |  4 ----
 3 files changed, 20 deletions(-)

diff --git a/Documentation/driver-api/driver-model/devres.rst b/Documentation/driver-api/driver-model/devres.rst
index 5f2ee8d717b1..f23dbe5d6606 100644
--- a/Documentation/driver-api/driver-model/devres.rst
+++ b/Documentation/driver-api/driver-model/devres.rst
@@ -459,7 +459,6 @@ SERDEV
 
 SLAVE DMA ENGINE
   devm_acpi_dma_controller_register()
-  devm_acpi_dma_controller_free()
 
 SPI
   devm_spi_alloc_master()
diff --git a/drivers/dma/acpi-dma.c b/drivers/dma/acpi-dma.c
index a58a1600dd65..d5beb96ef510 100644
--- a/drivers/dma/acpi-dma.c
+++ b/drivers/dma/acpi-dma.c
@@ -276,21 +276,6 @@ int devm_acpi_dma_controller_register(struct device *dev,
 }
 EXPORT_SYMBOL_GPL(devm_acpi_dma_controller_register);
 
-/**
- * devm_acpi_dma_controller_free - resource managed acpi_dma_controller_free()
- * @dev:	device that is unregistering as DMA controller
- *
- * Unregister a DMA controller registered with
- * devm_acpi_dma_controller_register(). Normally this function will not need to
- * be called and the resource management code will ensure that the resource is
- * freed.
- */
-void devm_acpi_dma_controller_free(struct device *dev)
-{
-	WARN_ON(devres_release(dev, devm_acpi_dma_release, NULL, NULL));
-}
-EXPORT_SYMBOL_GPL(devm_acpi_dma_controller_free);
-
 /**
  * acpi_dma_update_dma_spec - prepare dma specifier to pass to translation function
  * @adma:	struct acpi_dma of DMA controller
diff --git a/include/linux/acpi_dma.h b/include/linux/acpi_dma.h
index 72cedb916a9c..3ef1ec7a04cb 100644
--- a/include/linux/acpi_dma.h
+++ b/include/linux/acpi_dma.h
@@ -65,7 +65,6 @@ int devm_acpi_dma_controller_register(struct device *dev,
 		struct dma_chan *(*acpi_dma_xlate)
 		(struct acpi_dma_spec *, struct acpi_dma *),
 		void *data);
-void devm_acpi_dma_controller_free(struct device *dev);
 
 struct dma_chan *acpi_dma_request_slave_chan_by_index(struct device *dev,
 						      size_t index);
@@ -94,9 +93,6 @@ static inline int devm_acpi_dma_controller_register(struct device *dev,
 {
 	return -ENODEV;
 }
-static inline void devm_acpi_dma_controller_free(struct device *dev)
-{
-}
 
 static inline struct dma_chan *acpi_dma_request_slave_chan_by_index(
 		struct device *dev, size_t index)
-- 
2.43.0.rc1.1336.g36b5255a03ac