docs: dmaengine: add explanation for phys field in dma_async_tx_descriptor structure

Describe the need to initialize the phys field in the dma_async_tx_descriptor
structure during its initialization.

Signed-off-by: Bhanu Seshu Kumar Valluri <bhanuseshukumar@gmail.com>
Reviewed-by: Bagas Sanjaya <bagasdotme@gmail.com>
Link: https://patch.msgid.link/20251113064937.8735-1-bhanuseshukumar@gmail.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

diff --git a/Documentation/driver-api/dmaengine/provider.rst b/Documentation/driver-api/dmaengine/provider.rst
index 1594598b331782e4dddcf992159c724111db9cf3..f4ed98f701c918ff81bc674845880f8d01efbf1d 100644 (file)
--- a/Documentation/driver-api/dmaengine/provider.rst
+++ b/Documentation/driver-api/dmaengine/provider.rst
@@ -411,7 +411,7 @@ supported.
   - This structure can be initialized using the function
     ``dma_async_tx_descriptor_init``.
 
-  - You'll also need to set two fields in this structure:
+  - You'll also need to set following fields in this structure:
 
     - flags:
       TODO: Can it be modified by the driver itself, or
@@ -421,6 +421,9 @@ supported.
       that is supposed to push the current transaction descriptor to a
       pending queue, waiting for issue_pending to be called.
 
+    - phys: Physical address of the descriptor which is used later by
+      the dma engine to read the descriptor and initiate transfer.
+
   - In this structure the function pointer callback_result can be
     initialized in order for the submitter to be notified that a
     transaction has completed. In the earlier code the function pointer