Merge tag 'soundwire-4.20-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/vkoul/soundwire into char-misc-next

Vinod writes:

soundwire updates for 4.20-rc1

 - support for multi-link streaming
 - updates in intel driver for multi-link streaming
 - Update Vinod's email
 - Fix rst formatting

* tag 'soundwire-4.20-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/vkoul/soundwire:
  Documentation: soundwire: fix stream.rst markup warnings
  soundwire: intel: Remove duplicate assignment
  MAINTAINERS: Update Vinod's email
  soundwire: intel: Fix uninitialized adev deref
  soundwire: intel: Add pre/post bank switch ops
  soundwire: keep track of Masters in a stream
  soundwire: Add support for multi link bank switch
  soundwire: Handle multiple master instances in a stream
  soundwire: Add support to lock across bus instances
  soundwire: Initialize completion for defer messages
  Documentation: soundwire: Add documentation for multi link

1 files changed, 36 insertions, 0 deletions

diff --git a/Documentation/driver-api/soundwire/stream.rst b/Documentation/driver-api/soundwire/stream.rst
index 29121aa55fb9..26a6064503fd 100644
--- a/Documentation/driver-api/soundwire/stream.rst
+++ b/Documentation/driver-api/soundwire/stream.rst
@@ -101,6 +101,34 @@ interface. ::
 	+--------------------+                             |                |
 							   +----------------+
 
+Example 5: Stereo Stream with L and R channel is rendered by 2 Masters, each
+rendering one channel, and is received by two different Slaves, each
+receiving one channel. Both Masters and both Slaves are using single port. ::
+
+	+---------------+                    Clock Signal  +---------------+
+	|    Master     +----------------------------------+     Slave     |
+	|   Interface   |                                  |   Interface   |
+	|       1       |                                  |       1       |
+	|               |                     Data Signal  |               |
+	|       L       +----------------------------------+       L       |
+	|     (Data)    |     Data Direction               |     (Data)    |
+	+---------------+  +----------------------->       +---------------+
+
+	+---------------+                    Clock Signal  +---------------+
+	|    Master     +----------------------------------+     Slave     |
+	|   Interface   |                                  |   Interface   |
+	|       2       |                                  |       2       |
+	|               |                     Data Signal  |               |
+	|       R       +----------------------------------+       R       |
+	|     (Data)    |     Data Direction               |     (Data)    |
+	+---------------+  +----------------------->       +---------------+
+
+Note: In multi-link cases like above, to lock, one would acquire a global
+lock and then go on locking bus instances. But, in this case the caller
+framework(ASoC DPCM) guarantees that stream operations on a card are
+always serialized. So, there is no race condition and hence no need for
+global lock.
+
 SoundWire Stream Management flow
 ================================
 
@@ -174,6 +202,7 @@ per stream. From ASoC DPCM framework, this stream state maybe linked to
 .startup() operation.
 
   .. code-block:: c
+
   int sdw_alloc_stream(char * stream_name);
 
 
@@ -200,6 +229,7 @@ only be invoked once by respective Master(s) and Slave(s). From ASoC DPCM
 framework, this stream state is linked to .hw_params() operation.
 
   .. code-block:: c
+
   int sdw_stream_add_master(struct sdw_bus * bus,
 		struct sdw_stream_config * stream_config,
 		struct sdw_ports_config * ports_config,
@@ -245,6 +275,7 @@ stream. From ASoC DPCM framework, this stream state is linked to
 .prepare() operation.
 
   .. code-block:: c
+
   int sdw_prepare_stream(struct sdw_stream_runtime * stream);
 
 
@@ -274,6 +305,7 @@ stream. From ASoC DPCM framework, this stream state is linked to
 .trigger() start operation.
 
   .. code-block:: c
+
   int sdw_enable_stream(struct sdw_stream_runtime * stream);
 
 SDW_STREAM_DISABLED
@@ -301,6 +333,7 @@ per stream. From ASoC DPCM framework, this stream state is linked to
 .trigger() stop operation.
 
   .. code-block:: c
+
   int sdw_disable_stream(struct sdw_stream_runtime * stream);
 
 
@@ -325,6 +358,7 @@ per stream. From ASoC DPCM framework, this stream state is linked to
 .trigger() stop operation.
 
   .. code-block:: c
+
   int sdw_deprepare_stream(struct sdw_stream_runtime * stream);
 
 
@@ -349,6 +383,7 @@ all the Master(s) and Slave(s) associated with stream. From ASoC DPCM
 framework, this stream state is linked to .hw_free() operation.
 
   .. code-block:: c
+
   int sdw_stream_remove_master(struct sdw_bus * bus,
 		struct sdw_stream_runtime * stream);
   int sdw_stream_remove_slave(struct sdw_slave * slave,
@@ -361,6 +396,7 @@ stream assigned as part of ALLOCATED state.
 In .shutdown() the data structure maintaining stream state are freed up.
 
   .. code-block:: c
+
   void sdw_release_stream(struct sdw_stream_runtime * stream);
 
 Not Supported