From mboxrd@z Thu Jan 1 00:00:00 1970 From: Shreyas NC Subject: [PATCH v3 1/6] Documentation: soundwire: Add documentation for multi link Date: Thu, 14 Jun 2018 17:01:58 +0530 Message-ID: <1528975923-15141-2-git-send-email-shreyas.nc@intel.com> References: <1528975923-15141-1-git-send-email-shreyas.nc@intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from mga03.intel.com (mga03.intel.com [134.134.136.65]) by alsa0.perex.cz (Postfix) with ESMTP id 7217E2675FC for ; Thu, 14 Jun 2018 13:34:10 +0200 (CEST) In-Reply-To: <1528975923-15141-1-git-send-email-shreyas.nc@intel.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: alsa-devel-bounces@alsa-project.org Sender: alsa-devel-bounces@alsa-project.org To: alsa-devel@alsa-project.org Cc: patches.audio@intel.com, gregkh@linuxfoundation.org, pierre-louis.bossart@linux.intel.com, vkoul@kernel.org, Shreyas NC , sanyog.r.kale@intel.com List-Id: alsa-devel@alsa-project.org From: Sanyog Kale Add example and documentation to describe multi link streams Signed-off-by: Pierre-Louis Bossart Signed-off-by: Sanyog Kale Signed-off-by: Vinod Koul Signed-off-by: Shreyas NC --- Documentation/driver-api/soundwire/stream.rst | 29 ++++++++++++++++++++++++++- 1 file changed, 28 insertions(+), 1 deletion(-) diff --git a/Documentation/driver-api/soundwire/stream.rst b/Documentation/driver-api/soundwire/stream.rst index 29121aa..11623aab 100644 --- a/Documentation/driver-api/soundwire/stream.rst +++ b/Documentation/driver-api/soundwire/stream.rst @@ -75,7 +75,6 @@ Slaves are using single port. :: | (Data) | +---------------+ - Example 4: Stereo Stream with L and R channel is rendered by two different Ports of the Master and is received by only single Port of the Slave interface. :: @@ -101,6 +100,34 @@ 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 ================================ -- 2.7.4