linux-kernel - [PATCH v2 1/2] dt-bindings: sound: simple-card: add sysclk-cpu-first flag

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Message-ID: <20260210164506.161810-2-stefano.r@variscite.com>
Date: Tue, 10 Feb 2026 17:45:05 +0100
From: Stefano Radaelli <stefano.radaelli21@...il.com>
To: Kuninori Morimoto <kuninori.morimoto.gx@...esas.com>,
	linux-sound@...r.kernel.org,
	linux-kernel@...r.kernel.org
Cc: Mark Brown <broonie@...nel.org>,
	Liam Girdwood <lgirdwood@...il.com>,
	Rob Herring <robh@...nel.org>,
	Krzysztof Kozlowski <krzk+dt@...nel.org>,
	Conor Dooley <conor+dt@...nel.org>,
	Jaroslav Kysela <perex@...ex.cz>,
	Takashi Iwai <tiwai@...e.com>,
	alexander.h@...iscite.com,
	pierluigi.p@...iscite.com,
	Stefano Radaelli <stefano.r@...iscite.com>
Subject: [PATCH v2 1/2] dt-bindings: sound: simple-card: add sysclk-cpu-first flag

From: Stefano Radaelli <stefano.r@...iscite.com>

The simple-audio-card driver can program sysclk for CPU and codec DAIs
during hw_params. Some setups require calling the CPU DAI sysclk first
so that the codec sees the final MCLK rate.

Document a new boolean DT flag, sysclk-cpu-first, which allows selecting
CPU-first sysclk ordering where needed. The property is supported both
as a top-level simple-audio-card property (prefixed) and on dai-link
subnodes (non-prefixed).

Signed-off-by: Stefano Radaelli <stefano.r@...iscite.com>
---
 .../devicetree/bindings/sound/simple-card.yaml        | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/Documentation/devicetree/bindings/sound/simple-card.yaml b/Documentation/devicetree/bindings/sound/simple-card.yaml
index 533d0a1da56e..ddad440636be 100644
--- a/Documentation/devicetree/bindings/sound/simple-card.yaml
+++ b/Documentation/devicetree/bindings/sound/simple-card.yaml
@@ -35,6 +35,13 @@ definitions:
     description: see tdm-slot.txt.
     $ref: /schemas/types.yaml#/definitions/uint32
 
+  sysclk-cpu-first:
+    description:
+      When mclk-fs is used, configure CPU DAI sysclk before codec DAI sysclk
+      so the codec sees the final MCLK rate.
+      This property only affects the mclk-fs code path.
+    $ref: /schemas/types.yaml#/definitions/flag
+
   system-clock-frequency:
     description: |
       If a clock is specified and a multiplication factor is given with
@@ -194,6 +201,8 @@ properties:
     $ref: "#/definitions/format"
   simple-audio-card,mclk-fs:
     $ref: "#/definitions/mclk-fs"
+  simple-audio-card,sysclk-cpu-first:
+    $ref: "#/definitions/sysclk-cpu-first"
   simple-audio-card,aux-devs:
     $ref: "#/definitions/aux-devs"
   simple-audio-card,additional-devs:
@@ -251,6 +260,8 @@ patternProperties:
         $ref: "#/definitions/format"
       mclk-fs:
         $ref: "#/definitions/mclk-fs"
+      sysclk-cpu-first:
+        $ref: "#/definitions/sysclk-cpu-first"
       aux-devs:
         $ref: "#/definitions/aux-devs"
       convert-rate:
-- 
2.47.3