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Subject[RFC PATCH 3/5] ASoC: audio-graph-card: Add bindings for sysclk and pll
Date
ASoC core provides callbacks snd_soc_dai_set_sysclk() and
snd_soc_dai_set_pll() for system clock (sysclk) and pll configurations
respectively. Add bindings for flexible sysclk or pll configurations
which can be driven from CPU/Codec DAI or endpoint subnode from DT.
This in turn helps to avoid hard codings in driver and makes it more
generic.

Also add system-clock related bindings, "system-clock-direction-out"
and "system-clock-frequency", which are already supported.

Cc: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Cc: Rob Herring <robh@kernel.org>
Signed-off-by: Sameer Pujar <spujar@nvidia.com>
---
.../bindings/sound/audio-graph-port.yaml | 71 ++++++++++++++++++++++
1 file changed, 71 insertions(+)

diff --git a/Documentation/devicetree/bindings/sound/audio-graph-port.yaml b/Documentation/devicetree/bindings/sound/audio-graph-port.yaml
index 766e910..4f50291 100644
--- a/Documentation/devicetree/bindings/sound/audio-graph-port.yaml
+++ b/Documentation/devicetree/bindings/sound/audio-graph-port.yaml
@@ -71,6 +71,77 @@ properties:
description: CPU to Codec rate channels.
$ref: /schemas/types.yaml#/definitions/uint32

+ system-clock-frequency:
+ description: |
+ Specify system clock (sysclk) frequency for CPU or Codec
+ component. Or if a clock is specified in the CPU or Codec
+ device node and a scaling factor is given with "mclk-fs",
+ sysclk will be calculated as a multiple of stream sample
+ rate and "mclk-fs". The rate is updated when stream starts.
+ $ref: /schemas/types.yaml#/definitions/uint32
+
+ system-clock-direction-out:
+ description: |
+ Specifies clock direction as "out" on initialization. It
+ is useful for some CPUs with fixed clocks.
+ $ref: /schemas/types.yaml#/definitions/flag
+
+ system-clock-id:
+ description: |
+ CPU or Codec component may have multiple clocks. A specific
+ clock may have to be configured. In such cases the clock
+ ID needs to be specified.
+ $ref: /schemas/types.yaml#/definitions/uint32
+
+ system-clock-source:
+ description: |
+ CPU or Codec component may have multiple sources for its
+ system clock (sysclk). In such cases the sysclk source
+ needs to be specified.
+ $ref: /schemas/types.yaml#/definitions/uint32
+
+ pll-id:
+ description: |
+ Specify PLL that needs to be configured. This is useful
+ when the CPU or Codec component has multiple PLLs.
+ $ref: /schemas/types.yaml#/definitions/uint32
+
+ pll-source:
+ description: |
+ When PLL has multiple reference clock sources, the exact
+ source needs to be specified for the required configuration.
+ $ref: /schemas/types.yaml#/definitions/uint32
+
+ pll-input-reference:
+ description: |
+ Specify how to calculate input frequency for the PLL.
+ Depending on the identifier, input frequency can be
+ calculated at runtime. For example if I2S bit clock is used
+ as reference, rate depends on actual PCM parameters (rate,
+ channels and bits) during an audio session. If a fixed rate
+ is used, then "pll-input-frequency" can be used instead.
+ $ref: /schemas/types.yaml#/definitions/uint32
+ const: 2
+
+ pll-input-frequency:
+ description: Specify fixed input frequency
+ $ref: /schemas/types.yaml#/definitions/uint32
+
+ pll-output-reference:
+ description: |
+ Specify how to calculate output frequency for the PLL.
+ Depending on the identifier, output frequency can be
+ calculated at runtime. If output clock is used for MCLK purpose,
+ then it may depend on "mclk-fs" scale factor. In such cases it
+ needs to be calculated at runtime. If a fixed output frequency
+ is needed, then "pll-output-frequency" can be used instead.
+ $ref: /schemas/types.yaml#/definitions/uint32
+ const: 1
+
+ pll-output-frequency:
+ description: Specify fixed output frequency
+ $ref: /schemas/types.yaml#/definitions/uint32
+
ports:
description: multi OF-Graph subnode
type: object
--
2.7.4
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