Re: [alsa-devel] [PATCH v3 1/4] dt-bindings: soundwire: add slave bindings

On Fri, Aug 09, 2019 at 02:34:04PM +0100, Srinivas Kandagatla wrote:

This patch adds bindings for Soundwire Slave devices that includes how SoundWire enumeration address and Link ID are used to represented in SoundWire slave device tree nodes.

Signed-off-by: Srinivas Kandagatla srinivas.kandagatla@linaro.org

.../devicetree/bindings/soundwire/slave.txt | 51 +++++++++++++++++++ 1 file changed, 51 insertions(+) create mode 100644 Documentation/devicetree/bindings/soundwire/slave.txt

Can you convert this to DT schema given it is a common binding.

What does the host controller look like? You need to define the node hierarchy. Bus controller schemas should then include the bus schema. See spi-controller.yaml.

diff --git a/Documentation/devicetree/bindings/soundwire/slave.txt b/Documentation/devicetree/bindings/soundwire/slave.txt new file mode 100644 index 000000000000..201f65d2fafa --- /dev/null +++ b/Documentation/devicetree/bindings/soundwire/slave.txt @@ -0,0 +1,51 @@ +SoundWire slave device bindings.

+SoundWire is a 2-pin multi-drop interface with data and clock line. +It facilitates development of low cost, efficient, high performance systems.

+SoundWire slave devices: +Every SoundWire controller node can contain zero or more child nodes +representing slave devices on the bus. Every SoundWire slave device is +uniquely determined by the enumeration address containing 5 fields: +SoundWire Version, Instance ID, Manufacturer ID, Part ID +and Class ID for a device. Addition to below required properties, +child nodes can have device specific bindings.

+Required properties: +- compatible: "sdw<LinkID><VersionID><InstanceID><MFD><PID><CID>".

•   Is the textual representation of SoundWire Enumeration
  

•   address along with Link ID. compatible string should contain
  

•   SoundWire Link ID, SoundWire Version ID, Instance ID,
  

•   Manufacturer ID, Part ID and Class ID in order
  

•   represented as above and shall be in lower-case hexadecimal
  

•   with leading zeroes. Vaild sizes of these fields are
  

•   LinkID is 1 nibble,
  

•   Version ID is 1 nibble
  

•   Instance ID in 1 nibble
  

•   MFD in 4 nibbles
  

•   PID in 4 nibbles
  

•   CID is 2 nibbles
  

•   Version number '0x1' represents SoundWire 1.0
  

•   Version number '0x2' represents SoundWire 1.1
  

This can all be a regex.

•   ex: "sdw0110217201000" represents 0 LinkID,
  

•   SoundWire 1.0 version slave with Instance ID 1.
  

•   More Information on detail of encoding of these fields can be
  

•   found in MIPI Alliance DisCo & SoundWire 1.0 Specifications.
  

+SoundWire example for Qualcomm's SoundWire controller:

+soundwire@c2d0000 {

• compatible = "qcom,soundwire-v1.5.0"
• reg = <0x0c2d0000 0x2000>;
• spkr_left:wsa8810-left{

• compatible = "sdw0110217201000";
  

• ...
  

• };
• spkr_right:wsa8810-right{

• compatible = "sdw0120217201000";
  

The normal way to distinguish instances is with 'reg'. So I think you need 'reg' with Instance ID moved there at least. Just guessing, but perhaps Link ID, too? And for 2 different classes of device is that enough?

Rob