linux-kernel - Re: [PATCH v3 1/2] dt-bindings: soundwire: add bindings for Qcom controller

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Message-ID: <76be1a0d-43ea-44c3-ef6c-9f9a2025c7a2@linaro.org>
Date:   Mon, 14 Oct 2019 18:34:46 +0100
From:   Srinivas Kandagatla <srinivas.kandagatla@...aro.org>
To:     Rob Herring <robh@...nel.org>
Cc:     vkoul@...nel.org, broonie@...nel.org, bgoswami@...eaurora.org,
        pierre-louis.bossart@...ux.intel.com, devicetree@...r.kernel.org,
        lgirdwood@...il.com, alsa-devel@...a-project.org,
        linux-kernel@...r.kernel.org, spapothi@...eaurora.org
Subject: Re: [PATCH v3 1/2] dt-bindings: soundwire: add bindings for Qcom
 controller

Thanks Rob for taking time to review,

On 14/10/2019 18:12, Rob Herring wrote:
> On Fri, Oct 11, 2019 at 04:44:22PM +0100, Srinivas Kandagatla wrote:
>> This patch adds bindings for Qualcomm soundwire controller.
>>
>> Qualcomm SoundWire Master controller is present in most Qualcomm SoCs
>> either integrated as part of WCD audio codecs via slimbus or
>> as part of SOC I/O.
>>
>> Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@...aro.org>
>> ---
>>   .../bindings/soundwire/qcom,sdw.txt           | 167 ++++++++++++++++++
>>   1 file changed, 167 insertions(+)
>>   create mode 100644 Documentation/devicetree/bindings/soundwire/qcom,sdw.txt
> 
> Next time, do a DT schema.
> 
Sure! I can do that in next version!

>> diff --git a/Documentation/devicetree/bindings/soundwire/qcom,sdw.txt b/Documentation/devicetree/bindings/soundwire/qcom,sdw.txt
>> new file mode 100644
>> index 000000000000..436547f3b155
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/soundwire/qcom,sdw.txt
>> @@ -0,0 +1,167 @@
>> +Qualcomm SoundWire Controller Bindings
>> +
>> +
>> +This binding describes the Qualcomm SoundWire Controller along with its
>> +board specific bus parameters.
>> +
>> +- compatible:
>> +	Usage: required
>> +	Value type: <stringlist>
>> +	Definition: must be "qcom,soundwire-v<MAJOR>.<MINOR>.<STEP>",
>> +		    Example:
>> +			"qcom,soundwire-v1.3.0"
>> +			"qcom,soundwire-v1.5.0"
>> +			"qcom,soundwire-v1.6.0"
> 
> This needs to be the actual versions supported, not examples. Elsewhere
> in QCom bindings, we've used standard SoC specific compatibles as there
> never tends to be many SoCs with the same version. Anything different
> here?
> 

These values of MAJOR MINOR and STEP are defined as part of IP spec. And 
most of the QCom IPs follow such scheme. We can read back these values 
from the Hardware registers.

Having SoC Names here might not be very efficient here.
We have used such compatibles on may QCom IPs, like BAM DMA, SLIMBus and 
other drivers.

>> +- reg:
>> +	Usage: required
>> +	Value type: <prop-encoded-array>
>> +	Definition: the base address and size of SoundWire controller
>> +		    address space.
>> +
>> +- interrupts:
>> +	Usage: required
>> +	Value type: <prop-encoded-array>
>> +	Definition: should specify the SoundWire Controller IRQ
>> +
>> +- clock-names:
>> +	Usage: required
>> +	Value type: <stringlist>
>> +	Definition: should be "iface" for SoundWire Controller interface clock
>> +
>> +- clocks:
>> +	Usage: required
>> +	Value type: <prop-encoded-array>
>> +	Definition: should specify the SoundWire Controller interface clock
>> +
>> +- #sound-dai-cells:
>> +	Usage: required
>> +	Value type: <u32>
>> +	Definition: must be 1 for digital audio interfaces on the controller.
>> +
>> +- qcom,dout-ports:
>> +	Usage: required
>> +	Value type: <u32>
>> +	Definition: must be count of data out ports
> 
> Up to how many?
> 
>> +
>> +- qcom,din-ports:
>> +	Usage: required
>> +	Value type: <u32>
>> +	Definition: must be count of data in ports
> 
> Up to how many?

Up to 15 data ports in total

> 
>> +
...

>> +Note:
>> +	More Information on detail of encoding of these fields can be
>> +found in MIPI Alliance SoundWire 1.0 Specifications.
>> +
>> += SoundWire devices
>> +Each subnode of the bus represents SoundWire device attached to it.
>> +The properties of these nodes are defined by the individual bindings.
> 
> Is there some sort of addressing that needs to be defined?
> 
Thanks, Looks like I missed that here.

it should be something like this,

#address-cells = <2>;
#size-cells = <0>;

Will add the in next version.


>> +
>> += EXAMPLE
>> +The following example represents a SoundWire controller on DB845c board
>> +which has controller integrated inside WCD934x codec on SDM845 SoC.
>> +
>> +soundwire: soundwire@c85 {
>> +	compatible = "qcom,soundwire-v1.3.0";
>> +	reg = <0xc85 0x20>;
>> +	interrupts = <20 IRQ_TYPE_EDGE_RISING>;
>> +	clocks = <&wcc>;
>> +	clock-names = "iface";
>> +	#sound-dai-cells = <1>;
>> +	qcom,dports-type = <0>;
>> +	qcom,dout-ports	= <6>;
>> +	qcom,din-ports	= <2>;
>> +	qcom,ports-sinterval-low = /bits/ 8  <0x07 0x1F 0x3F 0x7 0x1F 0x3F 0x0F 0x0F>;
>> +	qcom,ports-offset1 = /bits/ 8 <0x01 0x02 0x0C 0x6 0x12 0x0D 0x07 0x0A >;
>> +	qcom,ports-offset2 = /bits/ 8 <0x00 0x00 0x1F 0x00 0x00 0x1F 0x00 0x00>;
>> +
>> +	/* Left Speaker */
>> +	left{
> 
> space       ^
>> +		....
>> +	};
>> +
>> +	/* Right Speaker */
>> +	right{
> 
> ditto
> 
>> +		....
>> +	};
>> +};
>> -- 
>> 2.21.0
>>