linux-kernel - Re: [PATCH RFC 3/6] ASoC: soc: qcom: sc8280xp: add support for I2S clocks

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <8ce94679-d6ec-4953-b430-24c493e318e2@linaro.org>
Date: Wed, 8 Oct 2025 19:51:00 +0200
From: Neil Armstrong <neil.armstrong@...aro.org>
To: Konrad Dybcio <konrad.dybcio@....qualcomm.com>,
 Srinivas Kandagatla <srini@...nel.org>, Liam Girdwood <lgirdwood@...il.com>,
 Mark Brown <broonie@...nel.org>, Jaroslav Kysela <perex@...ex.cz>,
 Takashi Iwai <tiwai@...e.com>, Rob Herring <robh@...nel.org>,
 Krzysztof Kozlowski <krzk+dt@...nel.org>, Conor Dooley
 <conor+dt@...nel.org>, Bjorn Andersson <andersson@...nel.org>,
 Konrad Dybcio <konradybcio@...nel.org>
Cc: linux-sound@...r.kernel.org, linux-arm-msm@...r.kernel.org,
 linux-kernel@...r.kernel.org, devicetree@...r.kernel.org
Subject: Re: [PATCH RFC 3/6] ASoC: soc: qcom: sc8280xp: add support for I2S
 clocks

On 10/7/25 17:48, Neil Armstrong wrote:
> On 10/7/25 12:23, Konrad Dybcio wrote:
>> On 10/7/25 9:02 AM, Neil Armstrong wrote:
>>> On 10/7/25 00:21, Srinivas Kandagatla wrote:
>>>>
>>>>
>>>> On 10/6/25 7:37 PM, Neil Armstrong wrote:
>>>>> Add support for getting the I2S clocks used for the MI2S
>>>>> interfaces, and enable/disable the clocks on the PCM
>>>>> startup and shutdown card callbacks.
>>>>>
>>>>> Signed-off-by: Neil Armstrong <neil.armstrong@...aro.org>
>>>>> ---
>>
>> [...]
>>
>>>>> +static int sc8280xp_snd_startup(struct snd_pcm_substream *substream)
>>>>> +{
>>>>> +    unsigned int codec_dai_fmt = SND_SOC_DAIFMT_BC_FC | SND_SOC_DAIFMT_NB_NF | SND_SOC_DAIFMT_I2S;
>>>>> +    struct snd_soc_pcm_runtime *rtd = substream->private_data;
>>>>> +    struct sc8280xp_snd_data *pdata = snd_soc_card_get_drvdata(rtd->card);
>>>>> +    struct snd_soc_dai *cpu_dai = snd_soc_rtd_to_cpu(rtd, 0);
>>>>> +    struct snd_soc_dai *codec_dai = snd_soc_rtd_to_codec(rtd, 0);
>>>>> +    int index;
>>>>> +
>>>>> +    switch (cpu_dai->id) {
>>>>> +    case PRIMARY_MI2S_RX...QUATERNARY_MI2S_TX:
>>>>> +    case QUINARY_MI2S_RX...QUINARY_MI2S_TX:
>>>>> +        index = sc8280xp_snd_i2s_index(cpu_dai);
>>>>
>>>> What is the mclk and bitclk rate set here, we can not rely on the
>>>> default rate.
>>>
>>> The default rates are set in DT:
>>> +        assigned-clocks = <&q6prmcc LPASS_CLK_ID_PRI_MI2S_IBIT LPASS_CLK_ATTRIBUTE_COUPLE_NO>,
>>> +                  <&q6prmcc LPASS_CLK_ID_MCLK_1 LPASS_CLK_ATTRIBUTE_COUPLE_NO>;
>>> +        assigned-clock-rates = <1536000>,
>>> +                       <24576000>;
>>
>> Is there a way to infer these rates based on the DT audio
>> connection graph?
> 
> Good question, it's not done for pre-audioreach. Let me investigate.

OK so since we have fixed 48KHz stereo setup, we can hardcode those frequencies in the card...

FS is 512 and the MCLK / BCLK is 16, as standard so I can calculate those.

Will drop the DT rates and do it in the card.

Neil

> 
> Neil
> 
>>
>> Konrad
>