Message-ID: <0827a05c-117d-3d4c-2e3a-f8d80e256ca0@linaro.org>
Date:   Fri, 24 Feb 2023 11:59:26 +0100
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Subject: Re: [PATCH 2/4] ASoC: dt-bindings: wlf,wm8524: Add a property to
 specify power up sequency time
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To:     Chancel Liu <chancel.liu@nxp.com>, Mark Brown <broonie@kernel.org>
Cc:     "lgirdwood@gmail.com" <lgirdwood@gmail.com>,
        "robh+dt@kernel.org" <robh+dt@kernel.org>,
        "krzysztof.kozlowski+dt@linaro.org" 
        <krzysztof.kozlowski+dt@linaro.org>,
        "perex@perex.cz" <perex@perex.cz>,
        "tiwai@suse.com" <tiwai@suse.com>,
        "ckeepax@opensource.cirrus.com" <ckeepax@opensource.cirrus.com>,
        "patches@opensource.cirrus.com" <patches@opensource.cirrus.com>,
        "alsa-devel@alsa-project.org" <alsa-devel@alsa-project.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "devicetree@vger.kernel.org" <devicetree@vger.kernel.org>
References: <20230222113945.3390672-1-chancel.liu@nxp.com>
 <20230222113945.3390672-2-chancel.liu@nxp.com>
 <Y/YPkgOreByREmOz@sirena.org.uk>
 <VI1PR04MB4222996DB8494FD14A1D5FCEE3A89@VI1PR04MB4222.eurprd04.prod.outlook.com>
From:   Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
In-Reply-To: <VI1PR04MB4222996DB8494FD14A1D5FCEE3A89@VI1PR04MB4222.eurprd04.prod.outlook.com>
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Precedence: bulk

On 24/02/2023 11:56, Chancel Liu wrote:
>> On Wed, Feb 22, 2023 at 07:39:43PM +0800, Chancel Liu wrote:
>>> This property specifies power up to audio out time. It's necessary
>>> beacause this device has to wait some time before ready to output
>>> audio after MCLK, BCLK and MUTE=1 are enabled. For more details about
>>> the timing constraints, please refer to WTN0302 on
>>> https://www.cirrus.com/products/wm8524/
>>
>> According to that the delay is a property of MCLK and the sample rate rather
>> than a per board constant, it shouldn't be in DT but rather the driver should
>> figure out the required delay on each startup.
> 
> I can't agree with you more. From the power up to audio out timing table in
> WTN0302, the delay depends on sample rate and MCLK. Driver should calculate it
> rather than read it from DT. However as I mentioned in my last email, values in
> the table seem not accurate for all systems. It's a kind of compromise to get
> the value from DT. Do other codecs have a similar situation?

DT is for hardware properties, not for software compromises.


Best regards,
Krzysztof