linux-kernel - Re: [PATCH v3] ASoC: da7219: read fmw property to get mclk for non-dts systems

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Message-ID: <516fabd6-264d-a7bd-bf11-40d02154b1ef@amd.com>
Date:   Tue, 15 May 2018 15:13:47 +0530
From:   "Agrawal, Akshu" <Akshu.Agrawal@....com>
To:     Daniel Kurtz <djkurtz@...omium.org>
Cc:     Adam.Thomson.Opensource@...semi.com, Alexander.Deucher@....com,
        Support.Opensource@...semi.com, perex@...ex.cz, tiwai@...e.com,
        Liam Girdwood <lgirdwood@...il.com>,
        Mark Brown <broonie@...nel.org>, alsa-devel@...a-project.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3] ASoC: da7219: read fmw property to get mclk for
 non-dts systems



On 5/7/2018 12:09 PM, Daniel Kurtz wrote:
> On Sun, May 6, 2018 at 10:50 PM Agrawal, Akshu <Akshu.Agrawal@....com>
> wrote:
> 
> 
> 
>> On 5/4/2018 2:45 PM, Adam Thomson wrote:
>>> On 03 May 2018 08:59, Akshu Agrawal wrote:
>>>
>>>> Non-dts based systems can use ACPI DSDT to pass on the mclk
>>>> to da7219.
>>>> This enables da7219 mclk to be linked to system clock.
>>>> Enable/Disable of the mclk is already handled in the codec so
>>>> platform drivers don't have to explicitly do handling of mclk.
>>>>
>>>> Signed-off-by: Akshu Agrawal <akshu.agrawal@....com>
>>>> ---
>>>> v2: Fixed kbuild error
>>>> v3: Add corresponding clk_put for clk_get
>>>>  include/sound/da7219.h    |  2 ++
>>>>  sound/soc/codecs/da7219.c | 10 +++++++++-
>>>>  2 files changed, 11 insertions(+), 1 deletion(-)
>>>>
>>>> diff --git a/include/sound/da7219.h b/include/sound/da7219.h
>>>> index 1bfcb16..df7ddf4 100644
>>>> --- a/include/sound/da7219.h
>>>> +++ b/include/sound/da7219.h
>>>> @@ -38,6 +38,8 @@ struct da7219_pdata {
>>>>
>>>>      const char *dai_clks_name;
>>>>
>>>> +    const char *mclk_name;
>>>> +
>>>>      /* Mic */
>>>>      enum da7219_micbias_voltage micbias_lvl;
>>>>      enum da7219_mic_amp_in_sel mic_amp_in_sel;
>>>> diff --git a/sound/soc/codecs/da7219.c b/sound/soc/codecs/da7219.c
>>>> index 980a6a8..ecd46fc 100644
>>>> --- a/sound/soc/codecs/da7219.c
>>>> +++ b/sound/soc/codecs/da7219.c
>>>> @@ -1624,6 +1624,8 @@ static struct da7219_pdata
> *da7219_fw_to_pdata(struct
>>>> snd_soc_component *compone
>>>>              dev_warn(dev, "Using default clk name: %s\n",
>>>>                       pdata->dai_clks_name);
>>>>
>>>> +    device_property_read_string(dev, "dlg,mclk-name",
> &pdata->mclk_name);
>>>> +
>>>
>>> Personally am still not keen on this. To me the use of a
> device_property_*
>>> function suggests the same property resides in both DT and ACPI, but
> here we're
>>> only using this for the ACPI case. DT has no want or need for this. I
> still feel
>>> we should look at something more generic in the clock framework,
> although I do
>>> agree with Mark that this should be properly specced.
>>>
> 
>> I am not an expert in field of ACPI, IMO forming a Spec and changing
>> ACPI to have DT like clock framework is good to have but a bigger change
>> which should be taken up later.
> 
>> The current code of handling of mclk in the driver is usable only by DT.
>> The device_property (though ACPI specific) makes this code, a common
>> code for DT and ACPI based devices.
> 
>> https://www.kernel.org/doc/Documentation/acpi/DSD-properties-rules.txt
>> "....Still, for the sake of code re-use, it may make sense to provide as
>> much of the configuration data as possible in the form of device
>> properties and complement that with an ACPI-specific mechanism suitable
>> for the use case at hand......"
> 
> This sounds like a pretty reasonable justification for addressing the issue
> using DSD to me.
> For what its worth, you can add:
> 
> Reviewed-by: Daniel Kurtz <djkurtz@...omium.org>
> 
>

Hi Mark,

If you are Ok with this patch can you please take this.

Thanks,
Akshu