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From:   Steve Lee <steves.lee.maxim@gmail.com>
Date:   Thu, 14 May 2020 21:14:04 +0900
Message-ID: <CABff4NQh8ZtHUfn4KYcXfgbZgiaRQb_5s5e7sq0_jZkp2OMg4Q@mail.gmail.com>
Subject: Re: [V3 PATCH 2/2] ASoC: max98390: Added Amplifier Driver
To:     Mark Brown <broonie@kernel.org>
Cc:     Tzung-Bi Shih <tzungbi@google.com>, jack.yu@realtek.com,
        ALSA development <alsa-devel@alsa-project.org>,
        ryan.lee.maxim@gmail.com, ckeepax@opensource.cirrus.com,
        ryans.lee@maximintegrated.com, steves.lee@maximintegrated.com,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Takashi Iwai <tiwai@suse.com>,
        Krzysztof Kozlowski <krzk@kernel.org>,
        Liam Girdwood <lgirdwood@gmail.com>, nuno.sa@analog.com,
        geert@linux-m68k.org, dmurphy@ti.com,
        =?UTF-8?B?U2h1bWluZyBb6IyD5pu46YqYXQ==?= <shumingf@realtek.com>,
        Srini Kandagatla <srinivas.kandagatla@linaro.org>,
        rf@opensource.wolfsonmicro.com
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On Thu, May 14, 2020 at 7:17 PM Mark Brown <broonie@kernel.org> wrote:
>
> On Wed, May 13, 2020 at 07:58:12PM +0800, Tzung-Bi Shih wrote:
> > On Wed, May 13, 2020 at 6:53 PM Mark Brown <broonie@kernel.org> wrote:
> > > On Wed, May 13, 2020 at 04:45:23PM +0900, Steve Lee wrote:
>
> > > > Changes since V2:
> > > >       * Removed warn massage in max98390_dsm_calib_get func
> > > >         and add comment.
>
> > > The problem isn't the warning, the problem is that you have an empty
> > > operation.  You should either implement the function (eg, by caching the
> > > value written) or remove it and fix whatever problems you were running
> > > into further up the stack when it's missing.
>
> > The purpose for the mixer control is: to signal max98390 to start to
> > calibrate from userspace.
> > Thus,
> > max98390_dsm_calib_get() -> do nothing.
> > max98390_dsm_calib_put() -> call max98390_dsm_calibrate().
>
> In that case it should probably do something like read back if a
> callibration is currently running.

Thanks for feedback. I will follow this guide.