linux-kernel - Re: [PATCH 2/2] ASoC: cros_ec_codec: Reset I2S RX when probing

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Date:   Wed, 13 Jan 2021 14:58:41 +0800
From:   Yu-Hsuan Hsu <yuhsuan@...omium.org>
To:     Enric Balletbo i Serra <enric.balletbo@...labora.com>
Cc:     Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        ALSA development <alsa-devel@...a-project.org>,
        "Gustavo A . R . Silva" <gustavoars@...nel.org>,
        Takashi Iwai <tiwai@...e.com>,
        Liam Girdwood <lgirdwood@...il.com>,
        Guenter Roeck <groeck@...omium.org>,
        Mark Brown <broonie@...nel.org>,
        Prashant Malani <pmalani@...omium.org>,
        Pi-Hsun Shih <pihsun@...omium.org>,
        Benson Leung <bleung@...omium.org>,
        Cheng-Yi Chiang <cychiang@...omium.org>
Subject: Re: [PATCH 2/2] ASoC: cros_ec_codec: Reset I2S RX when probing

Enric Balletbo i Serra <enric.balletbo@...labora.com> 於 2021年1月13日 週三 上午12:34寫道：
>
> Hi Yu-Hsuan,
>
> Thank you for the patch.
>
> On 7/1/21 9:59, Yu-Hsuan Hsu wrote:
> > It is not guaranteed that I2S RX is disabled when the kernel booting.
> > For example, if the kernel crashes while it is enabled, it will keep
> > enabled until the next time EC reboots. Reset I2S RX when probing to
> > fix this issue.
> >
> > Signed-off-by: Yu-Hsuan Hsu <yuhsuan@...omium.org>
>
> If I am not mistaken this is the four version of this patchset (see [1]). Please
> prefix your patches with the proper version and maintain a changelog for them,
> otherwise makes difficult to follow all the discussions already done.
>
> [1]
> v1: https://lkml.org/lkml/2020/7/8/173
> v2: https://mailman.alsa-project.org/pipermail/alsa-devel/2020-July/170933.html
> v3:
> https://patchwork.kernel.org/project/alsa-devel/patch/20210106050559.1459027-1-yuhsuan@chromium.org/
> v4: https://patchwork.kernel.org/project/alsa-devel/list/?series=410441
Sorry that I forgot to add version. Will add v5 in the next patch. Thanks!
>
> > ---
> >  sound/soc/codecs/cros_ec_codec.c | 7 +++++++
> >  1 file changed, 7 insertions(+)
> >
> > diff --git a/sound/soc/codecs/cros_ec_codec.c b/sound/soc/codecs/cros_ec_codec.c
> > index f33a2a9654e7..28b3e2c48c86 100644
> > --- a/sound/soc/codecs/cros_ec_codec.c
> > +++ b/sound/soc/codecs/cros_ec_codec.c
> > @@ -1011,6 +1011,13 @@ static int cros_ec_codec_platform_probe(struct platform_device *pdev)
> >       }
> >       priv->ec_capabilities = r.capabilities;
> >
> > +     /* Reset EC codec i2s rx. */
> > +     p.cmd = EC_CODEC_I2S_RX_RESET;
> > +     ret = send_ec_host_command(priv->ec_device, EC_CMD_EC_CODEC_I2S_RX,
> > +                                (uint8_t *)&p, sizeof(p), NULL, 0);
> > +     if (ret)
> > +             dev_warn(dev, "failed to EC_CODEC_I2S_RESET: %d\n", ret);
> > +
>
> My comment in the first version is still valid, I guess. This command was
> introduced later and with an old firmware I suspect this message will appear on
> every boot, right? So, to solve the issue and get rid of this warn you're forced
> to upgrade the firmware. Would make sense to handle returned error value to warn
> when the firmware needs to be updated and error and break when is really an error?
>
> We have mapped ec error codes to linux error codes. So, it should be possible now.
Oh, I didn't notice it. Thanks for the remind. I will work on it.
>
> Thanks,
>  Enric
>
> >       platform_set_drvdata(pdev, priv);
> >
> >       ret = devm_snd_soc_register_component(dev, &i2s_rx_component_driver,
> >