linux-kernel - Re: [PATCH v2] ASoC: cros_ec_codec: Reset I2S RX when probing

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Message-ID: <CABXOdTf2x4zK9n0WN2djLxCbfQynF4p5v_opwB-DsEyRnRAd4g@mail.gmail.com>
Date:   Fri, 17 Jul 2020 07:32:25 -0700
From:   Guenter Roeck <groeck@...gle.com>
To:     Enric Balletbo i Serra <enric.balletbo@...labora.com>
Cc:     Yu-Hsuan Hsu <yuhsuan@...omium.org>,
        linux-kernel <linux-kernel@...r.kernel.org>,
        Tzung-Bi Shih <tzungbi@...gle.com>,
        Cheng-Yi Chiang <cychiang@...omium.org>,
        Guenter Roeck <groeck@...omium.org>,
        Liam Girdwood <lgirdwood@...il.com>,
        Mark Brown <broonie@...nel.org>,
        Jaroslav Kysela <perex@...ex.cz>,
        Takashi Iwai <tiwai@...e.com>,
        Benson Leung <bleung@...omium.org>,
        ALSA development <alsa-devel@...a-project.org>
Subject: Re: [PATCH v2] ASoC: cros_ec_codec: Reset I2S RX when probing

On Thu, Jul 16, 2020 at 10:47 AM Enric Balletbo i Serra
<enric.balletbo@...labora.com> wrote:
>
> Hi,
>
> On 16/7/20 19:23, Guenter Roeck wrote:
> > On Thu, Jul 16, 2020 at 10:09 AM Yu-Hsuan Hsu <yuhsuan@...omium.org> 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>
> >> ---
> >>  drivers/platform/chrome/cros_ec_proto.c        | 7 ++++++-
> >>  include/linux/platform_data/cros_ec_commands.h | 1 +
> >>  sound/soc/codecs/cros_ec_codec.c               | 9 +++++++++
> >>  3 files changed, 16 insertions(+), 1 deletion(-)
> >>
> >> diff --git a/drivers/platform/chrome/cros_ec_proto.c b/drivers/platform/chrome/cros_ec_proto.c
> >> index 3e745e0fe092c..2c60690d7147c 100644
> >> --- a/drivers/platform/chrome/cros_ec_proto.c
> >> +++ b/drivers/platform/chrome/cros_ec_proto.c
> >> @@ -572,7 +572,12 @@ int cros_ec_cmd_xfer_status(struct cros_ec_device *ec_dev,
> >>                 return -ENOTSUPP;
> >>         } else if (msg->result != EC_RES_SUCCESS) {
> >>                 dev_dbg(ec_dev->dev, "Command result (err: %d)\n", msg->result);
> >> -               return -EPROTO;
> >> +               switch (msg->result) {
> >> +               case EC_RES_INVALID_PARAM:
> >> +                       return -EINVAL;
> >
> > As we have learned, this may impact other callers of
> > cros_ec_cmd_xfer_status() which only accept -EPROTO as error return
> > value. In addition to that, the code is odd:
> >
> >     if (msg->result == EC_RES_INVALID_VERSION) {
> >         ...
> >     } else if (msg->result != EC_RES_SUCCESS) {
> >         switch (msg->result) {
> >         ....
> >         }
> >     }
> >
>
> Ack, this is odd.
>
> > I really dislike the notion of changing error return values of
> > cros_ec_cmd_xfer_status() one by one. That can only cause ongoing
> > trouble with callers expecting specific error return codes (as we have
> > already seen).
> >
>
> Hmm, that's a good point. Ok.
>
> Let's apply the Guenter's patch that maps the errors *and* fix the callers of
> cros_ec_cmd_xfer_status which only accept -EPROTO (there are few).
>
> Yu-Hsuan, can you take care of this and send a patch series with all the
> required patches? If not, I can work on this next week.
>

I can look into it as well. Let me know - I don't want to duplicate work.

Guenter

> Thanks,
>   Enric
>
> > Guenter
> >
> >> +               default:
> >> +                       return -EPROTO;
> >> +               }
> >>         }
> >>
> >>         return ret;
> >> diff --git a/include/linux/platform_data/cros_ec_commands.h b/include/linux/platform_data/cros_ec_commands.h
> >> index 69210881ebac8..11ce917ca924c 100644
> >> --- a/include/linux/platform_data/cros_ec_commands.h
> >> +++ b/include/linux/platform_data/cros_ec_commands.h
> >> @@ -4598,6 +4598,7 @@ enum ec_codec_i2s_rx_subcmd {
> >>         EC_CODEC_I2S_RX_SET_SAMPLE_DEPTH = 0x2,
> >>         EC_CODEC_I2S_RX_SET_DAIFMT = 0x3,
> >>         EC_CODEC_I2S_RX_SET_BCLK = 0x4,
> >> +       EC_CODEC_I2S_RX_RESET = 0x5,
> >>         EC_CODEC_I2S_RX_SUBCMD_COUNT,
> >>  };
> >>
> >> diff --git a/sound/soc/codecs/cros_ec_codec.c b/sound/soc/codecs/cros_ec_codec.c
> >> index f23956cf4ed84..b5ff30b7f1aa8 100644
> >> --- a/sound/soc/codecs/cros_ec_codec.c
> >> +++ b/sound/soc/codecs/cros_ec_codec.c
> >> @@ -1034,6 +1034,15 @@ 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 == -EINVAL)
> >> +               dev_info(dev, "Missing reset command. Please update your EC firmware.\n");
> >> +       else if (ret)
> >> +               dev_err(dev, "failed to EC_CODEC_I2S_RESET: %d\n", ret);
> >> +
> >>         platform_set_drvdata(pdev, priv);
> >>
> >>         ret = devm_snd_soc_register_component(dev, &i2s_rx_component_driver,
> >> --
> >> 2.27.0.389.gc38d7665816-goog
> >>