Date:   Sun, 19 Jul 2020 12:47:59 -0700
From:   Guenter Roeck <groeck@...gle.com>
To:     Yu-Hsuan Hsu <yuhsuan@...omium.org>
Cc:     Enric Balletbo i Serra <enric.balletbo@...labora.com>,
        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 Fri, Jul 17, 2020 at 11:51 AM Yu-Hsuan Hsu <yuhsuan@...omium.org> wrote:
>
> Guenter Roeck <groeck@...gle.com> 於 2020年7月17日 週五 下午10:32寫道：
> >
> > 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
> Hi Guenter,
> Really thanks for your assistance! Could you help me on those patches?
> Since you wrote that patch, I think it should be the most efficient
> way to make them merged.
>

Untested patch series is at crrev.com/c/2306731. I'll try to get a
successful CQ pass with both chromeos-5.4 and chromeos-4.19 and submit
the relevant patches upstream after it passes.

Guenter

> Thanks,
> Yu-Hsuan
>
> >
> > > 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
> > > >>

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