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

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Date:   Wed, 8 Jul 2020 12:16:25 +0200
From:   Enric Balletbo i Serra <enric.balletbo@...labora.com>
To:     Yu-Hsuan Hsu <yuhsuan@...omium.org>, linux-kernel@...r.kernel.org
Cc:     Benson Leung <bleung@...omium.org>,
        Guenter Roeck <groeck@...omium.org>,
        Cheng-Yi Chiang <cychiang@...omium.org>,
        Liam Girdwood <lgirdwood@...il.com>,
        Mark Brown <broonie@...nel.org>,
        Jaroslav Kysela <perex@...ex.cz>,
        Takashi Iwai <tiwai@...e.com>,
        Tzung-Bi Shih <tzungbi@...gle.com>,
        Gwendal Grignou <gwendal@...omium.org>,
        Lee Jones <lee.jones@...aro.org>,
        Yicheng Li <yichengli@...omium.org>,
        alsa-devel@...a-project.org
Subject: Re: [PATCH] ASoC: cros_ec_codec: Reset I2S RX when probing

Hi Yu-Hsuan,

Thank you for your patch.

On 8/7/20 9:11, 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>
> ---
>  include/linux/platform_data/cros_ec_commands.h | 1 +
>  sound/soc/codecs/cros_ec_codec.c               | 7 +++++++
>  2 files changed, 8 insertions(+)
> 
> 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,

Is this a new command not available in the firmware that is already in the field?


>  	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 8d45c628e988e..5495214e73e68 100644
> --- a/sound/soc/codecs/cros_ec_codec.c
> +++ b/sound/soc/codecs/cros_ec_codec.c
> @@ -1034,6 +1034,13 @@ 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_err(dev, "failed to EC_CODEC_I2S_RESET: %d\n", ret);
> +

With an old firmware I suspect this message will appear on every boot, right?
So, to solve the issue and get rid of this error you're forced to upgrade the
firmware. Is that true?

>  	platform_set_drvdata(pdev, priv);
>  
>  	ret = devm_snd_soc_register_component(dev, &i2s_rx_component_driver,
>