linux-kernel - Re: [PATCH v6 2/2] ASoC: cros_ec_codec: Reset I2S RX when probing

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Message-ID: <f440cf94-066d-ed90-213c-08ca17025cf5@collabora.com>
Date:   Thu, 14 Jan 2021 11:15:56 +0100
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>,
        Prashant Malani <pmalani@...omium.org>,
        Pi-Hsun Shih <pihsun@...omium.org>,
        "Gustavo A . R . Silva" <gustavoars@...nel.org>,
        alsa-devel@...a-project.org
Subject: Re: [PATCH v6 2/2] ASoC: cros_ec_codec: Reset I2S RX when probing

Hi Yu-Hsuan,

On 14/1/21 7:54, 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>
> ---
> Returns the error code when it fails to reset.
> 
>  sound/soc/codecs/cros_ec_codec.c | 12 ++++++++++++
>  1 file changed, 12 insertions(+)
> 
> diff --git a/sound/soc/codecs/cros_ec_codec.c b/sound/soc/codecs/cros_ec_codec.c
> index f33a2a9654e7..40e437aa1d55 100644
> --- a/sound/soc/codecs/cros_ec_codec.c
> +++ b/sound/soc/codecs/cros_ec_codec.c
> @@ -1011,6 +1011,18 @@ 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 == -ENOPROTOOPT) {
> +		dev_info(dev,
> +			 "Command not found. Please update the EC firmware.\n");

Nitpicking a bit. I'd add which command is not found to give more information to
the user that gets into that path. Command not found is too generic for me.

But,

Reviewed-by: Enric Balletbo i Serra <enric.balletbo@...labora.com>

> +	} else if (ret) {
> +		dev_err(dev, "failed to EC_CODEC_I2S_RESET: %d\n", ret);
> +		return ret;
> +	}
> +
>  	platform_set_drvdata(pdev, priv);
>  
>  	ret = devm_snd_soc_register_component(dev, &i2s_rx_component_driver,
>